ninjette.org

Go Back   ninjette.org > 1986 - 2007 Ninja 250R > 1986 - 2007 Ninja 250R Tech Talk

Notices

Reply
 
Thread Tools
Old August 28th, 2021, 08:21 AM   #1
tomsninja2020
Guest
 
Posts: n/a
Unhappy Help with a 1986 Ninja 250 that will not rev up

I have a 1986 Ninja 250 that I bought from a friend. Long story short this bike has been raced and abused. It was also highly modified for that purpose. I have been working on getting it back to stock. one of the problems that I am having is that It will not rev over 5000 RPM's or if it does it bogs really bad. Very slow to come up to speed. Not sure if I used the right jet needles in it or not. The ones that I am using come from a rebuild kit. The ones that came with it were the clip style but it does not want to start when using those.

Took it out for a quick spin the other day and a mile down the road it lost power and died. Not sure what to check and work on at this point.

In addition to it not revving up, there is a popping/ticking sound coming from the right upper side of the engine that only happens when gassing it up. At idle it is fine. any help with these problems would be greatly appreciated.

Thanks
Tom

Last futzed with by tomsninja2020; August 28th, 2021 at 08:43 AM. Reason: added info
  Reply With Quote




Old August 28th, 2021, 08:37 AM   #2
ducatiman
ninjette.org certified postwhore
 
ducatiman's Avatar
 
Name: Gordon
Location: new york
Join Date: Sep 2009

Motorcycle(s): '95 DUCATI 900SS/SP '07 DUCATI SS800 '19 HONDA CBR650R

Posts: A lot.
MOTM - Nov '18, Mar '17
Tom-

On the 32mm, metal slide equipped carbs....non-adjustable, original needles are N52H in lh carb, N52I in rh carb. Are you using these? With what main jets? Frankly, kit tuning components are notoriously "copy-cat" crapshoot, may work, may not. Kit is meant for your year 250? Or a more common later model? Note 32mm metal slide carbs only used in 86-87 models.

Check valve timing/clearances as yet? Truly clean carbs/circuits?
__________________________________________________
gordon@customcarbservices.com
Custom Carb Service
www.customcarbservices.com
ducatiman is offline   Reply With Quote


2 out of 2 members found this post helpful.
Old August 28th, 2021, 08:38 AM   #3
Triple Jim
Guy Who Enjoys Riding
 
Triple Jim's Avatar
 
Name: Jim
Location: North Carolina
Join Date: Jul 2016

Motorcycle(s): Ninja 250

Posts: A lot.
MOTM - Oct '18, Aug '17, Aug '16
Hi Tom, welcome to the board!

The first thing you need to do is make sure the carbs are spotlessly clean, including the small, nearly hidden passages, etc., and also return them to stock, with genuine Keihin stock size jets. Trying to get it running right with aftermarket parts will be a long and questionably successful job.

If you like, Ducatiman here on the board is expert at doing this, and can get them into like-new condition quickly.

Edit: He posted while I was typing.
Triple Jim is offline   Reply With Quote


Old August 28th, 2021, 08:50 AM   #4
tomsninja2020
Guest
 
Posts: n/a
I think the kit that I got was for the '88 ninja 250 instead of the '86 because I was not able to find the '86-'87 EX250-E rebuild kit. So do you suggest that i buy the correct needles? The spark plugs were black and oily from running extremely rich I believe.

How do you tell the difference between the LH and RH needles?
  Reply With Quote


Old August 28th, 2021, 09:03 AM   #5
ducatiman
ninjette.org certified postwhore
 
ducatiman's Avatar
 
Name: Gordon
Location: new york
Join Date: Sep 2009

Motorcycle(s): '95 DUCATI 900SS/SP '07 DUCATI SS800 '19 HONDA CBR650R

Posts: A lot.
MOTM - Nov '18, Mar '17
no good, 88 and up are 30mm, 86-87 are 32mm. Different innards required. Assure your mains are correct, pilots too if you used from the kit.

pilots #35 mains 108 (could vary slightly)

Long ago, i sold a set of these early model 32mm carbs to member @Ghostt.
__________________________________________________
gordon@customcarbservices.com
Custom Carb Service
www.customcarbservices.com
ducatiman is offline   Reply With Quote


Old August 28th, 2021, 09:05 AM   #6
ducatiman
ninjette.org certified postwhore
 
ducatiman's Avatar
 
Name: Gordon
Location: new york
Join Date: Sep 2009

Motorcycle(s): '95 DUCATI 900SS/SP '07 DUCATI SS800 '19 HONDA CBR650R

Posts: A lot.
MOTM - Nov '18, Mar '17
Quote:
Originally Posted by tomsninja2020 View Post
I think the kit that I got was for the '88 ninja 250 instead of the '86 because I was not able to find the '86-'87 EX250-E rebuild kit. So do you suggest that i buy the correct needles? The spark plugs were black and oily from running extremely rich I believe.

How do you tell the difference between the LH and RH needles?
correct factory needles are clearly marked, N52H goes in lh, N52I goes in rh carb.
__________________________________________________
gordon@customcarbservices.com
Custom Carb Service
www.customcarbservices.com
ducatiman is offline   Reply With Quote


Old August 28th, 2021, 09:14 AM   #7
ducatiman
ninjette.org certified postwhore
 
ducatiman's Avatar
 
Name: Gordon
Location: new york
Join Date: Sep 2009

Motorcycle(s): '95 DUCATI 900SS/SP '07 DUCATI SS800 '19 HONDA CBR650R

Posts: A lot.
MOTM - Nov '18, Mar '17
Quote:
Originally Posted by tomsninja2020 View Post
So do you suggest that i buy the correct needles?
YES....assures a known starting point for factory, like new running performance, Provided all your other reported work is ok. Please tell me you've retained the airbox?
__________________________________________________
gordon@customcarbservices.com
Custom Carb Service
www.customcarbservices.com
ducatiman is offline   Reply With Quote


Old August 28th, 2021, 09:21 AM   #8
DannoXYZ
ninjette.org certified postwhore
 
Name: AKA JacRyann
Location: Mesa, AZ
Join Date: Dec 2011

Motorcycle(s): CB125T CBR250R-MC19 CBR250RR-MC22 NSR350R-MC21 VF500F CBR600RR SFV650 VFR750F R1M ST1300PA Valkyrie-F6C

Posts: A lot.
MOTY - 2018, MOTM - Nov '17
Hi Tom, in addition to non-compatible rebuild parts mentioned above, you may have petrol delivery issues from tank to carbs. Make sure tank vent-hose is not clogged.

Also make sure petcock vacuum diaphragm works. Test by applying vacuum to petcock and measuring flow. Should flow freely from petcock.

DannoXYZ is offline   Reply With Quote


Old August 28th, 2021, 09:33 AM   #9
DannoXYZ
ninjette.org certified postwhore
 
Name: AKA JacRyann
Location: Mesa, AZ
Join Date: Dec 2011

Motorcycle(s): CB125T CBR250R-MC19 CBR250RR-MC22 NSR350R-MC21 VF500F CBR600RR SFV650 VFR750F R1M ST1300PA Valkyrie-F6C

Posts: A lot.
MOTY - 2018, MOTM - Nov '17
i recently restored an ex-racer 1st-gen 250 too!



had to completely disassemble carbs down to every last nut, bolt and individual part and scrub all hidden secret petrol passages.
http://n4mwd.blogspot.com/2013/10/se...-passages.html


Last futzed with by DannoXYZ; August 29th, 2021 at 04:08 PM.
DannoXYZ is offline   Reply With Quote


1 out of 1 members found this post helpful.
Old August 28th, 2021, 01:52 PM   #10
tomsninja2020
Guest
 
Posts: n/a
Quote:
Originally Posted by ducatiman View Post
YES....assures a known starting point for factory, like new running performance, Provided all your other reported work is ok. Please tell me you've retained the airbox?
i had to buy one off of eBay.
  Reply With Quote


Old August 29th, 2021, 05:30 AM   #11
tomsninja2020
Guest
 
Posts: n/a
Quote:
Originally Posted by ducatiman View Post
Tom-

On the 32mm, metal slide equipped carbs....non-adjustable, original needles are N52H in lh carb, N52I in rh carb. Are you using these? With what main jets?
This came with adjustable Dynojet needles as it had pod filters and a 2 into 1 exhaust. Should I put the adjustable needles back in with the clip in the 5th groove from the top with the main jets that came with it?

thanks
Tom
  Reply With Quote


Old August 29th, 2021, 08:56 AM   #12
ducatiman
ninjette.org certified postwhore
 
ducatiman's Avatar
 
Name: Gordon
Location: new york
Join Date: Sep 2009

Motorcycle(s): '95 DUCATI 900SS/SP '07 DUCATI SS800 '19 HONDA CBR650R

Posts: A lot.
MOTM - Nov '18, Mar '17
Quote:
Originally Posted by tomsninja2020 View Post
i had to buy one off of eBay.
so you've got stock airbox back on it now?
__________________________________________________
gordon@customcarbservices.com
Custom Carb Service
www.customcarbservices.com
ducatiman is offline   Reply With Quote


Old August 29th, 2021, 08:57 AM   #13
ducatiman
ninjette.org certified postwhore
 
ducatiman's Avatar
 
Name: Gordon
Location: new york
Join Date: Sep 2009

Motorcycle(s): '95 DUCATI 900SS/SP '07 DUCATI SS800 '19 HONDA CBR650R

Posts: A lot.
MOTM - Nov '18, Mar '17
Quote:
Originally Posted by tomsninja2020 View Post
This came with adjustable Dynojet needles as it had pod filters and a 2 into 1 exhaust. Should I put the adjustable needles back in with the clip in the 5th groove from the top with the main jets that came with it?

thanks
Tom
need answer to above question prior to opining on this one.
__________________________________________________
gordon@customcarbservices.com
Custom Carb Service
www.customcarbservices.com
ducatiman is offline   Reply With Quote


Old August 29th, 2021, 01:07 PM   #14
tomsninja2020
Guest
 
Posts: n/a
not yet because of having to carburetors off so much
  Reply With Quote


Old August 29th, 2021, 01:14 PM   #15
tomsninja2020
Guest
 
Posts: n/a
when I try to start it that way it pops and sputters but does not start. So i guess that is still to rich? My scooter is a lot easier to work on then this. I guess that want happens when you buy a used motorcycle that sat since 2009. I did have it going for a while but I could not get past 5,0000 rpm's the engine would just bogg or die. I have a limited amount of resources that I can work with as well as funds. So any and all help that you can provide me would be greatly appreciated.

thanks
Tom
  Reply With Quote


Old August 29th, 2021, 01:32 PM   #16
Triple Jim
Guy Who Enjoys Riding
 
Triple Jim's Avatar
 
Name: Jim
Location: North Carolina
Join Date: Jul 2016

Motorcycle(s): Ninja 250

Posts: A lot.
MOTM - Oct '18, Aug '17, Aug '16
If you think it's too rich, with the starter lever in the run setting (off) hold the throttle open and crank the engine. That will clear out excess fuel.

If that doesn't get it started, it's because being too rich isn't the problem.
Triple Jim is offline   Reply With Quote


Old August 29th, 2021, 01:52 PM   #17
jkv45
Rev Limiter
 
jkv45's Avatar
 
Name: Jay
Location: WI
Join Date: Jul 2013

Motorcycle(s): '06 SV650n, '00 Derbi GPR, '64 CA77 Dream 305, '70 CL450 Scrambler, numerous dirt bikes

Posts: A lot.
MOTM - Jun '18, Oct '16
Quote:
Originally Posted by tomsninja2020 View Post
I have a 1986 Ninja 250 that I bought from a friend. Long story short this bike has been raced and abused. It was also highly modified for that purpose. I have been working on getting it back to stock. one of the problems that I am having is that It will not rev over 5000 RPM's or if it does it bogs really bad. Very slow to come up to speed. Not sure if I used the right jet needles in it or not. The ones that I am using come from a rebuild kit. The ones that came with it were the clip style but it does not want to start when using those.

Took it out for a quick spin the other day and a mile down the road it lost power and died. Not sure what to check and work on at this point.

In addition to it not revving up, there is a popping/ticking sound coming from the right upper side of the engine that only happens when gassing it up. At idle it is fine. any help with these problems would be greatly appreciated.

Thanks
Tom
What mods were done? Pod filters? Different pipe?

I would pull the carbs, throw away any parts from the kit, and replace them with stock OEM parts.

The carbs should be gone through carefully and thoroughly.

The stock 38 (EDIT: 35?) Pilot jets are just fine. Your idle mixture adjustments may be more open than normal, somewhere in the 2.5 to 3.0 turns out most likely. Use the stock needles in their proper position per ducatiman. You may want to add 1 small shim to richen the mid-range if you have pods and a pipe - but don't go overboard. A Main Jet in the range of 108 should be close. Use only OEM jets, and richer isn't better.

Check that you have the "collars" (Needle Jets) in the carbs (https://faq.ninja250.org/images/e/eb/Jim_carb_2.jpg) . They stick up into the venturi from the bottom, and fall out when you disassemble the carbs.

Look over this section for more info - https://faq.ninja250.org/wiki/Intake

When you get finished, and before you try to start it, you may want to install new plugs. That would give you some idea of what's going on if you are still having issues. Be careful of counterfeit NGK plugs from no-name online supplies.

You may want to check the valves while you are at it. It's not going to run if they are way off - https://faq.ninja250.org/wiki/How_do..._the_valves%3F

Last futzed with by jkv45; September 1st, 2021 at 07:08 AM.
jkv45 is offline   Reply With Quote


Old August 29th, 2021, 02:55 PM   #18
DannoXYZ
ninjette.org certified postwhore
 
Name: AKA JacRyann
Location: Mesa, AZ
Join Date: Dec 2011

Motorcycle(s): CB125T CBR250R-MC19 CBR250RR-MC22 NSR350R-MC21 VF500F CBR600RR SFV650 VFR750F R1M ST1300PA Valkyrie-F6C

Posts: A lot.
MOTY - 2018, MOTM - Nov '17
Quote:
Originally Posted by tomsninja2020 View Post
not yet because of having to carburetors off so much
Quote:
Originally Posted by tomsninja2020 View Post
when I try to start it that way it pops and sputters but does not start. So i guess that is still to rich?
All tests needs to be done with airbox installed and connected to carbs. It does very important function of smoothing and providing laminar flow of air into carbs. If you search on here for "pod filters", you'll find every case of pod-filters having mid-range problems are resolved with re-installing factory airbox and jets. Simple enough to tighten hose-clamps on carbs to rubber manifolds. Then slide airbox onto carbs once they're firmly held in place.

I started racing these bikes 5-yrs ago at tail-end of 35-years of trial & error development between millions of 250 racers. Those who've come before me have compiled extensive list of upgrade-mods for these bikes. Even though rules allow it, not a single racer amongst MILLIONS used pod-filters because they provide zero gains in performance and introduces too many problems. Stumbling and surging mid-range is biggest issue, not to mention instability in cross-winds. Racers are lying cheating bastards who'll do anything and everything to gain an unfair advantage over their competitors. They only use what works, pod filters don't.

Need to test these with airbox installed:

1. Do clearing test outlined above. Then start bike with no choke. Does it start and run better?

2. Do same clearing test again. Start bike with full-choke. Does it start & run better?

3. what procedure did you use to clean carbs?

4. which one of these needles looks closest to one you have in bike?


Last futzed with by DannoXYZ; August 29th, 2021 at 04:00 PM.
DannoXYZ is offline   Reply With Quote


Old August 29th, 2021, 03:34 PM   #19
ducatiman
ninjette.org certified postwhore
 
ducatiman's Avatar
 
Name: Gordon
Location: new york
Join Date: Sep 2009

Motorcycle(s): '95 DUCATI 900SS/SP '07 DUCATI SS800 '19 HONDA CBR650R

Posts: A lot.
MOTM - Nov '18, Mar '17
"bike sitting since 2009", modded with unknown carb "kit" internals.....

I'd suggest a pro carb clean & setup, returning to all OEM stock internal tuning components on carbs .....installed WITH factory airbox....a known starting point.
__________________________________________________
gordon@customcarbservices.com
Custom Carb Service
www.customcarbservices.com
ducatiman is offline   Reply With Quote


Old August 30th, 2021, 08:49 AM   #20
tomsninja2020
Guest
 
Posts: n/a
1 and 3
  Reply With Quote


Old August 30th, 2021, 04:31 PM   #21
DannoXYZ
ninjette.org certified postwhore
 
Name: AKA JacRyann
Location: Mesa, AZ
Join Date: Dec 2011

Motorcycle(s): CB125T CBR250R-MC19 CBR250RR-MC22 NSR350R-MC21 VF500F CBR600RR SFV650 VFR750F R1M ST1300PA Valkyrie-F6C

Posts: A lot.
MOTY - 2018, MOTM - Nov '17
We're trying to gather information to help you, so please give data that's necessary to troubleshoot.

Quote:
Originally Posted by tomsninja2020 View Post
1 and 3
1. Ok, #1 adjustable needle should've come with your DynoJet kit. What main jet sizes came with this kit?

2. #3 needle has more gradual taper at tip than DynoJet needle? Can you take photo and post here? Are you able to zoom in and get clear view of numbering on needle?

3. What main jet size came with bike?

4. what brand 2-1 exhaust is on bike? Please post photo

5. have you verified petcock flows petrol continuously when vacuum is applied?

6. have you confirmed that needle collars are installed with correct orientation? Internally, there is tapered end. This should face away from main jet and towards carb-venturi / needle.

7. what procedure did you use to clean carbs

8. measure all valve clearances and post here.


There's basically 3-4 areas of concern that may be causing you problem. Most likely you have them all to certain extent. Your data will point towards ones to address first.
DannoXYZ is offline   Reply With Quote


1 out of 1 members found this post helpful.
Old August 30th, 2021, 05:56 PM   #22
tomsninja2020
Guest
 
Posts: n/a
The Jet needles, main jets and the pilot jets that came with it are all unreadable , sorry I wish I could be more hopeful here. It did run last week but would not rev over 5000 and most of the time after 10 minutes of running it would die. Petcock does work as expected.

I replaced the pilot jets and main jets with ones that came with the '88 kit since they don't make a kit for the '86 ninja. I did just today ordered the correct jet needles for the left and right hand carbs.

I put as close to stock mufflers as I could find along with the air box. Valves have been checked and adjusted per the manual. Checked that the timing chain and camshaft markings all are in line and they are. I had taken the engine apart a month ago to replace a rod bearing.
  Reply With Quote


Old August 30th, 2021, 05:57 PM   #23
tomsninja2020
Guest
 
Posts: n/a
jet needles that came with the bike.
Attached Images
File Type: jpg jet needles.jpg (101.9 KB, 12 views)
  Reply With Quote


Old August 30th, 2021, 08:02 PM   #24
DannoXYZ
ninjette.org certified postwhore
 
Name: AKA JacRyann
Location: Mesa, AZ
Join Date: Dec 2011

Motorcycle(s): CB125T CBR250R-MC19 CBR250RR-MC22 NSR350R-MC21 VF500F CBR600RR SFV650 VFR750F R1M ST1300PA Valkyrie-F6C

Posts: A lot.
MOTY - 2018, MOTM - Nov '17
Hmm, dying after 10-mi. still sounds like fuel-flow problem...

well, you should bundle ALL parts from DynoJet kit back in box and return it. Cannot use DynoJet needles with factory jets and factory needles with DynoJet jets.

Now that you're getting factory needles, we need to find out what size jets you have that came in those carbs. Hopefully factory sizes.

Last futzed with by DannoXYZ; August 31st, 2021 at 10:11 AM.
DannoXYZ is offline   Reply With Quote


Old August 30th, 2021, 08:26 PM   #25
ducatiman
ninjette.org certified postwhore
 
ducatiman's Avatar
 
Name: Gordon
Location: new york
Join Date: Sep 2009

Motorcycle(s): '95 DUCATI 900SS/SP '07 DUCATI SS800 '19 HONDA CBR650R

Posts: A lot.
MOTM - Nov '18, Mar '17
Quote:
Originally Posted by ducatiman View Post

pilots #35 mains 108
__________________________________________________
gordon@customcarbservices.com
Custom Carb Service
www.customcarbservices.com
ducatiman is offline   Reply With Quote


Old August 31st, 2021, 05:52 PM   #26
tomsninja2020
Guest
 
Posts: n/a
Update:

I put the air box back on and found out that I had fouled spark plugs from running rich. put in another set. Put the original #35 pilot jets that came with the bike in and that fixed most of the low end issues. The ones that I had were #40 and way to rich. The upper throttle/RPM range is still suffering from the rich condition due to the wrong jet needles. I should have the right ones by Friday( one from CA and the other from MS)

Thank you everyone for the help thus far.

Tom
  Reply With Quote


2 out of 2 members found this post helpful.
Old September 1st, 2021, 02:02 AM   #27
tomsninja2020
Guest
 
Posts: n/a
Ordered #108 main jets to fix the rest of the issues. I will report back when everything is installed. Again thank you for the help.

Any Ninja owners around south central Minnesota let me know.

Thanks
Tom
  Reply With Quote


Old September 2nd, 2021, 02:38 PM   #28
DannoXYZ
ninjette.org certified postwhore
 
Name: AKA JacRyann
Location: Mesa, AZ
Join Date: Dec 2011

Motorcycle(s): CB125T CBR250R-MC19 CBR250RR-MC22 NSR350R-MC21 VF500F CBR600RR SFV650 VFR750F R1M ST1300PA Valkyrie-F6C

Posts: A lot.
MOTY - 2018, MOTM - Nov '17
You're welcome Tom!

Interesting data you're providing us. Helps build up database of known facts for searches and troubleshooting in future.

Please take photo of your new factory '86-87 needles compared to ones that came on your bike. I suspect they used ones from different model-year. Which would explain some of your mid-range issues.

I wished I had datalogged some runs with my wideband before selling. Would be interesting to have actual AFR data of factory configuration.
DannoXYZ is offline   Reply With Quote


Old September 2nd, 2021, 03:43 PM   #29
tomsninja2020
Guest
 
Posts: n/a
are #108 main jets going to be to lean for here in Minnesota. Elevation is 1,158' In my 150 scooter I run #125 but that is a gy6 150 engine so not sure how much difference that makes. I just don't want to have to chase jet sizes till I find the right one that works.
  Reply With Quote


Old September 2nd, 2021, 09:07 PM   #30
DannoXYZ
ninjette.org certified postwhore
 
Name: AKA JacRyann
Location: Mesa, AZ
Join Date: Dec 2011

Motorcycle(s): CB125T CBR250R-MC19 CBR250RR-MC22 NSR350R-MC21 VF500F CBR600RR SFV650 VFR750F R1M ST1300PA Valkyrie-F6C

Posts: A lot.
MOTY - 2018, MOTM - Nov '17
Quote:
Originally Posted by tomsninja2020 View Post
are #108 main jets going to be to lean for here in Minnesota. Elevation is 1,158' In my 150 scooter I run #125 but that is a gy6 150 engine so not sure how much difference that makes. I just don't want to have to chase jet sizes till I find the right one that works.
Usually the opposite. Elevation has less air-density, so mixtures tend to be too rich. General rule of thumb is lean out mixtures by 2% for each 1000ft altitude.

Also you got Keihin jets right? Other brands may have #108, but they are actually different hole diameter.
DannoXYZ is offline   Reply With Quote


1 out of 1 members found this post helpful.
Old September 3rd, 2021, 05:02 AM   #31
ducatiman
ninjette.org certified postwhore
 
ducatiman's Avatar
 
Name: Gordon
Location: new york
Join Date: Sep 2009

Motorcycle(s): '95 DUCATI 900SS/SP '07 DUCATI SS800 '19 HONDA CBR650R

Posts: A lot.
MOTM - Nov '18, Mar '17
Quote:
Originally Posted by tomsninja2020 View Post
are #108 main jets going to be to lean for here in Minnesota. Elevation is 1,158' In my 150 scooter I run #125 but that is a gy6 150 engine so not sure how much difference that makes. I just don't want to have to chase jet sizes till I find the right one that works.
108's were supplied as new in that version EX. Provided your carbs/circuits are truly clean...you'll be fine. Also provided you've actually sourced OEM Keihin jets.
__________________________________________________
gordon@customcarbservices.com
Custom Carb Service
www.customcarbservices.com
ducatiman is offline   Reply With Quote


Old September 5th, 2021, 04:11 AM   #32
tomsninja2020
Guest
 
Posts: n/a
I got the bike to rev up a little better but it still has an erratic idle to it and the carb slides do not seem to lift. It had good acceleration up to 4000 RPM but after that it just was flat. Can I pull the air box out of the way enough to check that or what would cause them not to lift. When I open the throttle it is sputtering like it is not getting enough fuel to keep going. Did find pin holes on the slide diaphragm and repaired them but I ordered a new set to be on the safe side.

Thanks
Tom
  Reply With Quote


Old September 5th, 2021, 06:36 AM   #33
ducatiman
ninjette.org certified postwhore
 
ducatiman's Avatar
 
Name: Gordon
Location: new york
Join Date: Sep 2009

Motorcycle(s): '95 DUCATI 900SS/SP '07 DUCATI SS800 '19 HONDA CBR650R

Posts: A lot.
MOTM - Nov '18, Mar '17
using the correct needles and mains?

contrary to black, plastic later model 30mm slides, your 32mm metals require "dressing" if not a certain degree of polishing, with special attention given to their guides (in the bodies). Lift can be checked/confirmed using moderate compressed air. (within my service I perform this routinely on EX500 carbs that use metal slides) The return springs are correct length, not causing binding in any way? Note some jet "kits" require cutting of springs, a no-no if returning back to OEM spec.

35 year old diaphragms, if never replaced, should be, especially those with holes of any size.

"Erratic" idle? IF your carbs circuits are truly clean, are synched and pilot screws set correctly (with new orings)....it should idle decent.
Furthermore, blocked transition ports could be causing some issue with reluctance to run over 4K threshold. I'll submit your carbs are not truly clean.

You've confirmed adequate valve clearances?
__________________________________________________
gordon@customcarbservices.com
Custom Carb Service
www.customcarbservices.com
ducatiman is offline   Reply With Quote


Old September 5th, 2021, 02:18 PM   #34
tomsninja2020
Guest
 
Posts: n/a
Question

Quote:
Originally Posted by ducatiman View Post
You've confirmed adequate valve clearances?
What are the correct valve clearances? I am using .004 inches for intake and .006 inches for exhaust.

also were does the engine pull fuel at idle? is it the transition ports or the area around the mixture screw?

The thing that I am not understanding about this engine is this. My 150cc scooter engine runs just fine. Idles like it is supposed to and everything. This engine does not idle correctly, is hard as hell to start and keep running. If i do get it to run and in gear I cannot turn the throttle more then a quarter turn or the engine will bog and or die. Like I said before, new rings were installed last year but have yet to really seat and break in. Compression for both cylinders is around 90 to 100 psi with the new rings and cylinder honning. New head gasket, new rod bearing on #2 cylinder. Still makes a lot of noise from that side of the engine. CCT has new springs and bearings in it.

I am at a loss here because I have put so much time and effort into this bike and it still will not run right.

thanks
Tom
  Reply With Quote


Old September 6th, 2021, 05:05 AM   #35
tomsninja2020
Guest
 
Posts: n/a
[QUOTE=ducatiman;1293350]no good, 88 and up are 30mm, 86-87 are 32mm. Different innards required. Assure your mains are correct, pilots too if you used from the kit.

pilots #35 mains 108 /QUOTE]

Can I use #40 pilot jet as that is all I have right now?
  Reply With Quote


Old September 6th, 2021, 06:03 AM   #36
ducatiman
ninjette.org certified postwhore
 
ducatiman's Avatar
 
Name: Gordon
Location: new york
Join Date: Sep 2009

Motorcycle(s): '95 DUCATI 900SS/SP '07 DUCATI SS800 '19 HONDA CBR650R

Posts: A lot.
MOTM - Nov '18, Mar '17
You had posted previously...."The ones that I had were #40 and way to rich."

2 sizes over the correct 35...you tell me.

Wait till you get the correct jets.

AFA valve clearances.....you've got no manual? An underseat sticker present perhaps?

Your transition ports may be clogged, due to way overich #40's in there, or existing varnish present. In addition to suspect slide action....
__________________________________________________
gordon@customcarbservices.com
Custom Carb Service
www.customcarbservices.com
ducatiman is offline   Reply With Quote


Old September 6th, 2021, 11:02 AM   #37
DannoXYZ
ninjette.org certified postwhore
 
Name: AKA JacRyann
Location: Mesa, AZ
Join Date: Dec 2011

Motorcycle(s): CB125T CBR250R-MC19 CBR250RR-MC22 NSR350R-MC21 VF500F CBR600RR SFV650 VFR750F R1M ST1300PA Valkyrie-F6C

Posts: A lot.
MOTY - 2018, MOTM - Nov '17
Quote:
Originally Posted by tomsninja2020 View Post
I got the bike to rev up a little better but it still has an erratic idle to it and the carb slides do not seem to lift. It had good acceleration up to 4000 RPM but after that it just was flat. Can I pull the air box out of the way enough to check that or what would cause them not to lift. When I open the throttle it is sputtering like it is not getting enough fuel to keep going. Did find pin holes on the slide diaphragm and repaired them but I ordered a new set to be on the safe side.
Quick test is to look at slides when revving and see if they lift fully. Vacuum increases with RPM and you should see slides lift higher and higher. At mid-range, they should be at least 50% open.

If not, reach in there with your fingers and help lift slides up as you increase throttle. Does it redline now?

If so, you've got slide issue. New diaphragms may help. May also need to scrub out vacuum-ports from beginning to end. Also make sure vacuum-chambers are sealed.
DannoXYZ is offline   Reply With Quote


Old September 7th, 2021, 06:46 PM   #38
tomsninja2020
Guest
 
Posts: n/a
Just a quick update: #35 pilot jets installed, #108 main jets (i Think), correct needles with no shims. Carbs cleaned. Fuel mixture screws 2.5 turns out. Seems kind of boggy and I have a hanging idle problem. I can touch the throttle and the RPM will hang at a high idle even with the idle adjuster turned down. I think that is a lean condition right? So how can i fix it? I did notice that there was a tiny o-ring missing from the air cut valve assembly. Does any one know what size it is and if I can go to my local hardware store and get a new one?

The Taiyo Giken Petcock is leaking gas in the fuel line even in the on position. I would like to replace it with a new one, but I am not sure want to get. The one I have has that special silver disc on the petcock lever and I cannot seem to find another petcock that it would fit. If someone could help me with this I would appreciate it.

Thanks
Tom
  Reply With Quote


Old September 8th, 2021, 04:06 AM   #39
ducatiman
ninjette.org certified postwhore
 
ducatiman's Avatar
 
Name: Gordon
Location: new york
Join Date: Sep 2009

Motorcycle(s): '95 DUCATI 900SS/SP '07 DUCATI SS800 '19 HONDA CBR650R

Posts: A lot.
MOTM - Nov '18, Mar '17
"#108 main jets (i Think)" huh? OEM Keihin jets are marked

AFA hanging idle....are carbs correctly synched? Bowl fuel levels set correct? Pilot screws may need further fine tuning, setting at 2.5 not perfect for all.

I'll get back on the "oring' size (its actually a "D" ring, but a oring could be subbed)

Is it able to freely rev now?
__________________________________________________
gordon@customcarbservices.com
Custom Carb Service
www.customcarbservices.com
ducatiman is offline   Reply With Quote


Old September 8th, 2021, 06:01 AM   #40
jkv45
Rev Limiter
 
jkv45's Avatar
 
Name: Jay
Location: WI
Join Date: Jul 2013

Motorcycle(s): '06 SV650n, '00 Derbi GPR, '64 CA77 Dream 305, '70 CL450 Scrambler, numerous dirt bikes

Posts: A lot.
MOTM - Jun '18, Oct '16
Hanging RPMs usually mean there is a vacuum leak somewhere.
jkv45 is offline   Reply With Quote


Reply




Similar Threads
Thread Thread Starter Forum Replies Last Post
1986 ninja 250 james250ninja 1986 - 2007 Ninja 250R Tech Talk 17 September 5th, 2017 07:40 AM
1986 Ninja 250 parts DanteCoal Motorcycle-related 6 February 24th, 2016 10:07 AM
1986 ninja 250 james250ninja Motorcycle-related 2 May 28th, 2015 07:30 AM
1986 ninja 250 james250ninja Pictures 12 August 19th, 2014 05:58 AM
1986 ninja 250 build marines2060 1986 - 2007 Ninja 250R Tech Talk 40 May 24th, 2013 10:06 PM


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


Motorcycle Safety Foundation

All times are GMT -7. The time now is 02:48 PM.


Website uptime monitoring Host-tracker.com
Powered by vBulletin®
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
User Alert System provided by Advanced User Tagging (Lite) - vBulletin Mods & Addons Copyright © 2024 DragonByte Technologies Ltd.
Except where otherwise noted, all site contents are © Copyright 2022 ninjette.org, All rights reserved.