acceleration Bog

ThatmendoguyYT · June 13th, 2023, 02:25 PM

New member here, i've tried searching through all the forums, google searches, youtube videos, E.t.c.. i cant find any help. so let me explain.
i have a 2004 Ninja EX250F. got it about a month ago and it rode fine when i got it. after a few rides it started to bog out mid range, then got worse and worse, eventually only gaining speed if i was WOT (full throttle). so i took the carbs out, deep cleaned them multiple times, found out the jetting was 105/48 and one washer on the needles. after installing all the clean parts and got the carbs back onto the bike, it starts but not normally. now its either full thottle or NO throttle. choke doesnt help, open airbox doesnt help, ive tried taking the jettig down one stage and working my way up two stages higher. nothing works. i live at 660 feet elevation, stock airbox, and halfway open stock mufflers ( cut at the end removing one stage of baffles. ) the cutoff valve or fuel accelerator is in good shape, diaphrams are looking good, washers removed from the needles, and fuel mixture is set 4 turns out because thats the only way it idles. it revs high in neutral, but as soon as you click it in gear and try to give it gas it bogs out unless you roast the clutch and keep it high revs, then you must ride full throttle 24/7. any suggestions or has ayone dealt with this?
battery is fully charged-safety features on clutch and shifter removed-carbs are 100% spotless and passage ways clear- all the o-rings and gaskets are still in the carbs- and i believe the CA Smog is removed since i cant find a canister anywhere. i was thinking maybe the petcock? oh and a full tank of fresh 87 Gas.

ducatiman · June 13th, 2023, 02:49 PM

48 pilots (4 sizes over stock!) with 4 turns! out on the screws? Those are some quite rich pilot settings right there! Sounds as if something is being compensated for. I had a set sent to me for servicing due to the fact that the exhaust stunk of gasoline....found pilot jets had been radically reamed. Replacing with stock 38 corrected the issue.

Overall mileage on bike? Valves been checked recently for adequate clearances?
Vacuum hoses accounted for? And hooked up correctly?

Triple Jim · June 13th, 2023, 03:08 PM

If the points that ducatiman made check out, I'd bet the carbs are not fully clean. There are passages that are very hard to get truly clean in these.

https://n4mwd.blogspot.com/2013/10/s...-passages.html

ducatiman · June 13th, 2023, 03:42 PM

Agreed with TripleJim above.

A few years ago, I exposed a transition mixture port on EX500 carb, drilling and removing the large,deep brass cap covering it. I can understand that if/when these get varnished, extreme measures must be taken to clean/clear them. Note the (inaccessible) mixture ports both allow air and fuel to mix....air via the air correction jets and fuel via the pilot jets. Quite tricky little buggers, these carbs.

ThatmendoguyYT · June 13th, 2023, 04:46 PM

Quote:

Originally Posted by ducatiman

48 pilots (4 sizes over stock!) with 4 turns! out on the screws? Those are some quite rich pilot settings right there! Sounds as if something is being compensated for. I had a sent sent to me for servicing due to the fact that the exhaust stunk of gasoline....found pilot jets had been radically reamed. Replacing with stock 38 corrected the issue.

Overall mileage on bike? Valves been checked recently for adequate clearances?
Vacuum hoses accounted for? And hooked up correctly?

Thanks for saying that about the size 48 pilot. i come to realize its running the 38 stock and i was one number off when typing this. miles are sadly unknown because i got the bike with a trailtech speedo and it is a naked build. title is also blank for mileage. the build has around 900 miles on it according to the speedo, ever since hat was installed. i have not checked valves yet. trying to beat around the bush but im not having any luck, as the carbs have been removed and installed 25 times since ive had it on one month. valves are next after i rebuild the whole carbs

Triple Jim · June 13th, 2023, 05:17 PM

Normally with this engine, when the valves get out of spec they close their clearances until they don't seat when the engine is cold. When it warms up, they do seat and it runs normally. When this happens, starting gets finicky and it doesn't want to idle right until it warms up. Again, I'm betting that not all the hard-to-get-to passages in the carbs are clean.

ducatiman · June 13th, 2023, 05:53 PM

Quote:

Originally Posted by Triple Jim

Normally with this engine, when the valves get out of spec they close their clearances until they don't seat when the engine is cold. When it warms up, they do seat and it runs normally. When this happens, starting gets finicky and it doesn't want to idle right until it warms up. Again, I'm betting that not all the hard-to-get-to passages in the carbs are clean.

was just making the general suggestion that on a "new to you" bike....ANY bike....an introductory valve clearance check should be 1st priority in assuring all will be well going forward.

Triple Jim · June 13th, 2023, 06:46 PM

Understood, Gordon. The information was for Mendo. The way this engine behaves with out of spec valves is a little unusual, at least to me.

ThatmendoguyYT · June 14th, 2023, 03:17 PM

Well I've been paying attention to the reply section while taking the carbs off... Again.. I changed the fuel mixture screws to new ones, put one washer on both needles, lowered the floats, and now it's worse. I've gone back and forth so many times avoiding the valves because I feel like it's the carburators 100%. It was running and riding then once I took it off, bam! Issues! But hey maybe it is the valves. I have gauges and everything to check them. I just keep messing with the carbs. Also, could the cam chain cause issues? I forgot to mention a big part on my main question. A family member of mine tried to adjust it and undid the two bolts holding that huge spring down in the case. He pulled it up about an inch and put it back in once he realized it's the not the same adjustment as some other street bikes he rides. Boom, game changer? Maybe? Could it just be too much slack or possibly completely off timing now?

Triple Jim · June 14th, 2023, 04:59 PM

I doubt if that's the trouble, but the quick check is to take off the valve cover and see if overlap is very close to TDC. You can do that visually.

ducatiman · June 14th, 2023, 05:19 PM

I'd totally eliminate the (screw and locknut) valves from the equation, setting all the exhausts on the high side of spec.....especially if going through the effort of removing the valve cover for a visual.

DannoXYZ · June 14th, 2023, 05:27 PM

Verify cam-timing and valve-clearances while you're there.

Most likely, delayed timing of issues was due to crud in tank taking their time to work towards petcock and clog things up. And problems getting worse and worse shows it's most likely outside and upstream of carbs.

Do petcock flow-test to make sure petcock is flowing sufficiently 1st.
1. unplug ignition-coils
2. unplug petcock fuel-hose from carb-inlet and aim into measuring cup
3. crank engine for 10-sec.
4. how much petrol did you collect???

Carbs aren't factory-fresh clean - do search on here for "ducatiman clean carbs" for guides and photos of how to do deep-cleaning and restore carbs back to fully factory-fresh clean. It usually involves:

1. complete disassembly of carbs down to every last nut, bolt and individual component. If it can be broken down even more, do it.

2. scrub everything with brushes and PEA-based fuel-system cleaner. Note "spray" carb-cleaners no longer work due to removal of chlorinated compounds. Thanks a lot crunchy-granola tree-hugging bark-eating smelly hippies!!!

3. scrub out all secret hidden passages in carb-body: https://n4mwd.blogspot.com/2013/10/s...-passages.html

4. poke out all bleed-holes in carb-body, emulsion-tubes, all jets with matching gauge copper-wire. You'll find it'll push out plugs of dried petrol like little pieces of sand. No way chemicals will dissolve that!

5. ultrasonic-soak everything

6. micro soda-blast everything to remove chads and cling-ons from scrubbing

7. replace all rubbers: pilot-screw O-rings, fuel-rail O-rings, float-valves, float-bowl seals, even slide-diaphragms if needed

8. set float-heights with final functional wet-test to confirm

9. sync carbs with manometers

10. set mixture screws for "best-idle" speeds on warmed-up engine.

It's not easy, many expert mechanics have had to do it 4-5x before they got carbs back to factory-fresh clean where bike will run like fresh off showroom-floor. One guy had to pull his carbs 10x!!!

Also make sure internal filtre in fuel-hose wasn't installed backwards previously and wadded it self up, blocking flow. Best to replace with in-line external filtre so you can inspect and replace when needed.

June 13th, 2023, 02:25 PM	#1
ThatmendoguyYT ThatmendoguyYT Name: Mendo Location: Mendocino CA Join Date: Jun 2023 Motorcycle(s): 2004 EX250F Posts: 4	acceleration Bog New member here, i've tried searching through all the forums, google searches, youtube videos, E.t.c.. i cant find any help. so let me explain. i have a 2004 Ninja EX250F. got it about a month ago and it rode fine when i got it. after a few rides it started to bog out mid range, then got worse and worse, eventually only gaining speed if i was WOT (full throttle). so i took the carbs out, deep cleaned them multiple times, found out the jetting was 105/48 and one washer on the needles. after installing all the clean parts and got the carbs back onto the bike, it starts but not normally. now its either full thottle or NO throttle. choke doesnt help, open airbox doesnt help, ive tried taking the jettig down one stage and working my way up two stages higher. nothing works. i live at 660 feet elevation, stock airbox, and halfway open stock mufflers ( cut at the end removing one stage of baffles. ) the cutoff valve or fuel accelerator is in good shape, diaphrams are looking good, washers removed from the needles, and fuel mixture is set 4 turns out because thats the only way it idles. it revs high in neutral, but as soon as you click it in gear and try to give it gas it bogs out unless you roast the clutch and keep it high revs, then you must ride full throttle 24/7. any suggestions or has ayone dealt with this? battery is fully charged-safety features on clutch and shifter removed-carbs are 100% spotless and passage ways clear- all the o-rings and gaskets are still in the carbs- and i believe the CA Smog is removed since i cant find a canister anywhere. i was thinking maybe the petcock? oh and a full tank of fresh 87 Gas.

June 13th, 2023, 02:49 PM	#2
ducatiman ninjette.org certified postwhore 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	48 pilots (4 sizes over stock!) with 4 turns! out on the screws? Those are some quite rich pilot settings right there! Sounds as if something is being compensated for. I had a set sent to me for servicing due to the fact that the exhaust stunk of gasoline....found pilot jets had been radically reamed. Replacing with stock 38 corrected the issue. Overall mileage on bike? Valves been checked recently for adequate clearances? Vacuum hoses accounted for? And hooked up correctly? __________________________________________________ gordon@customcarbservices.com Custom Carb Service www.customcarbservices.com Last futzed with by ducatiman; June 13th, 2023 at 07:04 PM.

June 14th, 2023, 03:17 PM	#9
ThatmendoguyYT ThatmendoguyYT Name: Mendo Location: Mendocino CA Join Date: Jun 2023 Motorcycle(s): 2004 EX250F Posts: 4	Update.. Well I've been paying attention to the reply section while taking the carbs off... Again.. I changed the fuel mixture screws to new ones, put one washer on both needles, lowered the floats, and now it's worse. I've gone back and forth so many times avoiding the valves because I feel like it's the carburators 100%. It was running and riding then once I took it off, bam! Issues! But hey maybe it is the valves. I have gauges and everything to check them. I just keep messing with the carbs. Also, could the cam chain cause issues? I forgot to mention a big part on my main question. A family member of mine tried to adjust it and undid the two bolts holding that huge spring down in the case. He pulled it up about an inch and put it back in once he realized it's the not the same adjustment as some other street bikes he rides. Boom, game changer? Maybe? Could it just be too much slack or possibly completely off timing now?

June 14th, 2023, 05:19 PM	#11
ducatiman ninjette.org certified postwhore 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	I'd totally eliminate the (screw and locknut) valves from the equation, setting all the exhausts on the high side of spec.....especially if going through the effort of removing the valve cover for a visual. __________________________________________________ gordon@customcarbservices.com Custom Carb Service www.customcarbservices.com

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
6.5k rpm bog	bigBug	1986 - 2007 Ninja 250R Tech Talk	22	February 2nd, 2022 03:05 PM
Lean Condition Causing Bike to Bog Down?	Hatter	2008 - 2012 Ninja 250R Tech Talk	11	April 3rd, 2015 02:27 PM
Low and mid range bog.	Lemonfresh	2008 - 2012 Ninja 250R Tech Talk	8	May 16th, 2014 12:05 PM
Advice Needed: Engine Bog @ ~6k 1/4 Throttle	MaxxVE	1986 - 2007 Ninja 250R Tech Talk	7	March 16th, 2014 05:10 PM
Was that a bog?	tsiratiug	2008 - 2012 Ninja 250R Tech Talk	1	February 15th, 2011 12:25 PM

June 13th, 2023, 03:08 PM	#3
Triple Jim Guy Who Enjoys Riding Name: Jim Location: North Carolina Join Date: Jul 2016 Motorcycle(s): Ninja 250 Posts: A lot. MOTM - Oct '18, Aug '17, Aug '16	If the points that ducatiman made check out, I'd bet the carbs are not fully clean. There are passages that are very hard to get truly clean in these. https://n4mwd.blogspot.com/2013/10/s...-passages.html

June 13th, 2023, 05:17 PM	#6
Triple Jim Guy Who Enjoys Riding Name: Jim Location: North Carolina Join Date: Jul 2016 Motorcycle(s): Ninja 250 Posts: A lot. MOTM - Oct '18, Aug '17, Aug '16	Normally with this engine, when the valves get out of spec they close their clearances until they don't seat when the engine is cold. When it warms up, they do seat and it runs normally. When this happens, starting gets finicky and it doesn't want to idle right until it warms up. Again, I'm betting that not all the hard-to-get-to passages in the carbs are clean.

June 13th, 2023, 06:46 PM	#8
Triple Jim Guy Who Enjoys Riding Name: Jim Location: North Carolina Join Date: Jul 2016 Motorcycle(s): Ninja 250 Posts: A lot. MOTM - Oct '18, Aug '17, Aug '16	Understood, Gordon. The information was for Mendo. The way this engine behaves with out of spec valves is a little unusual, at least to me.

June 14th, 2023, 04:59 PM	#10
Triple Jim Guy Who Enjoys Riding Name: Jim Location: North Carolina Join Date: Jul 2016 Motorcycle(s): Ninja 250 Posts: A lot. MOTM - Oct '18, Aug '17, Aug '16	I doubt if that's the trouble, but the quick check is to take off the valve cover and see if overlap is very close to TDC. You can do that visually.

June 14th, 2023, 05:27 PM	#12
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	Verify cam-timing and valve-clearances while you're there. Most likely, delayed timing of issues was due to crud in tank taking their time to work towards petcock and clog things up. And problems getting worse and worse shows it's most likely outside and upstream of carbs. Do petcock flow-test to make sure petcock is flowing sufficiently 1st. 1. unplug ignition-coils 2. unplug petcock fuel-hose from carb-inlet and aim into measuring cup 3. crank engine for 10-sec. 4. how much petrol did you collect??? Carbs aren't factory-fresh clean - do search on here for "ducatiman clean carbs" for guides and photos of how to do deep-cleaning and restore carbs back to fully factory-fresh clean. It usually involves: 1. complete disassembly of carbs down to every last nut, bolt and individual component. If it can be broken down even more, do it. 2. scrub everything with brushes and PEA-based fuel-system cleaner. Note "spray" carb-cleaners no longer work due to removal of chlorinated compounds. Thanks a lot crunchy-granola tree-hugging bark-eating smelly hippies!!! 3. scrub out all secret hidden passages in carb-body: https://n4mwd.blogspot.com/2013/10/s...-passages.html 4. poke out all bleed-holes in carb-body, emulsion-tubes, all jets with matching gauge copper-wire. You'll find it'll push out plugs of dried petrol like little pieces of sand. No way chemicals will dissolve that! 5. ultrasonic-soak everything 6. micro soda-blast everything to remove chads and cling-ons from scrubbing 7. replace all rubbers: pilot-screw O-rings, fuel-rail O-rings, float-valves, float-bowl seals, even slide-diaphragms if needed 8. set float-heights with final functional wet-test to confirm 9. sync carbs with manometers 10. set mixture screws for "best-idle" speeds on warmed-up engine. It's not easy, many expert mechanics have had to do it 4-5x before they got carbs back to factory-fresh clean where bike will run like fresh off showroom-floor. One guy had to pull his carbs 10x!!! Also make sure internal filtre in fuel-hose wasn't installed backwards previously and wadded it self up, blocking flow. Best to replace with in-line external filtre so you can inspect and replace when needed.