Idling issue

[blanzer]

Hello all, now that I figured out my bike wasn’t starting cuz a loose spark plug connection (derp), I now have an idling issue that I still can’t figure out. I thought it was a vacuum leak issue from my carb boots which I have now replaced, and I still think it might be air related but we shall see what you all think. My idle mixture screws are currently at 5 turns out and have to be far out for the bike to even idle. And it only idles around 1.75k-2k rpm’s. I can possibly turn the screw out more to lower it but I don’t think it can go out much more and I’ve had it pop out from being too loose before lol. Sometimes the bike won’t even turn over and I have to always give it throttle to start regardless. And sometimes in a sweet spot. Sometimes it won’t start no matter how much I try but if I turn on the choke it will immediately start up and if I turn it off it’ll idle fine. Valves are adjusted. Carbs are clean. I was reading maybe I need to move up a size jet? I’m all out of ideas and honestly getting tired of this bike after 7 years lol let’s see if you all can help.

[DannoXYZ]

No changes in jets needed. People increase jet size to make up for clogged dirty carbs. But it's only temporary measure as those clogs will increase over time and bike stumbles again.

Your carbs aren't factory-fresh clean. As shown by needing 5-turns on pilot screws.

Do search for "clean carbs ducatiman" for threads with procedures and photos.

[blanzer]

Originally Posted by DannoXYZ

No changes in jets needed. People increase jet size to make up for clogged dirty carbs. But it's only temporary measure as those clogs will increase over time and bike stumbles again.

Your carbs aren't factory-fresh clean. As shown by needing 5-turns on pilot screws.

Do search for "clean carbs ducatiman" for threads with procedures and photos.

Really? Guess I need to clean extra deep then cuz I’m tired of this. Is the chem dip or an ultrasonic cleaner better? Also what size ultrasonic do I need? Will a 2L or 2.5L fit it? Also, what do I need to remove in terms of rubber parts?

[DannoXYZ]

Both chem-dip and ultrasonic and micro-soda blasting. And poking out all bleed holes with soft copper-wire. Needs complete refurb with disassembly down to every last nut, bolt and individual part. Everything scrubbed with brushes and PEA-based fuel-system cleaner (including hidden secret passages in carb-body). Spray carb-cleaners no longer work due to removal of chlorinated compounds. Then ultrasonic soak everything. Micro soda-blast at very end to clean up. Adjust float levels with final wet-test. Replace all rubbers: fuel-rail O-rings, pilot screw O-rings, float-valves, float-bowl seals, and slide diaphragms if needed. Sync carbs and adjust idle.



Scrub secret hidden passages in carb-body. Scrub-brushes from amazon: https://www.amazon.com/Bottle-Cleaning.../dp/B01N6QEINN











Scrub with PEA-based fuel-system cleaner. Way, way better than useless spray carb-cleaners without any chlorinated compounds any more.

Red Line SI-1
Techron Concentrate Plus
3M Max Strength Fuel System Cleaner #08814
Royal Purple Max Atomizer 18000
Gumout All-in-One (may be off list soon due to reducing amounts of PEA.)

Completely disassemble emulsion-tube and pilot jet. Poke out all lateral bleed holes with soft copper wire. Dried petrol turns to plastic and cannot be dissolved again. Must be mechanically scrubbed away. Also poke out all bleed-holes in carb-venturi towards float-bowl. Especially the mixture-screw hole.



Bike ran perfectly fine when leaving showroom floor. It will again when carbs are restored to factory-fresh clean with all factory settings.

That's a lot of work and requires lots of experience and equipment. I just send my carbs to this outfit for refurb every winter when I'm overhauling my race bike. Since I run in stock class, restoring carbs to factory-fresh condition is one of "mods" that make HUGE difference compared to others running with clogged carbs causing stumbling and revving laziness.

EDIT: Forgot to add https://customcarbservices.com
Expert work, reasonable costs and fast turnaround!

[blanzer]

Originally Posted by DannoXYZ

Both chem-dip and ultrasonic and micro-soda blasting. And poking out all bleed holes with soft copper-wire. Needs complete refurb with disassembly down to every last nut, bolt and individual part. Everything scrubbed with brushes and PEA-based fuel-system cleaner (including hidden secret passages in carb-body). Spray carb-cleaners no longer work due to removal of chlorinated compounds. Then ultrasonic soak everything. Micro soda-blast at very end to clean up. Adjust float levels with final wet-test. Replace all rubbers: fuel-rail O-rings, pilot screw O-rings, float-valves, float-bowl seals, and slide diaphragms if needed. Sync carbs and adjust idle.



Scrub secret hidden passages in carb-body. Scrub-brushes from amazon: https://www.amazon.com/Bottle-Cleaning.../dp/B01N6QEINN











Scrub with PEA-based fuel-system cleaner. Way, way better than useless spray carb-cleaners without any chlorinated compounds any more.

Red Line SI-1
Techron Concentrate Plus
3M Max Strength Fuel System Cleaner #08814
Royal Purple Max Atomizer 18000
Gumout All-in-One (may be off list soon due to reducing amounts of PEA.)

Completely disassemble emulsion-tube and pilot jet. Poke out all lateral bleed holes with soft copper wire. Dried petrol turns to plastic and cannot be dissolved again. Must be mechanically scrubbed away. Also poke out all bleed-holes in carb-venturi towards float-bowl. Especially the mixture-screw hole.



Bike ran perfectly fine when leaving showroom floor. It will again when carbs are restored to factory-fresh clean with all factory settings.

That's a lot of work and requires lots of experience and equipment. I just send my carbs to this outfit for refurb every winter when I'm overhauling my race bike. Since I run in stock class, restoring carbs to factory-fresh condition is one of "mods" that make HUGE difference compared to others running with clogged carbs causing stumbling and revving laziness.

Sheesh that’s a ton. Thanks for info. This definitely looks like a job for someone else lol. Will save this incase I do decide to do myself though. Good to know about the carb cleaner. Explains why it doesn’t run right no matter how many times I clean them

[DannoXYZ]

Originally Posted by blanzer

Sheesh that’s a ton. Thanks for info. This definitely looks like a job for someone else lol. Will save this incase I do decide to do myself though. Good to know about the carb cleaner. Explains why it doesn’t run right no matter how many times I clean them

Forgot to add https://customcarbservices.com
Expert work, reasonable costs and fast turnaround!

[Krnluve24]

Took me 3 tries to completely fix my idle issue. Got my 2007 recently and it would never cold start without choke. Once it warms up the idle would never sit still at 1300. I adjusted the valves (motor sounds so perfect now). Chem dipped the carbs (everything apart but did not separate the dual carbs). Replaced the float valve and paid a lot of attention on the float seat. Adjusted the float height. Set mixture screw to stock spec. Bench sync’ed the carbs (was a little off). Replaced the petcock internal (was not closing). Now the bike starts perfect without choke and idle so smooth at 1300 rpm. I think the biggest thing I learned is that I did not know how a 250 suppose to behave when it was brand new. Now I know and in the future I can identify the irregularities much better.

[Triple Jim]

Originally Posted by Krnluve24

Now the bike starts perfect without choke and idle so smooth at 1300 rpm.

Welcome to the board, Krnluve! A friend of mine used to run Centreville Allstate before he retired.

You're right that out of spec valves make these engines run badly, especially when cold. But being able to do a cold start without using the enricher may mean you have the pilot screws set a little too rich. Did you adjust them for fastest idle?

[blanzer]

So I ended up taking apart the carbs completely. I chem dipped them for almost 24 hours, sprayed carb cleaner in every hole numerous times and used compressed air. Put them back together and it’s running exactly the same. 4.5 turns out, 2k rpm’s. Won’t idle otherwise. Beginning to think it’s another problem. Any ideas? I know I’m missing the breather hose that goes from the engine to the air box. Would that cause this? Otherwise idk if I need to check the valves again or change the air filter or what. I’m out of ideas.

[Krnluve24]

In my scenario I learned that if no amount of cleaning works then something has to be drastically changed which in my case it was the float system. Did you run a test on the float fuel level to see if the float height is to spec? My float height was set but the float valve won’t fully close so I replaced it and really cleaned up the float seat. My mixture screw was set at 2.5 turns.

[blanzer]

Originally Posted by Krnluve24

In my scenario I learned that if no amount of cleaning works then something has to be drastically changed which in my case it was the float system. Did you run a test on the float fuel level to see if the float height is to spec? My float height was set but the float valve won’t fully close so I replaced it and really cleaned up the float seat. My mixture screw was set at 2.5 turns.

No how do I go about testing that? May have to look into this next.

[ducatiman]

clear tube method, using remote, gravity fed fuel source

[blanzer]

Originally Posted by Triple Jim

Welcome to the board, Krnluve! A friend of mine used to run Centreville Allstate before he retired.

You're right that out of spec valves make these engines run badly, especially when cold. But being able to do a cold start without using the enricher may mean you have the pilot screws set a little too rich. Did you adjust them for fastest idle?

Forgot to say that months ago I was having issues and cleaned the carbs and I had the bike running like that. I had the screws out quite a bit but the bike was idling perfect for the first time in 7 years. And I was able to cold start without the choke. Just needed to give it gas, which I was also never able to do. Always needed the choke the whole time I’ve owned the bike, and whenever I tried to give it gas it would die. Then it was the opposite until it took a crap suddenly and has been the way it’s been now.

[blanzer]

Originally Posted by ducatiman

clear tube method, using remote, gravity fed fuel source

Thanks Gordon. If I can’t figure this out I’m just gonna have to bite the bullet and send them out to you. Finding a week where I can afford to do so is the issue lol otherwise I would’ve done it already since I have probably spent more than it would’ve costed to send to you

[ducatiman]

respectfully acknowledged and understood. If I can help answer any questions, either post up here or PM me.

[blanzer]

Originally Posted by ducatiman

respectfully acknowledged and understood. If I can help answer any questions, either post up here or PM me.

So I had an electrical problem. See my other post for info. But basically my R/R connector burnt out and melted. Upon disconnecting it and putting new connectors(I haven’t reconnected the R/R yet to see if it’s in working condition), I turned on the bike to test stator and it is now idling much better. I was able to put it now to 3.5 or 4 turns out(forgot which lol) and it is now idling below 2k. Any idea why? Would an electrical problem prevent it from idling correctly?

[Triple Jim]

It could. For example, if the voltage to the ignition unit was dropping too low and spark was erratic.

[ducatiman]

Originally Posted by blanzer

So I had an electrical problem. See my other post for info. But basically my R/R connector burnt out and melted. Upon disconnecting it and putting new connectors(I haven’t reconnected the R/R yet to see if it’s in working condition), I turned on the bike to test stator and it is now idling much better. I was able to put it now to 3.5 or 4 turns out(forgot which lol) and it is now idling below 2k. Any idea why? Would an electrical problem prevent it from idling correctly?

we are referencing both the pilot screws? At 3.5-4 turns out each? If so, I'd submit the needed overly rich settings are in compensation for constricted pilot passageways. They are tiny, clog quite easily. No secret these carbs are difficult to clean properly. Correct pilot screw settings should be nearer to 2 1/2 turn out, idle should be near to 1100-1200 with correct tuning.

Repair/correct the electrical end of things first.....then tuning.

[blanzer]

Originally Posted by ducatiman

we are referencing both the pilot screws? At 3.5-4 turns out each? If so, I'd submit the needed overly rich settings are in compensation for constricted pilot passageways. They are tiny, clog quite easily. No secret these carbs are difficult to clean properly. Correct pilot screw settings should be nearer to 2 1/2 turn out, idle should be near to 1100-1200 with correct tuning.

Repair/correct the electrical end of things first.....then tuning.

Electrical is resolved. Bike is running horrible still lol. Had to idle at 2k with both screws at 4.5 turns out. Not to mention it won’t idle perfectly until it’s really hot. But that may be normal. Turns right on though. Sometimes when riding and then stopping it also drops the idle and dies if I don’t give it throttle. Think it’s really just clogged pathways? I didn’t use any copper wire so possibly? Is there a way to know when it’s clean when cleaning? Cuz I had carb cleaner and air blowing through everything. Soaked in chem dip for a day. Took them completely apart. All o rings and everything were replaced or still in good condition. Any other tips? I know I should use that other machine but don’t have access to one right now. Hopefully I have a good month of work and I can maybe afford a week off to ship them to you cuz I’m over it lol

[Triple Jim]

Originally Posted by blanzer

Not to mention it won’t idle perfectly until it’s really hot. But that may be normal.

No, when the carbs are right, and with correctly adjusted valves, it takes only a little warming up before the idle behaves.

[ducatiman]

So moving forward.... @blanzer you posted you checked/set your valves early on in the thread. At what spec?

Factory spec is 0.003-0.005 inches for the intake valves and 0.004-0.006 inches for the exhaust valves. Exactly where are yours set?

[blanzer]

Originally Posted by ducatiman

So moving forward.... @blanzer you posted you checked/set your valves early on in the thread. At what spec?

Factory spec is 0.003-0.005 inches for the intake valves and 0.004-0.006 inches for the exhaust valves. Exactly where are yours set?

I always aim for the looser end so I don’t have to do it as often. I suppose I can check them again just to be sure. I’ll check them out later today. I don’t have the super accurate feeler gauges I have the ones with a range on them, so for .005 on the intake I use the .005-? And if that fits, then I use the .006-? And make sure that doesn’t fit. Might be putting them too loose perhaps?

[ducatiman]

Rare i get a 250 to work on live, right here. However an EX500 twin vid to be attached, running perfectly after valves set and carb/petcock refurbs and carb pilot set and synch.

I prefer to use the mid-spec on intakes, loose end on the exhausts.

Anyways, here's the vid, during which I was checking for petcock leaks. Note steady 1200 rpm idle.

https://www.youtube.com/watch?v=cZ4X5uOb6Xk

Added a bonus vid....a '38 BMW I got running from a long slumber. Similarities in idle, no?

https://www.youtube.com/watch?v=Y8JSrpUpNig

[blanzer]

Update: Valves were out of spec it seems. I bought new feeler gauges cuz the ones I had sucked. So they are now in the mid range of spec. But it’s still not starting properly or idling correctly. Sometimes I can only start with the choke. It’s struggling in general. I’ve been riding around and having to rev a little at lights so it won’t die. I’m at a loss. I’m assuming it must be the carbs. Just started a new job making good money and can work remote so hopefully one week I can just stay home and I’ll ship you the carbs Gordon.

[ducatiman]

ready and willing anytime, just gve me a pm prior to sending.

[Triple Jim]

I agree that dirty carbs are likely, Nicholas.