I need help setting the idle, I recently cleaned and balanced the carbs I put in new jets I believe 38s but I will double check I wrote it down somewhere, I have 2 shims under the needles and I started with 2.5 turns out on the pilot jets. I was getting some surging and the rpms stalled when I blimped the throttle so I backed them out 1/2 than another 1/4 so I believe they are at 3.25 turns out now. It's running a tiny bit better and less of a stall when blimped. For some reason it struggles when I bring the idle down with the idle control to around the 1200 to 1500 it sounds a lot better when I have the idle set between 1500 and 2k

My question is what controls the idle? I thought that it was/is mostly the pilot jets but I have them set way out but I'm still not idling how I would like. I do have a wide band o2 connected and when I'm idling even around 1500 2k my a:f is at 22.4:1 maxing out my wideband gauge, when I have the choke on It sometimes goes up to 22:1. What can I do to enrichment the a:f at idle other than backing out the pilots even further

I feel good about the needle height and jet choices the bike runs great when I ride it and great through the lower mid and upper range, the only issue I am having is I'm not happy with the the idle. I still have some rpm stalling when off the throttle when riding and I pull in the clutch it doesn't drop down how I would like. I Lubed the throttle cables and they snap back how they should so I know that's not the issue. Brand new petcock and filter, I rewired the ignition system with 18ga wire it has strong spark and good even compression, I do have an adjustable timing sprocket but I have it at stock so I don't think that should be the issue

Only thing I can think to do is warm it up take it on a small ride so it's at running temp and pull off the tank and check the balance again? Any other suggestions are more then welcome

Just to double check the #2 carb is the one I set them equal to right?

Sorry for the long post but thanks for the help

 

Hi , slow idle jet controls feed at idle but that looks the right size 38, as your problem is only with idle, are the float heights correct, and what colour are the plugs,

 

Thanks for the response, plugs are new but I'll go check them, and aren't the float heights not adjustable on the f2? Guess I missed that piece of information on the first post the bike is a 94 cbr f2

And just to clarify there are 3 "jets" please correct me if I have the names of the jets mixed up
1- tall skinny with holes on the side inside the float bowl (pilot?) (slow jet?)
2- short stubby inside the float bowl (main?)
3- d shaped out side the float bowl (I mistakenly called that the pilot) (a/f)

 

Hi tampa, never looked for the tang adjustment just noticed float level 13.7mm, and heres a ready reckoner to set the jets position right , did you bench sync the carbs or have you got a synchroniser, as the slow jet is right and jet needle doesn't come into play got to be looking at mixture screws and petrol feed , tank
https://www.fowlersparts.co.uk/parts...omponent-parts

 

I used a syncronizer with an auxiliary fuel tank, I have the tank on now brand new petcock with brand new fuel filter

I just went out to try to run it and I couldn't get it to run with the choke off any where near 1200-1500 wouldn't even stay alive under 2k no matter how much I cranked up the idle control yesterday I was able to get it to somewhat idle and was able to run it off of the choke and ride it around the neighborhood, I'm going backwards. sounds great from 3k up I'm debating about just trying larger pilot jets I double checked I have 38 pilots and 140 mains currently I do know most if not all of my packing is blown out on a muzzy exhaust and I have the mixture screws at 3.25 turns out which is already past the stock 2.5 I would want to be at. I've cleaned the carbs a million times and am very confident that the mixture screw paths are clean and clear and all of them are good with good orings and I know for a fact the pilot jets are perfectly clean used cleaner and compressed air I cleaned them really well along with the mains, pulled them cleaned them then the carb bodies, but if I can't get anything to work or if I switch out the pilots I might as well pull the mixture screws again and recheck them since the carbs will be off.

I've looked at the floats their all plastic no metal tab to adjust and from reading other posts it does appear that they are not adjustable But i have checked them all to make sure there are no holes and t they are fine and they all seem to work fine

I'll go ahead and read the link the gave

 

OH and since you were the one helping me with my spark issues I thought I would let you know what the final issue was, the bolt that holds the timing gear wasn't torqued down appropriately so the gear was loose enough that it didn't pass the pickup like it should. But with timing gear torqued down appropriately and the new 18ga wiring and icm plug everything is now within spec including the resistance between icm and coils and I have a really strong spark. So now just need to figure out the fuel issues and it should run really well, thanks for the help with the spark

 

Its got to be Pilot screw and Slow Idle jet, even clip on the needle jet as you can see from this chart main jet kicks in later ,if you have the clip in the wrong position its adding to your woe's ,I would return pilot screws to factory spec needle clips to leaner and go from there

 

Yeah that's what it's looking like the problem will be. I have 2 shims under the stock needles but I do have a set of clip needles that I might try instead. checking the carb database everyone is running them in the 2nd position so I should be fine there. I'm not sure what stock unfortunately.

When I watch my mid range on my wideband I get between 13.5: to 14.5:1 when I blip the throttle so I feel pretty good with where their set

I think 38s are stock maybe 35s are? The bike had 38s when I got it but it has always had idle issues never really ran right at idle.

I just ordered a set of 40s I notice a lot of people running them on the carb database so I figured I could give that a try should definitely enrich the mixture at idle and I'll reset the mixture screws to the stock 2.5 when I put the new jets in and obviously rebalance them at that time

 

Sounds good to me

 

New pilots worked wonders idles how it should great throttle response. With the wideband I get between 15.3:1-16:1 max when warmed up still a tiny bit lean but I think going to 42s would enriched it too much and that was with the filter off just exposed carbs. So I'm happy with where it sits and how it idles, best it's ran since I've had it. I also have the mixture screws at 2 turns out instead of the stock 2.5

Thank you for all the help with diagnosing the spark and recomendations with the carbs and the info you posted, your keeping these forums alive and helpful! Safe riding!