bralkan Posted January 1, 2012 Share Posted January 1, 2012 I've combed the forum for topics that address the issue and made some progress, but I'm at my wits end. I have replaced the intake boots / gasket. I have pulled main jets, pilot jets, pilot screw, starter jet (Air inlet) and soaked in carb cleaner. I have replaced the rubber o ring, metal oring, and spring on the pilot screw. I upped the pilot jets to 47.5 from the 42.5 (I was going to go to 45 but I seemed to have lost one....). Main jets are still stock (135 I think). Now, the issue. About 2 years ago the bike started doing the "Stick at 4k RPM" issue. I let it sit for awhile and finally started looking at it again. What is it doing now? After tinkering with it I have it starting rather quick on full enrichener. If I blip the throttle after it is warm and I blip it over 4k, it will stick at 4k RPM. If I ride and load the bike to get it below 4k rpm, it will idle at 1.2k (Full choke/enrichener). If I get it over 4k RPM and turn off the enrichener I can keep the bike running. If I turn the enrichener off and let it drop to 3-4k RPM, it will stall and die. From what I understand, this is an issue with the pilot screw / pilot circuit. However, I have soaked and cleaned and soaked again. If I spray carb cleaner into the pilot jet housing (with jet removed), it will spray straight out of the hole at the outlet to the manifold (where the pilot screw rests). The spark plugs are grey. I'm not sure what else to do at this point.... right now the Pilot screws are at 2.5 or 3 turns out (I forget at the moment). Increase the pilot jets again? Back the pilot screw out more? Any ideas / help is greatly appreciated! Link to comment Share on other sites More sharing options...
Moderator drewpy Posted January 1, 2012 Moderator Share Posted January 1, 2012 did you clean the spray bar, as you didn't mention it. If you have brass floats, the height should be 26mm top of float to top of carb body (with the carb upside down) sometimes the butterfly seals/bearings can wear (mikexs can supply those) if you have the later plastic floats, the float height is measured via a clear tube from the bottom float bowl (with fuel in) to within 2mm of the top of the float bowl. have you pod filters on the bike or running stock? Link to comment Share on other sites More sharing options...
bralkan Posted January 1, 2012 Author Share Posted January 1, 2012 did you clean the spray bar, as you didn't mention it. Not that I know of. Where is this located? I didn't see it mentioned on my diagrams. If you have brass floats, the height should be 26mm top of float to top of carb body (with the carb upside down) This was one of the first things I adjusted. When I started messing with the bike, I pulled it with a lawn mower and noticed that fuel would spit out the intake side of the carb. I took the float bowls off and "raised" the floats to ~32mm from the top of the float to the carb body. I thought that was spec? If its 26mm, I would need to lower them. Could this cause the pilot circuit to be starved of fuel? sometimes the butterfly seals/bearings can wear (mikexs can supply those) I'll renew these if nothing else above seems to be it! if you have the later plastic floats, the float height is measured via a clear tube from the bottom float bowl (with fuel in) to within 2mm of the top of the float bowl. have you pod filters on the bike or running stock? I have the brass floats. I am running stock airboxes at the moment, although the original air filter element has been removed and it is a sketchy piece of foam in its place. Thanks Drewpy! I remember you when I first started posting here 2 years ago. Thanks once again for the help. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted January 1, 2012 Moderator Share Posted January 1, 2012 spray bar is accessed when you take off the diaphram and mains inside the carb. It should just tap out through the diaphram side. its HZ in this diagram 32mm is wrong and 26mm will richen your carbs too. Its a known error with Haynes. 3 turns out for the pilot circuit mix screw. Link to comment Share on other sites More sharing options...
bralkan Posted January 1, 2012 Author Share Posted January 1, 2012 Thanks! I'll clean the spray bar and adjust the floats and report back! Link to comment Share on other sites More sharing options...
bralkan Posted January 2, 2012 Author Share Posted January 2, 2012 Ok! I lowered the floats. I first tried 26mm but my left (looking forward) carb was leaking fuel out of the air inlet. I raised it to around 28mm and it seemed to do ok on the center stand. It will now idle off choke. There are still some issues, however. Once warm, if I blip over 4k rpm it is still sticking at 4krpm. I was unable to clean the spray bar - there are 3 screws stripped on one hat and 1 screw stripped on the other. I don't have a lot of experience drilling out screws, particularly ones on a part that isn't easily replaceable. I may see if I can get a local shop to remove them for me. I am getting backfire (exhaust) and the pops in the carbs when off the enrichener. Off enrichener, the throttle response is a bit sluggish on the low end though it may have gotten slightly better once warmed up. I have a video below... http://dl.dropbox.com/u/12150479/20120102_081140.mp4 Link to comment Share on other sites More sharing options...
Moderator drewpy Posted January 2, 2012 Moderator Share Posted January 2, 2012 those spray bars needs cleaning. don't drill out the screw on the diaphram caps, use either a long gripper or try and get it in a vice and turn the carbs. my left carb leaked at first , but it fills the right carb too and mine stopped after a bit and has been fine ever since. try 27mm as a compromise. your still too lean! 3 turns out on pilot mix screw? BTW check that the pilot tip hasnt broken off in the carb, common on PO's who mess and tighten them up too much. Link to comment Share on other sites More sharing options...
bralkan Posted January 3, 2012 Author Share Posted January 3, 2012 Never would have thought vice grips would work, but it did the trick. Thanks! Thankfully, I have some screws from a set of donor carbs. I should be 3 turns out on the pilot mix. I'll double check. Unless both of the pilot screws broke at the same place they should be ok. One I had renewed awhile ago (it was missing!), so I think the are good. Spray bars (also called needle jet?) are being soaked in Chemtool right now. The bar on the left in the pic was in the left carb (looking forward). Pretty nasty. Also, on the floats - where should the tang be when the carbs are upside down? Fully depressing the float needle? Sitting just above? Link to comment Share on other sites More sharing options...
Moderator drewpy Posted January 3, 2012 Moderator Share Posted January 3, 2012 with the carbs upside down, the tang should be just resting on it. Use a vernier caliper to measure the height Link to comment Share on other sites More sharing options...
berniebee Posted January 3, 2012 Share Posted January 3, 2012 A "just in case" suggestion: Make sure that the throttle cable is not sticking and that there is a bit of cable play at the throttle grip. Throttle shaft sticking? Quick way to check: Next time it sticks at high RPM, grip the carb throttle shaft and see if you can rotate it towards the idle stop. No movement should be possible if the throttle plate is at idle position. Link to comment Share on other sites More sharing options...
bralkan Posted January 6, 2012 Author Share Posted January 6, 2012 Had to, go out of town. I messed with the floats again today and bam! She lives! Thanks so much for the help. I do have another question... W The rear brake (drum) likes to catch really bad. When I press the pedal it doesn't engage immediately and then it will catch causing the wheel to lock. If I depress and repress the pedal it works normally. Once I travel the brake will catch again. Can this be renewed or otherwise fixed? Link to comment Share on other sites More sharing options...
Moderator drewpy Posted January 6, 2012 Moderator Share Posted January 6, 2012 needs adjusting properly ie its over reaching on the brake arm, or the shoes are worn causing the same effect. Also check the return spring in the brakes are working as it may flip the shoe into the drum causing a lock up situation Link to comment Share on other sites More sharing options...
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