DanielA Posted March 24, 2018 Share Posted March 24, 2018 I have an 86 FZ600 that had been sitting in my garage for 25 years. I fully cleaned the carbs and jets, washed the tank, replaced all oils and got it started. It's still very hard to start without using starting fluid and there is afterfire from time to time when engine is still cold. I'd adjusted the air fuel mixture to a little to the rich side and afterfire stopped when engine warms up. Everything seems fine except that it still doesn't start without using starter fluid when cold. I'm thinking it's the valve clearance that needs to be shim. Does anybody know the factory specs of the valve clearance. I know the FJ600 specs is intake 1.1 to 1.5 and exhaust 2.1 to 2.5, just not sure if it's the same for the 86 FZ600. I just checked them today and they are at 0.2 to 0.8 on the intake side, 1.2 to 1.6 on the exhaust side. I also changed to Hindle exhaust when I bought it 30 years ago. Just wonder if it needs to be tuned even richer to compensate for the straight exhaust. What is the factory specs for idle rpm. It's at around 1200 now. It's with IC ignition. Do I need to do timing on this bike, if so, how? Thanks to all in advance. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted March 24, 2018 Moderator Share Posted March 24, 2018 no idea what you mean by 1.1 etc intakes should be 0.11 - 0.15mm and exhaust 0.16 - 0.20mm cold I suspect carbs, they'll need stripping and vapour blasting then a thorough blasting with carb cleaner and air line. cold start device maybe blocked or letting in air I would suggest getting hold of a haynes or yamaha service manual, they are only £20 timing is set on these but you can advance them by dremel but as you are not even sure regarding valve clearences, i'd leave well alone. 1250rpm is the top idle speed adjustment so your ok there Link to comment Share on other sites More sharing options...
pilninggas Posted March 25, 2018 Share Posted March 25, 2018 If it starts but only with extra fuel (easystart or whatever) then it means that not enough fuel is getting on cold start. The initial response by people is that it must be choke, but in my experience choke will be okay (clean it though as the pintle or whatever may be gummed), but having rebuilt a lot of carbs it is usually blocked/gummed idle jets. I'd look here first. If it will run then clearances are further down the list and are probably best left until other things are sorted. btw, cleaning the carbs means different things to different people, any bike that has had a long lay up needs the carbs forensically cleaned. seals should be replaced with viton and diaphrams replaced. Good luck, they are nice bikes Link to comment Share on other sites More sharing options...
DanielA Posted March 25, 2018 Author Share Posted March 25, 2018 Thanks for your input. I meant 0.11mm when I types 1.1. I did clean the whole carb with carb cleaner, checked all jets holes with lights coming through, pressure air to check all channels, checked all diaphragms and needles, replaced float needles and measured the floats heights. The fact that all valve clearance are off by nearly 0.05 to 0.1mm, will that affect cold starting this much? This is one that I suspect. Another problem I suspect is the butterfly valves on carb that may not be closed tight enough that is letter extra air in. Any comments? Link to comment Share on other sites More sharing options...
Moderator drewpy Posted March 25, 2018 Moderator Share Posted March 25, 2018 there's not just jets but drillings within float bowl. could be the seals on the butterfly throttle. start bike (eventually) and spray your easy start around the carbs and see if the revs rise, that'll tell you if you have any leaks. could also be water in fuel tank, mine had a shit load in so drained off. Also check filter not clogged with rust particles Link to comment Share on other sites More sharing options...
pilninggas Posted March 25, 2018 Share Posted March 25, 2018 if the butterflies are 'too closed' then it wont start with or without easystart as not enough air will be getting in. If the butterflies are too open then it will start and the revs will jump up. I always statically balance carbs by using a sliver of aluminium tin-can as a shim and set them to all be closed by the same amount using the sim as the calibrated reference winding the individual butterfly down until the shim is a sliding fit; the idle adjust is then wound down till it runs at the required idle speed. Any clean and newly installed back of carbs should be statically balance imho - dynamic balancing can be done at the next service. 1 Link to comment Share on other sites More sharing options...
DanielA Posted March 26, 2018 Author Share Posted March 26, 2018 I did spray starter fluid around the carb to check for leaks begore and it seems fine. Carb was took apart and forensically cleaned with carb cleaner and in ultrasonic for hours. Then pressure aired all channels and slots to make sure they are clear. The fact that the bike idles stable with good throttle response, I don't think there is any problem with the channels nor gas going in from the pilot or main jets. Choke plunger also cleaned with pressure air to make sure they are not clotted. Putting the choke on revs up the idle so I don't think the choke is the issue here. As mentioned before gas tank was fully cleaned, I also coated it with some tank coating. Cleaned with fresh gasoline 3 times before I put it bsck onto the bike. This bike does not have a gas filter and I added on the fuel line after the petcock. BTW I changed all the gaskets on the petcock as it was leaking fuel and fixed the variable resistor in the fuel gauge sending unit. I'll work on the valve shims in the coming week and see what happens. Still one question I have that left unanswered by anyone. It is the air fuel mixture with the after market Hindle exhaust I have on. Do i need to richen the fuel to compensate for the bigger exhaust installed? Anybody. Thanks to everyone here. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted March 26, 2018 Moderator Share Posted March 26, 2018 I think you would need to contact Hindle themselves. I have an aftermarket one on mine and dyno'd it. The fuel was too rich so had the drop the needle. I did go up 1 jet size for the K&N filter though Link to comment Share on other sites More sharing options...
DanielA Posted March 26, 2018 Author Share Posted March 26, 2018 7 hours ago, drewpy said: I think you would need to contact Hindle themselves. I have an aftermarket one on mine and dyno'd it. The fuel was too rich so had the drop the needle. I did go up 1 jet size for the K&N filter though Thank you, creepy. Appreciate for your input. Just now, DanielA said: Thank you, creepy. Appreciate for your input. Sorry for my typo. Drewpy 2 Link to comment Share on other sites More sharing options...
slice Posted March 26, 2018 Share Posted March 26, 2018 OOOOHHHHH CREEPY that's going to be remembered..! 1 Link to comment Share on other sites More sharing options...
Moderator drewpy Posted March 26, 2018 Moderator Share Posted March 26, 2018 55 minutes ago, slice said: OOOOHHHHH CREEPY that's going to be remembered..! 3 Link to comment Share on other sites More sharing options...
blackhat250 Posted March 26, 2018 Share Posted March 26, 2018 Creepy will be like quasimodo ," with his fooked hip,,,,,,,,,,,,, 3 Link to comment Share on other sites More sharing options...
DanielA Posted March 27, 2018 Author Share Posted March 27, 2018 Once again I apologize for my typo, Drewpy. Here is the update. I took out the carb and went through all the little holes around the butterfly again with a very thin wire, took out the jets again and pressure aired all jets and fuel channels again, shim the valve to the right specs, checked the sparks and sparks looks fine. The bike turns but still won't start. Since I don't have my air filter on, I tried covering the intake with my hand while turning the engine and there is actually gasoline coming back on to my hand so I don't think getting gas into the engine through the carb is a problem. What other possibility could there be. If I can still start it with starter fluid. It is about 2 degree C now. I tried putting the choke on and it is still not working. Will a cold temperature affects this much? I know gasoline needs to vaporize and it doesn't work as well in the winter but will it simply because of the cold temperature, or is this bike just not build for temperature this low. It was doing much better last week when it's at 10 deg C. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted March 27, 2018 Moderator Share Posted March 27, 2018 what about float height? Link to comment Share on other sites More sharing options...
DanielA Posted March 27, 2018 Author Share Posted March 27, 2018 I did checked and adjusted to factory height before. Link to comment Share on other sites More sharing options...
DanielA Posted March 27, 2018 Author Share Posted March 27, 2018 Just notice that when I put the choke on revs up to 3500 rpm then slowly coming back down to idle. This doesnt seem normal as it's suppose to stay up. I suspect it's the compression. Any comments? Link to comment Share on other sites More sharing options...
Moderator drewpy Posted March 28, 2018 Moderator Share Posted March 28, 2018 maybe worth checking as it a simple procdure. you can check either worn rings (squirting oil in bores and noting the difference) or valves not sealing. I usually let some choke off if it gets too high revs, 2k seems a reasonable self imposed limit on a cold engine. BTW mine started lovely after winter hibernation I drained out the carbs first though Link to comment Share on other sites More sharing options...
DanielA Posted March 28, 2018 Author Share Posted March 28, 2018 Everything works out fine today. It's about 10 deg C today. I did check the compression when cold. All of them are at 125 psi. After putting a little more than a teaspoon of motor oil in it shoots up to 160 psi. I guess the rings are what I am looking at next. Choke seems to be fine as well. I did take out the carbs and check the passages. I called the guy who did the ultrasonic cleaning for me last night and he said he didnt put the float boat in when doing it. I guess this is what makes the choke unstable, so I redo the float boats. Thanks for all your help. I guess I won't be working on the rings if the bike can start with the choke on at 10 deg C. I'm just happy with it now. Link to comment Share on other sites More sharing options...
DanielA Posted March 28, 2018 Author Share Posted March 28, 2018 BTW, I did the compression test when the engine is cold so I guess it gets better when it warms up. Link to comment Share on other sites More sharing options...
DanielA Posted March 28, 2018 Author Share Posted March 28, 2018 Just got everything put together and checked. It now starts with a snap of a finger. Thank you, Drewpy. Thanks, everyone. 2 Link to comment Share on other sites More sharing options...
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