gazzaecowarrior Posted June 28, 2009 Report Share Posted June 28, 2009 After spending a bloody whole week getting the gears nicely synchronised with no more phantom neutrals I was so looking forward to taking my bike for it's maiden run up the woods. Fired it up ok but it will only run with choke in and when the choke is off it soon dies. I spoke to the nice chap at TY trials and he said it sounds like the crank seals have gone. I just can't understand how they have gone so quickly as I had taken it for a quick rip up the street and it was running nicely but perhaps it was a bit hot. There doesnt seem to be any oil in the flywheel. Could it be anything else ? It feels like a air leak. Does anybody put any additional gasket sealant between the reed valve assembly and the inlet stub ? I have ordered new crank seals but I was just wondering if anybody thought it could be anything else before I take the engine apart again !!!! Gareth Quote Link to comment Share on other sites More sharing options...
helm Posted June 28, 2009 Report Share Posted June 28, 2009 Hi check that you also have enough fuel getting to the carb, I have just fixed a bike for a friend who was told seals gone or piston gone etc ,when I looked in the petrol tap the rubber gasket with the three holes had disolved into a sticky gum and completly blocked it,also check petrol cap vent , assume you have cleaned jets and set float height etc cheers Quote Link to comment Share on other sites More sharing options...
gazzaecowarrior Posted June 28, 2009 Author Report Share Posted June 28, 2009 Hi there. Thanks for your response. Yep, I am pretty certain the carb is set up right. I have fitted a new carb overhaul kit to it so all is as good as it can get there. The tap is brand new as I have fitted a Sammy miller seat and tank combo unit. I fitted an in line fuel filter too so I can see that fuel is running. The bike was running before I redid the gears / selector arm only this week. I had done a few laps up the street to ckeck the gears were all in sync. I am just suprised how the seals has gone so quickly ? I am struggling to work out what else it could be ? Quote Link to comment Share on other sites More sharing options...
tony283 Posted June 28, 2009 Report Share Posted June 28, 2009 It sounds like a classic "Blocked" Pilot jet! If you have just fitted a new tank etc it is quite likely the pilot jet will be blocked. A good blow through with compressed air. Tony Quote Link to comment Share on other sites More sharing options...
gazzaecowarrior Posted June 28, 2009 Author Report Share Posted June 28, 2009 Right. Thanks for that. I will give that a go. But I would be suprised as there is a fuel fliter in line. I use the same filter on my beta and i have never had any trouble witht the carb. But if it saves me pulling the engine apart again it can only be worth a try !!! Quote Link to comment Share on other sites More sharing options...
dave dix Posted June 28, 2009 Report Share Posted June 28, 2009 I second the pilot jet because if it was a crank seali doubt it would have started Dave Quote Link to comment Share on other sites More sharing options...
gazzaecowarrior Posted June 28, 2009 Author Report Share Posted June 28, 2009 Thanks for everybody's input. Well i shall strip the carb down and have a look. I have ordered a new reed block gasket so will have to wait for that till I fire it up. Would a blocked jetcause it to run so hot though ? I must confess I have forgottten how hot the cyclinders get on air cooled bikes having owned modern bikes for so long. It did seem rather hot considering it had been running so long. Also if the crank seals have gone. What are the symptoms ? Gaz Quote Link to comment Share on other sites More sharing options...
tony283 Posted June 28, 2009 Report Share Posted June 28, 2009 As I said a very common problem especially with current fuels so check that pilot jet, when cleaned you can see through it save for the "S" inside the jet. Yams will run quite happily on full choke, and indeed it was the practice to drop the choke on the long road sections of the SSDT and ride through the burbles until you got to high speed. When you fit the new inlet gasket do NOT use any sealant! or you will have BIG BIG trouble!!! Remember the 2T motor relies on crankcase compression and if the seals were gone you won't have very much making it very hard to start. While waiting for the new gasket you can run it, even if the old one is split or broken and it should run fine. Tony Quote Link to comment Share on other sites More sharing options...
gazzaecowarrior Posted June 28, 2009 Author Report Share Posted June 28, 2009 Thanks Tony. just stripped the carb down and I think you could definately be onto something. The inline fuel filter seemed full of some white stuff and inside the float bowl seemed rather sticky. I have a horrible feeling that this is some sort of fibreglass residue from a new tank. Perhaps I hadnt flushed it through as much as I should have. The jets didn't seem too bad but I have blown them all through as a matter of course and reset the float hieght. Im going to empty the tank in case it is contaminated and put some fresh fuel in and see how it goes. I will sadly have to wait for a gasket as it is damaged beyond repair when I took it out. I will keep you posted as to my success. Quote Link to comment Share on other sites More sharing options...
jon v8 Posted June 28, 2009 Report Share Posted June 28, 2009 I have recently had exactly the same problem with a Miller tank,blocking the carb and causing wierd running issues.I took the tank off,flushed it then dried it thoroughly.Back together with a new filter and its fine.Thing is the tank has done at least 3 years work so I reckon its taken all that time of washing to loosen off the little bits of flashing on the inner seams. Quote Link to comment Share on other sites More sharing options...
skippy1234 Posted July 1, 2009 Report Share Posted July 1, 2009 hi ihad the same problem if you look at my posting i replaced all gaskets etc and it was a tiny jet in the carb blocked its as sweet as anything now Quote Link to comment Share on other sites More sharing options...
gazzaecowarrior Posted July 1, 2009 Author Report Share Posted July 1, 2009 Hi Guys Good news. Bike started first kick. Runs sweet as a nut again. It must have been the carb. Thank god I don't have to do those crank seals as I was dreading that job. Thanks for all your advice. Until the next time !!!!!!! Gareth Quote Link to comment Share on other sites More sharing options...
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