mech. help

[Guest]

hey guys looked at that 78 -11 today cleanist bike i have seen. my buddy who was the original owner pulled the carbs for him and cleaned & sinc them this fall bike fires right up idle's great went down the road great but soon as it warmed up after a mile or so it starts breaking up just like before carb cleaning what do you think ? its buried in the back of his heated pole barn i'll have to dig out the back door in a couple weeks 5' of snow back there and put it in my frozen garage hope the bike doesn't get mad at me thank you

[mro]

gas cap vent plugged
fuel hose kink
Carbs too lean (will get leaner as engine heats up)
coil breaking down
pick-up coil wire problem
plus a slew of other unlikely things


mro
BTW,
when were all the electrical connections last cleaned?

[Guest]

elec cleaning

not sure on the elec cleaning probley not by this owner he put 6k on the bike i'll ask my buddy who put 34k on it thanks for the info

[trbig]

The stuff that you cleaned out of the carbs that came from the tank... The tank probably just made another donation.



Tod

[randy]

Carbs too lean (will get leaner as engine heats up)

Actually, if carbs are too lean, problem will get better as engine warms up. Too rich will get worse as engine warms up.

Me thinls the carbs are too rich or cap vent is plugged.

[Guest]

will check

hey randy thanks for the info can't wait to bring the bike home but the snow has to go wishful thinking in the u.p. arlo said it the best!

[egsols]

Ballist resistor going?

[Guest]

will check

ernei thanks sounds like i'll be busy cleaning and testing

[randy]

Ernie,
even if the ballast resistor was blown, it would still run while the starter button is held, so I don't think it's the ballast. But hey, stranger things have happened.

[Guest]

thanks

think spring!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[egsols]

Randy,

I remember reading a post about someone with a resistor that opened when the bike got hot. When the bike cooled again it closed and everything was fine. Is this possible?

[Guest]

will check

i put it on my check list think spring!!!

[randy]

I remember reading a post about someone with a resistor that opened when the bike got hot. When the bike cooled again it closed and everything was fine. Is this possible?

Yes, but if that were the case, it would still run with the starter button pressed.

[DiverRay]

I vote pickup coil wire. As I've had two '78's, and DID tell Yamaha about the problem IN 1978, I know how and why it happens. As the coils and wires are getting older, If you can afford it, try to get a set of new coils, and be sure to set the gap properly.

[Guest]

coil wire

hi ray thanks for responding haven't picked up my bike yet do to the snow but i will check the wire did find a set of oem coils at a dealer who is not liked very much in this area he wants $ 159.00 for them what do you think? i should be able to bring the bike home in 1-2 weeks still alota snow here in the u.p. i will start with the fuel system,then elec. conections,then coils etc.
thank you dick