[YR5 running problem]

4 hours ago, Snakebite68 said:

My first thought would be heat ceasing...

Does it actually turn over?

If not, check to see whether it starts as soon as it has gone cold (rather than overnight).

Not seized as I can kick it over easily but it refuses to start. The carbs are mikuni vm28sc with the floats separate from the float valve plate thing. Do I measure the height from the plate as I can't see any other way of doing it?

 

[YR5 running problem]

Hi guys new to the forum with a very stubborn YR5. I've totally rebuilt the motor after buying the bike as a non runner. Rebore pistons crank all the ignition and charging system a new Motobatt battery plus the carbs ultrasonic cleaned and checked. The problem is when I go out for a run the bike starts and ticks over fine but two miles of so into the run the bike either packs in altogether or drops onto one cylinder first and then stops and won't restart. Checking straight away the bike has a good spark on both sides and the plugs are wet but won't start? I push the bike home and it still won't start but if I leave it overnight it starts and runs perfect until I go for a run and the whole saga starts again. Oh plus even running with the filler cap removed makes no difference.

Any suggestions welcome before I give it a Viking funeral 

[Newbie saying hello]

Hi I'm Paul and I live in Warrington in the NW of the U.K. 

I've a few bikes including a YR5 Yamaha that's driving me nuts. Looking forward to joining in the fun and hopefully getting some help with the YR5.