fueling issue / hesitation above 4k

[spudboy6]

I changed my thermostat today and I took the tank off and did a compression test whilst there ,

Now went for a test ride and I have hesitation and sounds like a miss fire above 4k all the way through the revs

I re-stripped the bike checked my work (plugs leads fuel pipe air filter ect ) and can't see any issues bike is completely standard l9

The fuel tap is on and choke is off so I'm confused !

i then noticed my fuel pump wasnt working , removed the pump put 12v accross it and no pump ! , took it apart cleaned the contacts and now its running fine with 12v , fuel filter cleaned out aswell

re-fitted and i think its working but cant really tell not sure how to futhur diagnose it ?

the only other issue i have is the starter button is really stiff need to press it hard to get the bike to start so is this related ?

bike runs fine up to about 4/5K and it just stutters but if you wind the power on smoothly it will carry on just when you give it some it doesnt like it and it struggls to gain speed .


really need some help with this now as i need the bike running as its getting on my nerves !

[ross46]

all spark plugs torqued, no air leaks, were the carbs taken apart? start from the beginning and work through methodically, its the only way to do it, ross

[spudboy6]

I re-stripped the bike and was rebuilding it and was refitting a spark plug and it snapped in the head , got the thread out with the easy out so all along I had a fractured spark plug (Y)

[ross46]

been there, done that had it fractured so that you could see the full length of ceramic and the thread had broken up to where the washer on the spark plug is? your lucky it broke the spark plug rather than stripping the head!

[spudboy6]

Yea that's exactly what happened ! I could see all the ceramic and the threaded part of the plug was in the head , luckily I wound it out with an easy out

There is a god !

[ross46]

i couldnt do it that way, had to take the head off, this was on a single cylinder 2 stroke though, not as difficult, teaches you a lesson though!