XR75 wont start

[Vince H]

cheers alex that has cleared up a few things i guess it could be the valve guide then maybe?? or the actual piston and ring will check them next

[BultacoMacca]

To do a proper diagnosis you should probably do a compression test, and a leakdown test, on the engine before ripping it apart and spending money.
Most little bikes will push start and run on pretty low compression, but not keep running if you let the revs drop.
Someone more familiar can tell you what compression is usual for that motor, but I'd guess anything over 90psi might work ok.
If you've got spark and enough compression, then push starting the bike with a capful of fuel directly down the sparkplug hole can tell you a bit about if it could run.

[Vince H]

well ended up being a bent valve fixed that problem now my spark plug has died can someone tell me what plug i need as the one stated in the manual which is NGK C7HS i cant seem to get and the one that my local Honda shop told me to use a C7HSA is too small (just falls in the plug hole)  :'(

[matcho mick]

maybe "po" tapped the spark plug out to next size up? D series??,take the old plug to the shop??  too easy ,

[Vince H]

hey guys got the xr to start but it wont idle and doesn't seem to rev all the way out any suggestions seems to me like its getting to much fuel cause if i turn off fuel it will pick up in revs right before it runs out of fuel any other thoughts would be helpful tho as its sending me insane trying to get it to run :'(

[tony27]

Float valve would be a good place start

[80-85 husky]

make sure there is a main jet in there as well!

[shelpi]

Float valve would be a good place start

Yep, mine sticks every 2nd time its been standing around for a while and not poop in the bowl either  oh and the points timeing is the other thing that likes to have a tickle from time to time with a nice cleaning of the contacts

[TT5 Matt]

those carbs on xr200's down to the xr75's normally suffer needle/needle jet wear and come good with those parts being replaced