Hello hope someone can help,

My sr125 is having trouble re-starting when it's hot, it starts fine when cold and rides around fine but if I stop and turn it off it wont start again unless I mess about with the idle speed knob or if I leave it for 5 or 10 minutes. The spark plug looks ok it's not wet it's brown and I also checked the air filter and found that there wasn't one! I put one in but i'm still having the same problem. Any ideas what could be causing this problem.

Nice forum btw

Could it be that the carb is warm and that fuel is evaporating before it gets chance to get into the cyclinder? I had a similar problem on my 50 cc machine back when God was a boy.

Don't spose you can remember how to fix it?

Have you checked the plug gap is correct? I mean with a feeler gauge, not just that it looks ok.

Yep - sold the bike and bought an X5 200

Im not sure if this helps but when it's hot and I switch it off then can't start it again I can bump start it and it starts right away! does this mean there could be a problem with the ignition when it's hot?

My little stroker behaved that way when the plug was worn or dirty.

Hello thanks for the reply, I've changed the plug and have the correct gap (checked with a feeler guage) I've also put a new ignition coil and HT lead on as well as a new battery but still when it's hot it wont start. If I leave it for 15 minutes it starts again

Just an update for future reference. I bit the bullet in the end and took it to the garage. The mechanic did a compression test on it and found it to be low he said it could be the piston rings (£150) or worst case cylinder rebore (£250). I said to him I wouldn't mind having a go at doing the piston rings myself and he said fairplay and told me to bring the cylinder head etc and barrel back in for him to have a shufty. I did and it turned out that the rings and bore were in good nick I also told him that as I was taking it to bits I noticed the timing mark on the cam chain sprocket wasn't quite lined up as it says in the manual he says that could be a factor. He also turned the cylinder head upside down and with the plug refitted filled the recess where the valves are with WD40 to check for leaks it turns out the exhaust valve was leaking! So he suggested it be reground and seated correctly which he then had done. I collect the bits the next day and fitted it back together on Saturday afternoon and would you believe it? it's now running sweet as a nut I even got 65 out of it this morning lol but most importantly it starts on the button hot or cold I'm feeling well chuffed with myself. It cost me £36 for the regrind, he charged me half an hour labour for taking the valves in and out and I had a top end gasket set @ £15 and not only that the bloke was really helpful too he certainly spent more than half an hour messing around with my bike.

That mechanic is worth his weight in gold!

Make sure you go there when you need parts or oil or tyres if they do them, cos blokes like him deserve your support!

Yeah deffo I rang him up to tell him it worked and he was well chuffed and genuinly pleased that i'd actually phoned back to tell him it worked, I told him I would certainly use him again.

Well done
Sounds like your mechanic appreciates your efforts as much as you do his, great teamwork