Pit Bike Club

dorey1989 · 06-12-2009, 06:48 PM

Hi guys. Went out for a spin on my bike today (thumpstar 125 ripper) when changing and going along in 3rd the bike seems to lack in power then kick in again about 2 seconds after as if the chain isn't attached to the sprocket and then it suddenly is again. It doesn't always do it, it's 50/50 and it'll do it 2, 3 times until i chainge into 4th. I know these bikes get a problem with the gear box, is this the first symptom? I hope not as i hardly ridden the thing! Cheers, Rob

gaz56 · 06-12-2009, 07:14 PM

Alright mate, is it the clutch slipping? Like does the bike rev and the clutch 'catch on' every so often.

Or do the revs die and stutter.

dorey1989 · 06-12-2009, 07:23 PM

the revs die aswell. bike just goes dead then kicks back in, don't think its the clutch. It's been fine in all other gears so far it's just 3rd.

dorey1989 · 07-12-2009, 08:54 PM

Any ideas Gaz?

**Despise** · 08-12-2009, 05:16 AM

cleaned the carb?
stator pickup/pulse clean?

ignition coil wire (inside) and cap free from rust?

new spark plug, very cheap.

possible faulty ignition coil,CDI or stator component

dorey1989 · 08-12-2009, 03:48 PM

Thanks for the help. I'll go through your list and see if the problem stops.

gaz56 · 08-12-2009, 04:32 PM

After a bit of research (bored at work

) it seems that this is a very common issue with the 125 thumpster.
Only thing I can think of is a problem with the selector fork, or the gear itself.
Try opening her up and having a look for any worn teeth/bits of metal floating around.

Otherwise it looks like a new clutch, bottom end or worse, whole new engine.

dorey1989 · 08-12-2009, 05:07 PM

Cheers matey. Bit of a pain, I want it to last another 6 months or so until i'm in the right position to by one of those 140cc jobbys