TZR50 2003

[yammy76]

Hello all,

I would like to ask for your infinate knowledge, I have Been doing up a TZR 50 2003 model, I have done everything bar touch the engine.

it runs well on idle but makes no power at low RPM - anything below 9000 and it is so slugish. 9000 to the 12000 redline it is not a problem pulls like mad...(for a 50cc). Any suggestions would be grateful, as I would like some pointers before I get stuck in.

The engine is the AM6 type.

Thank you in advance

Steve

[drewpy]

might be that the pilot system in the carb has gunged up and the carb needs a good clean

[XJ6-boy]

have you checked the compression of the engine, the am6 uses rubber rings for the head gasket and will blow out very easily also the am6 is realy bad for pitting on the conrod small end eye so when you stip it down have a good look as these pits will eat away at the small end untill it fails then the needle barings will seize up your motor as they spray out.

[yammy76]

Hello, been away for a few days. It has had a rebore and piston has been replaced as it was previously blown (hole in the top) head gaskets renewed inner and outer. Had the carb off and cleaned all jets, needle and float also checked the reed valves. I noticed the main jet is size #100, is this too big? (A online service manual states #88) This TZR50 has a Arrow exhaust and a standard air filter.

Rare sprocket is two teeth smaller than standard, front as standard. 45/12

Thanks

Steve

[Airhead]

be wary of downsizing the jet, ask yourself this...why did it burn a hole in the last piston?

do plug chops to fine tune your carb jets, starting with the main jet #100 at wide open throttle

[yammy76]

I have read on here some chap had a #110 main jet and changed the gearing a little, so I will try this.And do tell please what are "plug chops" as I have no idea!

Thanks

[yamahatzr50declan]

i also have a similar problem and i think that it is because my timing doesn't retard as the revs go up. this suggests that maybe the cdi is broken?

Thanks