Yamaha Jog RR 50cc No bottom end power?

[dan5887]

Hi my names dan and i'm new to this Forum and to mopeds so any help would be really appriciated, i recently bought a jog rr 2007, but it seems to have no bottom end power at all, I knew the previous owner so I know abit about whats been done to it. It was derestriced from new and rode with a standard exhaust, Then a technigas exhaust was fitted. I'm not sure if the fault started when the exhaust was changed but i do now that when the exhaust was changed it did not have a bigger main jet or new rollers fitted at the same time. When the bikes going along a flat road it struggels to get to about 30mph but then picks up to about 45 really fast??? Ive cleaned out the carb, replaced the spark plug and cap and cleaned the air filter but still the same. Do i need to replace the main jet for a bigger 1 as the exhaust was changed? Also what weight rollers are required or where can i find out. Any help would be really appreciated cheers

[snowdude2004]

Usually when you change an air filter/ exhaust etc you will need to upjet it. When you've ridden it for a while take out the spark plug and check the colour of it and post a picture of it on here, that will tell you whether or not it needs upjetting.

I personally don't know a great deal about rollers however my friend has been playing around with sizes and the different weights do make a significant difference!
____________________
CBT passed: 26/09/09, Theory Passed: 18/08/10, Mod 1 passed: 20/10/10, Mod 2 passed: 26/10/10.
Current Bike: Honda CBR 400 Nc23

[dan5887]

Thanks for the reply, ok i will take a photo of the spark plug after a few miles. I removed the main jet and its a size 62, i'm guessing you would just take the jet size up in 5 untill it would run better? what sort of colour will the spark plug be if the engine is running to lean? Again many thanks for the reply

[N cee thirty]