After last months problem with my daughters TZR 50 I now have a new problem!

The bike is bogging down at anything from 1000 to 3500 revs, once above this its OK.

It starts up without the choke but dies after a few Min's and if you apply the choke it dies?

I am guessing there is too much fuel getting in to the cylinder? (plug seems wet)

I have tried to adjust the air screw but to no avail, i have cleaned the air filter.

It has a standard exhaust, air filter and jets.

On a different note I want to change the gearbox oil, but how much does it take, there is no level indicator?

If its running rich and altering the mixture screw makes no difference i would say its flooding and the float hieght needs checking or the float needle valve is sticking.

How do you check the float height?

I have had the carb off before to check and noticed that the needle clips in to the float.

This part of the needle goes in and out of the needle main body but can see no way of adjusting it?

Thanks

Rick

Here is a link to an online manual, its not the needle valve you alter its the tab on the float that sits on the needle valve, and you just bend it slightly to get the desired hieght.

http://www.rcscooter.net/manuales_taller/yamaha_tzr_50.pdf

A haynes manual would be a good purchase as it has a lot more detail. Checking the float hieght is easy to do but difficult(for me anyway) to explain, somebody else may be able to. If you have a haynes for any other bike the procedure is the same just the hieght will differ, you will find the hieght in the online manual.

Hi Dave, thanks for the info, unfortunately there is no haynes manual for this bike but the link you sent is very helpful.

I will be checking the float height.

It also told me the correct oil level for the bike.

Regards

Rick

Hi Dave,

Thanks very much for the info and the link to the manual its been a great help!

Took the carb off and had a tinker with as you suggested and she is running fine now.

Thanks again.

Regards

Rich

or it could be the pilot jet to big