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Mikuni Carb spitting out excessive fuel?

Posted: Fri Oct 28, 2011 8:55 pm
by jimmo
Posted on behalf of a mate.
His TS1 is spitting out excessive amounts of fuel from the Mikuni carb and when ridden it seems like its choke is stuck on?.

We have had the carb apart and checked for the obvious blocked/lose jets/floats etc and all is ok.
When the scooter is in neutral it does rev but not as it was before, and when you put any load on the motor it gets bogged down and wont pull(seems like its being flooded with fuel).

I have managed to borrow a new TMX carb which I will try tomorrow to see if this helps out, but i cant see what the cause could be?. The reeds look ok as far as i can see/feel and the compression feels good.

The carb is at least 10 years old so could this be the offending item?

We have checked stator readings and spot on, have tried with a new cdi unit and spark plug but still no joy.

Advice needed as we both are going to get the biggest hammer we can find and beat the motor to death!!

Re: Mikuni Carb spitting out excessive fuel?

Posted: Fri Oct 28, 2011 9:00 pm
by wack 63
Most likely to be worn needle and atomiser and slide if the carb is old.

Re: Mikuni Carb spitting out excessive fuel?

Posted: Sat Oct 29, 2011 4:39 pm
by Chris CSPE
You could also check to see that the reeds aren't damaged or broken, has this problem just started?

Re: Mikuni Carb spitting out excessive fuel?

Posted: Sat Oct 29, 2011 5:14 pm
by dapper
Mate had a similar problem in France and it was reeds loose. If it is that, put some loctite on the tiny screws that hold the reeds in

Re: Mikuni Carb spitting out excessive fuel?

Posted: Sat Oct 29, 2011 7:21 pm
by Craig H
My imola did the same and it turned out to be my reeds had a crack in it. When you stop the engine does smoke come out carb if so most likely your reeds imo.

Re: Mikuni Carb spitting out excessive fuel?

Posted: Mon Oct 31, 2011 9:51 pm
by jimmo
Chris CSPE wrote:You could also check to see that the reeds aren't damaged or broken, has this problem just started?
Spot on mate!! We put on a new TMX Mikuni,stator,plug etc but still would run properly.

I said it must be the reeds - and low and behold when we removed the reed block we discovered that one of the main boysen reeds had gone for a trip up the transfer ports!
Barrel and piston all ok,just waiting for new reeds from MBD - Happy Days indeed!

:fb: :fb: :fb:

Re: Mikuni Carb spitting out excessive fuel?

Posted: Tue Nov 01, 2011 12:28 pm
by dapper
Don't forget to Loctite the screws ;)