Trouble idling with reed valve...Any ideas?

[squirrelyc]

I bought the GT8O reed valve, ported cylinder, and Keihin clone carb setup from gasbike and im having trouble getting it to idle. It runs fine but when you let off the throttle it winds up like crazy then settles down and dies...Any thoughts? Thank You.

 

[Frankenstein]

Does your piston have a window in it?

 

[squirrelyc 1]

no it dosent, im looking to get one now. is there any way to tell if i need a type a or b without tearing it down? its a 40mm stroke

 

[squirrelyc]

Does your piston have a window in it?

no but im looking at them now...is there anyway to know if i need a type a or b without tearing it down..its a 40mm stroke

 

[gary55]

no but im looking at them now...is there anyway to know if i need a type a or b without tearing it down..its a 40mm stroke

The gt 80's I have seen use a type B piston. Be careful when ordering as some suppliers on the web have them named backwards. Look for the one that has the high pin.
They also have a boost port at the intake. With the reed and the Keihin carb you will probably need to go to a larger jet. Zeda sales the windowed piston if you want one and don't want to make it yourself. You will need the one described as a high pin. I don't know if a windowed piston helps with the boost port cyl. you have. I've never tried it. If you are going to try it or any other changes ie. expansion chamber etc. you should do them prior to jetting as they may change the engines requirements.

 

[squirrelyc]

The gt 80's I have seen use a type B piston. Be careful when ordering as some suppliers on the web have them named backwards. Look for the one that has the high pin.
They also have a boost port at the intake. With the reed and the Keihin carb you will probably need to go to a larger jet. Zeda sales the windowed piston if you want one and don't want to make it yourself. You will need the one described as a high pin. I don't know if a windowed piston helps with the boost port cyl. you have. I've never tried it. If you are going to try it or any other changes ie. expansion chamber etc. you should do them prior to jetting as they may change the engines requirements.

perfect, thank you

 

[Skullworks]

I have a gt80 with over 2000 miles on it.my bike has had the same problem twice.both times it was a vacum leak.check that your reed intake is tight as well as the hose to carb is tight.its a air leak!

 

[gary55]

Skullworks has a good point too. Their's a lot of gaskets on these intakes as well as the hose connections. Plenty of opportunity for leaks.