Hi,

I've rebuilt my carburator and have some confusion over the vacuum line. On the left side of carb I've got two inlet fittings. The lower one sends fuel to the bowl & the top one is the breather house. Now on the right side on the forward portion of the carb there is another smaller inlet valve that is a brass nipple. I believe this is the vacuum line?

Does this line run up to the petcock, connecting to the right-hand side? Both the brass inlet fitting & right side of the petcock are slightly smaller dimensions than all the other hose lines.

The person who owned it before has the line off the brass fitting run up to another fitting directly behind the radiator fan, and the fitting on right side of the petcock he's blocked it off. I'm guessing because of design flaws in the original setup.

However, top speeds should be about 50mph and I can't get above 20 on flat ground. Checked valve clearances & the belts in great shape & doesn't seem to slip. I've cleaned the rollers really well... So I'm guessing the issue is the carb setup?

I'm new to this.... Still learning... Any help is appreciated.

You can email me at olson.a.087@gmail.com

 

I am confident that your LT-A500F VInson has a similar carb and petcock to the recent LT-A500F Quadmasters I had here.

You have a vacuum petcock, which may have a faulty diaphragm. The hose to it connects from the fitting on the forward right side of the carb. There are 2 air vent hoses that connect further aft on the carb.

This was for the Mikuni carb. KeiHin carbs were also used, so the connection may be different.