Need some advice on what path I should take with my QT50

John Marcus /

Jul 09, 2021 07:06PM

I got my hands on a 1985 QT50. It was garage kept at a ranch for its entire life and last ran in 2010.

The fuel tank will need to be cleaned, hoses replaced, new break pads, and new tires.

I am not looking to "hop it up" but would like it to be reliable and do 28-32 mph consistently. I have read that the stock jet would lead to some "four stroking" and its a good idea to swap it out with another.

What I need some advice on is it worth rebuilding the stock carburetor and rejecting or should I just buy a aftermarket carburetor that is new and ready to go?

What jet size works well with a stock muffler?

Re: Need some advice on what path I should take with my QT50

Bob Naske /

bobqt50

Jul 10, 2021 05:19AM

Here's what's worked for me. original carbs can be easily rebuilt just need to take ALL the jets out- there's one underneath the main jet and the little tiny pilot jet next to the main jet. They sometimes get seized in. Then it would be time to get a new clone carb. I've got them in service and they work fine. 70 is stock main jet with stock muffler. Some of the four stroking is due to restrictive stock air cleaner. A cone shaped aftermarket $12 metal mesh air cleaner helps eliminate a lot of the 4 stroking and gets you slightly better top speed. Only downside is they are noisy compared to stock air cleaner box and if you have side covers there's no way to attach them to a cone air cleaner. Some will say drill some 3/8" holes in stock air cleaner box but it's never worked for me. The cone air cleaner will require different carb adjustment as you're getting more air in so mixture screw usually ends up another full turn out than original setting. You'll probably never eliminate ALL of the 4 stroking as the oil injection pump is factory set to give lots of oil at full throttle- to help in NOT seizing the engine. And lastly put a cheap little 3/16" fuel filter in the fuel line before the carb.