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96' Mach Z

593 Views 1 Reply 2 Participants Last post by  Free Air
I was out riding this weekend. I took my Mach z out on the lake and opend it up..a couple of questions..
1. There was about 1 and half foot of snow and it seems that my machine was topping out at 80-90km.!!! Thats pretty this normal for these conditions?
2. When getting to this speed my thumb throttle was just a little over 3/4 before being full. I found as soon as I pinned it all the way it would make the engine "bogg" down, also there were a few back fires at these speeds...
Could this mean its missfiring??
Also the person I bought the sled from said he put a "boost bottle"?? He said it keeps the gas distribution in the carbureators even so you dont have to fiddle with the jetting??
When driving it from a start the power band is there, when it hooks up it will pick the front end up 3 feet in the air and take off like a rocket...but it seems at the higher speeds is where it starts acting up?
Any suggestions??
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Sounds like you are running lean on the top end. Check your spark plugs. Do a "clean cut". Rap it out for about 30 seconds, top speed, then hit the kill switch. Check the color of the plugs. If they are white, you are dangerously lean. Boost bottles are a poor mans supercharger, they have little to do with jetting. They must be carefully designed for the engine in order to work right. Kind of like an expansion chamber exhaust, but it's on the intake..

If you are lean, WHY are you lean?

Main-jet to small, install larger main-jet.
Main-jet plugged up with gum, clean carb.
Carb running low on fuel, filter clogged, pump faulty..
Carb loose or rubber mount cracked open allowing air leak into engine..
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