Me again, so I got the head reinstalled (thanks for the torque and lash settings Williebee). It starts good, idles good... great acceleration from stop to 1/2 throttle, then it bogs bad.... I can nurse it up to 3/4 throttle but nothing but bog after that along with a small intermittent backfire through the exhaust. The main needle is at 1/2 on the adjustment slots (and there are 2 small plastic washers there.) Too rich? I didn't want to move to the top setting and take out the washers for fear of running to lean and over heating it. Any ideas?

 

That sounds too rich to me. Especially the backfire bit.

 

Ok, I leaned it up to the top but same results. Could I be off a tooth on the valve timing? It revs great with no load.

 

If it is carbureted I would check the fast jet in the carb to see if it is clogged, that is an easy fix and thats where I would start. That certainly would explain the symtoms you are having....

Regards,

Max

 

Even though I had cleaned the carb a few days ago before the head gasket replacement, I will do that again tomorrow to make sure that ain't it... Thanks for the suggestion!

 

Maybe you'll find the problem, keep us posted I'd be interested to hear what you find...

Max,

 

It's not the cam timing, I swapped the carb from my other ATV and was able to run wide open.
Not sure if it's the original carb though. After the swap and first few runs, I noticed that the fuel pump wasn't making any noise and then it started to not run. When I took the fuel pump off there was gas in the upper end of it. What I'm thinkin is there is a leak in the pump diaphram and gas is getting to the top and then the pump fails to pump. It also leaks from the top so a new pump is in order anyway .
I checked some online parts places and the want 140$ for a replacement, Ouch. I checked at Advance Auto and they have an aftermarket pump from Mr Gasket that runs 44$, and puts out 2-3.5 lbs pressure. There is also a Mikuni Pulse Fuel Pump that works off of crank case vacum for 20$. I could hook it to the existing crank case vent? Any thoughts? Is there a place I can get a re-build kit for the original pump? I only paid 650 for the pair of ATV's and need to get another battery and a muffler/spark arester still....anyone know where I can get a muffler/spark cheap?