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View Full Version : running hot. Top end rebuild


YFZ#426
08-13-2006, 07:51 PM
what is stock compression on 06 yfz and quad is running hot should i try bigger impeller and any tips for top end rebuild
GPracer2500
08-14-2006, 01:17 AM
2006 YFZ has a 11.4:1 compression ratio piston.

What happened that your 2006 yfz needs a new top end?
atvrulz
08-14-2006, 10:06 AM
You should engine ice coolant. I do and it keeps my engine cooler.
YFZ#426
08-14-2006, 03:17 PM
it is running really hot and is burning radiator fluid really fast i tried everything. right now i have a 160 main jet in and i dont really want to go much richer unless u think i should. and i do run engine ice but that did nothing.
GPracer2500
08-14-2006, 03:25 PM
160 sounds real lean for your typical piped/filtered YFZ.
jshtex
08-14-2006, 05:21 PM
Originally posted by GPracer2500
160 sounds real lean for your typical piped/filtered YFZ.

I agree, and you are way better off running too rich then too lean.

I have a buddy with an 06 that is putting a top end in his as we speak. This bike has already seen 10 or so XC races though. I am not saying that is normal, just posible.

But I bet if you richen yours up some it will run cooler.
YFZ#426
08-14-2006, 06:51 PM
wut size main would you recommend or that is most common for a yfz to run with a pipe and filter
Toadz400
08-14-2006, 08:46 PM
Remember that the '06 jetting is different from the '05's, but 160 does sound lean for your '06 anyway. I would try at least a 165 or a 168. Let us know how it runs after that and it should help cool it down a bit. I always have my 450 jetted a little on the rich side just to be safe and it works wonders for keeping it cool, only had my fan come on twice and that was when I had stock jetting when I first bought it (lean from the factory like usual).
pnut420
08-15-2006, 02:12 PM
Sounds lean to me. Yosh is pretty good about giving you jetting specs, Im sure if you called them they would tell you about where you need to be, like toadz said though I would think you need at least a 165 in there.

Is it getting hot while riding slow or more in the top end? Also the red light should come on if you still have it. Loosing coolant from the overflow tank is normal when you jump alot. When it under pressure and you jump if wants to shoot it through the cap of the overflow tank.

My light came on two times in Sand mountain, but it was 100+ out and I was just sitting there and had my fan removed, other than that nothing.