OK guys, been scratching my head for a few days on this one and I think I have the answer. But here is the problem. At Idle and you give it a little gas it bogs and will die, sounds like it is running on one cylinder, once you feather the throttle and get it above 3000 RPM it seems to run fine and will stay running on top forever, then let it idle back down and it is like running on one cylinder.

Went through the carbs, they are in great shape, stock jetting 55 Pilots, with DPM. Clutches are in good shape. 150 pounds compresion on both cylinders, all seals and gaskets are fine, no leaks.

So what is the problem?

Check the plugs, again.

I did not read that you checked and/or changed them.

BTW. Nice machine. Those H.O's were a freak thing. Pretty much fastest machine ever made in 99', even against the the big boys.

Originally posted by mtrsprt@Feb 12 2004, 04:37 PM
Check the plugs, again.
that's where all the news shows up good and bad.

Try changing the plug wire caps, its common for those to go bad and do freaky things to the '99 670HO.

Thanks Guts,

TT, that is exactly what I figured out, the sled is up north right now, but this weekend that is the first thing that I am going to do.

If all was good before this started. I would clean and sinc my carbs. make sure to clean out the pilots. could be running lean from dirty pilots

Same sled and had a very similar thing happen this past weekend. Turned out the one of the plug caps was off. It was on the plug but not snapped down.

Dam I love that sled though. I got a new REV 600SDI this year and had a friend riding my old 670HO. The freakin thing just flat out rips. We didnt run them side by side but it will crush my REV Im sure.
Thought about selling it and then thought again :p

I bought 1 of those 670ho in december first month had nothing but problems.a doo guy on trail said to unplugg all plugs and clean with dialect cleaner BECAUSE they are spring loaded plugs!!!! did this it worked BUT my problem is similair to yours now but a little different.now when i first start it i cant accelarate over 3000rpm until sled warms up same symptoms as you sounds like running on one cylinder so again went north this past weekend and cabin parking lot full of skidoo guys so i ask again about this issue they said let it warm up and use dry gas ive done this for the past two weekends and it has been absolutely PERFECT now i was a polaris guy for the past 10 so i wasnt sure if i had made a good choice!@!!! after last weekend i can say i absolutely love this machine and #### does it go.hope this helps and keep spanking those bigger sleds :tongue: :rolleyes: