VintageVmax.com

The weather hasn't been too helpful here in Southwestern PA lately, but I still took the '83 Vmax around the yard a few times in the inch of snow that is here.

A bit of background. Last year my thermostat stuck ( I think ) and seized up the motor. I rebuilt it but had to put in sleeves as I couldn't get cylinders that I could afford. Wiseco pistons were installed and everything buttoned up.

First thing I notice is that the sled sounds louder. Not exhaust, just an overall more noticeable loudness of the engine. Any idea WHY???

I removed the thermostat so water is flowing all the time. Low range power seems good, mid range seems good, wide open... well, it almost sounds like it is missing. It doesn't rev up as fast as it used to and my yard is so small that I can only stay in the throttle for about 200 feet. I have the needle set on position #4 and my jetting is all stock for the '83 with #330 main jets.

Bear in mind that the sled had excellent top end power before the rebuild and thermostat removal. No carb changes were made.

Thoughts???

Thanks

Donnie

Hi Donnie, First off the Wiseco's if fitted properly will be looser in the bore when cold and the steel sleeve is going to have a somewhat different sound when running than a chrome bore aluminum one will. That may be all it is and nothing to worry about.

It will be had to tell what you have untill you get it broken in some so don't be to worried if you think it feels different than before. You do have new parts in there and they are different than the originals so it might never be exactly the same.

Just keep a close eye on your plugs and remember to let those Wiseco's warm up good befor you start hammering on it. They will be more prone to cold siezure than oem and watch for anti freeze getting into your cylinders. Some of the sleeved engines I have seen have a deeper groove for the cylinder to head O-ring and the stock Yamaha one isn't thick enought to compensate for it and they can leak. I would have to measure again to be sure but I think the stock O-ring is about .060 and the stock groove on a chrome bore cylinder is about .030 which give you an approximate .030 squish on the O-ring. I have seen sleeved engines with a .050+ groove for the O-ring and that just isn't enough squish to keep them sealed. I had bought a batch of .090 O-ring to keep on hand just in case I run into that problem again and still have some left so if anyone needs some let me know.

Good Luck, Phil (opsled)

I have 20 over Wiseco pistons and cast sleeves, i always warm it up for 3 to 5 min before driving it and then take it easy for the first mile or so and my last sled lasted until 15,000 kilmeters ar 10, 11,000 miles before it died and i rode that sled hard . You dont want Cold Seizure.