Ideas for a vintage racing sled??

[crwdog]

new to the board. just though you would like to se my 1973 yamaha SR292 vintage racer. Only 113 ever built. 292cc single cylinder that hit 58hp on the dyno. Its fun to race in the 440 stock class and beat up on some of the twins!!!

[91LT250R]

If you live in Vermont and want a free sled check this out. Somebody is giving a way a free 82' yamaha SS440 here.

[AHood]

Originally Posted by Smokin'Gun

Yea I got dual AAEN pipes that i found at a used parts shop, milled the head down raised the compression to 185psi per cyl., had it ported to hell, found some NOS wiseco high comp. pistons and i had a guy cryogenically freeze the pistons and cut ports in them, balanced the crank, lightened the flywheel, put a NOS comet race clutch on it, got bigger mikuni carbs and im probably forgetting something but thats the gist of it. Its going on in a pro-stock oval chassis that im getting from a friend soon. My guess is anywhere from 95-110hp its only a 250cc twin cylinder f/a motor (change of plans) and the motor made 80hp stock. I gotta get the chassis and stuff so hopefully ill be racing next season with it.

i call Bull $hite on this. what 250 twin Free Air ever made 80 hp stock. and "anywhere from 95-110 hp now" so basically your free air cooled 250 twin that was built in 1972 makes more power than todays best 250 GP engines. you just listed every trendy cool sounding thing that you could think of to say that has been done to the engine. cut ports in the pistons? unless it has intake boost port transfers that was a waste. by the way there is no such thing as wiseco high compression pistons. if the dome was actually higher it would hit the head and explode. an NOS race clutch. the only thing that makes a clutch "race" is the tuning parts you put in it" this post is pretty old but i just had to laugh and blow up your spot.

[fast350]

Originally Posted by AHood

i call Bull $hite on this. what 250 twin Free Air ever made 80 hp stock. and "anywhere from 95-110 hp now" so basically your free air cooled 250 twin that was built in 1972 makes more power than todays best 250 GP engines. you just listed every trendy cool sounding thing that you could think of to say that has been done to the engine. cut ports in the pistons? unless it has intake boost port transfers that was a waste. by the way there is no such thing as wiseco high compression pistons. if the dome was actually higher it would hit the head and explode. an NOS race clutch. the only thing that makes a clutch "race" is the tuning parts you put in it" this post is pretty old but i just had to laugh and blow up your spot.

amen....i also call bull shit on that one

[crwdog]

yep, getting pretty deep

[Smokin'Gun]

Well if you want to get techincial with it here goes. Wiseco made pistons back in the 70s for snowmobiles that were designed to stand up to the greater pressures of high compression motors. Therefore they were called Wiseco High compression pistons. The motor that I have came out of a late 70s ski-doo oval sled. If you wanna be a douchebag about it ill dig out one of my ski-doo books and scan the pages sometime. Its not free air, its liquid cooled which was a misprint on my part. Ski doo did make a race clutch for these motors (its differently tuned than the stock one) because alot of people took these motors and put them into their older sleds which were heavier than the aluminum chassis that they were origionally in. I bought it off ebay for almost 400$ in the original package therefore its a NOS racing clutch. There are already ports in the pistons on that motor but with a good porting job these slots on the piston can be opened up more. I never said im going to randomly cut slots in the pistons. Do some research next time.

[fast350]

those hp claims just seem a bit excessive to me

[tecateboy]

yea i think so too, its probility not that much lower, but they do seem high.

[Smokin'Gun]

Well i could be wrong i could be thinking of the 340 that is low 70s hp and the 245 is upper 50s/lower60s and the 454 is low 90s I think thats what it is but im not sure. I am positive that the factory super stock blizzards had 245 motors that did pull low 70s hp but the motor i have is just an oval racing blizzard not a super stock. But the other things where the guys tellin me there is no such thing as a wiseco high comp piston where i have 2 of them in a teal box from the late 70s that say high compression piston on the side. And the thing about the clutch is kinda stupid too when again i have a yellow and black box from ski doo that says "Race clutch assembly" right on the side

[tecateboy]

i dont know, in one of your posts here you were saying that they were held back by shitty ports, carbs and pipes, i think they must have had some pretty good stuff on them to put out that kind of power.