thats the hydrogen 643 2 stroke or better yet a 1286 OP 2 stroke:mart.cummins.com/imagelibrary/data/assetfiles/0058689.pdf

mart.cummins.com/imagelibrary/data/assetfiles/0058689.pdf, brapp its time to make an 1286 OP 2 stroke!

Hmm think it is a 77 tho. Looks like a cleated track, but no rear sway bar, which only the 77 had. 78 up had a Yokohama rubber track. Also 77 had short aluminum skis & pencil ski shocks. This one doesn't have a full wrap around front bumper which is correct for 77. Had a pin clipped hood hinges. 76& 77 hoods weren't drilled for windshields. They came with headlines & taillights, but this one doesn't even have the headline hole cut out and the red stripe on the seat, that I hadn't seen before.

A sr 643 beats viper 700 triples and on so I think the Srx has no chance, but the srx are not even close of slow,

@@engine_headpro8127 English 101 is in order.......

@@milojanis4901 im swedish so you know.

The 76 340 SRX would have put you to bed!.

I had 3 GP433's from the early 70's, two were mod sleds, one was a stocker!..from Wyoming USA 🇺🇸 🤠

It probably would. I wouldn't recommend it.

It's a free air needs cold weather and is at its best for the first rip

@@bones6173 if that's the case, then how are the old free air dirt bikes and 2 stroke street bikes able to run all summer? Just gotta tune em.

If your racing they great like a dirtbike just have to keep a good clip u can't get good performance on the trail with stopping and going and yes all free air engines get hot go liquid they last longer happy building motorcycles don't have hoods the do have all the parts under hood bikes don't free air sucks in deep snow because over open hood venting everything gets wet belt slip is a big issue and free air bikes do have overheat issues I could go on forever but just saying freeair is great it's lightweight and has know water pump cc for cc free air has a little more but if not breathing at full speed the liquid cooled will hold its performance u could try efi on a free air

OK the motor I request is early 70s Polaris to late 70s TX 340 or 440 I've rode most free air modles up to 81 eltigre 5000 free air the cats just couldn't take the heat good luck been on 2 strokes since I was 4 sleds to bikes I'm 51 years old

Thats the new hydrogen 643 yamaha 2 stroke

Waylon Thompson Actually, more work was done than a spring,lmao. I pitched the stock clutch and put on a comet 102 with some machine work and tuning... My race motor cylinders were sleeved and drag ported, carbs bored and pipes modified. It would pack the skis as far as you wanted. It’s the one sled of over a dozen old ones I miss. Beside that my 1984 Yamaha RZ will smoke your heavy Ducati,lol

@Waylon Thompson LOL I READ THESE POST ALL THE TIME IT IS ENTERTAINING. BEST THIS WEEK IS THE 107MPH 1978 EXCITER ON BARE ICE CREEK IN WOODS....IT WAS GEARED UP FOR THE SPEED BUT ONLY 46 HP...LOL

Put in the old bravo smaller lighter

I believe I heard somewhere between 110-120 HP which was huge for it's time but they were so light the power to weight ratio was incredible.

I owned a lot of the older SRX machines. the 77 had 96hp my 76 had 102 and my 1980 had the lowest at 86hp. But the 1980 was the quickest off the line and midrange, but the 77 had it by a few miles an hr on the top end..the 76 was just a beast, factory stock oval racer, and ate up the others.

@@brucetaylor7995 there was something wrong with your 77. It should I have ate the other ones up. My Dad was a Yamaha Polaris dealer we had all of the SRXs from 76 thru 80 & 81 front strut suspension. My brother still has the 77. He won a lot of races with it untill the IFS SSRs & RXLs came out. 1977 was a very limited build dedicated ice oval racer. We felt lucky to get one as some dealers didn't. I have it on good authority that Polaris dynoed a 77 right out of the crate at 107 hp!

The 77 was a pure race sled. They were built to be light and very fast.

Yeah I see that

Tdavid G skip to 1:25 for the launch. What I meant RC was not much had to be done to them. They came this way. Just studs and get the clutches dialed for the holeshot. They came with over 100HP and factory twin race pipes. Not sure of the actual build numbers on these, maybe 500 or so to comply with whatever the build number rules were back then.

I had a 78, it was fast and a low center of gravity wide stanch road burner