79 srx 440

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VinYammy

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I have a 79 srx 440. Will a polaris primary clutch fit the taper? would it have to be from a twin or a triple, my comet is scrape. Also has any one tried Kiehin 40mm PWK carbs? I have a pair from a polaris XC700 cable and all. My srx cables are shot. I have a shed full of Yammies and this is my first srx. I'd really like to get It tweaked for ice racing this year. if any of this has worked please let me know some clutching and jetting!!!!!!!!!!
 
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I STILL OWN THE 79 SRX I BOUGHT NEW. I DRAG RACED IT FOR YEARS. I CAN,T TELL ANYTHING ABOUT WHAT YOU WANT TO DO HERE BECAUSE I NEVER DID IT TO MINE. WHAT I CAN TELL YOU IS I HAD BEST RESULTS WITH THE 102 c COMET. AS FARR AS CARBS, A SET OF STANDARD ROUND SLIDE 39.5 CARBS WORKED BEST FOR ME. GUESS I CAN,T HELP YA. !! 3:16 (yammie tony)
 
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I have a friend who runs the P-85 on his 76, 77 and 78 SRX's with very good luck. You will run into a couple of issues. One is belt width the P-85's are set up to run a 1 3/8" belt and your stock SRX belt is 1 1/4" so if you are running the stock Yamaha secondary you will need to shim is open 1/8 in to get the belt to work. The other problem is that the P-85 is an overdrive clutch (larger diameter) as compared to your stock one or a 102 Comet. When you combine the wider belt with the large diameter primary you will find that the stock secondary can't open far enough to let the belt bottom in it which will cause the belt to streatch and burn when it is about 1/2" from reaching the top in the primary. It will destroy your top end HP and you will end up overreving in 1000ft radar runs. That problem can be solved by milling about 3/16" of material off the snap ring side of your secondary helix. We checked it buy removing both primary and secondary springs and the spark plugs. We then maually rotated the engine with a belt on to make sure the belt could make it to the top of the primary without streatching. We found 3/16" to be the number but you should check yours just to make sure. He runs the almond/gold Polaris spring and 41 gram trail weights with some notching for engagement. The 41 gram race weight seems to shift to quickly and will pull the rpms down to far on the engine but all his stuff is set to run at 9500 to 10,000 so you would have to play with it depending on your engine. You can also buy a jackshaft for your SRX that will allow you to run the matching Polaris secondary and eliminate alot of these problems.

Good Luck, Phil (opsled)
 
Thank you guys for post'n replies. I have alot of learning to do with this project. My two boys and I took everything apart this last weekend and started cleaning it. This sled sat for a number of years under a pine tree. Yuk, But it's cleaning up quiet will. As I posted previously I was thinking of bigger carbs and newer clutch. The Comet 102C that it has, the towers are gouged, broken buttons and wore cams. So I just looked in my pile of parts and wondered about a polaris clutch. The 30mm x1:10 taper is pretty common and i could probably find a direct match, but wanted to know any advantages with a p-85 for oval racing.
Also the Carbs, I bought a pair of 40mm Kiehin PWK's at a swap meet and wondered if they would do any good. They came from an XC700, so they can move some air, But I don't know were to start with the jetting. Can I run without filters?
I guess in the end I want an oval racer just like the other SRX kids!!!
Keep post'n and I'll keep wrench'n!!
 
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There is so much you could do. What do you want to accomplish? Full mod oval sled?
 
Yes, there is alot I can do to this sled. I mostly want an improved stock sled for oval. I would like to get these 40mm Kiehins on the intake and jetted...
Next, some fresh pistons and clean ports if need be. I want to do all the fabricating in my garage. I don't want costly outsourcing for engine work.
Then, get clutching figured out . Do i run p-85 or Comet 102C??
Finally,put some stinger pipes on for entertainment. Do the stock pipes have divergent cones in the can on the end, or are they open. Or just get some Aaen Pipes????
All in all, get it out on the pond and test & tune chassis set-up.

So guys, just throw some specs that have been tried and i'll digest it.
Clutching..Jetting...Piping...Studding...RPM target... all that good stuff!!!

This is going to be my winter racer!
I flattrack race a 78' XS650 bike in the summer time.
 
AAEN MADE GREAT SRX PIPES BUT YA NEED FULL MOD PORTING AND PROBLEY .44 CARBS. THEY ALSO RAN AT 10,200 SO YOU WILL NEED ALITTLE MORE THAN JUST A CLEAN-UP. I THINK ITS WASTE TO RUN ANYTHING BUT A 102 c. BUT THATS JUST MY OPINION. 3:16 (yammie tony)
 
I just sold some 42 taper bored mikuni's. I didn;t ever think a port motor would flow them. they were from a ski doo 617 with rotary case. So now I have these 40mm K's
 
The polaris p-85 i am concerned with the rotational mass, but would the over drive benefit the straight aways???
 
THOSE .42 WOULD WORK, BUT .44 BEST. ANYBODY THAT RACED A 440 SRX CAN TELL YA THEIR CRANKSHAFTS WERE NOT THEIR STRONG SUITE. EXACTLY ON THE HUGE MASS ON THAT SHORT PTO STUB. BE CAREFUL. 3:16 (yammie tony)
 
YAMMIEGOD3:16 said:
AAEN MADE GREAT SRX PIPES BUT YA NEED FULL MOD PORTING AND PROBLEY .44 CARBS. THEY ALSO RAN AT 10,200 SO YOU WILL NEED ALITTLE MORE THAN JUST A CLEAN-UP. I THINK ITS WASTE TO RUN ANYTHING BUT A 102 c. BUT THATS JUST MY OPINION. 3:16 (yammie tony)
Click to expand...

I put a comet on my 83 540 V-max and am willing to accept that it may have offered a wee bit better performance than the stock clutch, (Difficult to say as there was 7000 kls on the stock one when the spider grenaded) but I had to rebuild the thing every few hundred k's. The fiber bushings in the weights were done in a little over a hundrd miles, I found it very poorly made. Anybody else experience this? I find it odd that they are so highly recommended and I'm watching and listening closely as I too have 79 SRX that I want to give basically the same treatment. G.
 
would one use a p-85 from a twin or a triple. the twins have the boss on the back and the triples don't.
 
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