Throttle Junkie35
New member
Hello, Im working an SRV and have some questions on clutching. I have Driven a few different ones in the last few weeks and noticed they are a little sluggish off the line. All of them. Once the rpm's are up they are a hoot. I tightened up the secondary and it helped some but it seems a higher engagement would be a better option or possibly a lighter weight at the base. I have the stock clutch on it now, but I do have a comet 108 exp that was off of an srv that I may look into throw'n on. It has a red spring and m10 weights. I would like to see if anyone else has a good known set up that they have tried. Thanx for the space.
Bob Vehring
New member
I have Notched A1 arms with a red spring in mine, my engine is not stock tho
Throttle Junkie35
New member
The one Im working on has a PSI single on it. But any way, the weights on the 108 I have are toast. Im thinking the notched a1's are what I mite try. Then I believe I'll have to run the 89L belt also.
Did your set up make it more responsive on the low end??
Your name sounds familiar. Did you race a Rupp in the mid 80's??
Did your set up make it more responsive on the low end??
Your name sounds familiar. Did you race a Rupp in the mid 80's??
Bob Vehring
New member
I have twin 39.5 taperbores, alot of porting, Aaen single and more compression Yes it was me with the Rupps back in the early 80s and this same SRV was run in C /Imp back then, it was yellow and blue then, my wife Wendy drove them both.
The A 1's in there now have notches that IMO are a little to big for trail riding, leaves very hard at 5000. Taking it trail riding in a week and will put a different set in which just has a flat ground in to the arms to hopefully make it a bit more polite on the trail
One of the old drag sleds from back then, still have it
One of my kids oval sled, powered by a 600 cc SRV
The A 1's in there now have notches that IMO are a little to big for trail riding, leaves very hard at 5000. Taking it trail riding in a week and will put a different set in which just has a flat ground in to the arms to hopefully make it a bit more polite on the trail
One of the old drag sleds from back then, still have it
One of my kids oval sled, powered by a 600 cc SRV
Throttle Junkie35
New member
I just checked the comet calibration chart. They are calling for standard A1 weights. Maybe I'll try that. 5000 engagement would be alot for a stock motor Im guessing.
Funny, I was a kid getting a flywheel pulled off my old yami enduro at Town and Country Service center and remember a guy working on a Rupp nitro liquid or a Magnum on a trailer outside while I was there. I remember seeing Vehring on it. Maybe Reagan?? I dont remember exactly. I just remember they were Rupp liquids and had blue lettering. Small world.
Funny, I was a kid getting a flywheel pulled off my old yami enduro at Town and Country Service center and remember a guy working on a Rupp nitro liquid or a Magnum on a trailer outside while I was there. I remember seeing Vehring on it. Maybe Reagan?? I dont remember exactly. I just remember they were Rupp liquids and had blue lettering. Small world.
Bob Vehring
New member
Regan was a little kid back then, he's 34 now and races USSA Ovals. Steve sponsored our sleds then and I did alot of work there. I still see Steve once in a while, he has a Harley shop now builds V Rods
Throttle Junkie35
New member
Ya I was a little kid back then too. Im 36. It looks like the 10m polaris weights I have are 49g similar to the a1. So I wonder what the difference in profile would do?
Bob Vehring
New member
Looking over my notes, over the years I have had many combinations, Silver/A1,, Purple/ A3, Pol. red/ 10 MB, White / Pol J1, Silver/A2 Now all this is meaningless because my sled has change alot over the years. Single custom carb, Duals, Single pipe, dual pipes. Really big compression at times, less now. and many gear changes.
All you can do is start testing. Remember if all bushings are not good, and move freely, nothing will work right. I just put a new spring in my ElTigre 6000 tonight and have a new Red for my SRV because they were old, springs loose there pressure over time. Look everything in there over real close, I found a crack just starting on the moveable sheave on my SRV at the beginning of this year
All you can do is start testing. Remember if all bushings are not good, and move freely, nothing will work right. I just put a new spring in my ElTigre 6000 tonight and have a new Red for my SRV because they were old, springs loose there pressure over time. Look everything in there over real close, I found a crack just starting on the moveable sheave on my SRV at the beginning of this year
Throttle Junkie35
New member
Ya, I need all new tuning componets and rollers etc. I figure I'll start with the red/ a1 and see what happens. Im not looking to make it in to a lake racer, just looking to make it more fun out of the hole. Im sure I'll try multipul set ups before Im done with it. Then we will need some snow.
I too had a cracked moveable sheave on my Eltigre EXT this year. I have collected quite a few sheaves and spiders that need to go to the scrap yard soon.
I'll have to keep this thread in mind as its probly the end of the season now and I'll get bored and start tearing in to this thing.
I know RPC made a dual carb kit and have seen vmax540 twin pipes on srv's. How well does that set up work?? Just curious.
I too had a cracked moveable sheave on my Eltigre EXT this year. I have collected quite a few sheaves and spiders that need to go to the scrap yard soon.
I'll have to keep this thread in mind as its probly the end of the season now and I'll get bored and start tearing in to this thing.
I know RPC made a dual carb kit and have seen vmax540 twin pipes on srv's. How well does that set up work?? Just curious.
Bob Vehring
New member
I have had the RPC kit for 25 years, love it. The stock set up has no way to adjust mid range, part throttle, and a terrible intake manifold.
I have a '83 VM doubt the pipes would work well on the SRV completely different engine. I did try '81 SRX pipes on the VM, didn't work well. Somewhere I still have a set of race pipes for the SRV from back when it was raced, but their 9000 pipes, not what I want on the trail.
Last night I put a different set of A 1's and a new red spring in my SRV, just a flat ground on the arms instead of the notch brought the engagement down to about 4200, from 5000, On the stand it only seems to shift out at around 7600 now which is low. Have to wait for snow to see. Hopefully will get it out to Neosho pond some night next week
I have a '83 VM doubt the pipes would work well on the SRV completely different engine. I did try '81 SRX pipes on the VM, didn't work well. Somewhere I still have a set of race pipes for the SRV from back when it was raced, but their 9000 pipes, not what I want on the trail.
Last night I put a different set of A 1's and a new red spring in my SRV, just a flat ground on the arms instead of the notch brought the engagement down to about 4200, from 5000, On the stand it only seems to shift out at around 7600 now which is low. Have to wait for snow to see. Hopefully will get it out to Neosho pond some night next week
Throttle Junkie35
New member
So we finally got more snow and got around to playing the the srv. I knew my buddy had to clean the spark plug caps before I got this thing so I figured I would replace them. That actually made quite a difference in the bottom end. It never seemed to run bad but just not quite right.
Now I am still going to play with the clutching a bit and was wondering where this thing should shift at. Now it will go up to 6500 then drop to 6000 and feels like is lugging a bit when it shifts. I think I read somewhere it should shift around 7000. Im not sure tho. So Bob V can you help me out??
Now I am still going to play with the clutching a bit and was wondering where this thing should shift at. Now it will go up to 6500 then drop to 6000 and feels like is lugging a bit when it shifts. I think I read somewhere it should shift around 7000. Im not sure tho. So Bob V can you help me out??
Bob Vehring
New member
I believe 7200-7400 works well for stock sleds, mine is clutched for 7600 with pipe and porting.
Sounds to me like you have problems in the clutches/belt. Belt needs to ride at the top of sec. when stopped and just tight enough that it still slips in the pri. without pulling the sled forward. I always go through both clutches on all my sleds each season. Clean and inspect for any cracks Which I did find in the pri. of my SRV. this year. Make sure all the bushing are clean, move freely and not to much slop in them. Not just the movable sheave and cover, but also the bushings in the arms and rollars. Anything that binds up or does not move smoothly will cause shift out problems.
Sounds to me like you have problems in the clutches/belt. Belt needs to ride at the top of sec. when stopped and just tight enough that it still slips in the pri. without pulling the sled forward. I always go through both clutches on all my sleds each season. Clean and inspect for any cracks Which I did find in the pri. of my SRV. this year. Make sure all the bushing are clean, move freely and not to much slop in them. Not just the movable sheave and cover, but also the bushings in the arms and rollars. Anything that binds up or does not move smoothly will cause shift out problems.
Throttle Junkie35
New member
Great info Bob, Thanks.Bob Vehring said:
My secondary is all tip top, as well as the belt, 89x OEM Yami. Center to center is good and alignment is also spot on. I finally decided Im going to buy it so Im digging deeper in to it now.
I definately need to service the primary. I may rebuild the stock clutch so have something to compare it to.
Without even turning a wrench, I know the rollers are toast and probably the the wieght bushings. It rattles when you turn the clutch by hand. LOL. So my next question is.... does any aftermarket company make a rebuild kit for the older yami clutches?? I know I''ll probably get slammed for not using oem parts but I've kind of had it with the price of oem parts lately. Certain things I will only buy oem like electrical and belts but if there is a less expensive alternative Im all over it. Thanks for your help Bob.