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You send your stock heads, stripped down carb bodies, and reed cages...Mark will then CNC machine the head to accept the "ThunderDome2" combustion chambers, he bores the carb to his specs, which could be taper boring for the Storm...I'm not sure which models get tapered and which are straight bored, and he machines the reed cage which increases velocity at the tips...he returns them with a set of his reeds...you then get complete clutching for aggresive trail and lake race set ups...all instructions on install and setup and of course his backing for his product which means he's always there for help or problems if needed

Check him out at www.legendperformance.com
 

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My storm is a 93, after a failed rod bearing I had the crank rebuilt, and added 800 cylinders. I was told they were 95's , at the time I did not know about the upgraded nicisil cylinders. The heads are 800, I dont know the year. Milled the 750 case to make the 800 cylinders fit. I added PSI pipes, did the cooling upgrades they recomended and run there clutching.Clutch kit has PSI blue primary, looks like stock blue secondary and 10-60 weights, I think the helix is a 46/34 but I am just going from memory and could be wrong. I vented the carbs to the air box and use pSI's jetting specks for the 94 storm on the mains but went back to the 750 needles and needle jets after some testing. My older v-force reeds did away with the balance tube but I picked up a set of delta 2's and modified a set of factory boots to put it back on . With only 50 miles on the fresh top end I have only 100 psi on each cylinder, the reason I am looking into the milled heads. The stock 750 with 5,000 miles had 120 on all three befor it came apart. PSI recomends the 23/35 they claim both better acceleration and speed. To me It just seems to be geared to high to trail ride, I am constantly on and off the throttle at low speeds.
 

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Discussion Starter #144
Well I played with clutching alot this weekend. I was running a Almond/Red primary with 10/60 weights. In the secondary I had a 44/36 with a silver spring. Well after testing I found that the sled really likes lighter weights and a Team roller clutch. I put in 10/56 weights with the same Almond/Red spring. The secondary is a team roller with a 52/42 helix.
It is so responsive with this setup! It is a blast on the trail! I was doing my testing against a very well set up ZR 900. I was beating him off the start and I just kept pulling away from him.
I think it could get better with a more aggressive helix or a softer secondary spring. Also maybe some taller gearing would make it pull a little harder. The testing and tuning never ends.
 

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I tried the 23/39 combo but it won't fit without a longer chain. Yellowstorm, It would be interesting to see how the 23/35's or the 24/40 128mphstorm runs would work on your sled. 128mphStorm, whats the link count you run to fit the 24/40? Can the longer chain be looked up from another stock sled? All the sprockets I have have the rounded tooth and valley, maybe I already have the hyvo style chain? Thanks to all you guys for sharing your info.
 

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Here is what I have found with gearing in my testing, racing, and watching. Gear high for speed runs on ice or extremely hard packed snow. You will run a higher mph with the taller gear. Just bought some 25/39 gear for my XCR, for speed runs. Now for everything else gear low and the sled will be quicker unless you are traction limited. Taller gear will give you more traction because there is less torque going to the track. If traction is equal, it doesn’t matter what surface your racing on the lower gear will be allot quicker. I raced a 220hp XCR with my 160hp XCR, his had a 1.25 Ripsaw track with 96 studs and 25/39 gear. Mine had a 1inch Hacksaw track with 192studs and 22/40 gear. We were racing on packed snow and loose snow. It took him around a 1,000ft before he could get by me. Needless to say his sled is now getting geared lower. At the XCR Shoot out, the two quickest XCR’s were running 22/40 gear and we dominated every thing other then 200+ hp sleds.

yellowstorm800: You should have better responce with the lighter weights and the roller clutch for sure but drag racers never use the roller, they say a button is quicker/faster ??
 

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Discussion Starter #147
BattleStorm said:
yellowstorm800: You should have better responce with the lighter weights and the roller clutch for sure but drag racers never use the roller, they say a button is quicker/faster ??
Yes I was always told the same thing about the roller clutch but that is why we did the testing against the ZR900 before and after. Every run was close but I was pulling away from the ZR every time. The roller feels better in every range except i'm not quite sure about the top end yet. I don't think it pulls quite as hard up top as the button clutch but I haven't got to a lake to try yet. But that is where I think the taller gears will help me.
 

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the reason the roller clutch is quicker is because of it's sensitivity to backshifting which will also mean anything on the track when speedrunning that creates slight resistance or drag will cause a slight backshift and prevention from from full shiftout...that's why we prefer button clutches for racing other than snocross

PAStorm, I doubt you are running HYVO gears as it would require a 98 or newer jackshaft with 15 splines...Take a count next time you have your top gear off, and you probably have that collar/spacer that sits between the bearing and top sprocket where as the HYVO top sprocket has that spacer as part of the sprocket...hope that helps

4 of us went splits on a new radar gun and laptop that we farted with yesterday...amazing piece of equipment. Gives us acceleration graphs and time vs. distance graphs and a ton of other stuff we haven't got to play much with yet...but after a couple gear changes in my Mod sled I can see it's going to be an invaluable tool for tuning...I'll keep ya posted if interested
 

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I know I still have the stock 13 spline upper shaft. Since the 23\39 will not fit without a longer chain I am going to put the 21/39 in and give it a try, its easy enough to change.
 

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WOW Great Info guys!!

As mentioned I have 1996 Storm and was wondering if power band or thoughts on sweet spot. What I have read is 8000 I currently run 10-62 and still pull 8400
Seems like it pulls hard then lays back a bit at 80-90 mph 8400 rpm..
I am all stock pipes porting ect..

Thanks
 

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for doing a 2000 foot speed run I would be geared as tall as you can, get rid of the roller clutch and put in a red polaris spring and a r-7 or straight 34 or 36 helix. and as much weight as you can pull,
 

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Discussion Starter #152
bgbytor800 said:
WOW Great Info guys!!

As mentioned I have 1996 Storm and was wondering if power band or thoughts on sweet spot. What I have read is 8000 I currently run 10-62 and still pull 8400
Seems like it pulls hard then lays back a bit at 80-90 mph 8400 rpm..
I am all stock pipes porting ect..

Thanks
Try 10-64's or 10-64M's. That's what I had in mine last year with the stock pipes and porting, it pulled good at 8000rpm.
 

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I got a chance to try the 21/39's ,pulls real hard, a lot more responce at lower speeds but didn't have the room to run out the top end, only up to 70mph or so. At wot the rpm will hit 9400, will have to change weights, maybee 10-62 or should jump to the 10-64's ?
 

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Discussion Starter #154
PAStorm said:
I got a chance to try the 21/39's ,pulls real hard, a lot more responce at lower speeds but didn't have the room to run out the top end, only up to 70mph or so. At wot the rpm will hit 9400, will have to change weights, maybee 10-62 or should jump to the 10-64's ?
What were you running for RPM's before the gear change?
 

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Rpm befor the gear change was higher, 96-9700. It was above freezing wednesday when I ran it, may be the reason for the lower rpm.
 

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Discussion Starter #156
Do any of you Storm guys have a good crank? I just snapped the pto stub off tonight. I came out of a corner and stabbed the throttle and BOOM. I rolled to a stop and opened the hood and there it was. The primary was laying in the bottom of the belly pan with part of the crank still in it. I need this sled back together by the end of this week!
 

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Yellowstorm800 really sorry to hear your misfournte! This is the first I have heard of this on a Storm crank!

I have a quick question for the group:

My 1996 storm is now running 10-64 and still pulls 8200-8300 and runs very hard up to 80-90 and then is slow to get up from there? speedo has only been up to 100-110? I have stock spring in the secondary 2nd hole EPI Spring..

How far of a run to get top speed? Going to radar run next weekend.. I have stock gearing now will try that this weekend also have heard runs above 120 on speedo. maybe loosing traction I have 168 picks 1.00 in stock track.
 

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Discussion Starter #159
PAStorm said:
With the money you have invested in the rest of your motor, do you really trust just putting in a used crank?
I found one this weekend. I didn't buy it yet because we are going to split the cases tonight and make sure it is good. I am still putting new outer bearings on and new crank seals. I just want to make sure that the centers are good.

Bgbytor800 - Depending on how long the radar run is you should probably just run stock gearing. It also sounds like your secondary is to tight. Maybe try a running a softer spring.
 
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