2001 srx first time running 8bu setup help

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furg69

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Feb 16, 2009
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40
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newfoundland
Hey guys just installed the full setup of yamaha gear on my 2001 srx 700. 8bu weight with 3.6 and 2.4 rivets. WWW primary and green secondary. The sled now runs terrible only revving to about 7600 or 7700 rpms. Any suggestions ? I have heard nothing but good stuff about this setup before trying it. All the products in used are brand new.
 
Hey guys thanks for the response. I'm running a 51/43 helix. I wanted this kit for 1000ft snow drags. I removed the 3.6 grams from the tip now it revs to 8100 off the line and maintains 8200 to 8300 so it's better now the tip.is empty. Maybe I gain a 100 rpm with the secondary twist ??? Any thoughts ? Races this Sunday would like it figured out
 
70 twist with green (dot ) spring for start. you can go to 80 twist but no more than that. your still a tad lite for a 01. 3:16x (yammie tony)
 
Put a new belt on the sled tonight broke the belt in and now with the 8bu with the 2.4 I first hole, tip empty, same www primary and green seconday , same 51/43 helix. Sled now only pull 8000rpm then drops back to 780ish and slowly crawls to 8200 to 8300. I'm stumped as I though I shouldn't have my tip empty but with the 3.6 grams it only pulled 700 rpm max
 
u can try to run a stiffer primary spring or remove some weight from the first hole...tip does have a effect but it have a more huge effect on top end
 
Look for hauck orange primary and add the 3.6 rivits back and try
What gears are you running for 1000ft
 
I have stock gearing on the sled. Running a 121 x 1 inch track. I don't have a hauck orange just yamaha supplies and maybe a red heel clicker spring. Sled feels so slugish. Might have to go back to stock
 
maybe issue is some where else, check powervalves, carb settings, seem low on power. You could also try stock setup to see if your rpms come back that will eliminate carb, and powervalve issue if their is one
 
if your dialing in clutching, you don,t want to use a brand new belt. better off with one thats broke in. let me ask, whats your clutch engagement. also i would give your pv a good check over. 3:16x (yammie tony)
 
i have a lifetime worth of testing these weights, i believe your problem lies in the helix your using, especially for snow drags. 3:16x (yammie tony)
 
Works great with stock parts again. Tried the 8bu setup again with tip empty and 2.4 in first hole www primary and green at 70 degrees. BUT switched back to stock 47 helix and adjusted the secondary for the new belt. Seems better. But haven't tried it on flat just quick spurts around the garage
 
Tried the stock stuff works perfectly. Installed the 8bu with 2.4 and tip still.empty same www primary and green at 70 in the secondary BUT I put the 47 stock helix back and also set the seconday for the new belt not it revs to 8400 to 8500 off the line and stats around there. Should this work ?
 
I think There is still an underlying reason why your not pulling the recommended weight. What elevation are you Testing that at? I don't know if it will make a big difference but maybe?
 
Running at sea level actually tested on the Atlantic Ocean lol. I'm over revving now I assume of i see 8500 off the line? Maybe I should toss the 3.6 back in the tip or Alittle less. And keep the stock helix instead of the 51/43
 
Sled pulls 8500 and sorta stays doesn't does or gain rpms. But I think I should see 8100ish off the line and climb to 8400 -8500
 
furg69, after reading your post sounds like its overshifting resulting in low rpm. Theres a few reasons why it can do that. The w/w/w primary spring is a lower tension spring then the stock y/w/y is and will upshift sooner. The 8bu weights are aggressive in curvature and upshift sooner. A larger helix angle will upshift the sec clutch sooner. The key to all this is to have them work together. You might have a better result using the stock y/w/y primary spring with its 45/128 force where as the w/w/w is a 45/119 spring, this will raise the rpm and slow the upshift some. As for the rear clutch I would have a couple questions.

1.) do you know for a fact the helix angles are 51/43 or is it a coded helix from like bender or hauck, etc and someone told you it was that angle?

2. ) what sec spring wrap are you using with the green dot Yamaha sec spring? what kind of belt deflection spec are you running ?

you are correct in your rpm swing you desire, 8100 out of the gate and get it to climb to 8500rpm on peak about 300ft out from start.
 
Thanks Mr viper. My secondary is also done with a green yamaha spring wrapped at 70. The helix is a advantage edge and it has 51/43 engraved on it. So sunday I ran the sled in 700 stock with the 8bu with tips empty and 1st hole 2.4 www primary and the Secon dart with the 51/43 @ 70 . I did come first place but the 700 stock class here is full of fx nytros and 600 doos, assaults, and cats. So wasn't really a true 700 in the race. I'm still very impressed with the way it worked but with this over revving it's losing some hp and performance . Maybe since adjusting my belt deflection to spec I can add the 3.6 grams back in the tip?
 
the advantedge helix is what caused your problem, those helix shift more aggressive then what they are stamped due to the radius on which they are cut, its really comparable to about 55/47, which would overshift the clutchs with 8bu front weights and the soft w/w/w primary spring. Kinda think of a stick shift car, you drop the clutch and go from first gear to third gear, it bogs, low on rpm and takes a long distance to recover lost rpm and come back into the powerband of the engine.
To remedy the problem with the parts you already have on hand, I would use the stock primary spring in front clutch the y/w/y and then youll be able to add some tip weight back in to bring the rpm to 8500rpm.
Your other option is to use a smaller helix angle, something more in the line of a 50/44.
 
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