1998 srx gearing/clutching

vibeline

vibeline

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Nov 2, 2006
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47
Location
Belle River ON (home of no snow)
I am working on a 98 srx700
this is the current setup
1" preadator track (9830) with 144 studs up the middle.
viper rear suspension, viper front shocks, apex mountain skis
21/39 gears 68 link chain
straight 47 helix red spring wraped at 40 deg.
www primary spring with 8dn00 weights with 4.5 gram rivits in both holes
with set up its running 108 mph (GPS) at 8800/8900 rpm (too much rpm)
I tried more twist and the rpm went up and I lost MPH
What do I do to get the rpm down to 8500?

The belt is going about 1/4 of an inch from the top of the primary.

How much RPM will 1 tooth on the top gear pull out of the engine?
How much RPM will 1 tooth on the bottom gear pull out of the engine
 
A couple of years ago my srx7 ran the same r's as yours and I went up 2 teeth on top [25/38] and still only down to 8700. Found out my clutches were tired and had them rebuilt.
 
go with heavier rivets or you could put a steeper helix
Pat
 
I ran a 98 with 8dn00 weights, set up like you have and helix 2070 from Bender....worked great! If interested in the helix still have it, sold the sled, so no use for it now.
 
Steeper helix

Try a steeper helix. Bender used to sell a "clutch kit" for those sleds using the stock weights. It was shipped with a 53/43 helix. This will help get your r's down too.....at least on the initial shift but you may still overrev on top end.

Madmatt
 
2070=49/47

If your over revving that far with a 45/119 primary spring and a 47 finish helix, then you need to drop your front spring shift force down(your already pretty soft) or add more weight to the tips of what you have. Are you sure you have 4.5 rivets in them?? you'd have to be making alot of power to over rev to that rpm with 53.25 grams and only a 119kg shift on the spring. Having geared the sled down to 1.85 like you have will allow you to run more clutch weight. You can run a 1/4"x28 tap thru the weight holes and put bolts and nuts in there for more weight.
 
mrviper

I am 99% sure they are 4.5 gram rivits they are the ones I ordered. I should have weighed them before I put them in. I will tap the holes and try some screws with nuts.. I tried a 39 helix today. still reving arould 8800 I went 112 mph on the gps. My buddy was out with his phazer gt he ran a whopping 77.7 MPH on the gps. Its a tippy turd...LOL

Thanks for all the input guys
 
I have the same issue with 8dn20's and 4.5g rivits
over reving on top half ( 8900-9000) with a 51/43

I added some bolts/nuts to the tip last night. had to grind down the nuts to clear the clutch flanges at the rollers

anyway. took them to work and weighed them..
a whopping .5 grams heavier each swing weight. after all the grinding :o|

I understand Hauck sells weighed nut/bolt combos at 5, 5.5, and 6 grams
I guess I will order them. they must be heavier density metal than what i used, because my bolt/nut just clear.

Ramb
 
Tip: use allen head fastners, they are heavier then hex head ones, when you tap the weights take your time and use cutting oil, I like to use a 1/4"x28 fine thread tap and bolts. Dont try to force the tap thru with 1 turn, tap them fine thread and use some blue loktite on the bolts and you can open up the world to any amount of weight you want to add, as long as you can clear the inside of the spider walls, check your clearance! The allen head fasteners wont interfere with rollers.
 
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