i changed the bottom gear and killed the power!!!

hookedonblue

hookedonblue

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Joined
Sep 25, 2004
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49
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CORNER BROOK, NL
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www.westernsnoriders.com
Hey everyone, i raced my 2002 srx 700 with 136" mountain performance ext kit this weekend at the uphill drag event here at the local ski resort. it was a wicked weekend for racing with over 280 sled from all over racing the 800 foot uphill 4 lane track. well all was good til i placed my sled on the line and it was slow as hell. My cousin and i decide that we would change the bottom gear to a 40 tooth and leave the top tooth to its origional 23 tooth. we tightened up the secondary to 90 degrees. ran it with stock jetting and all stock clutch components. before we changed the gear it ran perfectly. does this make sense that by going bigger on the bottom gear by one tooth it will make the sled over rev and rob top end power. i need help on this one boys.

i know, i know there are posts all over the forums about race setups, clutch setups and jetting, but i need someone to take a personal interest in my case because i really need some expertise on this cituation.

Gimme some things to work with to get me the most outta my sled. i wanna jet it right and cluch it right, i want a killer set up for what the best primary spring to use, the best weights to use, the best helix weather it be a multi angle or not. " BRING IT ON BOYS "


HOOKEDONBLUE
 
you should drop the twist to around 50-60 also, that rear suspension is not helping anything for drag racing as it is very high and has a very high aproach angle. drop the rear and front suspension.
 
Changeing gearing will effect clutching so if it not adjusted yes you made it worse.You need good track speed for this.
 
The gearing was probably not what caused your problem.. Why did you tighten the secondary?? If you had a good shift out before I would have left it alone. To tall a gear ratio for that kind of run uphill run!!! Jetting can safely come down 2-3 sizes.. What do you have in this sled for clutching?? What do you have for tuning parts??? Ramps, weights, springs???
 
The correct gearing depends on the type of course and power the machine can produce on that day. A good rule of thumb is gear as tall as you can without losing acceleration. By gearing to a 40 tooth from a 39 i assume , automatically lesens the load on the engine therefore creating more power , alternatively increasing rpm . Now by wrapping the secondary to 90 degrees may not necessarily give you the best performance because the belt probably ended up in an inefficient aea . Getting the belt to go all the down on the secondary or up on the primary is not a high priority , finding wich combination between primary and secondary gives you the best performance in a short drag.If a sled increases rpm it is automatically geared higher , the higher the engine speed now may require lower gearing and this is probably what happened ...just call it testing thats what i would do....
 
stock weights, stock rivets. stock helix. white secondary at 70.

Bender orange primary no shims. I cant even begin to describe how dead on this was for me in my SRX climbing hills out west
 
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You changed the driven sprocket to a bigger size, which gears it down. That makes more torque and lowers your top end speed. The lower gearing (added torque) makes it easier for it to pull the weight you have in your clutch and thus the over-reving. What top end speed were you getting? I personally believe that a mountain sled that you want to hill climb with should'nt really do over 80-85mph. The added torque will give you better track speed when climbing, night and day difference when in powder. For example, my cousin's Mountain SRX will waste my Viper when drag racing because he is geared and clutched for it. When we hill climb, his set up is only getting him about 36-38mph track speed compared to my 48-50mph track speed. He can't touch where my sled will climb. If your going to play with the gearing, you'll have to also add/remove weight from the clutch to make sure you're at the target rpm, and then test to see what works the best. Different type of snow will also affect it, make sure you keep notes on set up, temp, and type of snow (hardpack, powder, wet, etc.).
 
You need to add some tip weight to bring your rpm's back down and it will pull hard again. 95% of the time when you make gearing chages you have to adjust the clutching to compensate for it.
Do you want a drag set up or and all around?
 
a drag set up is what i am looking for, i am always racing, even when im trail riding, i never ride moderate...loli want to get the most out of my srx, i have never pushed it to its limits, now i am ready to do so. i wanna turn some heads...i want it to f#*!@n rock, if you know what i mean.
 
I would get some heel clickers then.With your 136" track that thing will holeshot hard.
 
pro116 said:
I would get some heel clickers then.With your 136" track that thing will holeshot hard.
Click to expand...

Another vote for the heelclickers. If you know that you're not going to be changing the gearing often, decide what you are going to run for gearing and then start setting up the clutching for it.

Great looking SRX by the way.
 
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