SRX testing

Viktory2k1

Viktory2k1

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Joined
Dec 10, 2014
Messages
654
Age
53
Location
Waukesha, Wisconsin
I finally got to test sled on lake. Ride is way better and the acceleration is shocking with Mrvipers setup. I hit 105 in a very short amount of time and it still wanted to go faster. Tach was at 8000 so I bet at 8500, I would be doing 115. I wish I had a radar or some accurate way to see actual speed. TORS switch is replaced and I turned idle up to maybe 2100 but sometimes it seems to take a while to idle down to that speed. Still have traction issues with 240 studs. I can't replace them as funds are getting low. I bought them too short. At best, they clear track lugs by 1/4". Maybe 3/16". Thats an expensive screw-up on my part.
When I got home I pulled plugs and all 3 are a nice medium brown, just the way I like. I feel much better now that I replaced the TORS switch.
 
Get your rpm to settle on 8300/8400 and you should be set.

And to get your idle hang to drop, back out your fuel screws 1/2 turn.
 
rpm for a 98-99 srx is 8300rpm not 8500rpm, your close so it just needs fine tuned.

I would start by removing about 96 of those studs, with 240 studs thats a whole bunch of rotating weight. You actually get better traction with less studs because you apply more pressure per pick then you do with a whole bunch. Think of it like a guy from the circus that lays on the bed of nails, the reason he can do that is the amount of nails, it decreases the pressure appled by having more points so it supports the weight, if you removed half of those nails he would look like a strainer!
 
It has more traction then the 144 I had so I bought 96 more, just didn't perform as well. I needed 1.4 something total length but I bought 1.325. I didn't measure the non lug thickness of track. Yeah, a lot of weight, probably like 15 pounds. Lake is bare in spots and snow in others so when I hit the bare ice, it takes off and then back to snow.
As far as rpm goes, thats where I let up on throttle. It will hit max rpm I believe but this is my first time on lake this year so being cautious. It was daytime but someone must have built a fire on lake because out in the middle, there was a pile of partially burnt wood and I may not have seen it in time at night. Also it was my first time hitting triple digits on speedo, ever. Actually wasn't that bad, I have panic attacks and didn't start to have one.
If it doesn't hit 8300, what would I need to do? Put secondary spring 1 hole tighter? I think it will, just a little gun shy. Speedo was still climbing. I kept thinking about something going wrong with driveline and locking track. Thats why I liked the way it got up to that speed so fast. Again, thanks for all the help.
Oh yeah, gonna buy a helmet cam.
 
ssrrxx, I have right around the same miles. Your rings have to be out of spec, I re-ringed at 8000 miles for insurance.

I just put pistons/rings, wrist pins/bearings in this season. I was getting allot of blow by because of the piston/ring wear and the wrist pins were worn also allowing the piston to rock in the bore causing a loss of compression.

I would tear it down before something lets loose....
 
Yeah, I've been keeping a close eye on it. Compression is still 118-116, it passed a leak down test at 11k.

Normally a sled with this many miles, I'd have rebuilt a couple times already. But since I bought this sled new in 97, I know everything that's been done to it, how it's been stored, how it's been ridden, etc. Now it may go tomorrow, but there's something telling me that I'll get " ONE MILLION MILES" out of her.

Referenced Austin Powers arch enemy.

Seriously thou, it's on the to do list. It's just so much fun walking away from "some" of these newer sleds on top end, then stop, and chat about reliability.
 
I have another spring for drive. Right now I am running a WWW and I have a new YWY. Would this be a higher force spring?
Ok same engagement and slightly higher rate on ywy. maybe I will try it. Rate on www is 2.25, ywy is 2.5. Total force on www is 119 and ywy is 128.
Any ideas on how much higher this will change the rpm?
 
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Viktory2k1 said:
I have another spring for drive. Right now I am running a WWW and I have a new YWY. Would this be a higher force spring?
Ok same engagement and slightly higher rate on ywy. maybe I will try it. Rate on www is 2.25, ywy is 2.5. Total force on www is 119 and ywy is 128.
Any ideas on how much higher this will change the rpm?
Click to expand...

You don't want to change the rate if it was straight shifting. By that I mean when you pin the throttle it hits max rpm and stays there. If you pin it and hits max rpm then slowly rises or falls then you need to change the rate. The YWY will increase rpm's all around. All you can do is try it, but it will shift slower than your current spring.Do you have different helixes?...........................SRXtreme
 
UNTIL you run the sled wide open and the rpm is off leave it alone.....
 
thats what I thought. I let off, not sled...
Not sure if I want to go 115. Maybe a gear change to keep it where it is.
GoPro white should be here today so I can post videos..
Clutch parts came for wildcat, see if GF likes it. we got new snow 1" and 1-3" on the way.
 
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What nobody has pointed out here(SRXtreme is hinting at it) is that at full throttle your motor should go to your max rpm immediately. Say 8300 is your peak rpm, the engine should be at 8300 the second the throttle lever hits the handlebar and it should stay at 8300 until you run out of gear. Speed is irrelevant(not completely irrelevant, but for this conversation it doesnt matter). You are trying to get the clutches to shift at the peak power of the engine so you maintain maximum acceleration. Not so fast that it pulls the engine rpm down, but also not so slow that it over revs.
 
Eric_04 said:
What nobody has pointed out here(SRXtreme is hinting at it) is that at full throttle your motor should go to your max rpm immediately. Say 8300 is your peak rpm, the engine should be at 8300 the second the throttle lever hits the handlebar and it should stay at 8300 until you run out of gear. Speed is irrelevant(not completely irrelevant, but for this conversation it doesnt matter). You are trying to get the clutches to shift at the peak power of the engine so you maintain maximum acceleration. Not so fast that it pulls the engine rpm down, but also not so slow that it over revs.
Click to expand...

Theres more then 1 way to skin a cat and I will agree to disagree with your clutching idea on a srx. I have raced them for years and youll find the sled will do alot better coming in at 8000-8100rpm when you slam the throttle and let the torq. curve accelerate the snowmobile and let the motor build the topend rpm to 8300 peak hp for the 98-99 like he has, or 8500rpm for the 2000-02. The more you load down a srx engine the faster it goes, like a tractor they love load, not a straight to 8500rpm shift. I know you think I am wrong thats fine but winning results, r/d testing on timers and dyno tuning to learn where the power curve is doesnt fib with this method, its proven.
 
OK, did more testing today with camera. Had a wind from the north so I went east to west. 8000 is where it wants to stay. Probably not the best snow conditions. 2" of snow with a little frozen slush underneath. I also tested my wildcat, that one is spot on. I know this isn't the place for it but that one has a D&D orange primary, 62 gram weights, 60/46 helix, red/white secondary in hole 4. That one is 8300 and pulls hard. It is clutched for most use of torque which is pretty much what those are about. The problem is with my Go pro cam setup. I had it set up with default settings and it looks like I am like 10 feet from sled. I didn't watch the videos since they were "enhanced" by youtube but maybe you can see the gauges. I am very disappointed with my camera results. I did not put the ywy spring in. Mrviper, you may be able to use your ears instead of trying to see the tach and speedo. I am not familiar with the cam yet. Here is the links:
http://youtu.be/5I31-xu2dIg Yami
http://youtu.be/rvj4o1IlMrE Wildcat

I am more than willing to learn if you hear something wrong with yamaha. The AC vid is here just to show that even a 21 year old sled still can go. I made that "kit" up myself with very little guidance. I apologize for the horrible camera skills. I am just having a hard time understanding all the clutching principles.
 
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i think you did just fine with the camera, i can listen to it and hear whats going on, the video is a help. I would do 1 of the following things, which one you do is up to you.
1.) you can use the yellow/white/yellow spring that will keep everything the same except raise the topend rpm a little bit which is what you need, it will shift slightly slower then the w/w/w.
2.) you can keep the w/w/w spring and take off .5 gram from the tip rivet head, grind the thick head of the rivet down some to remove a 1/2 gram. You need a digital gram scale to do this, they are available at office max. or any of the like stores.

personally if it were my sled I would keep the w/w/w and grind off a 1/2 gram on each tip,and recheck my rpm, if i still need a tad more i take a nice sharp drill bit and drill into the head with a small diameter bit to get more weight out without removing the rivet but if you dont have the tools or are not wanting to buy them you can just swap to the yellow/white/yellow. The 98-99 srx doesnt make as much hp as the 2000-02 does 137hp vs 140hp and this is why its just a tad bit low on topend rpm, not a big deal, you only need 300rpm to be right in there.
 
mrviper700 said:
Theres more then 1 way to skin a cat and I will agree to disagree with your clutching idea on a srx. I have raced them for years and youll find the sled will do alot better coming in at 8000-8100rpm when you slam the throttle and let the torq. curve accelerate the snowmobile and let the motor build the topend rpm to 8300 peak hp for the 98-99 like he has, or 8500rpm for the 2000-02. The more you load down a srx engine the faster it goes, like a tractor they love load, not a straight to 8500rpm shift. I know you think I am wrong thats fine but winning results, r/d testing on timers and dyno tuning to learn where the power curve is doesnt fib with this method, its proven.
Click to expand...

I dont think you are wrong, not trying to start any arguments. There are many ways to clutch a sled, nearly everybody does it slightly different than the next person. I have spent a few years testing and setting up drag sleds that have many a 1st place trophy and cash. My own and quite a few others. As you said, theres more than 1 way to skin a cat.
 
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