vmax clutching help

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sleeper_dave

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Joined
Oct 26, 2009
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111
Age
45
Location
St Clair Shores, MI
I am clueless when it comes to clutches... I've been doing some reading, and plan to do some more reading, so maybe you guys can point me in the right direction.

I have kind of a bastard sled. The motor is kind of pieced together, a 600 twin with the head cut down a little bit (same effect as thinning the head gasket), wiseco pistons with the holes on the intake side opened up a bit, exhaust ports slightly modified, really just squared up at the top a bit, and a set of SLP twin pipes. The chain case is from a '94 vmax 600 ST (long track) but the chassis / suspension is from a '96 vmax XT. Jetting is stock ('94 ST) primary with a 160 main, needles at #1 (leanest) position, and the air screw is about at 1 turn right now. No boost bottle.

I got it out on the fresh motor for the first time today, and adjusted the carbs a bit. Got the carbs dialed in a bit closer than it was when I started (above is what it's at now) and now it's plain as day that the clutches need a lot of work.

The clutches are off of a '94 vmax 600 ST, but I don't believe they're stock to that machine. I believe the primary is off of a '97 SRX / SXR (I never remember which way those letter go) and the secondary more closely matches the parts manual for a '95 / '96 Vmax, but it may be a match for the primary, I just don't know.

Off the line it's okay. Doesn't creep at idle, goes at a reasonable RPM. If I stay in it, it pulls pretty good. Up top, though, it'll rev right up to about 9000 RPM and it'll only run about 70 mph. If I try to cruise in the midrange (30-40 mph, hell, anything but WOT) for a bit, it'll "upshift" and when I gun it, nothing. If I let off the throttle, grab a handful of brake, then gun it, it'll take off like a rocket again. If I am cruising at 30-40 and grab the throttle, and just stay in the throttle for a while it'll eventually get going, but it is not responsive at all. Won't backshift for shit.

The other issue I've had is that the belt is very difficult to get on and off. I believe it's a stock belt, but I have 2 spares that I can try as well. I don't recall which was on the sled when I got it, as I've had the damn thing apart for so long. The spacing and alignment are set per the manual for a '94-96 vmax.

I'm clueless when it comes to clutches. I've been through a couple of motors enough to know enough to be dangerous, and I've basically rebuilt 2 sleds now from the ground up (a phazer and now this vmax). But I've never pulled a clutch apart. So, if anyone could provide any advice or point me in the right direction that would be great.

Oh, another wrench in the works... I'm 150 miles from any snow, and our damn lake never froze this winter. So that will only make this more difficult. I got about 15 miles on this sled today, up north, on trails that were barely rideable, and I'm not sure if I'll have another chance to ride this year or not.
 
Anyone?

I've been doing a lot of reading on clutching, and I think the first thing I need to do is tear into them and see if they're in good shape or if they're totally messed up. From what I've read I can do this without special tools - is this correct?

Does anyone have any pictures of a stock vmax clutch or a stock SRX clutch that I can compare to what I have? What changed in these clutches over the years? I'm not talking about setups, I'm talking about the whole assembly - what do I need to know to recognize what I have and make sure I get the right parts to maintain it or set it up right?
 
I tore them both apart last night. Secondary is serviceable but could use new bushings. Primary is fubar. There is no bushing on the clutch cover, at all. The rollers are shot, they have excessive play and don't roll very well. The bushings in the rollers appear to be gone. The weights have severe wear, see attached pic. They're bad.

So now I'm either looking for a complete primary in good shape, or bushings, weights, rivets, and rollers.

Supposedly this clutch is from an SX-R 700. That's what's written on the face of it and the guy I bought the sled from (a poor decision, as it turns out) said the clutch was from a newer 700. It looks like all the clutches are the same except for the tuning, though.

As far as the actual weights, I see that yamaha put a wide variety of different combinations in the 94-96 vmaxs. How different are they? What should I put in, if I don't buy an entire clutch? How would a clutch from a newer machine perform compared to a clutch from a 94-96 600? For example, what if I bought a clutch from a 98 sx 600 (currently available on ebay)? Could I get away without swapping the spring and weights?
 
sleeper dave im pretty sure the clutches on yamis hasnt changed in years. Like you said its just different weights and springs in them. Did you try the tech section here. There is about two million clutch setups on there. sure their is some good info you can use
 
I bought the one off ebay. The weights and rollers match the part number for one of the stock 96 vmax setups. Spring and rivets are different. I'll put it on, get it working, then add weights or change the springs if I need to. If it worked well enough on a newer 600 maybe it'll work well enough on mine out of the box. Hard to say since I have pipes and a tiny bit of port work done. As long as it doesn't over rev at WOT and it launches and backshifts okay, i'm good. An 80% solution is good for me.
 
First your gearing for the ST is lower then that of a XT which may get you a better hole shot and low but will hurt the top end.

Clutching is a must my DX had twins on it and was not clutched and that things suxed compared to the XT (bought it clutched or i would give you my config).


Not sure if Turk is still on here but he can tell you what setup to run. i know there are posts on here with setups but i couldn't find any when searching.
 
I found the same when searching... there didn't seem to be a whole lot of info. I ordered that '98 SX clutch, and looking at part numbers at yamahapartshouse.com it looks like it has the same weights as a '96 XT but different rivets and spring. I figure I'll put it on and see how it does, and I can always change the rivets and spring next season. It's hard to know where to start, because I have a motor, carbs, and gears out of a '94 ST, SLP pipes, minor port work on the exhaust, the head cut for a proper squish, and the intake hole in the side of the piston opened up a bit. And of course a '96 XT chassis and suspension, with a camoplast track (1" i think) with studs. So I don't think i'll find a good setup here, I'll just have to tune the thing.

Reading AAEN's guide to clutching it seems that the lower gearing shouldn't affect actual clutch tuning too much, but it will affect performance. Again, i'll see how it runs and go from there. I've talked to a couple of people with these sleds stock that said they wouldn't mind a little more go out of the hole and that they didn't really wind out all the way on top anyway, so who knows. Maybe i'll gear it up a bit.

My first goal is to get a good rideable setup, so that I can go down the trail and keep up with other riders. I can mostly keep up on my '85 phazer but I have to slow down in the whoops and my back hurts when I'm done! Once I have this thing reliable and rideable I can worry about tweaking it for performance. I'm about 60 miles south of you, braindead, and as you know we've had very little snow this year. Lake St. Clair never even froze enough to ride, and it's kind of hard to go 200 miles north and try to tune the thing in on a trail, when everyone else just wants to go for a ride!

I just noticed I forgot to post the pic of the weights before. It's attached now... you can see why it was barely rideable!
 

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Yikes! yeah depressing year for sure, i have 3 sleds now just picked up a 97 SX and selling the DX but i haven't even listed the DX yet as i know i will just get low balled.
 
let us know what rpm are doing on a pull from low to top.and what rpm pipes have to turn.we can get you close alot of great guys here that have wore clutches out in testing.
 
[QUOTE

I just noticed I forgot to post the pic of the weights before. It's attached now... you can see why it was barely rideable![/QUOTE]


yikes!! I have never seen weights worn like that..not even a little.Wander how that can even wear down that much.You'll have to get some new ones for sure.
 
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Yea I think the spider bushings are the only part of that clutch that's actually serviceable. The rollers are shot - a massive amount of play. I think that contributed to the wear / damage to the weights. There was also no bushing on the primary cover. I started looking at weights, rivets, bushings, etc., and if I can find everything I need, it'll cost me a few bucks. Cheaper to buy a used primary. So I bought a used primary out of a '98 600 SX (I assume Vmax 600 SX but the description didn't say vmax) which, according to the parts manuals I found online, uses the same weights and rollers as the '96 XT, just different spring and rivets. I'll see how it runs (probably in the fall, now) and go from there. Hopefully I can just add a little weight and change the spring and be in the ballpark.

The pipes are SLP twin pipes for a '94-'95 (maybe '94-'96) vmax 600. Not sure what RPM they like.

That sled was an awful buy. I'm in it way too far at this point. The guy who sold it to me had to know it was ****ed. The clutch was shot, the motor was hurt, and the chassis was bent. None of it apparent on inspection in his back yard, though, and there was no place to test drive it (other than 60 feet across his yard). The motor started on one pull and ran fine despite a chunk missing from one piston. The chassis looked fine until I had the motor out. I have now replaced everything that was fubared, and all I'm using right now is one cylinder, the water pump and electronics, the chain case / chain / gears, the secondary shaft, and the secondary. And the seat. The rest has been replaced. At least I turned it from a '94 ST into a '96 XT with a near-new studded track.
 
Dave I can tell you this much from a personal experience. The 500/600 Twins eat clutch parts like they are going out of style. I rebuilt my dads clutch about 800 miles after the dealer had serviced it and replaced the same parts that i replaced. go figure...
 
I wander why that is....does not make any sense why it would wear faster because it is a twin cyl.What gives with that..everything is spinning like on a triple...we had a 95 vmax600 here and the clutch's were no issue at all..go figure
 
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