6 spring clutch mod into xj650 turbo, not without its issues

Ive done the 6 spring clutch basket/ assembly swap from a 700x liquid cooled maxim into my turbo 650. As the title states not without its issues.

I initially started by putting the 700/750x outer basket into the 650 turbo. This is the one that connects directly to the crank. I noticed that the outside of the basket's aluminum perimeter was slightly different than the 650 turbo one it replaced. All other dimentions appeared identical. I then installed the inner basket, complete with its metal plate (the plate that is held with the wire retainer). I then installed my 650 turbo metal plates and friction plates into this assembly (As I had just replaced my frictions). Then the 6 plate pressure plate/outer clutch assembly went on with 6 ebc springs. I noticed that the clutch pushrod seemed tight. Assembled and drove and the clutch was slipping even from taking off from the start. Off comes the cover again.

It looked like the clutch push/pullrod was contacting/bottoming out on the nut and shaft behind it. I did use the 650 push/pullrod. Perhaps the 700/750x shaft behind the push/pullrod is shorter? It was clear that it was bottoming out here, therefore not allowing the clutch to engage completely. My solution was to add another clutch friction and metal plate, therby increasing clearance back there, So now I am actually runnning 9 friction plates. However, when buttoned up this time, pulling out the clutch lever caused a rubbing sound. I am now guessing that the clutch rubs on the inside of the clutch cover. My solution, not ideal was to back off the adjustment nut of the clutch to allow mimimal clutch throw out. Obviously this is not ideal. Perhaps now i need to just machine the lip of the outer clutch cover to allow clearance between it and the inside of the outer clutch cover.


But Questions Remain:

1. Why didnt it work in the stock configuration, why did the clutch pushrod bottom out on the shaft/nut behind it? How does it work on the maxim x?

2. Can i just perhaps clearance the inside clutch cover and run it?

3. How do I know that the clutch push/pullrod is also not bottoming out on the inside of the clutch cover?


The good news is that it appears to be able to hold 15psi now. Now I need to figure out my spark cut issue, or why above 13 or so psi, the bike starts to misfire.

 

We tried this swap once, and the clutch disintegrated after 50 miles or so.....as in blew up, scattered, destruction, locked up the rear wheel while going down the road (yikes!). I don't know whether it was due to an installation, equipment, or non-compatability issue. The "stack" on the 700's is taller than on the other (5-spring) models, that's why different DRIVE PLATES are specified on those models (2.00m thick vs. 1.55mm thick on other models); the friction discs are the same.

Pivot axle, gear, pushrod, bearing, and cover are all the same, so the issue won't be there, although the main axle that the primary gear/basket rides on may be different between those models.

Theoretically, you should be able to pull the entire clutch system out of a 700 or 900 model (the six-spring models) and just go to town. With 15+ boost running, just be careful, an engine case can only contain so big of a bomb...........


P.S. we never tried this again, it was a little unnerving the first time.......

 

well the thinner drive plates probably explains why the pushrod was so close to the main axle/ nut. perhaps i can machine a mm or two off the pressure plate to get clearance with the inner side of the clutch cover back in check.

did you use the 700x outer basket or the stock 650 one?

did you ever take a picture or examine the clutch that exploded.. Would be nice to know what happened.

 

Used the 700-X outer basket....you have to, it's a little bit taller than the other versions (to accomodate the taller stack). I wouldn't recommend cutting the pressure plate, there's just not that much material there.

No images, but we examined the failure in the best NTSB manner than we know, and could not determine the source/cause of failure....the outer basket survived just fine, but the clutch springs had been destroyed and the spring bolt bosses in the inner hub had been sheared off, along with a significant damage to the pressure plate and the hub. So again, hard to tell if it was an equipment/installation/other failure. It ran fine and operated wonderfully up until when it failed.

 

Hmm, you used the 700x clutch springs right? I used the 650 turbo ones.. from EBC.

I do know that at one time i did shim the springs with a washer to increase their tension. Unfortunately, the shim caused the springs to coil bind and the first time i pulled in the clutch it fully compressed the springs, then since I was still adding pressure via the clutch lever at full coil bind, it then pulled one of the spring bosses off. Perhaps thats what happened to yours?? you hit full coil bind? Hence why i ask what springs were used. I do know the 700x ones are taller, at least in this clutch i have here.... Just a thought.

 

been about 100 kms now, still hasnt blown up, ive been taking it easy, going to pull the cover off tonight and give it a full inspection.

 

Hi Farmer,

Could you please snap some photos tonight when you pop off the cover to give us some visuals on your swap and point out some of the problems, if there are any remaining? Thanks

 

Re: 6 spring clutch mod into xj650 turbo, not without its is

ok, So i determined the clutch was only beginning to rub on the bolts that hold the clutch cover on. what is the purpose of these bolts, why is the clutch cover a two piece ordeal? and why is the inner cover rubber mounted? is this inteded to somehow reduce vibration to reduce the chance of the cover cracking? Could i remove these bolts and aluminum weld in its place? of course the cover wouldnt be able to be separated then, but i can handle that.

I noticed the lip of the 6 spring pressure plate was a bit thicker than the 5 spring one, and the 6 spring has the teeth that stick out past the pressure plate surface.

so far i have removed not even a mm from the outside face of the pressure plate, moreso to allow the chuck to grab it square. I have taken not even a mm off the back face of the pressure plate, not done yet but hopefully this will prevent rubbing on those bolts.

if anyone knows the reasoning why the clutch cover is a 2 piece unit please let me know. I would like to eliminate these bolts, or at least make them slightly more low profile.

thanks

 

The cover is a 2-piece "unit" simply to make cosmetic differences between different models easier, as far as I know.

There's no functional reason that you couldn't just weld up the two layers.

 

Re: 6 spring clutch mod into xj650 turbo, not without its is

farmer on a side note you where talking about spark brake up what are the plugs gap at?? i run mine at .25 but if you have stock turbo coils maybe .22 or so also what is the wide band saying when it brakes up??

 

i know that i gapped them pretty tight. i will need to take another look and get back to you.

on a plus note, i machined half a mm off the front of the pressure plate, and i also modified the screws that hold the cover plate on, and now no more clutch rub on the cover. Ive put about 500 kms on the thing and the clutch hasnt exploded and appears to hold all boost thrown at it so far...

 

Re: 6 spring clutch mod into xj650 turbo, not without its is

the two piece cover is probably for expansion somehow since it's a rubber mounting or easier to manufacture that way.
here's what happens if something snaggs in there

 

ouch, what happened?

Ive also noticed wear marks on the bosses from the springs rubbing up against them. maybe this contributed to chacal's failure?

Ensuring the spring is centered within the bolt head when tightening down the bolts is probably not a bad idea either.

Either way, I now have a 9 plate 6 spring clutch. Bring on more boost.

 

I'm convinced! I'm ordering my 6 spring clutch assembly right now.

 

Re: 6 spring clutch mod into xj650 turbo, not without its is

my bike is a midnight maxim and pretty sure i had 6 springs?? cant remember for the life of me anyone know?? i guess i could pull the oil fill hole and look lol but thats to hard lol.

farmer so your now on 13psi?? are you getting wheel spin yet ?? ive noticed on these colder nights (roads colder maybe 70f) i get wheel spin in first since your turbo is almost instant boost i would think that baby spins pretty good

 

you will have 5. only the liquid cooled got the 6. and maybe the 700n aircooled.

yes, im getting spin in 1st from 5 grand on, especially on greasy or cold pavement. sometimes second gear also.

 

I'd love to see a video post of you riding with the new clutch to see the difference. I just bought the xj 700 x clutch with Kevlar discs and hi-performance springs.

On your turbo engine, where is the port for the oil supply? I thought about using one of the crankshaft plug ports to support the turbo? I'd rather go the route of the original turbo engine if possible, but I don't know where that is?

 

Re: 6 spring clutch mod into xj650 turbo, not without its is

This picture shows it best for now.



Buy the oil check valve off a seca turbo off ebay. tap the hole into the galley and screw it in, You will probably need a check valve. Then, get some custom stainless braided feed lines made up and call it a day.

 

Re: 6 spring clutch mod into xj650 turbo, not without its is

Famer you should do a full write up on this and make a step by step with pics and then maybe we can get it sticky too I'm doing this this winter for sure

 

next time that sidecover comes off, sure..

wow. im now running about 14 psi backing off to 12, and Im starting to have trouble using full throttle in 1st gear, thing just wants to lift.. violently. 2nd gear you still need to hold on hard too. Need to get a good video going through the gears before winter. 5000km and going strong since the turbo, no real issues no breakdowns.

 

Yes, We want to see the video!

 

In other news, Heavier springs for the 6 spring clutch need to be sourced.

In the colder weather at 15 psi I am starting to get a hint of clutch slip. So someone ambitious should source out heavier springs (Im already running the ebc stiffer ones)