Installing Hartz 4 Clutch

[Yoshi]

Here comes a tutorial for installing a proper clutch on a smallframe. There are few tricks to make installation easy so this post will be a reminder for myself too how to do it and what has to be taken into consideration.

Installing Hartz 4 clutch requires splitting the cases, since the clutch comes with it's own backing plate to fit behind the big primary gear.

After the backing plate is on it's place, it's time to begin assembly.

Add the clutch basket, add a dab of loctite and tighten the screws evenly to allow the damper springs to fall into their places. In this engine I have a DRT Sport primary with 24/69 gears.

Add the clutch spider, but leave the nut out for now. If you have not mounted the clutch before, use lapping paste to mate the cones together.

Add springs and the plate on top of the spider.

Thread a flywheel puller (M28x1.0mm) onto the spider - this is the reason for leaving the nut out

I used a 30mm socket with the puller bolt to compress the springs.

Springs compressed.

Add the clutch discs (soak in oil overnight if new), intermediate discs and the top cover plate. Use loctite on the screws and compress the cluch all the way by tightening them evenly.

Tighten the rest of the screws and remove flywheel puller.

Add the clutch nut with loctite.

Add the pressure plate.

My PK XL2 cover had to be grinded a tad to avoid rubbing the clutch. In addition to the grinding there is a 1mm spacer and two gaskets around it.

1mm washer between the rear hub and bearing, 1mm spacer between the case and brake assembly. To prevent rear wheel touching the spaced out clutch cover.

[tzsteve]

There a nice clutch but not the easiest to fit

[Deleted]

Next job - gear selector shaft seal? 😂😉

[tzsteve]

Easy job once you get the shaft out, just use the end of a drill bit etc to push it along the holr

[108]

This is great info!!

Any torques specs for the clutch screws (especially the inside ones)?

[Yoshi]

I didn't use a torque wrench on any of the screws and just went with wrist estimation of snug. I think the exact torque is not important so with these, but you can always take a look at the metric thread torque spec cheatsheet. Using thread lock is a must though.

[tzsteve]

They dont need any extreme tightening. On my yam it was 4 nm, as the last post said just hand tight,

Do not use loctite

And get a few spare screws look for A4 stainless flange head that take a torkx bit these have a lower profile than the allen key types so wont rub on the clutch cover

[Yoshi]

Why no loctite though? I like to put a small dab of soft threadlock in places that tend to do fast spinny things. Got clutch cover screws turning loose once and the sound was not pretty once one of them got in contact with clutch cover.

[tzsteve]

Sorry mate,
i got confused no loctite on the screws holding the plates in, but loctite on the ones holding the basket to the gears, the loctite just isnt needed on the ones holding the plates in, its never used there on bike engines and can cause problems when you come to taking the plates out especially on the lo grade screws supplied with the kit they are A2 stainless and can chew up very easily destroying the head of the screws making it even more dificult to get them out

[jonnysnatchsniffer]

its a lot fucking easier than the mk1 lol at least you can compress the clutch with the threaded bit on the inside of the spider
better than winding nuts down on m5 set screws that curve like a banana when you have xxxl springs in and
yr thinking fuck this, if it lets go, its gonna fuckn hurt