nz 350 clutch problem

Basic info on DKW NZ 350's

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Dirk
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nz 350 clutch problem

Post by Dirk » Tue Jun 16, 2015 8:00 pm

Hello all,

Got my nz 350 back yesterday, today I drove for some miles
in first, second and sometimes third gear.
Every now and then when shifting down or up my clutch tends to "stick",
also a few times it was grinding because the gearbox didn't engaged
into the right gear..

Last year when the whole motor was disasembled the guy who did the work
put in 3 instead of 4 of the clutch plates with kork because the kork was still
to thick, he said that when driving it after some 1000km it would be possible
to put in the 4th one.

Any ideas what is happening and what I should do?

It occurs only when the engine is warm.

regards, Dirk
Dirk
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Posts: 81
Joined: Sun Oct 19, 2008 6:22 pm
Location: Deventer, The Netherlands

Re: nz 350 clutch problem

Post by Dirk » Fri Aug 07, 2015 12:38 pm

In Holland we sing "het is stil aan de overkant" when the counterparty doesn't respond when getting slaughtered in a soccer match..
Frank
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Re: nz 350 clutch problem

Post by Frank » Fri Aug 07, 2015 9:57 pm

Hi Dirk,

Here in Finland we understand nothing about soccer :lol:



Hard to say if your problem is the clutch or the gearbox. My guess is the clutch, because I cant find out what would be temperature sensitive in the gearbox.

There is something strange if you cant fit all 4 cork plates (the corks are too thick, or you have an NZ250 clutch cage).

The NZ cork clutch works very nicely if the parts are ok and the clutch is correctly assembled and adjusted.


In my opinion:

1. Dismantle the clutch and check that you have the right clutch cage for NZ 350.
If the cage is correct, check the grooves in the clutch cage (where the "wings" of the clutch discs comes), so there are not worn notches, where the wings will stick.
If there are small notches, file, or grind the grooves to get a good surface. If badly worn try to find a better clutch cage.

Also check that all other parts in the clutch are correct, dont forget to check the clutch mechanism and also that the clutch inner cage is not bottoming and hitting the outer cage.



2. Check the clutch discs and the steel plates that they are straight on an good straight surface. If the discs or steel plates are warped, the will bend more when they get warm and the clutch will drag. Dont use warped or very scratched steel plates, scrap them and try to find better or new ones.


3. If the cork discs are too thick, grind them to correct thickness with sanding paper on an straight surface. I measured a NOS cork disc and the corks are 5,1 - 5,8mm on the same disc in dry condition.


4. Mount the parts as shown in the parts, or w/s manual, check also that all 6 clutch springs are of the same lenght and wire thickness (there are different springs on different NZ types).
If the springs are ok, tighten all 6 nuts that holds the springs, so that 1mm of the 6 bolts can be visible outside the nuts.


5. Dont mount the engine cover yet!
Adjust the clutch lever free lash on the clutch adjuster screw on the right side of the engine, so you have 4-5 mm free lash at the clutch lever.

Then pull the clutch lever so its bottoming against the handlebar and lock it with an cable tie in engaged position.
When the clutch lever is locked, check that the clutch plate cover (lifts) opens the same amount on every side, if not openig straight, then adjust on some of the 6 nuts so the cover opens straight.

6. Cut the cable tie, mount the engine cover and fill the right amount of oil (1 liter) of SAE 30 or SAE 50 single grade motor oil (SAE 30 Lawn mower oil works fine)

7. Good luck and dont hesitate to ask if I was unclear with something.


//Frank
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