91hzh 30% Nitro and Shims

[Paulo uk]

Someone down the field said that I would need to add a a shim to my hzh in order to run 30% nitro through it - at this particular time I was honking round the sky with a borrowed tank of 30% oipti and it seemed to be flying rather nicely. I have read up on the reasons for needing one, but I cant find anything relating to it in the manual nor can I find the shims online to buy. Any help much appreciated.


Paul

[Paulice]

Hay Paul.
Are you talking about the OS HZ-R ?
If so yes you need to have 0.30mm shim's under the head, you can run with 0.20mm but it might be more difficult to tune. It's in the OS manual for this motor.

I Don't know about the HZH

[Cuppa]

Ran in my 91HZ-R on 30%lv with both shims supplyd .01-.02 found it quite easy to tune up, once i get a couple more gals fuel through it i will try it with just the .02 shim, i'm realy looking forward to getting my 700 back in the air re-( wot i did today)

[Paulo uk]

Hay Paul.
Are you talking about the OS HZ-R ?
If so yes you need to have 0.30mm shim's under the head, you can run with 0.20mm but it might be more difficult to tune. It's in the OS manual for this motor.

I Don't know about the HZH

Nope its the hzh - cant find a decent manual either online!

[Paulo uk]

Anyone know where i can get shims?

[Paulo uk]

Ok found shims now - Im guessing theres no way of telling if they are already in the engine without taking the head off?


Paul

[millerman]

Ok found shims now - Im guessing theres no way of telling if they are already in the engine without taking the head off?


Paul

unless you have an xray machine nope

[Paulo uk]

Shizzle just sold the xray machine on fleabay, will take the head off, cheers.


Paul

[Cuppa]

I think you will see that the motors are fitted with the .01 from the factory and you should have the .02 in the box that is from new. short of that pop the head off and check with a vernier, its hard to eyeball. my 91HZ-R came with the thicker shim in the box any head shim configuration should be in the manual

[Paulo uk]

Cheers cuppa.

Paul

[millerman]

i checked my hz-r tonight and that only has the .1 mm shim in so i added the .2mm one tiny bit less compression which is ok for running in
after a gallon i will remove the .1mm shim and that will give a bit more torque back