ccs77

First off, I tried really hard to find the motor sub forum with no luck so I sincerely apologize if this is in the wrong section. I'm looking for shimming information on this motor. There seems to be not much support help on line in the way of a digital manual etc...

How many and what size shim am i wanting to run in this motor? I run 30% nitro fuel.

It came stock with two .3mm shims installed which made it nice for break in since the compression was kind of low, but do I take a shim out or take them both out and install one of the .1mm shims the motor came with now?

Thanks for any help you could give guys, again I'm real sorry if this is in the wrong place.

o.s. power

iTrader: (14)

I think you would be smart to leave the shims in there. If you start taking them out, you are playing with fire and can risk severe damage to your engine.

ccs77

OK, that's cool, but would I be even smarter to add one of these .1mm shims it came with?

mremtr

iTrader: (1)

Why do you want to take out or add a shim ? Most of the engines from Europe can run just fine on 25% some reqire you to add .001mm shim if your going to run 30% plus . Otherwise leave it alone . Don't run it with a lean bog and it should hold up well . I have seen so many of those engines get wiped out because they were tuned right on the edge when cold. Warm it up during practice ,for at least 1/4 of a tank before you deside to lean it too destruction !!

T. Thomas

If you are going to run 30% fuel, you need to add one of the .1mm shims. This will get the compression right for the high nitro content of the 30% fuel. If you run 25% you do not add any shim, you run it stock.

sracer

iTrader: (2)

Has anyone else herd that you should put both shims in and break it in with 20% then take 1 shim out and run 30% and tune?

ccs77

I have heard that you add all shims to make break in easier, but I didnlt do it. My motor started just fine with the bump box I use.

So you actually ADD one of those shims to lower compression when running a higher Nitro Content fuel? Thank god I asked. I was pulling shims out...

I was trying to relate it to full scale four stroke motors and higher octane fuel. The higher the compression the higher octane fuel...

Thanks for the input.....

sport10

For some reason the motor forums is under the ON ROAD section. It should be a seperate forum not under and other forum except General Forums IMO.