VS_Rody
i have a stupid question, are those cylinder and piston sets inter-usable

1. euro in euro 2 crankcase
1.1 euro in shimo 2 crank case
2 euro 2 in euro crank case
2.2 euro 2 in shimo crank case
3 shimo 2 in euro crank case
4. shimo2 in euro 2 crank case
5. 2104 in shimo 2 crank case
6. 2104 in euro 2 crank case
7. 2104 in euro crank case

wonder if anyone has this info? cheers

All the sleeves of the R21 engines are interchangeable.
The Shimo2 and Euro2 have some extra lubrification porting for which you need the Shimo2 crankcase(which is the same for the Euro2).

Hope this has cleared things for you.

I was told the Hasi has a slight different diameter sleeves and so parts are not interchangeable.

Hasi was not in the listing.
I do not think OS does this, unless the qty's Hasi takes are very important which I doubt. But since I do not know for sure maybe somebody who has a Hasi measures the outside diameter of the sleeve and so we can clear this.

A friend who is doing some OS (based) engines had several models side by side and he did notice that, maybe more like a tolerance thing.

The Hasi is not based on the Shimo 2 or Euro 2. It does not have the extra oil ports. I can measure later.

ok, thanks
1. then may i use euro 2 or shimo 2 cylinder piston set in some models with inner head without inner o-ring?
2. with that said, i can just pick to buy either euro2/shimo2 for euro2/shimon2 crankcase
3. how about euro2/shimo2 cp set into 2104 (even the crankcase has no lubrication trim inside)?

thanks so much, you are appreciated

oh, i know that now, then hasi is probably based on the euro or 2103 crankcase, the previous model

1) Yes you can but the extra oil ports will not be of any use.
2) Yes, you can also buy the Shimo2 or Euro2 crankcase.
3) Yes you can but the extra oil ports will not be of any use.

that means with or without inner o-ring is not sleeve dependent. it is the hear sink which has circular o-ring guide, to determine to use o-ring or not

If you speak about the o-ring in between the crankcase and the underhead, this also you can use with out without on any R21 type crankcase.

The extra cooling/lubrication holes can be made to work with grinding some slots in the sleeve.

I have made even some of those ports on my 5 port R21

I just bought a o.s speed euro2 and I’m just curious if it’s highlights are considered to be more of a top end or bottom end engine…I believe I’ve heard it’s more of a top end engine but I don’t 100% know for sure

I have seen and measured many OS (based) engines but have not seen any Euro spec engine but I believe the exhaust port will be a little bit higher for a higher top rpm that suits the European style tracks.

Toying on the idea of returning to the noisy (and greasy) things. My last car of this was an MRX4X and a wicked RB C5 many many many moons. Loved it, enjoyed it but needed to let it go. 20 years after I return and wondering what is the VS Equivalent to an R21 Euro II if there's an equivalent.