New 21 CMB Beta

[timothy johnson]

Anybody have any info on the new CMB 21 in an outrigger?

 

[JoachimRuess]

The new CMB Beta is a real powerhouse. I have it in an outrigger from Jörgen Andersson.

The engine is revving good, and has very good torque.

Look at the video from a test run at our (little) pond.



cheers

Joachim

 

[Chris Davis]

Jim Wilson Dist 9 just dominated Sport 21 and A Mono at the Nationals in Marysville WA with this engine. Very powerful engine.

 

[dwilfong]

The P/L is a drop in for the MAC/CMB engs also.

Just put one in my MAC-VAC hybrid eng.

 

[shoboat]

Fellas,

It has great timing numbers right out of the box.

I think CMB got it right on this engine. They did their homework.

It pulls quite a bit more propeller than most other 21 engines.

I know working on a couple of other boaters set ups it will pull

more propeller and rev pretty hard also. You cannot go wrong

with this engine, and I think you will not be buying a lot of parts

to keep it running well for quite a few years. And Stu has them

in stock now.

Thanks For Reading,

Mark Sholund

 

[Andy Brown]

The new CMB 21 Beta just won 3.5cc Hydro at the World Champs in Dessua, Germany this week against a large field of tough competition.

The winning 21 Beta was pushing an Eagle SGX and expertly driven by Kjell Gunner Noddeland of Norway.

 

[jose barreiro]

WOW that rigger is fast ?? any engine mods or just bone stock out the box ??

 

[timothy johnson]

Sounds good Andy do you know anything about the prop,fuel etc. Thanks Tim

 

[JoachimRuess]

The only modification done on the Beta in the video is the valve from a Mac .21. This is because i have too little room for the original carb. I think with original valve and carb the speed has to grow up.

BTW: prop is a ABC 52X70 SS prepped by Mark Sholund.

 

[Ross Petersen]

What pipe best suits this engine so far.

 

[JoachimRuess]

For me AB .21 Parabolic works best.

( and is muffled enough for european competition)

Regards

Joachim

 

[Greg Bonahoom]

I ran mine for the first time today and was very impressed. I was running a jae, cmb nitro pipe at about 8", and an h7 prop. Ran it all day, trying different props, pipe lengths, plugs, etc. Never needed the retrieve boat! The thing came back every time.

 

[BobBonahoom]

With a little help from you friends!

 

[Ray Sametz]

With a little help from you friends!

When they grow up they never give you any credit.

 

[LarryConrad]

With a little help from you friends!

When they grow up they never give you any credit.

 

[Ted buckley]

With a little help from you friends!

When they grow up they never give you any credit.

X2

 

[Bob Morton]

Humor is all ways a good thing

 

[timothy johnson]

I ran mine for the first time today and was very impressed. I was running a jae, cmb nitro pipe at about 8", and an h7 prop. Ran it all day, trying different props, pipe lengths, plugs, etc. Never needed the retrieve boat! The thing came back every time.

Sounds great Greg, what fuel / % nitro were you running? I have the same combo, I will run it on Sat for the first time. Also did you change the head CL . Thanks Tim

 

[BobBonahoom]

Tim and others, Greg and I have 2 Beta engines and we have now run both of them. We are running 65% nitro with 18% Klotz Super Techniplate (20% castor). We have the head clearance set at 0.008" but are moving it down to 0.006" for our next outing. We are running CMB 21 nitro pipes at 7-1/2", using a 97 Od plug with one coil pulled out. We found that pulling the coil makes launching with the short pipe reliable. The key to making this set-up work is running rich on the needle. We are at 78 on the older Borris meter. Props are H7s. Oh, and we cut off the low speed needles.

IMPORANT!

There is something important we learned and this is critical. If you take all the head shims out, you will get down to about 0.008" HC, BUT the water head may not seal the button to the liner when you tighten it down. We noticed fuel coming out of the water exit and realized that it was not sealing. This caused us to set way too lean a needle, etc. The fix for this was to put a few thick head shims on top of the head button to insure a good squeeze on the button by the water jacket. Not too much shim though, or you may not seal the O-ring. I used two 0.020 head shims in each engine. After we did that, we stopped blowing plugs, opened the needles up and the engines really came alive. Hope this helps.

 

[eekern]

Tim and others, Greg and I have 2 Beta engines and we have now run both of them. We are running 65% nitro with 18% Klotz Super Techniplate (20% castor). We have the head clearance set at 0.008" but are moving it down to 0.006" for our next outing. We are running CMB 21 nitro pipes at 7-1/2", using a 97 Od plug with one coil pulled out. We found that pulling the coil makes launching with the short pipe reliable. The key to making this set-up work is running rich on the needle. We are at 78 on the older Borris meter. Props are H7s. Oh, and we cut off the low speed needles.

IMPORANT!

There is something important we learned and this is critical. If you take all the head shims out, you will get down to about 0.008" HC, BUT the water head may not seal the button to the liner when you tighten it down. We noticed fuel coming out of the water exit and realized that it was not sealing. This caused us to set way too lean a needle, etc. The fix for this was to put a few thick head shims on top of the head button to insure a good squeeze on the button by the water jacket. Not too much shim though, or you may not seal the O-ring. I used two 0.020 head shims in each engine. After we did that, we stopped blowing plugs, opened the needles up and the engines really came alive. Hope this helps.

Good find bob.