CMB 101 tunning issue

[Tofastformellow]

Gday , i have a 06 cmb 101rs , yeah the crappy one with the AAC liner. fuel is 50% as it dosent go well on 25% (not like i want it to)

ok , so i have the motor running pretty well in a mono , i can get it to second stage , and its pulling pretty hard , but

when i pulled it down it had one head shim in it

the probelm is it just keeps eating plugs , it dosent matter what plug, mc9,os8,Hp, nosram, enya, etc etc. it just keeps spitting them .

usually the plug looks fine , it just wont light up again , after a run ...

i pulled the button and added another .0004"shim , and now it only pulls a smaller prop , with the same result ...

i have tried propping up , but i am now at the top of the props i have for it ... and am unsure as to what to do next with the dam thing .

the boat is reliable enough, and fast enough , but i want it to stop eating plugs ,

where do i start ?

with my old evo 2000, i added shims until it stopped eating plugs , but then it was hardly competative as it had to be run so underpropped.

i am looking for a new angle on fixing this plug eating monster

many thanks

Jason

 

[John Knight]

Jason,

What is the pipe and the length? What is the head clearance now?

 

[Tofastformellow]

pipe is a cmb 90/100 silent stock at 12 inch , started at 13" worked down .

, head clearance now at , 0.0016"

was at .0012 out of the box.

Jason .

 

[dave roach]

You need to open up the head clearance to .012 to .016 sound like you have .0008 tenths to .0016

Dave Roach

 

[steve wood]

Gday , i have a 06 cmb 101rs , yeah the crappy one with the AAC liner. fuel is 50% as it dosent go well on 25% (not like i want it to)
ok , so i have the motor running pretty well in a mono , i can get it to second stage , and its pulling pretty hard , but

when i pulled it down it had one head shim in it

the probelm is it just keeps eating plugs , it dosent matter what plug, mc9,os8,Hp, nosram, enya, etc etc. it just keeps spitting them .

usually the plug looks fine , it just wont light up again , after a run ...

i pulled the button and added another .0004"shim , and now it only pulls a smaller prop , with the same result ...

i have tried propping up , but i am now at the top of the props i have for it ... and am unsure as to what to do next with the dam thing .

the boat is reliable enough, and fast enough , but i want it to stop eating plugs ,

where do i start ?

with my old evo 2000, i added shims until it stopped eating plugs , but then it was hardly competative as it had to be run so underpropped.

i am looking for a new angle on fixing this plug eating monster

many thanks

Jason

open head volume to .76 or more. set clearance to about .015. remove material from rear of case to achieve .003 to .004 clearance for the rotor, instead of the .023 or so that the factory gives you. that should do it

 

[Joe Warren]

Gday , i have a 06 cmb 101rs , yeah the crappy one with the AAC liner. fuel is 50% as it dosent go well on 25% (not like i want it to)
ok , so i have the motor running pretty well in a mono , i can get it to second stage , and its pulling pretty hard , but

when i pulled it down it had one head shim in it

the probelm is it just keeps eating plugs , it dosent matter what plug, mc9,os8,Hp, nosram, enya, etc etc. it just keeps spitting them .

usually the plug looks fine , it just wont light up again , after a run ...

i pulled the button and added another .0004"shim , and now it only pulls a smaller prop , with the same result ...

i have tried propping up , but i am now at the top of the props i have for it ... and am unsure as to what to do next with the dam thing .

the boat is reliable enough, and fast enough , but i want it to stop eating plugs ,

where do i start ?

with my old evo 2000, i added shims until it stopped eating plugs , but then it was hardly competative as it had to be run so underpropped.

i am looking for a new angle on fixing this plug eating monster

many thanks

Jason

open head volume to .76 or more. set clearance to about .015. remove material from rear of case to achieve .003 to .004 clearance for the rotor, instead of the .023 or so that the factory gives you. that should do it

Newier engine comes with a .8 head .1 volume(cup) in the piston. A newier head @ .017-.18 might fix your problem if you cannot change the head volume by yourself. We run 1.0 cc head plus the piston volume .1 @ .016 on 60 percent. also consider the stinger size of your engine... You must let the heat out.

 

[Joe Warren]

Gday , i have a 06 cmb 101rs , yeah the crappy one with the AAC liner. fuel is 50% as it dosent go well on 25% (not like i want it to)
ok , so i have the motor running pretty well in a mono , i can get it to second stage , and its pulling pretty hard , but

when i pulled it down it had one head shim in it

the probelm is it just keeps eating plugs , it dosent matter what plug, mc9,os8,Hp, nosram, enya, etc etc. it just keeps spitting them .

usually the plug looks fine , it just wont light up again , after a run ...

i pulled the button and added another .0004"shim , and now it only pulls a smaller prop , with the same result ...

i have tried propping up , but i am now at the top of the props i have for it ... and am unsure as to what to do next with the dam thing .

the boat is reliable enough, and fast enough , but i want it to stop eating plugs ,

where do i start ?

with my old evo 2000, i added shims until it stopped eating plugs , but then it was hardly competative as it had to be run so underpropped.

i am looking for a new angle on fixing this plug eating monster

many thanks

Jason

open head volume to .76 or more. set clearance to about .015. remove material from rear of case to achieve .003 to .004 clearance for the rotor, instead of the .023 or so that the factory gives you. that should do it

Newier engine comes with a .8 head .1 volume(cup) in the piston. A newier head @ .017-.18 might fix your problem if you cannot change the head volume by yourself. We run 1.0 cc head plus the piston volume .1 @ .016 on 60 percent. also consider the stinger size of your engine... You must let the heat out.

 

[Tofastformellow]

Thanks guys

yeah , this motor comes with a .020" cup in the piston..

quote

"open head volume to .76 or more. set clearance to about .015. remove material from rear of case to achieve .003 to .004 clearance for the rotor, instead of the .023 or so that the factory gives you. that should do it"

i have heard of people taking the gasket out of the disk housing before , but dont have a good mill to do that properly myself.

quote

"Newier engine comes with a .8 head .1 volume(cup) in the piston. A newier head @ .017-.18 might fix your problem if you cannot change the head volume by yourself. We run 1.0 cc head plus the piston volume .1 @ .016 on 60 percent. also consider the stinger size of your engine... You must let the heat out. "

i think i will open up the silent pipe , but it should run ok stock . i have run spp on the evos2000's in the past , and got good reslults ... in setting up this new boat , it would be nice to get the stock gear to go like it should ..

thanks guys ...

jase

 

[Joe Warren]

Thanks guys yeah , this motor comes with a .020" cup in the piston..

quote

"open head volume to .76 or more. set clearance to about .015. remove material from rear of case to achieve .003 to .004 clearance for the rotor, instead of the .023 or so that the factory gives you. that should do it"

i have heard of people taking the gasket out of the disk housing before , but dont have a good mill to do that properly myself.

quote

"Newier engine comes with a .8 head .1 volume(cup) in the piston. A newier head @ .017-.18 might fix your problem if you cannot change the head volume by yourself. We run 1.0 cc head plus the piston volume .1 @ .016 on 60 percent. also consider the stinger size of your engine... You must let the heat out. "

i think i will open up the silent pipe , but it should run ok stock . i have run spp on the evos2000's in the past , and got good reslults ... in setting up this new boat , it would be nice to get the stock gear to go like it should ..

thanks guys ...

jase

Jase I dont know who the CMB people are setting the RS 101 up for?? But if left stk it will burn a hole right thru the top of the piston. Most of the RS 91-101 I have seen have the Rotor intake valve set up for the thin rotor disk. Most of the EVO 100-90`s You could find either rotor intake valve (thin .013 - thick .023) in those cases & You must check the clearence on the EVO`s.

 

[Anders_Martinelle]

But if left stk it will burn a hole right thru the top of the piston

I don`t know what you do guys but i have never been able to succeed with that???

And i use std head set to 0,0010-12" clerance?

Anders

 

[Roxyflash]

For what its worth better send the engine to Steve Woods and get it fixed up correctly.The money your wasting on plugs could cover the cost to have it fixed.To bad CMB wont stand behind the bad engines!

 

[aaron alberico]

Jas

i now what's your problem,

send it to me to rework for you...lol :lol:

then you will see some serious power and rpm's

regards Aaron