Turbo plug

[CMBracer]

Hello guys

I just got a turbo plug head for my .90 CMB...

And it's making me craysy.

On the supplied manual, it showes only one shim under the head. Which is one less that I am currently using on my two normal plug head.

Anyways I am trying one shim.. The engine fires right up (as normal)

Runs real good at first(still on the beach) but as I start to rev up the engine it stalls.

I have checked everything about the tanks/ fuellines no leeks. Haven't run over the carb/engine yet.

But I just swarped the heads and before there was no problems!!

Anyone got any ideas?????

Morten

 

[Twin_k90]

What heat range is the plug??

sounds like the plug might be too cold and fueling up,

twin plugs like to be rich and will burn more fuel than a single plug head,

i had the most luck on my CMB100 with a standard plug single head set at 17tho clearance.

Dale

 

[CMBracer]

Sounds as if you could be right on the money twin K90..

It makes perfect sense what you say, about two plugs being able to run richer...

Naturly I have been going in both directions, with no luck...

I will try leaning out the mix even more, see where it will get me.

Thanks Morten

 

[Twin_k90]

Dont go too far tho,

if you still have the bottom end needle wind it out and use the main needle to set the motor,

 

[TimD]

CMBracer,

Measure the clearance at top dead centre to the twin plug head and make sure the clearance is what twinK90 said (17 thou).

Also, what turbo plugs are you using? Do the rev's drop when you take the igniter off?

Tim.

 

[CMBracer]

RPM does not drop when I take igniter off!

CMB's own plugs (hot) Well they only make two and neither are really hot!!

I don't have a toll(spelling) for meassuring this..

Do you buys go in via the plug hole, and measure from piston surface TDC to head??

Or do you measure the distance from piston TDC to top cylinder and deduct head "drop" in cylinder.

By the way the head is sligtly konkave, thus making the distance larger at the middle of the cylinder...

Please let me know Morten