2 cycle long intake

[curtisfox]

I have a 2 cycle engine that lays on it side (horizantal ) and the carb is on the bottom ( crakcase end ). I want to tip it up but would have to run a long S shaped intake about 10" long all total. Would this work or is it a wast of time?
I know 4 stroke works well with this setup, but not sure about 2 cycle THANKS...........Curt

 

[curtisfox]

Maybe I should explan a little more: If I tip the engine up the carb would be pointed down tward the ground. I would like to make a intake that would go up along the side to put the carb somewere buy the cylinder head.

I just want to know if it is worth it all as far as keeping in tune? Will it lose power or gain? Any addvice would be a big help..........Curt

 

[camlifter]

on a 2 stroke the shorter the intake the better. it will probably still run but not as good. if it's an old chain saw motor, most used the tilly carb, which has no float bowl and can be run in any position. so you may not have to move it.

 

[rustycase]

Camlifter, do you think it is not correct that a longer intake tract improves the bottom end torque of a 2 cycle?
What do you think of boost bottles? They effectively increase intake volume???

...not to stray from this OP...

I think an all-position carb will ...run... fine, yet mounted downwards will not perform optimally when the enrichen circuit is enabled for starting... excess fuel demanded for starting will not flow into the motor, but dump out, while starting.
Kinda like the orientation problem with a cylinder mounted upside down with the plug taking excess fuel as the motor is shut off... it must be overcome when starting the next time.

...just thinkin'
rc

 

[curtisfox]

Its a clinton I think Kind of like a LawnBoy engine. It has a float and would like to keep the old time look if I could. I am sure it has reed valves in the bottom of the engine........Curt

 

[rustycase]

Yah, if it's got a float it ain't gonna work vertical...
r u sure it's got reeds? BONUS!

...msrfan used piece of 10-speed handlebar for curved intake tract on his briggs...
rc

 

[curtisfox]

Not sure about the reeds. I haven't took it apart. Its actually a old Jacobson motor bike engine that I found. Maybe I should just e-bay it and look for something else.

I supose I could run a weed eater-chain saw type carb and make somekind fake carb for looks

 

[camlifter]

Camlifter, do you think it is not correct that a longer intake tract improves the bottom end torque of a 2 cycle?
What do you think of boost bottles? They effectively increase intake volume???

that hasn't been my experience, the intake on a 2 stroke (and a 4 stroke) has a pulse. in other words a tuned length. 2 strokes need a shorter length to run best. even on 2 stroke trials bikes where low end is king they run a short intake and tune with the pipe, they have almost no expansion chamber.
boost bottles are a band aid for an improper length intake, which is why they work on some engines and not others.

 

[curtisfox]

So even if I tip it up with a chain saw carb it might be a little hard starting?

 

[camlifter]

the chain saw carb will have a diaphragm so it won't matter where it's at.

 

[curtisfox]

Yep I know but it will be a long way up to the piston. But laying down would be the same.

THANK YOU VERRY MUCH...............Curt

 

[rustycase]

Cam, I remember tunnel ram intake manifolds that were built for bottom end torque. even the hillborn injectors sat on a stack, except for the ones cammed for screaming top rpm.

...long narrow intake tract and small venturi for torque, dump the fuel right in there with a large bore quad for top end horsepower...

at least that's what I remember... which ain't sayin much!

I do agree w u that the boost bottles may be a fix for an improperly short intake tract.
..I think my kid's 450F has a plenum on it...they don't call it a boost bottle from the factory... bit I'll check...can't see in there very well for all the plastic and hoses and stuff... recent bikes sure are complicated!

Has anyone actually ran tests on these ht engines?

Best
rc