Can a HT have a plastic intake manafold?

[silverscreen]

Not necessarily. Sounds like you did not geat a good seal between your carb --- and your --- manifold. There is probable an air leak somewhere in that area. try to seal every joint between your carb and you manifold air tight.

 

[justinsidethegates]

yeah an air leak will give you all kinds of idling problems. you would have been fine with only using 1 90 or even a 45. was there any reason you wanted facing the usual way but off to the side? Hope you got ir running better since then.

 

[Neon]

a 2 stroke expelles some of its exhaust through the intake and that could heat things up.

Never heard that. No way it can happen. A small amount of gas is expelled through the exhaust. Look at the port arrangement on a two stroke and you will probably see why it doesn't happen. It would be an extremely bad scene if that did happen.

 

[Big Red]

Intake

This is gonna hurt, but BGF(ouch!!!) sells an extended offset intake manifold for about $10.00. Bolts right on and gets the carb away from the downtube.
Warning: If anything goes wrong with "Boygoslow", (bad part, lost in shipping,ect,) Do not expect him to make it right couse he wont. 99% of the time everything is good with him. But when it goes bad it stays bad.
Big Red.

 

[cloud_2901]

Neon, you never looked hard enough then

A 2 stroke can have blowback from the pressure wave generated by the exhaust and the previous combustion returning to the cylinder at not exactly the right time, a rather high possibility with these chinese engines I think, unless the inlet port is blocked by the usually present reed valves or a rotary valve system. We don't have them, so we get blowback, hence people selling boost bottles, that I don't think would have a huge effect, but I'm sure they would have some small amount of blowback entering them.

 

[motorpsycho]

if you want to make an intake extension out of plastic, it can be done.
you can't mount plastic right to the cylinder, but you can add an extension to the existing metal intake manifold.
You need to look for nylon plastic elbows which are used on car engines for some of the emissions parts.
It may be hard to find the right diameter but they are out there.
the nylon will handle the high heat better than pvc.
look for pcv (positive crankcase ventillation) nylon elbows and straight peices made for car engines.

 

[justinsidethegates]

Hmm very interesting but i think i'm going to try a piece of ABS plastic if i can find it in that small of a diameter or go back to the drawing board with a copper 45. they wont be touching each other directly but a piece of 1/2" fuel line as a coupler to the intake tube and another piece to the carb. Also just realized how old this post was that i accidentally brought back to life but it shows i used the search function AND managed not to start a new topic over something gone over so much. still need to figure out the best setup for this tho.

Another thought is has anyone thought about making an intake tube with both a long spout and a shorter one with a butterfly valve inside the longer one so it only kicks in when you go lets say 75% throttle +?