head porting

[Big red 200es]

A guy was supposed to do a porting in my head of 125m but he doesn't have the time . I can find another guy to do the job. But it is necessary ?

On this 3 wheeler I will have a dg pipe, a uni filter and may be a bigger carb.

Thanks
Nick

[RedRider_AK]

Head porting isn't "necessary", it just increases the volumetric efficiency of the engine (smoother transitions for the fuel/air mix to flow through = more power). You could probably do it yourself, given some time and common sense and ingenuity.

All you need is a Dremel, some grinding and rubberized polishing bits, and that's about it. Match the ports on the cylinder head and the intake manifold to the gasket, smooth out the ports to a polished finish with the rubber bits. Be sure the intake valve is closed when you're grinding on the head, so you can vacuum out the dust without having it fall into the cylinder and fly around in there.

I need a Dremel myself, I'm modding a 250 air-fooler engine to go into my StarLite play-snowmobile.

[Big red 200es]

So a porting will do a Difference ?

[RedRider_AK]

Obviously, if it's done right, it will, otherwise, nobody would get their engines ported and polished.

[Big red 200es]

ok thanks

NIck

[KASEY]

wow!!! thats some bad info if i ever seen any!!! port matching will do NOTHING for a 125m,,,, the only way you can do a proper porting job is to strip the head completely down,,, there is WAY more to a porting job than just grinding some aluminum out and shining it up inside,,, the heart of a port job starts at the valve seat, and with the valves in there is no way do it,,, if you want a little more performance get a higher compression piston and a cam,,,

[Big red 200es]

I know now the head is off.
So with a REAL porting made by a profesionnal do you think I will see the difference ?

And my 125m will have a DG pipe, a uni air filter and probably a bigger carb.

Thanks
Nick

[KASEY]

the little four strokes do not respond well to modifications,,, you can spend a ton of money and be really disapointed ,,, porting will only make a difference above like 6000 rpm's or more,,,, and without a higher compression piston and a cam,,, it won't make any difference,,,,,,

[Big red 200es]

Ok so you think im better to just put the head on and dont do the porting.
But do you think with a pipe and a uni air filter I will see a difference now is .50 oversize.And do you think a bigger carb will help me im not sure because he have a very long intake tube. Now the carb is the stock so 20mm.

Thanks a lot to help me to dont loose my cash

Nick

[Big red 200es]

nobody know

[Big red 200es]

An atc 200 carb will it fit ?

[KASEY]

probably the same size carb as a 185 carb

[Big red 200es]

So an atc 185s carb will fit.

Do you think I will see the difference ?

Sorry for all my question

THANKS
Nick

[Danold]

I would say re-jet the stock carb. Did you put the 20mm one on it? I know the 185 is a 22mm which is probabally to big.

[Big red 200es]

ok thanks
I will try the 20mm before.
Now the head is in piece so I can do test right now.

[DasUberKraut]

Have you had any success Big Red??? I was also wondering what engine mods I will be doing to my 125m.

I was thinking of the biggest piston they make, I thinks it's +2mm
A bigger carb. I actually have a stock carb off an 82 185s in a box I stripped off a parts bike but never measured it.
I PM'ed DirtCrasher and asked if bigger valves is worth it on the 125m. I'm thinking of having him rebuild a head for me with all the goodies and stainless exhaust studs.
Also considering swapping out sub trans for a TRX125 sub trans for High - Reverse gears.
If I do all that I'm guess I'll go all the way and redo all the bearings and seals and have the whole motor painted.

I was not aware they made a cam for the 125m. Unless it has to be done privately. I checked Powroll and Web Cams...I don't know any othe sources for performance ATC parts, especially for a 125. Seems like 200 and above are the only ones given love for the most part.