Match porting a 90cc-110cc honda clone

[Autophysn]

Before I begin, I would like to say I tried posting this in World class Help, but it did not let me. So if you feel this is miscatagorized, I appologize or recommend it be moved. ;)





OK, Here is the deal. I bought a 22mm carb from DR.ATV along with a intake manifold and one of those multi angle adaptors, so you can face the carb in any direction to clear anything. These are mainly used for CT50's, but I will need it to clear my electric starter. The intake manifold has a 25mm opening on both ends. I figure the larger diameter hole will not interfere with the carb, but at the base of the intake manifold where the 25mm hole will mount up to the stock 20mm hole/adaptor, is where I would suspect a problem to occure.

Now, I am assuming this immeadiate decrease in diameter will cause some sort of weirdness to occure, cause I would assume it would cause a disturbance in the flow. Or, even worse, causing the atomized fuel to collect and actually drip into the head.

Here is my question....
1) Does the above sound about right to anyone? I am a car mechanic, not a motorcycle mechanic :wondering

2) If so, what if I made a gradual mate-ing surface out of epoxy on the inside of the intake manifold to match the intake adaptor? Do you think this would help, hurt, or do nothing?

[Macs]

You may run into problems but i am a bit confused. What port is the head, Adapter, Intake, carb in that order

[Autophysn]

Well, (I am gonna try and get some pictures, I know it is a bit hard to explain in text) From outside in,
airfilter, carburetor (22mm), Intake manifold (25mm) inlet, outlet is also 25mm, to the adaptor plate (20mm) to the head (20mm)

the basic problem would be at the base of the Intake manifold coming from a 25mm hole to a 20mm hole.
My worry is the step would cause the atomoized fuel to collect and turn back into a liquid. Then we all know what happens from there :(

[Autophysn]

I suppose another way to ask this question is, when you guys hop up a string puller, by putting a larger carb and intake manifold, Do you match port the head to match the intake manifold as well?

[KASEY]

any time you can elliminate a disturbance in air flow it should help maybe not so much in performance but in just overall running quality.... it sounds like you did what would be necessary ,,, as long as the epoxy will stay put,,,,,,

[Autophysn]

I haven't done much to it yet, just got the stuff today, I had to do a little bit of grinding here and there cause of a screw up I did. Lost the square nuts they give you, LOL!

But otherwise, the only problem I had was that Dr.Atv sells you this 22mm carb replacement, and recommends a UNI POD filter. I assumed it would be a direct clamp on. It was not, The filter is too big too simply clamp on, I had to use a peice of radiator hose to take up some void and then clamp the filter to the hose.

I also did not like the fact that it looks like it was dropped, a flat spot on the intake side, oh well, Here it is, This is what I am talking about

http://i483.photobucket.com/albums/rr191/Autophysn/2.jpg?t=1235469687

http://i483.photobucket.com/albums/rr191/Autophysn/3.jpg?t=1235469718

This is the bottome peice, The adaptor is the stock 20mm hole and the intake manifold is 25mm. I have come to the conclusion that since the adaptor is billet and has alot of meat there, I will simply match port the hole to the intake, but it will be a drastic curve. I suppose some curve is better than no curve.

http://i483.photobucket.com/albums/rr191/Autophysn/4.jpg?t=1235469850


and here is the flat spot I was talking about

http://i483.photobucket.com/albums/rr191/Autophysn/1.jpg?t=1235469898

Sorry for the crappy picture quality....:(
Any thoughts, opinions, and or suggestions will be greatly appreciated, Thanks!