Head porting

Oldschool

Oldschool

New Member
#1
#1
Does anyone have any pictures of a ported head they could post to give a better idea of where material should be removed on the clone head.

Just looking for some mild porting to go with a mild 200.
Milled 160 head (.030 ).

I have a fari idea what I want to do but I would prefer to see a head that was done right.
 
Oldschool

Oldschool

New Member
#5
#5
A quick look at what you did ( considerably more radical than I need ) tells me I should be smoothing the sharp corners under the valve seats ( radius ) and givng the top of the runner a little contour around the valve guides. I don't want to increase port size just smooth things out a bit.

JD knows what I am after he gave me some pointers but I still would like to see what has been done.

I'm looking to make about 10 hp from the GX200 clone at 5000 rpm with as much low end torque as possible.

I chose a Tilly HL 166 carb ( just a little larger than stock ) and my own port match intake that swings the carb up and out of harms way

YouTube - More of the Baja

test video of the carb and intake on a GX 160 clone ).

The undercut stainless valves look interesting....
The NR 252 -0211 cam seems to fit the bill ( according to NR )...
Arc rod, header, flat top piston and .040 millled clone head.

I don't want to shift too much of the power and torque up the rpm range and I don't want or need the thing reving up beyond about 6000 rpm.

Basicly I just want to make the motor perform better and have some stronger internals. I'm not racing I just want a bit more power to go with a TAV upgrade.
This engine ran like crap but I know why. Made from too many different bits and pieces. Next one should be significantly better
 
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Oldschool

Oldschool

New Member
#7
#7
Your too kind:

Sure it looked good and sounded cool( if you look past the bog when I crack the throttle ), but it was not going to do what I wanted. This engine was stock 5.5 hp clone with a 6.5 head .It had a some valve and timing issues.

I'm scavaneging parts for my second build.

Question is have I selected the right parts in my list for what I need?

Looking for some input here. I have asked this question several times at other forums and get some mixed answeres
 
minidragbike

minidragbike

Supporting Speed Nut!
#8
#8
Oldschool said:
Your too kind:

Sure it looked good and sounded cool( if you look past the bog when I crack the throttle ), but it was not going to do what I wanted. This engine was stock 5.5 hp clone with a 6.5 head .It had a some valve and timing issues.

I'm scavaneging parts for my second build.

Question is have I selected the right parts in my list for what I need?

Looking for some input here. I have asked this question several times at other forums and get some mixed answeres
Click to expand...
I have seen your post on other forums

First thing you should do is buy a 6.5hp motor. The smaller motor makes the carb appear, and work like it's larger. Second the compression is way to low. The stock motor is only about 8.25:1, but you have a big chamber head so you may only be at 7.5:1. This will make the motor very lazy all by itself.
 
Oldschool

Oldschool

New Member
#10
#10
Well a couple of reasons for what's running in the video.
I bought the bike with a blown engine for next to nothing from the dealer. He gave a rod and some parts to rebuild it but that wasn't enough ( wrist pin failure on the 6.5 clone badly scored bore ).

So I brought back the rod and rings he gave me and asked if he had any scrap engines. At the time I didn't know how to identify the 5.5 externaly and the engine I made from odds and ends ended up with a 6.5 head because the 5.5 had a cracked casting in the rocker box.

On the upside the engines made good mock ups and let me work around the issues of the header and carb.

Today I'm heading back over to the BAJA dealer to see if I can sweet talk him into deal on a new GX200 clone he has with a taper shaft I know he isn't going to sell any time soon. Then the next build will begin I will have all the parts I need more or less and I'll be ready to buy some good internals

The GX160 clone you see in the video is no good to me 20mm crank so nothing fits just for starters. I found that out when I went to put a jack shaft on it a few weeks ago.

I have one other engine all rebuilt fresh and ready to go.
But Antaeus, the stationary engine has a weight problem ( 375 pound 10 hp brute )

In any event as you guys have said I've posted before at other forums asking a lot of questions. I just want to be sure I am making the right choices on parts and modifications
 
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Oldschool

Oldschool

New Member
#14
#14
The GX 200 clone is what I wanted in the first place. Thats what I thought I had there untill I pulled the crank out to swap with another and realized " one of these things is not like the other "...

Anyhow I thinks its realy good of the BAJA dealer to make deals like this. He knows I'm on strike right now and has been feeding me a steady stream of used parts and new in some cases. I also bought a mini quad from my son from this fellow that developed an issue ( too much metal in the oil for my taste ). He not only replaced the quad but upgraded me to a Kazuma from the JID SHOE TANG TWAN what ever it was. Can't see there was any profit margin in that sale.

Its been said before and I will say it again. If you find a good guy to deal with for parts or sales suport the man. The Boys at " Source One Motor Sports " are getting a sweet deal on some electrical upgrades to their shop( just a days work ). And I will be back to buy more from them later.

When the dust settle Ill have 2 new engines and a generator.
 
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