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Can any one give instructions on how to do case porting? I am looking info as where/what and how much to grind down. TIA

Eggy
 

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bacanal32 said:
Can any one give instructions on how to do case porting? I am looking info as where/what and how much to grind down. TIA

Eggy
in one of the how to articles there is a decent how to and specs on porting the cyl. look around, you'll find it.

what im interested in is what people thought of their bikes after this mod? stories please! tnx
 

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I haven't had much success with case porting.

1. When I ported my case and added my own 4 port barrel, I actually lost about 2K RPMs up top. Not good.

2. When I added my 4 port to a stock case, I get upwards of 12.4-12.7K RPMs. I can't explain it. I might have ported too much...could be the reason why I dropped RPMs with #1.

With both #1&2, I ran both bikes with the polini pipe and dellorto carb. In fact, I have the engine with the case porting and 4 port on the bike right now. I only top out at 10K RPMs. It could be something else, plus I might have to do more tuning, but that's the best I've gotten with a ported case and 4 port barrel. Other cag tuners may have different results. In my opinion, and with my experience, I'd just put a 4 port barrel on a stock case.

What I didn't mention, is that the engine that I had tach out at 12.7, had a mm64 4 port barrel. I did a similar port job on another engine, and I didn't get the same results.

-E




bacanal32 said:
Hmmm, I am really looking for crank case porting, not cyl porting. Thanks anyway.
 

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vinnie said:
when u guys port, which bit do u use for the dremel tools?
I opened up the ports by 2mm to match the barrel I ported and took off the 90 deg angle leading up to the barrel. Also made them 1mm deeper to match barrel.

I cut the corners off the bottom of the barrel to match the piston as well.

I used a carbide cutter bit and then a stone followed by 440 grit sand paper.
 

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WFO Racing said:
I opened up the ports by 2mm to match the barrel I ported and took off the 90 deg angle leading up to the barrel. Also made them 1mm deeper to match barrel.

I cut the corners off the bottom of the barrel to match the piston as well.

I used a carbide cutter bit and then a stone followed by 440 grit sand paper.
I have had to split a case recently and was wondering about case porting. What people have done this and does this method above seem to work well? Does it reduce crankcase voulme to much? If so, could that be corrected by FCC?

Here are some more pics.Any input on the matter would be greatly appreciated.
 

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so i should cut away the bottom of the transfer port at the lip of the cylinder so it is even with the piston opening when the bottom of the piston is flush with the bottom of the cylinder (where the tip of the pen is pointing to in the pics) ?
 

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should the transfer ports be as wide as the piston openings??
 

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I just finished my first port job. Worked very well. Now i see this and think i might have to try it!! Makes sense, clean up the passage's for the air to flow would only make things better. Although i still dont understand what the case area getting bigger or smaller will do for performance.

DK
 

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d.king said:
I just finished my first port job. Worked very well. Now i see this and think i might have to try it!! Makes sense, clean up the passage's for the air to flow would only make things better. Although i still dont understand what the case area getting bigger or smaller will do for performance.

DK
Think about the case area scenario for a minute and I know that you will for sure understand "stuffed cranks" and "stuffed cases". I will give you a hint but case volume has a direct affect on transfer port air velocity.
 

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the suspense is killing me..... :D
 

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I would think that, if the space was smaller, it would increase the speed of the air and aid in low speed power. I would also think that if i increased the area I would add to the high end power band.

I could be wrong! LOL
DK
 

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d.king said:
I would think that, if the space was smaller, it would increase the speed of the air and aid in low speed power. I would also think that if i increased the area I would add to the high end power band.

I could be wrong! LOL
DK
Sounds logical to me. However, I'm by no means a certified mechanic. Thats why I'd like some knowledge on this area. Doesn't appear as tho many people have attempted.

If they remove so much material in the C1's and they roar afterwards. Makes me wonder about cags, seems as though the same thing could be applied. Where are crediable sources when you need them....:D
 

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I have seen reed spacers for sale. They state that by adding volume to the crank case it will add to the bottom end. Sounds like i have it backwards!

DK
 
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