Cleaning up the ports

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jimcos3
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Cleaning up the ports

Post by jimcos3 »

Hey everyone,

I just picked up a '95 YZF 600R for a song (a $600 song!). It has a bad 2nd gear and a little fairing damage (already picked up the new pieces so no problem there). The only other other problem is the turqouise and purple paint job.

I'm thinking of tackling the tranny rebuild myself. While I'm in there I was considering cleaning up the ports. The exhaust headers need the weld ground down and I can match the exhaust ports to the headers. Maybe clean up any casting flaws on the intakes. Pretty much the standard stuff you would do to your dirt bike.

What is the general consensus on the heads of these bikes? Do they benefit from any mild porting work? I'm running a slip-on and a jet kit so there isn't a lot of mods to the engine. Thanks for any input.

dragracer1951
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Post by dragracer1951 »

You can make a flow bench for pretty cheap. Vacuum cleaner, plaster of paris casting of the head and a cardboard cyl. slip in a set of valves and apply suckage. make a bee from a metal ball soldered to a piece of wire. Vacuum gage at intake and exhaust side. use the bee to see where you want pressure and where you want vacuum. You can more it around and see the differential at the gages...
That'll give you a good idea where to either remove or add material. Yamaha heads benefit from a little more elbow at the valve pocket.
Don't just go hacking up a perfectly good head.
Jim


Hey Kid...
Is my tail light still working?

"...you can't tune a motor that's hurt. They run much faster on fuel then they do on aluminum." - Elmer Trett

haunter
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Post by haunter »

depending on the spare change you have laying around....

I would look for a tranny AND a torn apart FZR600 motor......

the FZR crank rods into the YZF600 stuff makes a real mean 660 :poke

and taken apart fzr 600 motors are pretty cheap.....esp since they also like to frag 2nd gear!
88 FZR 1000 - SuperTrap, K&N, FP kit - sold
90 FZR 1000 - 1040, Ohlins, 91 USD's...some other stuff - sold

93 FZR 600 - rat/cafe/POS/Trackbike Project
03 SV1000S - bye bye
06 R6 50th Anniversary - slip on, PCIII, race rails

jimcos3
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Post by jimcos3 »

Thanks for the tips Dr Jim. That sounds a little beyond my skill level (though I used make some pretty bitchin' plaster of paris sculptures back in grade school). Having seen my learning curve on 2-stroke cylinder porting, I'll stick to a flapper wheel on my exhaust headers. I have no intention of getting dremel happy on my cylinder head with the limited experience I have. Do you flow those cylinder heads in your shop? I was going to ask you about rebuilding my transmission anyways. If you might be able to fit that in I would bring it over anytime.

Which brings me to Haunter's suggestion about the FZR rods. How much longer is the FZR's stroke? Can you swap the pistons, cylinders, rods and cam chain and gain 60 cc's? That could be a kick! I'll have to look on some of the web sites to see what it takes. Have you seen it done, Haunter?

Thanks,
Jim

jimcos3
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Location: Seattle

Post by jimcos3 »

http://www.oldskoolyzf.com/forum/phpBB2 ... hlight=660

Here is the article on Jamie James' old YZF 660 built for him by Vance & Hines. If you go down the posts it is the one with the individual pages posted. The FZR rods are about 3 mm longer. They were able to make 120 HP out of the motor with 35 mm carbs, porting/valve job etc. it says (way more than my YZF 750 made). It might be a little difficult to source a lot of those parts. I'd rather start with a 750 anyways if I was going to really go crazy. I'm thinking this 600 will be a little sport tourer more than a giant killer.

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