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Post by chehystpewpur on Sept 29, 2019 23:44:13 GMT -5
some cylinders they are generic but the more racy they get the more specific they get due to port sizes and head design. and i would never re use a piston unless it had no sign of wear on it as the bottom of the skirts usually wear on the cylinder walls during dwell on top and bottom. its called rocking and its very apparent on high revving motors like 2 strokes. this one has some scuffing as the cylinder was daily use for a while before parking it then going to lc. but it was a running cylinder but went through much more abuse than normal for me the cylinder isnt bad but isnt perfect hence why i dont really want anything from it and will have somewhat reduced power vs if it was brand new but i figured you could learn something about porting or messing with the heads as you wouldnt feel bad if anything happened to it and neither would i. id assume your exhaust would limit max power and rpms on it but should still give for a fun ride nonetheless and its not an unreliable setup but could give you time to decide if you wanted more or less and if you really wanted you could try to hone the cylinder some but i think it may be plated so i wouldnt go too much just enough to smooth out the scuffs or say screw it and just break her in with new piston and rings and let her eat. as it was when i pulled it off it still made pretty good power and i would have never expected it had scuffing before i pulled it off but i think the piston bearing was going bad if i remember right so thats pry why it did. it got warm a few times and was the reason i went to water cooled as fl was just too hot for big power with the hr plus rides i liked to go wot on all the time.
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Post by christopher on Sept 30, 2019 5:54:54 GMT -5
Thank you for the information, still learning a lot and tinkering. Who knows if it runs good for my use, I may find out I like the setup and get another like it, then I'd have a few spare heads. I'm using an old Tecnigas chambered pipe, bought it used locally, made a huge difference. Struggled to 35 before with a little tuning goes 42 now and the 0-35 time is under 10 seconds.
Sent you a PM, about payment.
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Post by ThaiGyro on Sept 30, 2019 9:25:53 GMT -5
Maybe a proper Burt Munro piston kit and head shave is the trick.
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Post by chehystpewpur on Sept 30, 2019 11:16:13 GMT -5
i figured its worth a try i like my stage6 cylinder kits and am running the same one just lc with pretty good results. with a new pipe mine would pry be overkill for what i need but i still want more lol.
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Post by 190mech on Sept 30, 2019 11:52:14 GMT -5
Found a 50 squish type head in the pile of stuff Oldgeek brought to me..
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Post by christopher on Sept 30, 2019 16:43:46 GMT -5
Need to make sure what size piston pin you have before swapping topends..10 or 12.... Yeah, going to have to pull the cylinder and measure, don’t know what’s there now. I know I have a 16mm 15 spline crank shaft end but that’s it. Going to get an Athena gasket kit, comes with a few base gaskets to adjust squish. Plan on getting to a 0.8 mm squish if I can, don’t mind running premium I can get it up the street a few blocks.
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Post by christopher on Sept 30, 2019 20:02:06 GMT -5
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Post by 190mech on Sept 30, 2019 21:29:29 GMT -5
The piston edges appear to be flush with the top of the cylinder at TDC,is that right?Hopefully the piston edges are flush with the bottom of the transfer ports at BDC...
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Post by christopher on Sept 30, 2019 21:55:08 GMT -5
I'd have to look closer, I'll have a closer look after work.
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Post by christopher on Oct 5, 2019 13:37:25 GMT -5
Would using a copper shim or thinner shim as a cylinder base gasket be acceptable? I was thinking of spraying it with copper gasket spray. My paper gasket is 0.50 mm I know it must compress some during assembly. I have shims that are much thinner. Wondering up ways to reduce squish with what’s in my garage today.
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Post by oldgeek on Oct 5, 2019 14:42:47 GMT -5
Hope that piston pin clip did not end up in the cases or the exhaust, stuff a rag in there when trying to remove or install those pesky things.
As far as base gasket, I have used just a thin coat of Honda bond type sealer and no other gasket to tighten squish up a bit. Base gasket shim kits that come with some cylinders are aluminium, copper and brass. Anything will work.
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Post by christopher on Oct 5, 2019 15:21:16 GMT -5
Thanks, I’m going to use the thin copper colored one. I had a towel in there, it went flying across the garage somewhere. Trying to get the squish into the 0.8mm area.
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Post by christopher on Oct 5, 2019 20:23:33 GMT -5
Put in a 0.15mm copper base gasket, sprayed with some copper gasket. Removed the copper head gasket and left it out, sprayed a few coated of copper gasket on the head sealing surface, masked off the combustion chamber, the squish is now 0.85mm. Put a plug in and started, let it run about 5 minutes. Turned off and let it cool, checked torque still at 80 inch lbs. Started up let warm up and turned off will double check in the morning. Sounds different, idle sounds good, will put shrouds on and see how it runs tomorrow.
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Post by christopher on Oct 5, 2019 21:24:29 GMT -5
Miscellaneous ramblings from a newbie.
While I had it apart, did some work on the aluminum setup to see what I had for squish. It’s not any better on the squish front.
Measuring the squish, the solder looks like a nice even crushed piece. If I take anything off the head the angle of the squish band will be changed. The head is an o-ring setup with small lip so about 0.4 mm would be straight down. Then it would be into an angle.
Where’s the best place to take off 1mm?
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Post by 190mech on Oct 6, 2019 4:53:45 GMT -5
Aluminum cylinders are nikasil coated and the coating laps over the top of the bore,if you cut the 1mm from the cyl top you will have a good chance of the plating chipping,,Best option would be to step cut the head(loose the o-ring groove),that way the combustion chamber will remain the same,just sitting down inside the bore 1mm...
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