mods to 064 saw

[jpankey]

saw had 160 psi of compression but was sucking air from a crank seal is the reason taking the saw down . piston was showing wear on the exhaust side .I am looking at a big bore kit from baileys one moves it up in size 2mm a 066 big bore is 4mm larger but they tell me it needs machining to fit . Any body done this that would share what needs machining. Also what do you guys use to check squish with .I am shure the jug will need some machining off to get compression above 160 with no air leaks.

 

[066logger]

the mods you need to do are slotting the holes in the cylinder base and re tapping the crank case holes to 6mm. factory they are 5mm. i am in the process of doing this right now to my 064. i have heard of ppl going with stock 066 size or going with the bb kit. personally i think illl be going bb.

 

[southbound]

I put a 066 jug on a 064 and got lucky.. It fit with no mods....

What part of tn you from???

 

[jpankey]

East TN Cleveland.

 

[jpankey]

Saw has 120 psi with new jug how many thousandths needs to be removed from jug to get the back top 160 psi

 

[southbound]

Did you get the BB kit???

Have you run the saw yet??

you may need to run it to get the new rings to seat..

 

[jpankey]

Yes new 54 mm big bore kit is on the saw . Saw was ran just a few hours ago . then compression was checked its 120 psi .The 044 and 036 is higher . 044 has 150 psi . The 52 mm piston with aluminum melted that came out of the 064was 160 psi before tearing saw down.

 

[indiansprings]

I would have tried to find an nos 066 jug, there just have been too many issues with the BB jugs, I believe Brad's grenaded on his 064, I may be wrong. What was the squish on the saw, it should be making more than 120 psi.

 

[jpankey]

I haven't figured out a good method for measuring the squish band . Any suggestions are helpful. With the piston at tdc the piston is a good 1/8 inch down from the bottom of the spark plug hole.

 

[mdavlee]

Use small solder and check it across the wrist pin and then with 2 pieces front to back so the piston can't rock. If you want to take it apart a dab of grease will hold small pieces in place and then reassemble and turn over a time or two and then pull it apart and measure. Put the solder against the cylinder wall when you check it.

 

[jpankey]

if i use the soft lead solder smallest diameter like for electronics should it mash it any . we use solder to check the squish on the gm edm 2 stroke diesels but they are alot more robust.

 

[mdavlee]

I shoot for around .020" to .025". If it goes over that I try to lower it down some. If the squish is over .035" then I would want to remove the base gasket or machine the base down.

 

[Dennis Cahoon]

Yes new 54 mm big bore kit is on the saw . Saw was ran just a few hours ago . then compression was checked its 120 psi .The 044 and 036 is higher . 044 has 150 psi . The 52 mm piston with aluminum melted that came out of the 064was 160 psi before tearing saw down.

Those 064/066 cases were known to spin the bushing on the clutch side. Did you check the cases before rebuilding? That could be why it stuck in the first place, and will do it again if that case is air leaking.

 

[jpankey]

saws running

185psi very little squish . milled the base until piston struck then made some base gaskets .2011-11-27_14-50-11_787.mp4 video by pankeyc - Photobucket<embed width="600" height="361" type="application/x-shockwave-flash" allowFullscreen="true" allowNetworking="all" wmode="transparent" src="http://static.photobucket.com/player.swf" flashvars="file=http%3A%2F%2Fvid738.photobucket.com%2Falbums%2Fxx26%2Fpankeyc%2F2011-11-27_14-50-11_787.mp4"> maybe you can click on picture and hear it live.

 

[jpankey]

silent treatment

New guy gets the cold shoulder I guess.

 

[trappermike]

:msp_biggrin:
So jpanky do you know your squish clearance now or you still a little unsure how to check? Easiest way I find to check it is to insert a piece of solder(Try the thin stuff,if it doesn't squish you need thicker) into the spark plug hole until it touches the outer cyl. wall,turn the motor over TDC and check the solder thickness-I use digital calipers,really easy. It's best to check the clearance on 4 points around the piston,front,rear,both sides, bend the solder to reach where you need to check.
So you have lots of compression now,if you have .020" clearance you're ok,if not enough make a little thicker gasket. You going ok.
Did you check for a main bearing loose and turning in the case creating an air leak yet like suggested? Better do that or maybe more molten aluminum is in your future...$$$
Your compression sounds a little high,if you know how to raise the exhaust port a little(2mm maybe) properly you could take advantage of that and gain a little more power still.I think I would shoot for about 160 psi and raising the exhaust port incrementally until you get there,just cut a little and comp. test ect. And yes you could widen the port a little while you're doing it (1.5mm each side is safe on 064). If you modify the port be sure to put a new chamfer on the top edge of the port.
If you don't wanna modify your port you can try running it as is,it might be ok,or you could raise the cyl. a little more which lowers comp. a bit...
Whatduya think?

 

[jpankey]

yeap . we milled the jug till piston touched then made a head gasket out of .010 x6 inch brass shim stock. wasnt any leak working the throttle and phone camera was more than i could do while chewing gum. pleased with saw piston just kissing on outer edge after hard run.