Tanaka 650...hole in piston... popup fix??

[SawGarage]

hey guys..



i've 'acquired' my buddy's Tanaka 650 (Said it was his favorite wood saw...liked it MUCH better than the Husky 455 and 55 rancher he has now...)

anyway, the reason it was 'parked' was a hole in the piston...

I have yet to measure quench, etc...but was thinking of welding a piece of sheet on the top of the piston, and making a pop-up for a bit more compression...

Just thinking outloud...I have ported 4 cycle engines, as well as some minor work to 2 stroke bikes/4 wheelers... so looking for some

THOUGHTS??


also, while it's apart, I think a little port work is in order... (atleast a cleanup...)

if 'fixing' the old piston isn't feasible, there's a piston & cyl avail for round 50 bux...

your insight is greatly appreciated.

Jay

 

[djberg]

i would care far more as to why it went lean before worrying about compression...

 

[SawGarage]

i would care far more as to why it went lean before worrying about compression...

hmm...

how in the world did you find this post? wow....I would think it would have been on the 10th page by now...lol:jawdrop:

anyway, I agree...I'm not sure why...but there's little ways (That I know of..) to tell without it running...

it's been WELL used....maybe it was just time to blow up? (atleast I've heard of this on 2 stroke dirtbikes, etc...)

pistons are almost impossible to find, or else I would try that 1st..

J

 

[djberg]

http://www.arboristsite.com/forumdisplay.php?f=79

not a very hot thread... just look @ the dates...

i'm not too sure on how i even stumbled across it, i was just exploring the site.

if you cant find a piston you could always pay some one to mill you one.

but i would do a leak down on it first, or are you planning on just rebuilding everything from the crank cases up?

 

[BlueRidgeMark]

Seriously. You want to weld a sheet on top to fix a piston?

 

[griffonks]

http://cgi.ebay.com/TANAKA-CHAINSAW...=ViewItem&pt=US_Chainsaws&hash=item518e98256a

Good used piston & cylinder on ebay for $50.

 

[djberg]

two cylinders and no non holy piston solves nothing... unless the piston is in the cylinder and they just are not showing it...

 

[djberg]

or just to fill the hole you could g buy an at home aluminum welding kit...

the ones you see on tv that all you use is map gas...

 

[SawGarage]

Ah...thanks for the link... might just buy that...

The piston is sticking out the bottom, upside down...

Seriously. You want to weld a sheet on top to fix a piston?

?? how is this any different than those that make a pop-up piston? it was more of fill the hole, then add some thin sheet to dome up the piston...

I didn't think this was out of the question...maybe i'm out in left field somewhere...

or just to fill the hole you could g buy an at home aluminum welding kit...

the ones you see on tv that all you use is map gas...

ya think that would work?? i did think about that...I have one of those kits...

I guess the worst that could happen is I'd be in the same boat..

J

 

[djberg]

i watched the sales guy fut a 3/8" hole in the bottom of a soda can and totally filled it. now the scary part was when he drove a screw driver through it and the "weld" held and the screwdriver went through the base of the can.

i absolutely would not run the saw this way. but of done right it would hold enough tho get your compression spec,

 

[Jacob J.]

We had an 066 with a hole in the top of the piston once. I wire brushed it off and took it to a buddy who is good on TIG. He filled the hole and slightly domed it in under a minute. His weld was so smooth I didn't even have to sand it. It made a good running saw. This was in the days before low-cost aftermarket pistons.