064/066 BB hybrid

[nmurph]

here goes my conversion of a perfectly good 064 into a 99cc hotrod. i hope so, anyway.

first off, you will notice the quality of hte 066BB kit is vastly better than the 07900BB. the ports are nicely shaped, even and beveled. the beveling could be a little more even. but it is still pretty good and will just need some minor reshaping to be optimal. the nickasil is applied evenly to within a couple of mm of the top. it is not unevenly honed as with both 7900BB kits that i received. the piston is well finished with only a minimal amount of flashing on the windows. i don't remember if it was mtn or aussie that said this kit is as good as OEM. that really isn't an overstatement. this kit begs the question of the 7900BB; why can't the quality of that kit match the quality of this kit? the cost is the same.
i planned to port this saw bf i ever assembled it. i did a little mapping and it doesn't look like there is much extra metal to file away. this disappoints me, but i guess the port work has already been done on this kit. the intake can be widened about 4mm. the exhaust is already to within a couple of mm of the of the piston skirts, so i don't think i dare go any wider there. i will blend the transfers, smooth the tracts, set the squish and call it good. thanks to mtn, i have the M6x25mm cylinder bolts to make sure that everything stays put when it is assembled. one thing about this kit is that there is no decomp, so it may take some careful pulling not to rip the shoulder out again.
i get off at lunch to go to the dr for the final check of the shoulder surgery and then i'm coming home to rip into the saw. i will take plenty of pics.

 

[nmurph]

more 066BB pics

 

[nmurph]

and more

 

[mdavlee]

That kit does look pretty nice.

 

[tlandrum]

thats a good looking cylinder to be after market. they have come a long way

 

[mtngun]

Thanks for the pics and the evaluation of the kit.

BTW, i'm not seeing any pics or attachments in posts #2 and #3.

On my kit, the exhaust port was 0.150" from the edge of the skirt, so the exhaust could be widened a little.

But for the most part, I agree with you that the porting is pretty good and there is little room for improvement. If I had to do it over again, I'd still widen the exhaust to 0.100" from the skirt, and still stretch the upper transfers a little, but leave the intake and the piston alone.

The reason the Makita BB kits are not as good is because the Makita transfer ports are more complicated to cast. Plus, the 066 kit is the flagship of the line, so they give it more attention. Plus, I keep bugging Grande Dog to improve the 066 kits.

I hope your kit works out for you.

 

[nmurph]

mtn, you mean to blend the tranfers tw the intake??

why shouldn't i make the intake the same width as the exhaust?? i do have some room to grind there.

 

[mtngun]

mtn, you mean to blend the tranfers tw the intake??

Yes. Though the transfers are pretty decent out of the box, and it may not make much difference.

why shouldn't i make the intake the same width as the exhaust?? i do have some room to grind there.

That's what I thought -- until I tried it. There was no increase in power, but fuel consumption went way up, and it lost 1000 rpm off the bottom end.

Because it has 175+ degrees of intake duration. The intake time-area is already very aggressive.

 

[olyeller]

Just to clarify

Just to make things perfectly clear, Murph, this is the 066BB kit from Bailey's, right? And does the piston clear the case without any grinding? I'm getting set to order the same kit for my 064 and I was waiting to hear about your kit before I ordered.

Can't wait to hear how it all goes for you cuz I'm next!

Olyeller

 

[nmurph]

yes, and i don't know bc i got home late yesterday and didn't have time to work on the saw.

 

[ms290]

Glad you jumped in my thread to tell me of yours. Looks like a high quality kit and im not going to be scared of bolting one on my 066.

 

[olyeller]

Murph:

Did you have time to mess with your saw and new 066 BB kit yet? I ordered mine today.

Olyeller

 

[nmurph]

i had to finish changing the clutch spring on a 262 last night. i had to fab up a tool to fit so i didn't get to it. this morning i have about 20,000sf of yard to spray, then i'm on to it. i want to put it in the wood by lunch!!!!!!

 

[caotropheus]

BTW, i'm not seeing any pics or attachments in posts #2 and #3.

Same here!

 

[nmurph]

update

well i finally had a few hours to get the 064 to where i wanted it. i installed a bailey's 066BB kit that bumps the displacement to 99cc. i did not experience any problems with the skirt hitting the case. i did have to lengthen the bolt slots about 3mm to the front and rear to get the bolts to fit. i replaced the M5's with M6's as suggested by mtngun. i left the base gasket off and used a little yamabond for a final squish of .020-.021. the compression is 185psi after a couple of minutes of running to burn off the assemble oil and letting it cool. i will check it after is has a few hours to see how much more compression i get. i rebuilt the carb and replaced the fuel line and tank vent. i also opened the baffle in the muffler and made the opening about .75x1.5". i scrubbed it down and blew everything out well. it weighs about 15.5lbs empty. i have only run it enough to make a couple of cuts in a 20" log. it feels great so far, but then again, what would you expect me to say?? here are some pics. the only thing lacking is a bushing in the flywheel side of the chainbrake. i have a 36" bar and a neigbor with a big chunk of oak stump that needs sawing. i have to go pressure wash the house. i hope i get to run the saw some more today.

here are some before and afters.

 

[nmurph]

http://www.arboristsite.com/attachment.php?attachmentid=149747&stc=1&d=1283626049

 

[nmurph]

 

[bonden]

That's a nice looking saw you got there nmurph . i am building me one 064 with 660 cylinder thees days mild ported.

 

[olyeller]

Nice

Nice update with pics, Murph. I've been waiting impatiently to hear how your progress has been going. I got my 066 BB kit in from Bailey's this week and it's very good quality, like the pics you posted here.

I'm glad to hear about the the piston skirt clearing fine without grinding. This is good news, what I was hoping for. My cases are apart so all I can do is compare piston heights, and the BB piston is actually just a pinch shorter than the stocker. So I figured it would all bolt up OK.

I'm going to take the cylinder bolts out to 6mm and slot the cylinder base holes next. But on Tuesday I'm going fishing with my father-in-law for about 9 days so my progress will be interrupted.

Let us know how your saw performs. What did you do to your carb settings?

Olyeller

 

[mtngun]

the compression is 185psi after a couple of minutes of running

Gotta love the compression on the current 066 BB kits. That gives it some grunt.