Makita/Dolmar P/C Kit from Watsonr Arrived Today!

[nstueve]

Yeah I put an AM kit on my 6401 a couple years back and really liked it. Originally when I started looking at the 84cc BBK for the kita's people were still scoffing at them saying they were unreliable and not as powerful as a OEM cylinder blah blah blah...

What I really want to know is if any of the porters have looked at the cylinder timing numbers yet???????

Also to the OP, If you pull the base gasket and put in a beer can gasket or two you be at a perfect 0.020 squish. I also indexed my spark plug when I had the cylinder off. That probably makes very little difference but who knows.

PS: people need to quick posting about Makita's... Interest in them will get all stirred up again and I won't be able to pick them up cheap...

 

[nmurph]

I don't think people were saying the BBK were weaker than OEM, just that for (at that time) $80 more you could have OEM reliability. I've had a Bailey's BBK for about 3 years with nary a problem. I have a 6421 that I can't decide whether to sell it as-is or to BBK it.

 

[watsonr]

I'll bet it would pull a 36" easily but the oiler won't... what a disappointment. I did advise him to buy an auxiliary oiler if he wanted to go bigger. My post wasn't clear after reading it again.

The OP... nice saw, needs a bigger bar, 28" would be perfect!

 

[watsonr]

Yeah I put an AM kit on my 6401 a couple years back and really liked it. Originally when I started looking at the 84cc BBK for the kita's people were still scoffing at them saying they were unreliable and not as powerful as a OEM cylinder blah blah blah...

What I really want to know is if any of the porters have looked at the cylinder timing numbers yet???????

Also to the OP, If you pull the base gasket and put in a beer can gasket or two you be at a perfect 0.020 squish. I also indexed my spark plug when I had the cylinder off. That probably makes very little difference but who knows.

PS: people need to quick posting about Makita's... Interest in them will get all stirred up again and I won't be able to pick them up cheap...

The one I grabbed for the milling build wasn't cheap!

 

[nstueve]

The one I grabbed for the milling build wasn't cheap!

They never are unless you know exactly where to look (ie: not ebay, not HD...). I just got 3 partials saws I can build into 2 good runners for under $150 not that long ago...

I don't think people were saying the BBK were weaker than OEM, just that for (at that time) $80 more you could have OEM reliability. I've had a Bailey's BBK for about 3 years with nary a problem. I have a 6421 that I can't decide whether to sell it as-is or to BBK it.

Yea the reliability was in question at that time and some saw builders weren't going anywhere near the AM kits due to quality in casting, poor timing numbers, etc...

 

[MCW]

Also to the OP, If you pull the base gasket and put in a beer can gasket or two you be at a perfect 0.020 squish.

Are you sure about the squish? I've installed and tested dozens of these kits from a few manufacturers over many years and never had squish below .020" with NO gasket fitted. Also variations between kits from even the same manufacturer can be .010"
Another thing to watch when not running a gasket is piston skirt to case clearance. I've had a BB kit on a Makita 6401 take off paint on the case with the piston skirt. No damage and only noticed it when I pulled it down to inspect it.

 

[nmurph]

Are you sure about the squish? I've installed and tested dozens of these kits from a few manufacturers over many years and never had squish below .020" with NO gasket fitted...

I agree. Now take this FWIW, it's been about 3yrs since I installed my last BBK, but every one I have done had the base gasket deleted and the squish was still north of .030". Things may have changed and tolerances may be better now. It would not surprise me if they were.

 

[nstueve]

I agree. Now take this FWIW, it's been about 3yrs since I installed my last BBK, but every one I have done had the base gasket deleted and the squish was still north of .030". Things may have changed and tolerances may be better now. It would not surprise me if they were.

Are you sure about the squish? I've installed and tested dozens of these kits from a few manufacturers over many years and never had squish below .020" with NO gasket fitted. Also variations between kits from even the same manufacturer can be .010"
Another thing to watch when not running a gasket is piston skirt to case clearance. I've had a BB kit on a Makita 6401 take off paint on the case with the piston skirt. No damage and only noticed it when I pulled it down to inspect it.

My kits are from northwoodsaw and the 6-8 that I have put in all came in at 0.017-0.019 with base gasket delete so I put in a single or double pop can gasket to boost it up to 0.020-0.022, just to keep them more to a work saw 0.020 squish.

I use a digital micrometer and 0.030-0.032 solder to measure squish above the exhaust, both transfers and the intake...

 

[watsonr]

My kits are from northwoodsaw and the 6-8 that I have put in all came in at 0.017-0.019 with base gasket delete so I put in a single or double pop can gasket to boost it up to 0.020-0.022, just to keep them more to a work saw 0.020 squish.

I use a digital micrometer and 0.030-0.032 solder to measure squish above the exhaust, both transfers and the intake...

And measuring is the only way to determine if you can delete the base gasket.

 

[nstueve]

And measuring is the only way to determine if you can delete the base gasket.

finishing my sentences now??? And I did just lie... My last kit was from weedeaterman.

 

[nmurph]

I would be careful using a micrometer bc the squish needs to be set according to the lowest reading. Because the mic is using a broad flat anvil, it is going to pick up the highest reading, giving a false number. I know we are only talking a couple thousandths, and if you stick with the north side of .020" you should be good. But a caliper is a better choice for measure squish solder IMO especially if you are getting close to the edge (I'm very careful if I'm going <.016" on a 346---I measure, and measure again, just to be sure I'm where I think I am). I have a couple of nice sets of mics and a nice caliper BTW, and for saw work the caliper is the tool of choice.

 

[nstueve]

I would be careful using a micrometer bc the squish needs to be set according to the lowest reading. Because the mic is using a broad flat anvil, it is going to pick up the highest reading, giving a false number. I know we are only talking a couple thousandths, and if you stick with the north side of .020" you should be good. But a caliper is a better choice for measure squish solder IMO especially if you are getting close to the edge (I'm very careful if I'm going <.016" on a 346---I measure, and measure again, just to be sure I'm where I think I am). I have a couple of nice sets of mics and a nice caliper BTW, and for saw work the caliper is the tool of choice.

Yep, that's why i leave some room for error. I'm not making race saws here so the miniscule amount of extra power to get to exactly 0.020 is not needed. I leave my rebuilds a little loose at 0.021-0.022 usually. If I'm off by 0.002 then my lowest will be 0.019 which wouldn't kill one of these BBK's. I usually do a dry fit with no gasket and no sealant and no rings, and measure squish on all 4 sides. Usually pretty uniform, but if not I have a couple mandrels that I can use some 60-100grit on to smooth off the side that is a little short. Once it's uniform around the top and i have fitted with several different base gaskets until I get 0.020-0.021 with rings installed. Then I install one last time with yamabond which may or may not bump me back up to 0.021-0.022. I also index the spark plug in the middle of my process somewhere. No complaints yet but I need to get the tree services start running them to test the AM top ends longevity.

 

[MCW]

My kits are from northwoodsaw and the 6-8 that I have put in all came in at 0.017-0.019 with base gasket delete so I put in a single or double pop can gasket to boost it up to 0.020-0.022, just to keep them more to a work saw 0.020 squish.

I use a digital micrometer and 0.030-0.032 solder to measure squish above the exhaust, both transfers and the intake...

Hey that's good but just remember that giving a generalisation via the forum may mean that everybody thinks all kits are the same. I had some original kits which were very high quality (a number of members here have and are running them) and they were all dead on .020" with no base gasket. Then another lot from a different manufacturer were all .030" - .040"
I'd run a saw at .017" squish, not a problem. Well actually I do run a couple of ported saws at that with hundreds of hours on them
Also you won't have an issue with top end reliability. I ran one kit for about 200 hours and it was fine when I pulled it down.

 

[MCW]

finishing my sentences now??? And I did just lie... My last kit was from weedeaterman.

How did the BB kit from Randy go? He is running the same kits as me and these are the ones that go from .030" - .040"
Unless Randy has changed suppliers recently?

 

[The Ripper]

This Makita BBK has to be the biggest bang for the buck,when you look at the investment of getting one ported,it's a no brainer. Just one question though, with the standard setting of .035 to.042 for squish,why are you guys setting it around .020-,+ I would think even with saw chains one would have to be concerned about crank flexing,rod stretching, case flexing and bearing wear ,which all can lead to the piston kissing the combustion chamber,particularly when turning 13,500 RPMs.

 

[MCW]

This Makita BBK has to be the biggest bang for the buck,when you look at the investment of getting one ported,it's a no brainer. Just one question though, with the standard setting of .035 to.042 for squish,why are you guys setting it around .020-,+ I would think even with saw chains one would have to be concerned about crank flexing,rod stretching, case flexing and bearing wear ,which all can lead to the piston kissing the combustion chamber,particularly when turning 13,500 RPMs.

You won't touch anything at .020" squish but will gain some compression which adds torque.
I know full race saws with .015" squish pulling huge rpm (and that is tight!) but causing no issues long term.

 

[nmurph]

Yep, no problems with bigger saws at .020" and 50cc saws at .015".

 

[nstueve]

Hey that's good but just remember that giving a generalisation via the forum may mean that everybody thinks all kits are the same. I had some original kits which were very high quality (a number of members here have and are running them) and they were all dead on .020" with no base gasket. Then another lot from a different manufacturer were all .030" - .040"
I'd run a saw at .017" squish, not a problem. Well actually I do run a couple of ported saws at that with hundreds of hours on them
Also you won't have an issue with top end reliability. I ran one kit for about 200 hours and it was fine when I pulled it down.

Yeah I realize what I was saying. I just wanted to give a contradictory review to what others had been seeing. More so newbies would understand to measure for themselves, but evidently that isn't what was read. Can't remember 100% on Randy's kit what squish read out to. Maybe 0.024 with gasket delete alone. It was the first one from randy that I did and was on the fly to get it done so notes weren't kept...

 

[Mac 6-10]

I believe my base gasket was around .015 so the ..024 squish without a gasket on Randy's kit would be a good estimate.

 

[watsonr]

That's what the mill saw came out with, .024 with no gasket and 165psi before the first tank went thru it.