BB Dolmar/Makita with a difference...

[mtngun]

Thanks for the 066 kit pics, MCW.

One thing that hasn't been answered is do the new 066 jugs have a tight combustion chamber, like the Bailey's jugs, or do they still have the humongous chamber ? I can't tell just by the pics, someone would need to CC it.

It could just be a shadow or a reflection, but it sure looks like the jugs still have the "black ring of death" at the top of the bore. Combine that with the skinny top land (pic below) and you're kinda screwed if you wanna get more compression out of it.

I'll probably continue giving my business to Bailey's, just for the support, but I am glad to see some competition. I hoping it'll motivate Grande Dog to try a little harder on the QC issues, like having good plating all the way to the top. If the Bailey's kits had consistently superior quality, that would give Baileys a competitive advantage over the cheaper Chinese kits. I'm more concerned with quality than with saving a few bucks.

 

[MCW]

Thanks for the 066 kit pics, MCW.

One thing that hasn't been answered is do the new 066 jugs have a tight combustion chamber, like the Bailey's jugs, or do they still have the humongous chamber ? I can't tell just by the pics, someone would need to CC it.

I'm not sure yet. When my 660 arrives I'll fit one of these kits to it and get a compression test. I'm not expecting anything different to any other aftermarket kit though.

It could just be a shadow or a reflection, but it sure looks like the jugs still have the "black ring of death" at the top of the bore. Combine that with the skinny top land (pic below) and you're kinda screwed if you wanna get more compression out of it.

Yeah they certainly do have the "black ring of death".

I'll probably continue giving my business to Bailey's, just for the support, but I am glad to see some competition. I hoping it'll motivate Grande Dog to try a little harder on the QC issues, like having good plating all the way to the top. If the Bailey's kits had consistently superior quality, that would give Baileys a competitive advantage over the cheaper Chinese kits. I'm more concerned with quality than with saving a few bucks.

Hey no dramas mtn. Some people seem to think I'm here to take the world by storm and ensure Baileys never sell another P&C kit. That's not the case at all. As far as saving a few bucks with the current exchange rate it's pretty difficult for me to compete anyway with the double freight (China to me then to the US) and the current exchange rate. My main market will be Australia and the odd interested overseas guy on this forum.

 

[Tohya]

After doing some port work on my 066BB jug I'm fairly certain that there is some NiSi up there at the top of the cylinder. Don't know how thick it is, but it is the same color as the unhoned NiSi in the ports. You still wouldn't want to stick a ring in it without honing it first.

 

[AUSSIE1]

After doing some port work on my 066BB jug I'm fairly certain that there is some NiSi up there at the top of the cylinder. Don't know how thick it is, but it is the same color as the unhoned NiSi in the ports. You still wouldn't want to stick a ring in it without honing it first.

I would tend to agree with you.

 

[Andyshine77]

The coating looks like it goes to the top, I'm guessing it's just not honed all the way.

 

[Grande Dog]

Howdy All,
There were so many questions flying around that I thought I could shed a little light on. There is only 2 companies manufacturing Big Bore kits for Dolmar / Makita and they're both in Taiwan. I can't speak for the other Big Bore kits but, if they are all coming from the same manufacturer, they're coming from Taiwan.
Regards
Gregg

 

[parrisw]

Looking good Matt. The 066 and 395 kits seem to have thicker piston crowns, then the 371.

 

[mtngun]

The coating looks like it goes to the top, I'm guessing it's just not honed all the way.

Can't tell just from the pics posted here, but on the aftermarket jugs I've examined, the "black ring of death" is not even, but comes down further in some spots that others, or more on one side than another The bad spots are always oversize in diameter, due to either machining error or due to casting/plating flaws. Obviously, such an uneven imperfection could not be caused by a rotating hone.

Here's my Bailey's 066BB jug. The "black ring of death" sweeps down in one spot, as indicated by the dotted line.

Here's a Bailey's 54mm 066 jug. Most of the "black ring of death" on this jug is due to machining error, but the dull crescent shape on the right appears to be casting imperfection that could not be bored, plated, and/or honed correctly because there wasn't enough metal there. We can debate whether it is missing plating or merely unhoned, but the bottom line is that the ring will not seal there.

I don't mean to second guess MCW. He's got the jugs to examine up close, I don't. We can only tell so much from photos.

Thanks for the information on BB sources, Grande Dog.

 

[MCW]

I don't mean to second guess MCW. He's got the jugs to examine up close, I don't. We can only tell so much from photos.

Hi mtn.
I'm not doubting you on the "black ring of death" at all mate. You're not second guessing me at all as I agree with you 100%. It's not just the photos, it is definately there
Like you mentioned it is only an issue if you wish to do a pop up etc to gain more compression. I'm sure the manufacturers don't expect people to alter their kits in the way we do on AS so under normal use and with normal people it's not considered a problem I suppose.

P.S. I love the way you've cut that cylinder in half. Great stuff and a lot more aluminium there than I would have thought.

 

[AUSSIE1]

Here's a Bailey's 54mm 066 jug. Most of the "black ring of death" on this jug is due to machining error, but the dull crescent shape on the right appears to be casting imperfection that could not be bored, plated, and/or honed correctly because there wasn't enough metal there. We can debate whether it is missing plating or merely unhoned, but the bottom line is that the ring will not seal there.

This would be very rare and not what most of us are seeing. That cut away shows to be an out of round cyl at the top. This isn't the same issue as the "colour" at the top of the cyl. Your cut cyl also has a recess that you call "the ring of death" if you look closely.

 

[MCW]

This would be very rare and not what most of us are seeing. That cut away shows to be an out of round cyl at the top. This isn't the same issue as the "colour" at the top of the cyl. Your cut cyl also has a recess that you call "the ring of death" if you look closely.

Yeah I just noticed that after you mentioned it Al. That is a bit more than just Nikasil missing.

 

[MCW]

As mentioned the Makita with the BB kit was sold to Wayne (gmax) on Saturday morning.
Now I still had trouble believing how much grunt that BB kit had so tonight after work I whipped the top off one of my other ported 7900's and installed my last remaining BB kit. Within 40 minutes the saw was back together and running. Apart from an idle adjustment not much had to be done as far as tuning goes.
Squish without a base gasket in this saw was .020" just like the Makita! (and no I didn't measure the same piece of solder! )
It doesn't however feel as tight as the Makita although I'm sure with the same squish compression would be similar.
All I will say is once again I am seriously impressed. This thing has every bit as much grunt as the Makita even though this saw only has a twin port muffler (ample for this kit). After adjusting the idle and leaning it out the tiniest bit I started ripping into a decent log with a 24" bar and semi chisel. This running in business is for the weak! (until my saw cold siezes anyway!).

Oh and my new MS660 arrived wth the pop up from Brad. Now THIS THING has nuts but that's in the Tale Of Three Saws thread. Goodbye 390XPG (if any Aussies here want to buy the XPG let me know or on eBay she shall headeth)...

 

[gmax]

As mentioned the Makita with the BB kit was sold to Wayne (gmax) on Saturday morning.
Now I still had trouble believing how much grunt that BB kit had so tonight after work I whipped the top off one of my other ported 7900's and installed my last remaining BB kit. Within 40 minutes the saw was back together and running. Apart from an idle adjustment not much had to be done as far as tuning goes.
Squish without a base gasket in this saw was .020" just like the Makita! (and no I didn't measure the same piece of solder! )
It doesn't however feel as tight as the Makita although I'm sure with the same squish compression would be similar.
All I will say is once again I am seriously impressed. This thing has every bit as much grunt as the Makita even though this saw only has a twin port muffler (ample for this kit). After adjusting the idle and leaning it out the tiniest bit I started ripping into a decent log with a 24" bar and semi chisel. This running in business is for the weak! (until my saw cold siezes anyway!).

Oh and my new MS660 arrived wth the pop up from Brad. Now THIS THING has nuts but that's in the Tale Of Three Saws thread. Goodbye 390XPG (if any Aussies here want to buy the XPG let me know or on eBay she shall headeth)...

Matt, I hope you sell the "390XPG" to someone you know, that saw is an absolute blast to run, hmmm I don't have a 87cc saw..... only kidding :hmm3grin2orange:

 

[MCW]

Matt, I hope you sell the "390XPG" to someone you know, that saw is an absolute blast to run, hmmm I don't have a 87cc saw..... only kidding :hmm3grin2orange:

Well actually you'd have an 87.9cc saw!
Sorry you can't have it Wayne, you've already stolen one of my saws already

 

[MCW]

OK guys. This video is mainly focussed on my new 660 but decided to also include one of my other 7900's that has had one of the BB kits fitted to it. Set up a bit rich with less than a tank through it. This BB 7900 is every bit as strong as the other one and don't underestimate it in this video. It's just that in this super hard wood, against a super grunty 660 wih pop up piston etc it looks gutless and slow. You won't find many pieces of timber much harder than this one although sadly they do exist in Australia! This is old Casuarina with a lot of knots and is very difficult to cut. Both loops of new RSC had visible cutter point damage after this video

P.S. This 660 is an absolute weapon and I already have a grin on my face...

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This video has also been posted in the "A Tale Of Three Saws" thread...

 

[AUSSIE1]

Matt the Dolmar will be quicker and hold it's grunt better with a 7 pin by the looks of it.

 

[MCW]

Matt the Dolmar will be quicker and hold it's grunt better with a 7 pin by the looks of it.

Nah mate in this particular piece of wood it really didn't show it's potential. It was also running pretty rich as well which didn't help. This piece of wood was nasty although the 660 made it look a lot easier than most saws would. Even a stock 7900 with 24" bar and RSC will eat most wood with an 8 pin.
Although I did have to run a 7 pin sprocket even on my modded 7900 when I originally cut these particular Casuarinas down on that Agriexchange job. They were old and very tough, even when green. Now they're even harder