Is there a difference between Dolmar 6000/6800 and the 6400/7300/7900 crankcase?

[CountryBoy19]

I found out last week that my Makita DCS6401 crankcase has cracked near the left rear antivibe mount/fan-shroud area. I'm considering an attempt to weld it up but plan b is replacing the case.

I found a 6800 half case (the side I need) listed affordably and comparing pictures of the 6400 case vs 6800 case, they look exactly the same from the fan/flywheel side.

Are they really the same?

 

[foeke]

I don't think so. The Dolkita's 6400/7300/7900 are the same other than the cubic capacity. They replaced the 6000/6800.

Sent from my SM-G935F using Tapatalk

 

[Griffdog1]

The 6000/6800 has the oil tank in the handle unit, the 6400,7300,7900 is an oil tank in case design. They are completely different.

 

[CountryBoy19]

The 6000/6800 has the oil tank in the handle unit, the 6400,7300,7900 is an oil tank in case design. They are completely different.

Then it has to be a 6400/7300/7900 case/tank misidentified as a 6800 because it looks exactly the same, right down to the oil tank as an integral part of the crankcase. Thanks for the replies!

I'm going to grab it... now trying to decide if I want to upgrade to 7900 P&C while I have it all torn apart. The reason I didn't do it before was bc I have a stripped cylinder screw (stripped head, not threads). Gonna have to tackle that no matter what now so it will be easy to do the P&C.

 

[Mac&Homelite]

I did a 6401 to a 7900 swap over winter break. I never got the opportunity to run it before the conversion due to time constraints but it was amazing to run after the swap. Gobs of power and that was even before it was fully broken in and tuned to max performance. Only downside is it probably drinks considerable more than the 6401 due to the displacement increase.

 

[Mac&Homelite]

@Dahmer You have more insight than I to the performance difference between the 6401 and the 7900 swaps.

 

[Deleted member 149229]

@Dahmer You have more insight than I to the performance difference between the 6401 and the 7900 swaps.

Still being gentle and breaking it in but when you put it to the wood you can really feel the difference. The 7900 conversion really wants to dig, the 6401 was great but that conversion is a whole different animal.

 

[Deleted member 149229]

@Dahmer You have more insight than I to the performance difference between the 6401 and the 7900 swaps.

Mac&Homelite was the one that did my build and he did a good job. He had enough brains to leave the saw rich until I get the rings seated, he didn’t lean it out to look impressive.

 

[CountryBoy19]

Still being gentle and breaking it in but when you put it to the wood you can really feel the difference. The 7900 conversion really wants to dig, the 6401 was great but that conversion is a whole different animal.

From what I've seen the new 7910 kit has a muffler mismatch issue and the plastic hood for the relocated decomp doesn't like to match up well on older saws. Is it not that big of a deal?

It seems to me that it's enough of an issue to push more toward a high-quality AM big-bore kit. I heard weedeaterman had some nice kits and he was sending caber rings out with some of them. Thoughts?

I just have a hard time justifying $200+ on a "factory kit" that isn't even meant for my saw and has some fitment issues.

 

[cuinrearview]

Talk to @fordf150 , but I believe the kit includes a new top cover with correct placement of the hole for the decomp. I'm not sure what you're talking about with the muffler. I've yet to read of anyone calling any of the AM 79xx kits "high quality" or more powerful than OEM. Spend the coin and don't look back with regret.

 

[Deleted member 149229]

No trouble with anything with the OEM.

 

[computeruser]

From what I've seen the new 7910 kit has a muffler mismatch issue and the plastic hood for the relocated decomp doesn't like to match up well on older saws. Is it not that big of a deal?

It seems to me that it's enough of an issue to push more toward a high-quality AM big-bore kit. I heard weedeaterman had some nice kits and he was sending caber rings out with some of them. Thoughts?

I just have a hard time justifying $200+ on a "factory kit" that isn't even meant for my saw and has some fitment issues.

What fit issues, apart from the decomp moving? Hell, plug the decomp and use your existing cover if that’s a concern.

The AM kits end up costing nearly as much after you replace the rings and pin clips with ones that aren’t garbage. And you still end up with an AM p/c of questionable quality.

 

[AlfA01]

He had enough brains to leave the saw rich until I get the rings seated, he didn’t lean it out to look impressive.

Ditto. Haven't had the 'manly bits' to go tweaking it yet. I'm running a little rich and I pulled the plug see where it was exactly--looks nice and rich chocolate mocha-ish.

Talk to @fordf150 , but I believe the kit includes a new top cover with correct placement of the hole for the decomp. I'm not sure what you're talking about with the muffler. I've yet to read of anyone calling any of the AM 79xx kits "high quality" or more powerful than OEM. Spend the coin and don't look back with regret.

Yep. New top cover with the OEM kit, as it has a relocated deco valve. OEM all the way. Yes, if you have an older model saw like mine (2007), you will notice that the new cylinders have a larger exhaust side outlet where a 'tuned muffler pipe" extends into the exhaust port of the cylinder. The older models don't have that and are a flush mount versus the pipe that extends into the cylinder. Some modification to the muffler should be done to ensure a free flow transition from the exhaust port to the muffler, in this case.

What fit issues, apart from the decomp moving? Hell, plug the decomp and use your existing cover if that’s a concern.

The AM kits end up costing nearly as much after you replace the rings and pin clips with ones that aren’t garbage. And you still end up with an AM p/c of questionable quality.

Yep. After installing this kit with such ease and having the saw immediately fire up and run as if it came from the factory as a big bore is just awesome. I wanted that ease and reliability. I'm not saying you don't have some adjustments to make, but this kit is exactly what you get when you buy the saw new. Not so convinced by the aftermarket stuff yet. I'd rather port, polish and muffler mod to gain some HP than risk AM parts that may fail prematurely.

Cheers,

 

[CountryBoy19]

What fit issues, apart from the decomp moving? Hell, plug the decomp and use your existing cover if that’s a concern.

The AM kits end up costing nearly as much after you replace the rings and pin clips with ones that aren’t garbage. And you still end up with an AM p/c of questionable quality.

Apart from the already mentioned muffler port size issue, according to my brief reading the new plastic cover doesn't line up well. Sometimes misaligned from the decomp and if using old non-cat muffler it needs trimmed around the muffler to prevent melting. Those were a few things I saw mentioned but never saw pictures posted etc so idk if those are true. I'm just a woodburner/firewood cutter so idk that I would ever wear out an AM BB kit as long as it wasn't defective from the start.

 

[cuinrearview]

as long as it wasn't defective from the start.

Key

Besides the chance of crap parts from the get, the power produced will not be the same. But I guess you'd never know the difference. What's the price difference? Don't forget to add quality gaskets and a ring, because I DEFINITELY would not trust China to make those.

 

[Deleted member 149229]

Get bad AM Parts and not know they were defective until the saw scatters saves you zero money. That’s all I am a firewood cutter but now I get done a lot faster.

 

[Mac&Homelite]

I had no issues with any fitment on the oem 7910 swap. Fit and finish on the piston and cylinder was excellent and the plastic top cover fit perfectly. I got a great deal on a lightly used big bore kit and plan on installing it on a 6401 sometime in the coming weeks. The castings are not as nice on the aftermarket kit and the transfer ports and intake/exhaust are definitely not as nice. I went with this big bore due to price and to see how it performs. I will not be putting new rings or circlips in the piston, but I may do some light port work on the cylinder before I install it. If and when the BB kit fails, I will be replacing it with an oem 7910 from Nate for sure.

 

[r black]

I agree with tim @cuinrearview ... ..... use oem parts from @fordf150 includes cover I have done the a/m 54mm big bore china kits and they run well (done 3 so far ) .............however they are a bit cheesy ...and not near the quality........ the saws I have converted all have been the Makita 6421 saws from the depo..........

 

[AlfA01]

I agree with tim @cuinrearview ... ..... use oem parts from @fordf150 includes cover I have done the a/m 54mm big bore china kits and they run well (done 3 so far ) .............however they are a bit cheesy ...and not near the quality........ the saws I have converted all have been the Makita 6421 saws from the depo..........

And, he seems to be a few bucks cheaper than some guys selling OEM kits on eBay. Support one of the AS bros, save a little dough and get good quality parts.......Its a win, win, win situation! Go for the OEM!

 

[fordf150]

there is no fitment issue other than the exhaust port size differences and for a firewood cutter i am not convinced thats anything to get excited over.


the $210 one on ebay is me...on my site or thru PM's it is $200 shipped.