Question for the Dolmar folks

[HandLogger]

My brother called me today from his local Home Depot. Specifically, he was asking for advice on a Makita /Dolmar saw badged as a DCS 6421 [former rental] saw that the store is selling for $322.00 "out the door."

We own and manage forest land in the Berkshires using Stihl equipment, so I don't know much about Dolmar saws. I do, however, have a good friend who owns a Dolmar 7910 and, having bucked logs right next him, I know that it will make any of our MS361s look like they where bought at a box store...which brings me to the crux of the post.

I understand that the 6421 in question can be modified -- via a "big bore kit" -- to equal the displacement of a 7910. If this is true, I'd appreciate any advice on where to purchase said kit and any other productive thoughts on anything else that may be required to turn said saw into something resembling a 7910...i.e., Is there a muffler modification needed, as well, or is it just a matter of installing a stock 7910 muffler?

In short, any thoughts on how to best go about modifying the DCS 6421 would be greatly appreciated.

Thank you for your time... PHOTO BELOW

 

[cgraham1]

You can just buy the Dolmar 7910 piston and cylinder kit and swap it. No other modifications are needed. If it has a cat muffler, I would uncrimp the muffler and remove all the guts.

 

[Big_Wood]

that's alot of saw for the money.

 

[HandLogger]

I'm not sure what I'm looking at, Clint, so please fill us in on the details of the saw in the photo.

Thanks for the post, regardless.

 

[Jeffkrib]

Yep I did the upgrade, theres nothing tricky about it, just PM Nate fordf150 and tell him what your doing.
He'll sell you the bits you need. The actual modification requres the muffler to come off 3, T25 torx screws from memory. The shrowd around the air filter, bolt holding the top bar and AV mount to the cylinder head. Then remove the carb boot from the cylinder head. Then make sure everything is clean before removing the 4 cylinder head bolts. Don't let crud fall into the engine at this stage. Then the piston comes off by removing the spring pins on the gudgon pin.

Putting the new bits is the reverse except you will need a ring compressor which Nate can sell you, its just a cheap plastic thing.
This was the first time Id pulled a 2 stroke apart, they are simple and designed to pull apart quick and easy.
No fancy tools requried.
I have a couple of links on my work computer which helped me. Ill post them up when I get into work.
If you have'nt run the saw yet in its 64cc form I would before doing the upgrade you will find with a 20 inch bar its pretty dam good. In the 79cc form its a blast.
I also upgraded to the heavy duty air filter. You will also need to tune it up after doing any mods.

If you do the upgrade my understanding is you will have the highest power to weight production built saw In the world. I'm happy for anyone to correct me if this is not true.
Also correct me if i missed anything..... Its been a year or so since i did it.

Cheers
Jeff

 

[HandLogger]

Cheers for the reply, Jeff. Is Nate (fordf150) located in Oz or in the states?

 

[HandLogger]

Adding a question to this thread...Is this the Big Bore Kit that would be used to increase the displacement of the Makita DCS 6421 in question?
https://www.baileysonline.com/Parts...olmar-7900-Makita-6401-Solo-681-Chainsaws.axd

 

[SteveSS]

Adding a question to this thread...Is this the Big Bore Kit that would be used to increase the displacement of the Makita DCS 6421 in question?
https://www.baileysonline.com/Parts...olmar-7900-Makita-6401-Solo-681-Chainsaws.axd

That is an aftermarket kit. Nothing overly wrong with it, but if you send @fordf150 a PM, he'll be able to price you out an OEM option that will be better in the long run. An OEM 7910 piston and cylinder will bolt right up to your 6421.

 

[SteveSS]

Cheers for the reply, Jeff. Is Nate (fordf150) located in Oz or in the states?

Nate is in Ohio.

 

[wde_1978]

@fordf150

http://performanceoutdoorequipment.com/products/cylinder-and-piston-kit-ps-7900-038130910

If You want power, durability, quality and a worry free swap then go OEM!

I like my Dolmar PS-6400 very much!
Many will argue otherwise but there is nothing wrong with that saw whatsoever!

And YES, a PS-7900/7910 will make You smile ear-to-ear.

 

[SteveSS]

One other p.s. to keep in mind....

The Home Depot Tool Rental Managers have quite a bit of flexibility in how they price these rental saws to get them moved out the door. It'd be worth it to see if he'll knock a few more dollars off the price to offset the price of OEM parts for your rebuild. Shoot for $250.00 and see what shakes out.

 

[cgraham1]

If you go with an aftermarket big bore kit, don't use the two piece rings that come in the kit. Upgrade to Caber rings.

 

[cus_deluxe]

One other p.s. to keep in mind....

The Home Depot Tool Rental Managers have quite a bit of flexibility in how they price these rental saws to get them moved out the door. It'd be worth it to see if he'll knock a few more dollars off the price to offset the price of OEM parts for your rebuild. Shoot for $250.00 and see what shakes out.

This is more what i was thinking. Rentals get whooped on pretty much no matter what. Id ask how many times this saw went out and if there were any straight gas episodes in its life.

 

[cus_deluxe]

Dont get me wrong, definitely a well built and solid saw platform. just wanna make extra sure on the history and stuff.

 

[computeruser]

Except for one ex-Rental I bought, sold, and later learned had a bad bottom end (that I sold to a lying thief of an AS member who was down on his luck, so I shipped it to him on the promise he'd pay me and, surprise, he never did), the worst that any of my ex-rental buys needed was a new A/V spring or two from being wrenched on by idiots who stuck the saw in the cut. These saws are built tough!

 

[cus_deluxe]

and later learned had a bad bottom end (that I sold to a lying thief of an AS member who was down on his luck, so I shipped it to him on the promise he'd pay me and, surprise, he never did)

now tell us how you really feel.

 

[computeruser]

now tell us how you really feel.

Still a bit pissed about it, all these years later. $250 down the crapper, but such is life.

 

[fordf150]

NWP big bore $129 with shipping we will call it $145, add caber rings for another $15 so that puts you at $160. 7910 OEM kit is $200 shipped. no brainer for me

 

[SteveSS]

For sure. The extra $40 is cheap insurance for genuine OEM parts.

 

[wde_1978]

NWP big bore $129 with shipping we will call it $145, add caber rings for another $15 so that puts you at $160. 7910 OEM kit is $200 shipped. no brainer for me

^-^-^-^ Nate is the man! ^-^-^-^

If You want the true feel of a PS-7900/7910 You'd be better off with an OEM kit!
AM kits are rumored to be all over the place quality and performance wise, which doesn't mean that there aren't really good ones.