Makita 6401 - few questions for the experts

[ctkelly]

Hello everyone. I recently acquired a used Makita 6401 and have been pretty impressed with it so far. Right now the only problem I have is its running a bit rich, but of course thats more desirable than running lean. I have installed the HD filter kit along with a new bar and chain. Starts good, runs good, etc.....so I guess is time to play with it and that leads me to my next set of questions.

Realistically, this saw is overkill for what I need on my own property. But thats not to say I wont venture out onto some other property and cut a few trees down and cut up for firewood. At the most I'll need/want to pull a 24" bar and chain, which many have claimed in stock fashion the 6401 will do just fine. Which kinda steers me in this direction....

Option 1 would be to have someone knowledgeable and reputable (I'll take suggestions here) port the 6401. I can probably manage the muffler mod myself, but if the price is right I can let the porter do that one also. My only concern is, do the 6401's lend to porting very well or are there minimal gains to be made here? I like the way the saw runs now, just looking for that little extra edge if I get into stuff thats bigger.

Option 2 would be again to have someone knowledgeable and reputable install the 7900 P&C and port the saw. Of course this would be the more expensive route but were talking about a 15cc size increase along with a port job. I suspect the gains here would be more obvious but maybe its overkill for my intended goal.

So bottom line goal is to run a 24" bar and chain well. Nothing super exotic as far as wood goes, oak, maple, pine etc run of the mill every day stuff. The way I look at it, if a 6401 in stock fashion can really pull a 24" bar and chain just fine, a ported one should give it a little extra edge to insure it will do the job well enough that I wont have to jump up to the 7900 setup. Which way would you go? Any suggestions for experts to port/work on the dolmar/makita saws?

Thanks in advance!

 

[jimdad07]

I have not ported a 6400/6401 myself, I have only ported a couple of saws. I think in stock form you will be pleased with it's performance. I have the 6400 (Dolmar colors, same saw) and have run it on an Alaskan saw mill with a 28" bar many times, that is a little over kill for the saw but it handles it fine. Porting would give you some good gains for sure with just about any newer saw, they are much more restricted to begin with than the older saws. I think I would start with a muffler mod but know you don't have to go too crazy on the muffler as it is pretty decently open to begin with but you can get some gains that way for starters. If you think the saw is running too rich, you should take it somewhere and have it put on a tach if you don't have one. If the saw is used it might need a little carb work. Good luck and keep us posted

 

[w8ye]

They tend to run a little richer with the HD filter when installed if the needles are the same as with the original filter.

I think that felt outer jacket is what does it?

There's no reason you cannot set the needles yourself. But I would do the high speed with the saw in a big cut.

Set it to where it just barely two strokes in the full cut and when you let up, it breaks into four stroke.

Here's a vid with the mixture set just right

[video=youtube;6hS3y44hjrI]http://www.youtube.com/watch?v=6hS3y44hjrI&feature=feedu[/video]

In this video you can hear little snips of four stroke

[video=youtube;k-Pyras0_qY]http://www.youtube.com/watch?v=k-Pyras0_qY&feature=related[/video]

 

[blsnelling]

I doubt you'll find many that have ported a 6400. Most will simply step up to the 7900. So info will probably be limited. BTW, that 038 above is actually quite rich. It barely cleans up under load.

 

[w8ye]

I converted my 6400 to a 7900 with HD filter and I have a 24" bar.

It seems to do real well in a big tree trunk. It is not ported but just stock. I have the regular non cat muffler with the screen removed and the hole and shield cover are modified with a scrench per Brad Snelling's suggestion.

I have several 60cc saws and this one has a lot more umpf. The original 64cc P&C is no slouch. It is a open port cylinder with pretty good porting the way it is. The 7900 cc Cylinder is closed port.

 

[ckelp]

my (stock) 6401 is has a 28" bar and it pulls it though red oak just to let you know..:msp_wink:

 

[ctkelly]

I converted my 6400 to a 7900 with HD filter and I have a 24" bar.

It seems to do real well in a big tree trunk. It is not ported but just stock. I have the regular non cat muffler with the screen removed and the hole and shield cover are modified with a scrench per Brad Snelling's suggestion.

I have several 60cc saws and this one has a lot more umpf. The original 64cc P&C is no slouch. It is a open port cylinder with pretty good porting the way it is. The 7900 cc Cylinder is closed port.

Can you tell me or point me to the post that explains exactly what brads recommendations were for the muffler mod? I was going to do a twin port to mimic the original setup on the other side, we have some pretty experienced welders at work. But from your picture it looks to be a super simple modification to do in the mean time.


Thanks to everyone who has replied. I was considering investing in a tach and finding a big piece of wood to bury into to set the carb and I still may very well do that. Its not quite as rich as that 038 though lol. Mine cleans up pretty good under load. I'll do the muffler mod pending info, get a tach and get the carb setup closer to optimal and order a 24" bar and chain.....take it out and cut it, easiest way to know if I'll be satisfied with it "stock".

 

[IthacaMan]

I converted my 6400 to a 7900 with HD filter and I have a 24" bar.

It seems to do real well in a big tree trunk. It is not ported but just stock. I have the regular non cat muffler with the screen removed and the hole and shield cover are modified with a scrench per Brad Snelling's suggestion.

I have several 60cc saws and this one has a lot more umpf. The original 64cc P&C is no slouch. It is a open port cylinder with pretty good porting the way it is. The 7900 cc Cylinder is closed port.

w8ye,Could you go into more detail as to what the scrench muffler mod is? ctkelly,I would say try running a 24" on it before doing any mods and see what you think of it.Before I did the OEM 79cc on mine it had no trouble with the 24" and I think stock they are rated up to a 28".

 

[rms61moparman]

Run it for a while as a 6401, I think you will find that you really don't need any more power than what you have.
The 6401 piston skirt is pretty narrow for porting, but a good porter can find some gain that the factory left "on the table". The simple way to more power in these saws is to install either a 7900 top end or a big block aftermarket top.
For the price of a port job you can go from 64cc to 79cc and the gains will far outweigh the ported 6400.

They are a LOT closer to a 70cc saw powerwise than a 64cc.


Mike

 

[nmurph]

What he said......we can walk you through the piston/cylinder swap. It's a simple job, or send it to me and I will do it for you.

 

[blsnelling]

I converted my 6400 to a 7900 with HD filter and I have a 24" bar.

It seems to do real well in a big tree trunk. It is not ported but just stock. I have the regular non cat muffler with the screen removed and the hole and shield cover are modified with a scrench per Brad Snelling's suggestion.

I have several 60cc saws and this one has a lot more umpf. The original 64cc P&C is no slouch. It is a open port cylinder with pretty good porting the way it is. The 7900 cc Cylinder is closed port.

That's a REALLY good looking 7900, and I'm not a huge fan. I might would actually own one if someone would make an unlimited coil for them. Tuning in the wood isn't a huge deal, but it's just something I hate.

 

[FATGUY]

That's a REALLY good looking 7900, and I'm not a huge fan. I might would actually own one if someone would make an unlimited coil for them. Tuning in the wood isn't a huge deal, but it's just something I hate.

that's 'cause you have no taste....:msp_biggrin::msp_biggrin::hmm3grin2orange:

 

[blsnelling]

that's 'cause you have no taste....:msp_biggrin::msp_biggrin::hmm3grin2orange:

Or it could be because I DO have taste

 

[blsnelling]

For as much fun as I initially made of the HD filter cover, I now actually think it significantly improves the looks of the 7900. In stock form, they're about as cool as an AMC Pacer:msp_ohmy: Are you going to try to tell me these are tasteful next?!!!

 

[nmurph]

Brad, what year is YOUR Pacer?

 

[blsnelling]

Brad, what year is YOUR Pacer?

Over my dead body! I'm embarrassed to even admit that my Dad had one for a while

 

[mtngun]

The Pacer was ahead of its time. I was a huge fan back in the day.

 

[rms61moparman]

For as much fun as I initially made of the HD filter cover, I now actually think it significantly improves the looks of the 7900. In stock form, they're about as cool as an AMC Pacer:msp_ohmy: Are you going to try to tell me these are tasteful next?!!!

You know Conway Twitty drove a 77 AMC Pacer!!!
Hard to get much cooler than that!
Bom Bom Bom!

I guess it is true that beauty is in the eye of the beholder, but to these eyes the STOCK 6400/7300/7900 is the best LOOKING saw made in many years.
Hard to beat that timeless teardrop design.

Mike

 

[w8ye]

Non envasive modifying the outlet of a Dolmar 6400 non cat muffler

This was originally suggested by blsnelling but it would be time consuming to find the thread.

The muffler has crimped seams so to disassemble, the very edge of the crimp would have to be removed to separate and modify the insides and then TIG weld or braze the muffler back together. The end result can look good but most of us do not have a TIG welder.

A simple mod without even removing the muffler would be to take the scrench and more or less "wallow out" the opening.

You somewhat re-form the outlet with the scrench. Remove the screen and stick the screw driver end of the scrench
in the hole. Slowly raise up the scrench and force the outlet hood upwards. Work slowly and twist the scrench back and forth. Your ultimate goal is to raise the center of the hood and blend it all back into the sides to make the hood outlet half round. While you are at it, try to also force the scrench down while moving it from side to side to reform the hole in the muffler and make the hole aim more towards the direction you want the exhaust to go. When satisfied, replace the screen if needed.

Some people have reached under the hood with a small bit in a die grinder and opened up the hole to the full size of the inside of the hood. But this would need to be done off the saw and the muffler cleaned before re-installation.

This will not work so well on the CAT muffler as the outlet is too far back towards the cylinder and you will risk the exhaust melting part of the brake lever.

 

[FATGUY]

So when are you gonna tell everyone you traded the Caddy in on this little gem?