Makita 7900 seems hot

[Greenerpastures]

It doesn't suffer from a lack of power and if in bigger wood or needing to rip, I've now got my 395. So, I'll leave it stock. Might be selling it soon anyway. But thanks for the suggestions.

I only mentioned the muffler because it makes a saw breathe more easily, in regard to
you saying the saw was a little hot for comfort.

That 395 is some beast, exelent choice for milling, did you need to upgrde the airfilter on the XP.

Regards, john

 

[CR888]

Anything that has 14000 fires inside it per minute may get a little warm, perhaps even hot.

 

[Jacklefty]

I've got a makita 6421 with the cat muffler and I have removed the cat which is pretty darn easy and it breaths life into your saw and cools it down a lot. If your having trouble with heat that's what I would do. I do believe the old 7900s had problems with the oilers being to stingy with the oil on larger bars. But I believe they cured that widen they went to the 6401/6421, 7901 model updates. If you are curious find the p/n of the oiler and cross it with the 7901. I do believe they are different or even updated to the new oiler.


Oh and btw... if you are interested I can talk you through the muffler mod.heres a pic of my muffler. You can see that I welded the seam and put in a 2nd exhaust port on the starter side. Removing the cat and putting a 2nd port greatly improved my saw. I also put a big bore kit on mine with caber rings which is awesome I'll tell you!

 

[Greenerpastures]

I've got a makita 6421 with the cat muffler and I have removed the cat which is pretty darn easy and it breaths life into your saw and cools it down a lot. If your having trouble with heat that's what I would do. I do believe the old 7900s had problems with the oilers being to stingy with the oil on larger bars. But I believe they cured that widen they went to the 6401/6421, 7901 model updates. If you are curious find the p/n of the oiler and cross it with the 7901. I do believe they are different or even updated to the new oiler.


Oh and btw... if you are interested I can talk you through the muffler mod.heres a pic of my muffler. You can see that I welded the seam and put in a 2nd exhaust port on the starter side. Removing the cat and putting a 2nd port greatly improved my saw. I also put a big bore kit on mine with caber rings which is awesome I'll tell you!

Hi Jacklefty
Thanks for the information on the muffler mod. And good to know the oiler problem was just output related,
I did not know if it were a failure related issue, but as I only use an 18" bar, I will never need to upgrade to
the more modern pump.
I will keep you in mind if i need to upgrade the muffler, but I think removing the spark guard and using 40:1
will suffice for my needs, if not I will be in touch, nice job with the flares on the starter side, that should help big time.

 

[Jacklefty]

Hi Jacklefty
Thanks for the information on the muffler mod. And good to know the oiler problem was just output related,
I did not know if it were a failure related issue, but as I only use an 18" bar, I will never need to upgrade to
the more modern pump.i
I will keep you in mind if i need to upgrade the muffler, but I think removing the spark guard and using 40:1
will suffice for my needs, if not I will be in touch, nice job with the flares on the starter side, that should help big time.

Thanks sir! Any time! That 7900 should scream with that 18" bar! Even just cutting slots in the starter side of the muffler like I did will help out. It's real easy to do as well.

 

[Greenerpastures]

Thanks sir! Any time! That 7900 should scream with that 18" bar! Even just cutting slots in the starter side of the muffler like I did will help out. It's real easy to do as well.

I had the muffler off just to check everything was ok, and removed the spark arrestor.
I did not want to modify it as if any problems occur with the saw under warranty,
it would be an excuse for the supplier not to cough up.
I also sold my tig welder, but I suppose someone else could weld it back together.

 

[Jacklefty]

Cost me $20.00 at a fab shop. I got a horrible harbor freight welder that I didn't trust welding it back together with.

 

[Greenerpastures]

Well I took the spark arrestor out, and re fueled with 40:1.
The EPA should be charged with destruction of property,
for the saw is completely different now,
pulled out the choke, pulled the cord and engine fired, and died,
Put off the choke, had to pull two more times which was the normal
and it started right up.

Before removing the arrestor, it would take two pulls with choke,
and the four pulls in total offered more resistance, not that is some
restriction to put in the way of the exhaust gases, absolutely stupid.

Ran the saw and it is cooler, still plenty of fuel getting in, so after a few
hours cutting i will adjust carb, if need be, it is a little rich.
On the downside, it makes more noise, sensitive hearing is a pain,

And from this simple lesson, I just pulled the spark arrestor out of my CS-501,
which I can not test until I get a shorter bar, but am looking forward to,
just to compare the stock set up from the factory with my other small saw, which
is still stock too, just to see how much effort was put into setting the carb, will it
be rich, hope so as I read some of the CS-501 's came rather lean, which is far from
good, considering they will get leaner as they break in.