Makita/Dolmar Big Bore vs. HD air filter kit

[Desko74]

Let me ask you guys!
I am planning to upgrate my Makita DCS 6400 with Big Bore kit.
I have heard that if I am thinking about Big Bore, better to use with the HD air filter kit together.
Does the Big Bore goes fine with the regular air filter?
What do you think about it?

 

[kevin j]

I went to the HD air filter for cleaning reasons. Not sure I noticed any power increase (7900 stock). Air velocity on the small filter was high and tended to bring larger chips into the V shaped grooves. Larger filter and slower airflow, reduced the influx of chips and had more area to deal with them. Was maybe 10 years ago, about $80 then. Well worth it.

I used the Krylon plastic paint made for lawn furniture. Sort of brittle, but matches the gray. I supupose the black shows everyone hey I have the big filtert, but wasn't my thing. so I painted the cover.

 

[blsnelling]

The HD air filter is not a requirement. Lots of 7900s were sold with the standard filter.

 

[lone wolf]

The HD air filter is not a requirement. Lots of 7900s were sold with the standard filter.

I use mine for milling and it don't pick up much dust at all. No need for anything but stock here.

 

[cgraham1]

I've seen posts stating the the HD filter actually reduces power vs. the standard filter setup, due to the way the HD filter necks down at the base...

 

[Tenderfoot]

I've seen posts stating the the HD filter actually reduces power vs. the standard filter setup, due to the way the HD filter necks down at the base...

I guess theoretically, but I have my saw set up with one and could not tell a difference, but it does appear to seal better and keep dust out.

 

[Ash_403]

I guess theoretically, but I have my saw set up with one and could not tell a difference, but it does appear to seal better and keep dust out.

Yes, it does help keep the dust out. I've ran the HD filter now for a few years, and no more fine dust found in the 90* carburetor elbow.
I didn't notice any difference in the saw performance/power. Mine is still stock, other than the filter.

 

[buzz sawyer]

Kept the stock filter on mine and it's fine. What I thought was unusual was that a muffler mod didn't seem to increase power.

 

[Desko74]

The HD air filter is not a requirement. Lots of 7900s were sold with the standard filter.

May be was not correct.
I am talking about 84,6 ccm cylinder-piston kit. (Big Bore)

 

[Homelitexl903]

I think from what people have said is the 7900 oem p/c is better than the after market big bore kit for a 6400 upgrade. I wouldn't know but have read that many times.

 

[Desko74]

I think from what people have said is the 7900 oem p/c is better than the after market big bore kit for a 6400 upgrade. I wouldn't know but have read that many times.

But the price in my country, oem 7900: 250 dollar, 84,6 ccm Big Bore 110 dollar.
And far us I have heard these 84,6 ccm BB kits, works fine.

 

[Tenderfoot]

Yes, it does help keep the dust out. I've ran the HD filter now for a few years, and no more fine dust found in the 90* carburetor elbow.
I didn't notice any difference in the saw performance/power. Mine is still stock, other than the filter.

I found a thin coating of silcone grease on the mating surface helps a lot. I do it on all my saws and have had next to no sealing issues since I started.

 

[cgraham1]

But the price in my country, oem 7900: 250 dollar, 84,6 ccm Big Bore 110 dollar.
And far us I have heard these 84,6 ccm BB kits, works fine.

The AM big bore will probably work just fine.

I've had both (OE 79cc and AM 84cc), and power is very close between the two, but I believe the OE parts are better quality. Most big bore kits do come with crappy two piece rings... If it was my saw, I would replace the ring with a good Caber one before installing the new top end. I would also check the clearance in the squish band area, as a lot of AM cylinders leave too much clearance, which lowers compression. You may be able to run without a gasket if there is room. The HD filter is not a requirement and won't add power over the stock filter, although it may last longer between cleanings.

 

[procarbine2k1]

I'd spend the extra on the OEM piston and cylinder, I've had both.
The standard filter is pretty decent, but I wrapped the filter flange with electrical tape (just a couple times), to get a little better seal (I noticed some fine particled sawdust getting by on mine).

 

[farmerdoug]

I just purchased the 7910 with the HD filter installed. I also have the standard filter. My observation is that it is a nice setup. I don't really see how the air intake is more restrictive like someone mentioned. Outside of one comment, it appears most people who have the HD are happy with it.

 

[cgraham1]

I just purchased the 7910 with the HD filter installed. I also have the standard filter. My observation is that it is a nice setup. I don't really see how the air intake is more restrictive like someone mentioned. Outside of one comment, it appears most people who have the HD are happy with it.

Well there was a guy who tested both on a saw, and the HD filter actually made the saw slower. It was posted here, or on another forum... but I can't really remember who it was. FWIW, I still run the HD on mine, and it hauls ass (and I'm happy with it).

BTW, I was just replying to the OP's original question, where he asked if the big bore kit would need the HD filter to get the most out of it... and the answer is no. Does it work better than the regular one to keep fines out of the engine? I believe that it does.

Let me ask you guys! Does the Big Bore goes fine with the regular air filter?
What do you think about it?

 

[Jeffkrib]

I started with a 6400 with standard filter and upgraded it with a 7910 P&C and HD filter.
I cut dry Aussie hardwood and I can tell you the standard filter let a lot of fine particles through. The HD filter has not let a spec through. If you cutting dry dusty wood go with the HD filter.

 

[mdavlee]

Well there was a guy who tested both on a saw, and the HD filter actually made the saw slower. It was posted here, or on another forum... but I can't really remember who it was. FWIW, I still run the HD on mine, and it hauls ass (and I'm happy with it).

BTW, I was just replying to the OP's original question, where he asked if the big bore kit would need the HD filter to get the most out of it... and the answer is no. Does it work better than the regular one to keep fines out of the engine? I believe that it does.

That was me. I was having a hard time tuning one after porting with the HD setup. Changed it back or just took the filter off and it gained 10% power. It does filter better and will probably keep the intake skirt in better shape til it's wore out.

 

[Ash_403]

I found a thin coating of silcone grease on the mating surface helps a lot. I do it on all my saws and have had next to no sealing issues since I started.

A couple of years ago I was about to do just as you mentioned, when I found an HD filter kit on the E-bay that was too good a deal to pass up.

You have a good tip worth mentioning, though.

 

[Tenderfoot]

A couple of years ago I was about to do just as you mentioned, when I found an HD filter kit on the E-bay that was too good a deal to pass up.

You have a good tip worth mentioning, though.

I do it with the HD filter and all my saws (or anything with an air filter). Cheaper then a rebuild.