porting with a dremel???

[nstueve]

I know the guys who port will automaticly be thinking get a better tool... I am wondering 1 simple thing...

Does anyone make a good burr that's 3-4inches long for reaching the top of the 6400-7900 Dolmar transfers? I am going to be lightly modding my 7901 kita and was wondering what bit/burr I should use to reach up the transfers??? The 1/4in shank burs for my die grinder are not as small and easy to operate in a small confined area. Hoping my dremel would do the trick for a good touch up job but need recommendations on longer burrs...

Has anyone used the "diamond dust" burrs before or do they clog quite easily with aluminum?

 

[Scooterbum]

They make a flex shaft for the dremel that will work fine.

 

[TALLGUY]

I just use the flex shaft attachment that came with my Kirby vacuum
:jester:

 

[nstueve]

I have the flex shaft, 3 dremels and about 500 different bits to put on it but all of them have a 1.5in shaft and can't reach the top of the transfers...

Looking a 3/32in shaft bits right now. hoping to find some micro carbide burrs with 2-3in shaft for the extra reach...

 

[blsnelling]

I'm not sure you want to be grinding it that part of the transfers. You're liable to loose velocity and do more harm than good. I could be wrong though. The 7900 is not my forte.

 

[nstueve]

I'm not sure you want to be grinding it that part of the transfers. You're liable to loose velocity and do more harm than good. I could be wrong though. The 7900 is not my forte.

I was less going for grinding and more for "smoothing," The transfers are long and narrow which makes it harder even for OEM cylinders to cast nice clean transfers. I was more or less aiming to remove the rough casting and leave the same size...

Thanks for your input though brad... I'll keep it small to keep velocity up...

 

[Scooterbum]

That slight pebble grain is for turbulance, slows the charge down. You slick it up too much and it'll slide right past the piston and out the exhaust before it can even ignite.

 

[nstueve]

That slight pebble grain is for turbulance, slows the charge down. You slick it up too much and it'll slide right past the piston and out the exhaust before it can even ignite.

well how about some where between polished glass and rough casting buggers in the transfers??

 

[blsnelling]

Is this an aftermarket cylinder?

 

[nstueve]

nope OEM 79cc Dolmar Mahle cylinder

 

[Homelite410]

Best just leave it rough!

 

[SawTroll]

I'm not sure you want to be grinding it that part of the transfers. You're liable to loose velocity and do more harm than good. I could be wrong though. The 7900 is not my forte.

I suspect you actually are wrong, but I can't prove it.....

 

[nstueve]

i'd kinda like to see/hear what stumpy or others have done when porting these saws???

 

[benjy]

dremmel works ok... only thing i found was that it lacked a bit of torque but anyway i have just dont my 372 ports with it no problem just take your time and keep it moving. i used a double cut carbide burr was great, i had a diamond bur clogged up in about 20 seconds so go for the carbide cutters IMO.

 

[BloodOnTheIce]

I polish my transfers to a near mirror finish, it allows for the fuel to maintain velocity. :hmm3grin2orange:

 

[Tree Sling'r]

I would leave them be, not worth scuffing the finish while your trying to angle your Dremel. Since I am outfitted well with porting tools, I do knock off the casting marks on the uppers with a right angled hand piece. I used to go all out on the uppers, but realized I was probably doing more harm than good.

 

[tlandrum]

once again the less is sometimes more theme comes to mind.

 

[jakew88]

Never ported a saw. But the head I've done for cars, rule of thumb is, exhaust; smooth as possible, intake; golf ball type finish, if a mirror like finish is made on the intake the walls will wet and the fuel and air wont atomize, a little turbulence in your intake is a good thing. Also has an effect on port velocity.

 

[TJfromCC]

tools for porting

This is a better setup for porting. It uses a flex shaft system View attachment 267894

 

[TJfromCC]

If you want to start raising, or changing the trajectory on the transfer ports you will need a right angle like this one View attachment 267895