Dolmar 6400 upgrade questions

[fordf150]

I've got the 6421 makita. It's gonna get a 79cc conversion soon.

Any suggestions as to which kit I should get.

OEM 7900/7910

 

[NJAdam]

Are You asking me?

I didnt realize you were in europe. There are no more new ones in the usa that i can find.

 

[NJAdam]

I got it all together tonight and I'm real happy with it. This saw has some balls. I measured the squish with no gasket and had .031 so I left it out.

 

[NJAdam]

Does anyone know what a good rpm wot no load I should set it at using a tach.

 

[wde_1978]

For a PS-6400/7900 around 13.500 rpm (stay slightly under), for the newer PS-6420/7910 a tad under 12.800 rpm.

Those rpm's are where the ignition coils are limited to.

I try to tune my PS-6400 & PS-7900 between 13.200 and 13.400 and they both seem to like it!

 

[heyduke]

Does anyone know what a good rpm wot no load I should set it at using a tach.

i'm sure ther will be someone with a better way to do it, but this is mine.

new top end, i would set it to 11k. after a few hours i would lean the H until it hits the limiter. then lose the tach and put it in some wood and futz with H & L until you find the sweet spot. adjust the L until it is rich enough to let the motor spin up without hesitation, then lean the H until it will hold a good rpm undr load and "4 stroke" (sputter) when you lift the bar. check the low again for a quick spin-up. it helps me to film it with my digital camera on a tripod. i can hear the engine better on the recording than when it is a few inches from my ear.

 

[AlfA01]

I'll be doing the upgrade very soon. Ordered the OEM 7910 cylinder and piston kit, HD air filter kit and some other goodies yesterday.

 

[Deleted member 149229]

I'll be doing the upgrade very soon. Ordered the OEM 7910 cylinder and piston kit, HD air filter kit and some other goodies yesterday.

Putting the time and money to build that saw and imho OEM is the only way to go.

 

[AlfA01]

Putting the time and money to build that saw and imho OEM is the only way to go.

Over here in Greece, the 7900/7910 is rather expensive. Over 800 Euros is what most places sell them for. After some porting work, upgrades, etc., you are easily spending over 1000 Euros ($1195). That is why I started searching for a slightly used 6400 to upgrade. I found a new, but older model that was never sold. I bought it pretty cheap and ordered the kits from @fordf150 - Performance Outdoor Equipment. So, I'll essentially be running a new 7910 with all the bells and whistles for cheaper than I can pick up a new stock 7910.

Cheers,
Dan

 

[goldcountrycalifornia]

I tried going to the website linked above to get a 7900 kit for my 6400. Anyone know of a place to get an OEM kit these days?