Chainsaw Repair

Husqvarna - Stihl - Poulan - Jonsered - Dolmar chainsaws and more => Dolmar Makita => Topic started by: pigpen60 on September 09, 2014, 01:04:23 am

Title: makita 6421
Post by: pigpen60 on September 09, 2014, 01:04:23 am
I have a Makita 6421 in my possession that used to be a hd rental saw, and I was looking it over the other day and thought that the clutch drum bearing was bad. upon closer observation the bearing is fine but the shaft that it runs on is slightly undersized. anyone seen this before? should the bearing have a touch of grease?
Title: Re: makita 6421
Post by: 660magnum on September 09, 2014, 01:23:47 am
I have one of those type saws with a lot of time on it.

If the bearing gets bad, the clutch drum will occasionally make a ding sound at idle.

The shaft is as hard as the bearings. I doubt it is worn? Get a new bearing at the Dolmar dealer. Be careful, there are two different bearing sizes in those saws. You will have to take your old bearing in with you. The clutch drum may be worn? You could try a new one but there are two different sizes to match the different size bearings. The later, bigger, bearing lasts longer.

The shaft is the crankshaft. The chainsaw will have to be taken completely apart to to change the crankshaft$$$$$$
Title: Re: makita 6421
Post by: mdavlee . on September 09, 2014, 09:58:17 am
The bearing will be a tiny bit loose without the drum on. If there's slop with the drum and bearing then there's a problem.
Title: Re: makita 6421
Post by: KilliansRedLeo on September 09, 2014, 10:41:40 am
+1 on the above. If the bell and bearing are both worn and not the crank, I would replace the bell and the bearing with the larger bearing and matching bell.
Title: Re: makita 6421
Post by: pigpen60 on September 09, 2014, 06:52:36 pm
I took it to my dealer and he tried my drum/bearing on a 5105 and it was tight. he tried the 5105 drum/bearing on mine and it was loose. we both agreed the crank was wollered a bit, or not. a crank is out of the Q right now.
Title: Re: makita 6421
Post by: 660magnum on September 09, 2014, 07:05:57 pm
Put some grease or oil on it when you put it back together. As you use it the chain oil will keep it oiled.

Use the saw when you need it for now.
Title: Re: makita 6421
Post by: pigpen60 on September 10, 2014, 09:56:27 am
what is the reason for the larger bearing?
Title: Re: makita 6421
Post by: 660magnum on September 10, 2014, 10:14:25 am
The two bearings had the same inside diameter but the newer larger bearing was bigger on the outside. Apparently they had trouble with the original bearing?
Title: Re: makita 6421
Post by: aclarke on September 10, 2014, 01:34:22 pm
Is the new bearing metal caged and passed on to the drum?
Title: Re: makita 6421
Post by: 660magnum on September 10, 2014, 01:38:10 pm
The new bearing has larger needles. There are fewer needles and a more sophisticated cage.
Title: Re: makita 6421
Post by: Nathaniel Vansickle on September 10, 2014, 04:02:57 pm
 957223092

CLUTCH DRUM ASSY. PS-7900
newest bearing is the metal caged one that is pressed into the drum.
Title: Re: makita 6421
Post by: pigpen60 on September 11, 2014, 06:58:46 pm
took the 6421 out and tried her. buried her in a half rotten maple log and I figured she would have enough to eat through it but no go. had a new 20" full chisel chain on her and I had to really watch I didn't push her too hard or she'd bog. my 5105 did good even with me hittin the shop floor when I started it. granted the 6421 is used and likely abused I figured it would beat the 5105.
Title: Re: makita 6421
Post by: 660magnum on September 11, 2014, 07:45:36 pm
You get it fixed up and it will
Title: Re: makita 6421
Post by: pigpen60 on September 11, 2014, 07:54:57 pm
went down to hardware store to get a T27 driver, lookout!
Title: Re: makita 6421
Post by: 660magnum on September 11, 2014, 08:08:15 pm
The clutch removal socket for the Husqvarna 372XP works on the Makita-Dolmar 6421 clutch spider
Title: Re: makita 6421
Post by: pigpen60 on September 11, 2014, 08:47:10 pm
thanks