Dolmar 64xx/73xx/79xx series, smurfs and solo 665/675/681 thread

[psuiewalsh]

There was a loctite product and some people said it worked on 064 cases with bore issue s

 

[jk14]

There used to be some cases on ebay for decent prices. Not sure how that stacks up against new case halfs.

How does the crank look over all? Is there a lot of wear on the clutch bearing surface or anything like that?

Dahmer you have seen this in other saws?

I tried to pull a bearing out of my homedepot makita and that sucker was in there. Heating and pressing it wouldn't budge with the amount of force I was willing to use.

I didn't pull the bearing off the crank. I was a little disgruntled when I found the wore out bearing pocket and called it a night. New case halfs are about $100.

I had read somewhere that the service manual calls for using loctite bearing retainer when installing the bearings. Which leads me to believe that this is a known issue and that is their way of putting a band aid on it and is most likely the reason the reason that your bearing didn't want to come out of the case.

 

[jk14]

There was a loctite product and some people said it worked on 064 cases with bore issue s

I could see it working if we were talking about a case that was worn just enough to let the bearing slip out. However I'd be worried about alignment issues on a case that's really sloppy. That stuff does work though, in the right application.

Edit: here's what I have at work. The loctite 620 says it'll take up .015" diametrical clearance. Needs to be heated to 450° F. to release.

 

[mettee]

There was a loctite product and some people said it worked on 064 cases with bore issue s

There is a note someplace on the dolmar manual that says "glue" the bearing in.

 

[mettee]

Ooops yall already posted that. Should have read the next page

 

[mettee]

I looked on ebay, couldn't find any cases. There used to be a seller that had several whole cases with cranks for under 200

 

[Mycamaro_68]

I could see it working if we were talking about a case that was worn just enough to let the bearing slip out. However I'd be worried about alignment issues on a case that's really sloppy. That stuff does work though, in the right application.

Edit: here's what I have at work. The loctite 620 says it'll take up .015" diametrical clearance. Needs to be heated to 450° F. to release.

View attachment 162133

I have used the 620 at work several times with great luck. I have never tried it on crank bearings though. Have you measured the bore to see how far off it is? It would be interesting to see if it is worn equally in all directions or if it is only worn towards the front of the case from the tension of the chain.

 

[Mycamaro_68]

I have also used a center punch to dimple the bearing bore in 4 equally spaced spots around the bore. It wouldn't be super precise but it would help center the bearing in the bore until the retaining compound set up.

 

[brox]

Does anyone know the differences in the cranks over the years? I recently picked up a 7900 with a blown lower rod bearing. Looking at the different IPLs I see 038-120-100 listed for the 6400/7900 and 038-120-200 6421/7901 saws? I haven't been able to find a decent used crank yet but don't know if either part will work or if it has to be 038-120-100? Thanks.

 

[Fruecrue]

Does anyone know the differences in the cranks over the years? I recently picked up a 7900 with a blown lower rod bearing. Looking at the different IPLs I see 038-120-100 listed for the 6400/7900 and 038-120-200 6421/7901 saws? I haven't been able to find a decent used crank yet but don't know if either part will work or if it has to be 038-120-100? Thanks.

A Solo 665-681 crank will fit if you’re up for a bit of modification, adds 1mm of stroke.

 

[brox]

A Solo 665-681 crank will fit if you’re up for a bit of modification, adds 1mm of stroke.

Thanks for the info but I think that might be beyond my abilities at this point.

 

[mettee]

If you are replacing the crank it's not beyond your abilities.

And this thread will show you every piece you need.


Here, I'll help :

https://www.ebay.com/itm/Original-E...rentrq:a0e244901680aa11adc869e8ffe8bb19|iid:1

 

[brox]

If you are replacing the crank it's not beyond your abilities.

And this thread will show you every piece you need.


Here, I'll help :

https://www.ebay.com/itm/Original-Ersatzteil-Solo-Kettensage-675-Kurbelwelle/222335346632?_trkparms=aid=111001&algo=REC.SEED&ao=1&asc=20160908131621&meid=92f2bae5ab3043ad8029c23cca57bb9f&pid=100678&rk=10&rkt=10&sd=192137283279&itm=222335346632&_trksid=p2481888.c100678.m3607&_trkparms=pageci:9a1b49ac-24de-11e9-8bdf-74dbd1803c39|parentrq:a0e244901680aa11adc869e8ffe8bb19|iid:1

Interesting, that price is more reasonable than I have seen on the U.S. fleabay. Sounds like I need to do some more research on what it takes. Thanks for the link and ideas.

 

[Fruecrue]

Thanks for the info but I think that might be beyond my abilities at this point.

If you can replace a crank and use a dremel, you can do it.

http://opeforum.com/threads/stroking-a-dolmar-7900.14462/

 

[mettee]

It's that and the base gasket, and I believe it will run. You space the oil pump out and a couple other things. If you read through all the part numbers and links are there I believe.

I'm super tempted to do it myself.

 

[mettee]

If you can replace a crank and use a dremel, you can do it.

http://opeforum.com/threads/stroking-a-dolmar-7900.14462/

This is the guy who did it and that is the thread I meant. Had my threads confused for a second.

 

[dahmer]

Just sent all that info to @Mac&Homelite to see if it helps bail him out.

 

[brox]

Awesome, thanks for the help getting started. Looks like a lot of good reading! Thanks.

 

[Mac&Homelite]

@Mac&Homelite is fighting a 6401 that he was converting to 7900. Clutch side crank bearing fit is wore oversize and it also messed up his crank. He can give you more details than I.

Yes, yes I finally showed up. I'm not on OPE as much as the other site. Thanks for the tags @dahmer. Got two of these saws now, a 6401 that had both blown main bearings, and wallowed out races, bent crank and the bearing was spinning on one side of the crankshaft. The 6421 that was purchased to build because it was 'running' ended up having a blown clutch side main bearing, and a enlarged oil seal race on the clutch side. This one also had excessive wear where the clutch bearing rides on the crank. So... I can put together a saw assuming I can find a solution to the crank and do something about the oil seal issue, which the case is only over-sized by about .002-.003''

These saws had a nasty habit of eating the main bearings. I'm partial to believe that the plastic ball dividers are not a good idea in a saw with high temps, but that's me. Haven't run into the main crank bearing failing yet, but I did see a nearly new one on ebay with that issue. I always though it was odd that the manual says to use some sort of a glue on the one side. The bearings came out of the 6401 with no issue, as those were all messed up, but on the 6421, I had to use a hydraulic press to knock them out. Took quite a bit of force, and they gave a good pop when they came out.

6401 will live on as parts, namely the muffler assembly, but I still need to build the 6421 up somehow. These saws are darn tough though. Before I figured out the 6401 had the bent crank, I rebuilt the saw, new bearings, seals, ect and dimpled the races to get them to fit better. Also used some glue but I don't remember what. Ran for about 4-5 hard hours before the chain locked up and I knew it was done.

 

[Czed]