Thread: crankcase repair/ Dolmar 7900

I had a tree fall on my 7900 at work the other day. Landed right on the bar causing a lot of vertical pressure to be placed on top of the bar. In turn, this put a lot of pressure on the bar mount bolts. So much so it caused a tear to form between the two bolts. Looks the whole right side of the crank case needs to be replaced now. Any suggestions, how complicated is a tear down and repair like this, and how costly?. I know I can get the crank case part for about $120 but I am not sure if I can do the labor or not. Thanks

Are you mechanically inclined for this stuff? Do you have some basic tools? Do you want to buy some tools to do this?

I went through almost this same scenario earlier this yr with a 372XP. I am glad i did it myself, i feel so much more confident now with fixing/working on my saws now.

any advice on going about this, what tools I will need any tutorials etc? I am mechanically inclined and have lots of tools just want to make sure I not getting in to something completely over my head.

Good luck with yer busted saw d00d!


This guy has been here since 2009 and no one has Rep'd him yet!


He's about to get hit with some MotherChucker81 Rep!!


Help the man out guys!!!

You can fab a splitter that will pop the CC halves apart from some flat bar stock, a nut, and a bolt of the appropriate size. It takes some very basic welding skills to make the splitter. Actually splitting the cases is a breeze. Putting the bearing and seal in the CC half sounds complicated, but you only need to heat the new CC piece and freeze the good half of the CC with the crankshaft attached. They will pretty much slip right together and snug up with the bolts that hold the two halves together. You can probably do the whole operation in a couple of hours if you have never worked on this saw before. Take some pics as you go so that you will remember where the parts go. If you have some mechanical ability, don't be afraid to tackle it. We will be here to help you and make fun of you if you screw up!!!

Originally Posted by nmurph

We will be here to help you and make fun of you if you screw up!!!

Eh. Even if ya don't screw up.......

alrite, sounds good I found out how to fab up the splitter so thats not a problem. The only question I have is what do you mean about heating and freezing the CC?

CC = crank case.

Heating and freezing for taking it apart and putting it back together. It'll keep you from throwing a temper tantrum. Them tolerances are as tight as a tw....

Nevermind....

One tip that I used, buy yourself some ziplock bags and keep parts/screws together as you remove them. Easy to label and keep track for reassembly!

thanks for the advice all.....so can I literally put the good half in the freezer and hit the other half lightly with the torch when I am ready to put the sections back together?

We have that crankcase half (Clutch side) in stock, $106.80 + shipping.
Dolmar Genuine Parts#[DOL 038111141]#CRANKCASE, Cylinder#-#$106.80

Originally Posted by Edge & Engine

We have that crankcase half (Clutch side) in stock, $106.80 + shipping.
Dolmar Genuine Parts#[DOL 038111141]#CRANKCASE, Cylinder#-#$106.80

I would be all over that offer like white on rice. I have bought many parts from E&E and have not had any problems. Kyle will take good care of you.

OK guys heres an update

Edge and engine thanks for the part I will be ordering it soon

Here are some pictures attached I broke down the whole saw and you can see the damage

I had three questions

One how do I get the rest of the sprocket off to get to the drive shaft/spindle?

Two does any one have a good pick of a cc splitter I have seen some on you tube but I can not get a good image of one to get the design down?

Three do I need to put any kind of lubricant back into the cylinder before I close it up ?


Any other suggestions would be greatly appreciated... Thanks guys

The clutch drum should come off with a pair of pliers. It may be that the brake band has some tension on the drum bc of the distortion caused by the cracked CC.
Any oil will be fine for the reassembly. I usually use 30W.

I have the Husky splitter. I've seen them made with a 6-8" piece 3/8" x 2 1/2-3" piece flat stock. Drill or slot holes for bar bolts to go through. Then drill and tap hole for bolt to press against crank. Sizes are approximate. Clear as mud hope this wasn't confusing. Asslembly lube I use mixing oil. Couple or three drops on each crank bearing same on the rod and wrist pin. Put some on the piston, ring or rings, wet cyl. and spread with fingers. lay on the three bond or gasket and put her together. Probably need to invest in a inch pounds torque wrench. I picked up a nice used Snapon 3/8" dr. dial type that had just been calibrated with in. lb and nm for $20.00.
Shep