Farmertec 290/390 cylinder bolts

[BuckthornBonnie]

As has been mentioned here and elsewhere, the Huztl/Farmertec cylinder threads and bolts are different from OEM stihl.
They're also hex, not Torx. (T27 for Stihl's).
My last two 1127s I used the Farmertec screws except for one hole that I slowly worked an OEM screw in.
So... what's right? Buy and use the AM screws that go in by hand? Or work in the OEM? I read of another poster tapping to oem thread... what tap?
Personal experience: on disassembly of AM bolts BE CAREFUL as the hex head is soft and can strip. I had to drill one out before.

 

[Definitive Dave]

both OEM and Farmertec are self tapping and the threads are meant to be different, so OEM and AM parts can be interchanged and still result in a tight connection
cylinders should NOT be tapped and power/pneumatic/battery tools should not be used
Dave

 

[BuckthornBonnie]

I was thinking so, Dave. Thanks for the confirmation. Sad that I needed it despite sending an OEM screw into an AM cyl before--- just didn't wanna fight it on this build and second-guess while covered in Dirko.



AM cutoff, OEM whole

 

[BuckthornBonnie]

Also an observation re: AM wrist pin bearings for this series. I've used two before but noticed this tonight:

AM above. There's a fair amount of clearance around that pin. Probably fine, but different from this:

I never looked at em closely before. Heck, I haven't checked any bearing w the pin (usually just inspect the needles). The OEM is used.

 

[fearofpavement]

I always use the oem screws in the Farmertec cylinders. They screw in tight but do go in. I've never broken one going in or out but I have broken the tip off a T-27 before and that's a big pain in the butt. I have some better bits now...

 

[BuckthornBonnie]

Also want to clear up the oil seal retainer casting issue:

3 cylinders above 1 AM, 1 029S, 1 ms290. AM-


OEM 290 below:

 

[BuckthornBonnie]

The OEM cylinders do not have two steps for the seal on the clutch side. So the AM casting is correct.

 

[BuckthornBonnie]

I always use the oem screws in the Farmertec cylinders. They screw in tight but do go in. I've never broken one going in or out but I have broken the tip off a T-27 before and that's a big pain in the butt. I have some better bits now...

Was hoping you'd post... thanks. I know you've done a ton of these with only one? failure. Cool stuff.

 

[Randy's Mom]

Next time send it to an expert.

 

[BuckthornBonnie]

Next time send it to an expert.

What?

 

[Khntr85]

I have encountered these thing also....I always put dirko around my seals just as extra insureance....I use whatever case bolts I have on hand....I have had a hole that has been a little "striped"....I put a lot of red loctite on it, and it was solid as a rock a day or two later....


I will add I always use cheap eBay carbs, Pistons, etc....I have had great luck.....I have gotten a few "bad parts".....when you do enough like we have it will happen....here is what you do....take 3-5 clear pics of the problem, and send them a note and the pics threw eBay message.....they will get back with you and make it right, I have had 100% success rate like this, be polite it goes a long way.....I have had them re-send, seals, bearings, cylinder, a chainsaw bar that was bent.....I never lie to get a free part, I only want/deserve what I paid for!!!!


I know a lot of people don't like working on the ms170---ms390 clamshells, but I do....to me they ain't difficult and I really enjoy it....as @fearofpavement said before, I do t care if I sell them fast or not....they will eventually sell and I alsways have a saw around to use or let a close friend or relative use....