Chainsaw Repair

Husqvarna - Stihl - Poulan - Jonsered - Dolmar chainsaws and more => Dolmar Makita => Topic started by: jar944 on February 10, 2015, 08:08:42 am

Title: 7900 AM cylinder transfer ports
Post by: jar944 on February 10, 2015, 08:08:42 am

It has TINY ducts  :o So small the burr wont clear.

(http://img.photobucket.com/albums/v695/jar944/rps20150210_074337_290_zpshaiimdxz.jpg~original) (http://smg.photobucket.com/user/jar944/media/rps20150210_074337_290_zpshaiimdxz.jpg.html)

It makes the OEM ducts seem huge.

(http://img.photobucket.com/albums/v695/jar944/rps20150210_074129_719_zps5swabvhi.jpg~original) (http://smg.photobucket.com/user/jar944/media/rps20150210_074129_719_zps5swabvhi.jpg.html)

Title: Re: 7900 AM cylinder transfer ports
Post by: aclarke on February 10, 2015, 09:29:41 am

Several of the AM 7900 cylinders I've worked on had the ducts cast off-center to the bore. 

Title: Re: 7900 AM cylinder transfer ports
Post by: jar944 on February 10, 2015, 10:10:35 am

Quote from: aclarke on February 10, 2015, 09:29:41 am

Several of the AM 7900 cylinders I've worked on had the ducts cast off-center to the bore. 

Yeah I ended up with two cylinders and both are off center. The transfer ducts are the same in cross section on both sides (and both cylinders).

I may cut through the wall before I get up to the stock size.

Title: Re: 7900 AM cylinder transfer ports
Post by: srcarr52 on February 10, 2015, 11:37:46 am

Quote from: jar944 on February 10, 2015, 10:10:35 am

I may cut through the wall before I get up to the stock size.

Time to fire up the tig welder.

Title: Re: 7900 AM cylinder transfer ports
Post by: jar944 on February 10, 2015, 12:06:31 pm

Quote from: srcarr52 on February 10, 2015, 11:37:46 am

Quote from: jar944 on February 10, 2015, 10:10:35 am

I may cut through the wall before I get up to the stock size.

Time to fire up the tig welder.

Ha, yeah. I guess I should pad up the outside of the transfers before I see daylight.

Title: Re: 7900 AM cylinder transfer ports
Post by: mdavlee . on February 10, 2015, 12:58:34 pm

Weld some thickness on there or you'll have to devcon it later.

Title: Re: 7900 AM cylinder transfer ports
Post by: aclarke on February 10, 2015, 01:07:50 pm

Making the ducts as big as stock may be fruitless IMO.  Ive Added material (Devcon) to tighten up 372 and 7900 ducts that have been opened up too far with good results when the saws became lazy...

Title: Re: 7900 AM cylinder transfer ports
Post by: David Young on May 07, 2015, 08:24:56 pm

Pics Adam?

Title: Re: 7900 AM cylinder transfer ports
Post by: aclarke on May 08, 2015, 12:21:49 am

David. I'll take a few pics this weekend.