So I got a wild hair and decided to upgrade my pawn shop special 6401 to a 7900...not that it really needed it but thought it would be a fun project.
I decided to spend a bit more and go with the OEM Mahle 7900 P&C vs the Bailey 84cc Taiwan made BB kit. The 84cc BB kit is supposed to be a pretty good option but I went with OEM. Here's a pic of the 6400 and 7900 Cylinders side by side. 7900 is on the right:
Pistons. 6400 on left, new 7900 piston on right. The size difference is evident:
Carb, muffler, and original cylinder removed. Original piston shown here. Also, I used a T27 torx T-handle wrench for almost all bolts. I got the cheap Grip-on torx set from Toolking (the T27 is in the pic here). Complete garbage. The torx bit portion twisted when removing the rusted muffler bolts. Pay the extra money and get the Wiha or other high quality set. I usually dont buy cheap tools and I paid for it here.
New cylinder mounted. I used the metal gasket that came with it but was lazy and didn't measure squish. Oh well, if I get another wild hair maybe I'll tear it back down and measure squish. I used the piston ring compression tool set from Baileys for this job. Well worth the 8 bucks.
Here's the HD air kit mounted. The difference between the stock filter and HD filter is huge. I also trimmed down the H adjustment screw on the carb to allow it to adjust a bit richer if need be.
Old sprocket on left, new sprocket on right. Old one was pretty worn out and it looks like the design was changed a bit (same brand and model):
Old and new fuel filters. I also changed the sparkplug:
Some old parts:
Done! Got the black sparkplug cover too. Also new 22" bar and chain from Baileys
Original saw from pawn shop:
I started the swap last night and finished it up around midnight so I havent got a chance to cut stuff up yet but it started on the 4th pull. I used this post from Arboristsite for instructions on how to do this as I just started working on chainsaws last month (changed the carb in my 026): http://www.arboristsite.com/chainsaw/122884.htm.. Props to that guy! All parts were ordered from Cassadaga Edge and Engine. They had the best prices and shipping was pretty quick. All in all, it was a pretty easy project, the hardest part was popping the &*$# wrist pin clip back in...one went flying and is MIA, so I used one of the old ones.
I decided to spend a bit more and go with the OEM Mahle 7900 P&C vs the Bailey 84cc Taiwan made BB kit. The 84cc BB kit is supposed to be a pretty good option but I went with OEM. Here's a pic of the 6400 and 7900 Cylinders side by side. 7900 is on the right:
Pistons. 6400 on left, new 7900 piston on right. The size difference is evident:
Carb, muffler, and original cylinder removed. Original piston shown here. Also, I used a T27 torx T-handle wrench for almost all bolts. I got the cheap Grip-on torx set from Toolking (the T27 is in the pic here). Complete garbage. The torx bit portion twisted when removing the rusted muffler bolts. Pay the extra money and get the Wiha or other high quality set. I usually dont buy cheap tools and I paid for it here.
New cylinder mounted. I used the metal gasket that came with it but was lazy and didn't measure squish. Oh well, if I get another wild hair maybe I'll tear it back down and measure squish. I used the piston ring compression tool set from Baileys for this job. Well worth the 8 bucks.
Here's the HD air kit mounted. The difference between the stock filter and HD filter is huge. I also trimmed down the H adjustment screw on the carb to allow it to adjust a bit richer if need be.
Old sprocket on left, new sprocket on right. Old one was pretty worn out and it looks like the design was changed a bit (same brand and model):
Old and new fuel filters. I also changed the sparkplug:
Some old parts:
Done! Got the black sparkplug cover too. Also new 22" bar and chain from Baileys
Original saw from pawn shop:
I started the swap last night and finished it up around midnight so I havent got a chance to cut stuff up yet but it started on the 4th pull. I used this post from Arboristsite for instructions on how to do this as I just started working on chainsaws last month (changed the carb in my 026): http://www.arboristsite.com/chainsaw/122884.htm.. Props to that guy! All parts were ordered from Cassadaga Edge and Engine. They had the best prices and shipping was pretty quick. All in all, it was a pretty easy project, the hardest part was popping the &*$# wrist pin clip back in...one went flying and is MIA, so I used one of the old ones.
