rta01
ArboristSite Lurker
Finally got around to rebuilding a Makita 6400 (6421?) I mentioned in a post about a year ago:
First thought is I had something messed up internally. Removed the spark plug and pulled the cord. Spun as nice as you please.
So started looking back through all the various revisions of parts lists I have accumulated - here's what I found. One of the lists shows a Type 1 and Type 2 decompression valve. I reused the one I had and it is type 2 078-118-180. The type 1 is 001-131-150. Type 2 is for use with the black hood and Type1 is for use with the gray hood. (Decomp on right vs decomp on left.) I think all the 7900's had decomp on left - the aftermarket I got did. So I had gotten the gray hood as well. Never saw anything about a different decomp.
Am I on the right track?? I'll certainly never get it started with how I can pull it now.
Had collected all the parts I thought I needed and got an aftermarket 7900 cylinder and piston. Been putting off jumping into rebuilding, but took the opportunity the last couple of days since we were having so much rain and got it put back together mostly. That was an adventure, remembering where and how everything went together. But got it there nonetheless late today. Decided to give it a whirl, see if it would start/run. That's where the monster part comes in. Set the choke, made sure the stop switch was not on stop, pushed the decomp button, and pulled the cord. About broke my wrist. I can only pull one compression cycle. Checked the decomp button and tried again. Same results.Ended up buying a used Home Depot rental, Makita DCS6421 - 20", several years ago. Needed some initial love, but has worked well. Put 24" bar on for some of the bigger trees. Recently started leaking (really pouring out) fuel. Found it to be the flywheel side seal. Replaced the seal and the leak stopped for a very short while, but started again same place. New seal was destroyed. Found crankshaft to be wobbly. Bearing shot. Plan to completely rebuild with big bore. Do I really need this big of a saw? No, but, ..... well, you know. But still need a bigger saw than the Stihls to keep working on property now.
First thought is I had something messed up internally. Removed the spark plug and pulled the cord. Spun as nice as you please.
So started looking back through all the various revisions of parts lists I have accumulated - here's what I found. One of the lists shows a Type 1 and Type 2 decompression valve. I reused the one I had and it is type 2 078-118-180. The type 1 is 001-131-150. Type 2 is for use with the black hood and Type1 is for use with the gray hood. (Decomp on right vs decomp on left.) I think all the 7900's had decomp on left - the aftermarket I got did. So I had gotten the gray hood as well. Never saw anything about a different decomp.
Am I on the right track?? I'll certainly never get it started with how I can pull it now.