Recent content by dannyTheBoat

I did notice the 1 bad score, but that measures below the stroke of the top compression ring. I'll scrutinize the others a bit more. That cylinder had good compression before the motor came apart so I'm optimistic. Thanks for the suggestion on getting new jugs. I think I'll look for some spare...

Over the past week I have gotten in to the cleaning and re-work portion of the job. I used a wire wheel to clean up the exhaust and intake valves. Theres a before and after of one of the exhaust valves. the seat seems to be in good shape so I'm planning to lap the valves rather than cutting new...

Is there any risk in just doing the pistons rings anyways? My cylinders look pretty good and measure to within 0.01mm of spec. I'm going to give them a light hone to give the rings a nice surface to seat to. I've done valve lapping on globe valves for water before so I have a feel for that task...

I got the head and block off today. nothing too difficult came up. I made a scraper out of a chunk of copper tube and went to town on the heads, valves and pistons with that and a brass brush and some WD40. There was a good amount of carbon built up on the aluminum and on the exhaust valves. I'm...

Got the motor out and cam cover off yesterday. I was a lot easier than I thought it would be. I was concerned that the bolts would be seized. Everything looks in good health, but I haven't taken any measurements yet. The LHS cylinder had low compression at 120 psi when I got it in to the shop so...

I guess I should think more carefully about this then given y'all think it may be a bad idea. Maybe I'll just do the valves and exhaust while I work out the electronics. I guess I'll see what it looks like when I get into it. I've already got a lot of the of the internal parts for the motor. Is...

Anyone have good advice on engine enamel and the best primer to use. I've seen VHT mentioned. I'm also looking at this Dupli-Color ceramic enamel.

Sure it may be 'frivolous' but so is owning this bike in the first place really. Mostly I think it will be a fun project and since the motor is in decent health, it should be low risk. These machines are well engineered. It's not like I'm tearing into a Harley shovel head. That being said, it...

Is it safe to assume that my cylinders are in good shape if I have good compression? A guy I work with has honing tools so I am hoping to get away with a chem clean and a light hone of the bores. Going to the next OS bore is going to double my cost and more importantly the time required.

Thanks, The '81 P/N seems to match the 2a2 rings. Any opinions on these aftermarket Japanese rings I found on ebay? There is at least one set of older Yamaha OEM rings and German aftermarket rings but they are 4-5 times the cost. Thanks in advance. Japanese rings...

Getting back in to this after a busy month. I am looking around for piston rings and I see two different part numbers out there. Partzilla lists the rings as 2a2-11610-00 but I also see 12r-11610-00. Anyone know which one is proper for an '82 SOHC XS400SJ. My title says XS400RS but the bike...

You're not wrong Mike. My plan was always to do a rebuild anyways and I would rather do a bunch of work in one go than keep chasing problems. I could be totally wrong and it's not even the valve seals. The block, head, and cover are pretty corroded which is bad for heat transfer, and all the...

Oh damn I've got an SOHC so it looks like these won't work for me?

Do you still have these? I am getting ready for a re-build and looking for parts.

Hello everyone, I've had my XS400 since February as a learner bike to learn to ride and wrench. It has been a lot of fun riding and working on it and I have gotten a lot of great advice from the folk in this community on the fuel-air and exhaust systems. Due to an oil leak (likely valve seals)...