dillon0990
XS650 Enthusiast
All,
After finding black plastic when removing sump filter I determined it was at least time to replace the front cam chain guide. Following the popular youtube videos, I remove cam cover, head, and at first did not plan to remove the jugs. However, It lifted off the gasket and found the gasket to be in pieces, some stuck to the case and some the jugs, so decided to move forward. At first the cam guide looked good and only edges came off, but once I got it out I pulled on the black plastic and it was just sitting there, not even attached.
I knew I could remove the cylinders without pulling pistons out, but decided I came far enough. Might as well take some measurements, replace rings as needed, and other parts as needed (I am on a budget, well the wife says so). No compression issues before parking it. Failed to check before taking apart.
As of today I will be dropping the pistons and jugs to a machine shop to measure. If in spec for piston/cylinder clearance (0.050 to 0.055 mm piston/bore clearance), they will do a light hone. I checked end gaps of stock rings on one side and were in spec, but on the edge of limit. However, when remove rings from second piston I broke one. I will now buy 1st over rings and grind to minimum ring gap.
Current piston size for both L/R are 74.962 and bore is 75.013 (0.051 clearance when new). Thoughts on best 1st over piston ring sets?? where to buy?
I have seen some people discuss using a feeler gauge to determine if bore/piston clearance is in spec and if a .004" fits its probably out of spec, but I think it is flawed or misunderstood. Pistons are measured at the skirt perpendicular to the piston pin 10 mm from bottom. There is no requirement to measure the top of the pistons. With my piston in the bore I can fit a .006 " feeler gauge at the side, but from the bottom at the skirt, I cant even squeeze a 0.002" in. This leads me to believe the piston and bore are in good shape and in spec. THOUGHTS???
Cam chain is still intact, but thinking if I have everything apart I should replace it. I don't have the right tool, but think I may try the ball peen technique. I tested valves by placing them valve side up and using first gas and then tried again with water. No leaks at all, so I doubt I will mess with the valves/heads. Keep it or replace it????
Replaced clutch push rod bushing yesterday and will do seal once I get some gasket cement. It had a bad leak there.
I purchased the new clutch springs and allen head spring retainer bolts from tc bros. Friction disks look pretty good and were not stuck together. steels had no rust or anything and straight. Plan to leave them and see how clutch works once in the bike. (pretty easy to replace disks later if needed).
For reference, this is a 1977 xs650. owned by my dad for 35+ years. has been sitting without running for 10+ years, but ran when parked. the carb floats had pin holes, but then it sat until I decided to take it and convert to brat style with monstercraftsman brat kit.
I will update when I get measurements back. I pray I don't need a bore or new pistons.
After finding black plastic when removing sump filter I determined it was at least time to replace the front cam chain guide. Following the popular youtube videos, I remove cam cover, head, and at first did not plan to remove the jugs. However, It lifted off the gasket and found the gasket to be in pieces, some stuck to the case and some the jugs, so decided to move forward. At first the cam guide looked good and only edges came off, but once I got it out I pulled on the black plastic and it was just sitting there, not even attached.
I knew I could remove the cylinders without pulling pistons out, but decided I came far enough. Might as well take some measurements, replace rings as needed, and other parts as needed (I am on a budget, well the wife says so). No compression issues before parking it. Failed to check before taking apart.
As of today I will be dropping the pistons and jugs to a machine shop to measure. If in spec for piston/cylinder clearance (0.050 to 0.055 mm piston/bore clearance), they will do a light hone. I checked end gaps of stock rings on one side and were in spec, but on the edge of limit. However, when remove rings from second piston I broke one. I will now buy 1st over rings and grind to minimum ring gap.
Current piston size for both L/R are 74.962 and bore is 75.013 (0.051 clearance when new). Thoughts on best 1st over piston ring sets?? where to buy?
I have seen some people discuss using a feeler gauge to determine if bore/piston clearance is in spec and if a .004" fits its probably out of spec, but I think it is flawed or misunderstood. Pistons are measured at the skirt perpendicular to the piston pin 10 mm from bottom. There is no requirement to measure the top of the pistons. With my piston in the bore I can fit a .006 " feeler gauge at the side, but from the bottom at the skirt, I cant even squeeze a 0.002" in. This leads me to believe the piston and bore are in good shape and in spec. THOUGHTS???
Cam chain is still intact, but thinking if I have everything apart I should replace it. I don't have the right tool, but think I may try the ball peen technique. I tested valves by placing them valve side up and using first gas and then tried again with water. No leaks at all, so I doubt I will mess with the valves/heads. Keep it or replace it????
Replaced clutch push rod bushing yesterday and will do seal once I get some gasket cement. It had a bad leak there.
I purchased the new clutch springs and allen head spring retainer bolts from tc bros. Friction disks look pretty good and were not stuck together. steels had no rust or anything and straight. Plan to leave them and see how clutch works once in the bike. (pretty easy to replace disks later if needed).
For reference, this is a 1977 xs650. owned by my dad for 35+ years. has been sitting without running for 10+ years, but ran when parked. the carb floats had pin holes, but then it sat until I decided to take it and convert to brat style with monstercraftsman brat kit.
I will update when I get measurements back. I pray I don't need a bore or new pistons.