1978 Yamaha XS400-2E (2 cylinder engine)
The bike runs and feels to have good power, (it will speed up to 40mph from a stop light pretty quick if i make it) but feels like it could be better.
Engine does not have any bad sounding vibrations for as far as my noob ears can tell.
Have not looked at the pistons yet but plan to when i have time.
Did a compression test today and got a low reading for both cylinders, cold and immediately after being thoroughly warmed up, throttle wide open and with throttle closed.
The readings for both cylinders came out very close to each other which seems to be a good sign. About 100-115 psi for each.
I want this bike to be good enough to ride interstate hopefully.
I just am seeking some kind of idea as to what the cylinders and pistons will need. Does low compression always mean you must get the cylinders bored??
Im kind of hoping that all they will need is new piston rings and maybe a light honing of the cylinders. The mileage does not seem to be that much to cause the cylinders to warp, but maybe I'm wrong??
I've seen bikes have their first bore oversize at like 100k miles...
Any input is much appreciated for my peace of mind!!
The bike runs and feels to have good power, (it will speed up to 40mph from a stop light pretty quick if i make it) but feels like it could be better.
Engine does not have any bad sounding vibrations for as far as my noob ears can tell.
Have not looked at the pistons yet but plan to when i have time.
Did a compression test today and got a low reading for both cylinders, cold and immediately after being thoroughly warmed up, throttle wide open and with throttle closed.
The readings for both cylinders came out very close to each other which seems to be a good sign. About 100-115 psi for each.
I want this bike to be good enough to ride interstate hopefully.
I just am seeking some kind of idea as to what the cylinders and pistons will need. Does low compression always mean you must get the cylinders bored??
Im kind of hoping that all they will need is new piston rings and maybe a light honing of the cylinders. The mileage does not seem to be that much to cause the cylinders to warp, but maybe I'm wrong??
I've seen bikes have their first bore oversize at like 100k miles...
Any input is much appreciated for my peace of mind!!