g'day, i just picked up a honda trail 90 (ct90) and its not running to well,
it idles real high, and takes ages to die down, then when it does the slightest bit
of throttle makes it go nuts again. i've checked everything for leaks, the carby is
pretty worn but still functional. checked the timing, points etc, compression is good, electrics
are dodgey but puts off a good spark. i still couldnt figure it out, so i pulled it down.
the tappets were way to loose, but i dont think it would make it run like that.
the only things i can see is that at some stage it must of been left for years,
1. there is 2 very slight rust marks that are about 6x3mm and 2x2mm, and probly 1/100th of a mm deep, but enough for the rings not to gain contact on that point, also the piston seems to show weird rough scoreing marks on that side/spot but the rings are like new.
2. the exhaust valve/inlet face, has mini pits that are even more minute than that but i could imagine the valve may only be 50% efficient to its job.
i dont want to have to replace anything, but any idea's on what the issue may be,
let me know. cheers, 90seesee.
it idles real high, and takes ages to die down, then when it does the slightest bit
of throttle makes it go nuts again. i've checked everything for leaks, the carby is
pretty worn but still functional. checked the timing, points etc, compression is good, electrics
are dodgey but puts off a good spark. i still couldnt figure it out, so i pulled it down.
the tappets were way to loose, but i dont think it would make it run like that.
the only things i can see is that at some stage it must of been left for years,
1. there is 2 very slight rust marks that are about 6x3mm and 2x2mm, and probly 1/100th of a mm deep, but enough for the rings not to gain contact on that point, also the piston seems to show weird rough scoreing marks on that side/spot but the rings are like new.
2. the exhaust valve/inlet face, has mini pits that are even more minute than that but i could imagine the valve may only be 50% efficient to its job.
i dont want to have to replace anything, but any idea's on what the issue may be,
let me know. cheers, 90seesee.
