Maintenance & Technical > KX250 / KX125
She's Alive !
alan:
My book says 109-171 so it is outside the service limits! :-o :-o
hughes:
--- Quote from: TaKeN on March 29, 2007, 04:55:54 AM ---Just did a compression test with the throttle wide open,
and i got 105 PSI, this is with the engine stone cold,
Is this good or bad ??
Blackkx - Well, the cylinder and rad are quite warm, not scolding hot but hot enough to make you remove your hand after a few seconds :)
--- End quote ---
Retest with warm engine. Start engine up and get it up to operation temp and retest. Then compare the two readings.
hughes:
--- Quote from: TaKeN on March 27, 2007, 09:18:23 AM ---Whilst we are on the subject :)
When i checked the bore ( Cylinder )
On the bike, there were markings on the inside of the cylinder about 1/2 an inch wide going down the bore
There were probably about 8 or 6 of these marks all around the 360 degrees of the cylinder where the piston or rings have started to grow ( I assume ) Is this normal ?
The markings are spaced equally all around the inside of the bore. They weren't deep gouges.. just a different colour to the rest of the bore.
--- End quote ---
Cold seizure? This was after your rebuild right? Can you post some photo's of the piston and cylinder??
TaKeN:
Will retest with a warm engine tommorow.
As for a seizure, i don't think it has seized because the engine never locked up on me or stopped at all.
The marks look like wear marks to me, i will get some pictures up tommorow :)
Yes, this is after a fresh rebuild
Had the cylinder fixed, machined, welded, nicasil plated.
Then i put a new piston and small end bearing in , oh and new base and cylinder head gasket.
The " Marks " as i call them are not realy marks, they are just areas of the cylinder that look a little bit shinier than the other bits :(
TaKeN:
Update !
Engine was in pieces after i compression tested it , so i stuck the head back on and stuck some oil down the barrel to seal the ring against the bore a bit better ;)
I got 115 psi this time, ive not tested it warm yet.
Right, so, i remove the head, the exhaust and then the power valve cover. " OH **** " the arm with moves the power valve control shaft out has somehow jumped off :| , so the power valve hasn't been opening.
Is this why i was getting missfires ?
" Oh well, i might aswell remove the jug now whilst i'm here "
Here are the pictures that i would LOVE for you guys to have a look at and comment on, its currently 10 minutes past 3pm here and its realy sunny :)
http://images.filecloud.com/404622/New%20Nicasil%20Plate%20--%20Possible%20Damage%20001.jpg
http://images.filecloud.com/404623/New%20Nicasil%20Plate%20--%20Possible%20Damage%20002.jpg
http://images.filecloud.com/404624/New%20Nicasil%20Plate%20--%20Possible%20Damage%20003.jpg
http://images.filecloud.com/404625/New%20Nicasil%20Plate%20--%20Possible%20Damage%20005.jpg
http://images.filecloud.com/404626/New%20Nicasil%20Plate%20--%20Possible%20Damage%20007.jpg
http://images.filecloud.com/404629/New%20Nicasil%20Plate%20--%20Possible%20Damage%20008.jpg
http://images.filecloud.com/404630/New%20Nicasil%20Plate%20--%20Possible%20Damage%20009.jpg
http://images.filecloud.com/404631/New%20Nicasil%20Plate%20--%20Possible%20Damage%20012.jpg
These are big pictures, so they might take a while to load ;)
Please be honest with me and tell me whether it needs replating again or not, the piston appears to be ok :)
If you need any more pics please ask, but i would like to put the bike back together tommorow so i can have a good ride :)
Thanks again for all your help so far gents, i realy appreciate it.
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