RM 465 siezed!

Joined
Dec 12, 2003
Messages
3
Likes
0
#1
whilst riding my recently aquired RM465 today the engine siezed solid just after a 1/2 mile incline(not full throttle).it has 3-4 hrs on a new barrel /piston,32:1 bean oil,one size leaner main,one clip leaner needle.The piston has picked up on the left hand side of the exhaust port,would any one know if this could be a leaky crank seal causing a weak mixture?
 

Layton

Subscriber
Joined
Aug 2, 2000
Messages
898
Likes
0
#3
It was probably running lean because of the leaner clip position on the needle combined with the leaner main.
I guess I should ask why you leaned it out?
 
Joined
Jan 25, 2001
Messages
1,396
Likes
0
#4
Oh well if you’re not French :)

An old engine can get a bit drafty so a leak down test might be a good idea.
Check under the ignition cover. If it is oily it may be the seal leaking. The airfilter may be suspect as my the airbox to carb. The carb itself may be worn so it leaks past the air slide & the needle jet worn so it is too rich in some areas making you think you should lean it up.

You can build a tester from a hollowed out sparkplug with some gas fittings to a low pressure gauge & a tire valve. Make a puck to replace the carb & a plug for the exhaust (can be difficult, use imagination) & pump in psi. Should hang around for a minute without dropping much, if not then spray some soapy water around. You may find the manifold/base gasket area leaking.

At the end of the day & not trying to be too blunt, these old nails can never be jetted too close. They are big & imprecise air-cooled donks that require rich jetting to survive long applications on load.

Take the ally off the bore with caustic soda, hopefully it is recoverable.