dirtbike engine ?? [nklr]
Posted: Thu Sep 07, 2000 11:09 pm
Steve,
It's been a long time since I've overhauled a 2-stroke. To do
it correctly, you really need a service manual to find out what
the allowable clearances are. There should be NO up & down play
with the connecting rod (big end). There will be some side to
side clearance with the rod's big end. Piston/cylinder clearance
needs to be measured with feeler guages or inside/outside
micrometers. This clearance spec varies widely with each engine
design. It's also important to measure piston ring end gaps to
see if they are in spec. Unless the previous owner used top
quality premix/injection synthetic oil, you may need to
decarbonize the cylinder head. Make sure that the removable
exhaust baffle is clean & not clogged.
If your son's RT100 makes good power. doesn't make any unusual
engine noises, & has normal engine compression, it's unlikely
that you'll need to perform a top-end overhaul now. I would
perform a full engine tune-up now & go over the bike fully to
check for loose/missing nuts & bolts & safety related items.
Lube, adjust & check all cables, check the chain, sprockets, tires
& all bearings. Change the tranny oil.
Professor A9 Federal Way, WA. [USA]
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--- steve6018@c... wrote:
[snip]> Hey guys, > I've got about 3000 flawless miles on my y2k klr650. I just > bought my 12 yr old son a used Yamaha RT100,
> Any way we were cleaning out the carburetor on his rt100, and > took off the reed valve to clean out some carbon gunk.... I put > finger down in the motor and felt the rod. It has a little > play in it.... along with a little play in the piston skirt. > HOW MUCH PLAY IS NORMAL FOR A 2 STROKE MOTOR?? If anyone has > some expertise in this area it would greatly be appreciated! > I'm trying to decide if I shouild go ahead and put a new > piston and rod bearings in..... or wait and hope it doesn't > throw a rod before we get around to it.