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ATC350X 85
10-21-2002, 07:49 PM
Ive decided to do a new top end on my 86 250r. As far as I know this is the atc's first top end job. Providing that the cylinder is in good shape, should I hone the glaze off of it or will that damage the NicAsil coating? Also I dont think the reeds have ever been changed, Im thinking now is a good time to change them, anyone disagree? I probably wouldnt be taking this apart at all, but the base and head gaskets leak and its getting harder to start. Also, I plan on just putting in a factory size piston and rings.
MR ATC
10-21-2002, 07:58 PM
the 250R dose not have a niklesol coated cylinder it is a steel liner boreing/honeing is ok and after this long a standard size piston is not a good idea. yes replace the reeds if there steel there stock
ATC350X 85
10-21-2002, 08:19 PM
Do you think the cylinder is warped? Is that why you say it is not a good idea to put a stock sized piston in there? It is a low hours machine. When i take it apart should i measure it with an inside micrometer to check the wear? What is allowable wear?
OldSchoolin86
10-21-2002, 08:28 PM
Stock size is bad because your cylinder is just worn out in the direction that the crank throws the piston back and forth. An 86 250R isn't like the bikes out there now, the cylinder is more vulnerable to wear. You'll most likely need to mic it out and get the over size piston you need then get it bored to the fit the piston. As a general rule only go up to the next size that you need. Be shure to mic it out in the middle in the directon of front to back.
ATC350X 85
10-21-2002, 09:13 PM
I just read up on everything in my manual. I think I'll be ok. Any other tips or suggestions are more than welcome.
atc86r
10-22-2002, 04:40 PM
be careful with the exhuast flange bolts. they like to break. if you do get it bored get a compression tester.
atc86r
10-22-2002, 04:42 PM
stock silencer? clean it.
TimSr
10-22-2002, 04:54 PM
I agree with the others, it will likely need a bore job by now. Cylinders wear egg shaped even though they may not shows scratches or irregularities in the bore. Measure the bore in different positions, or if youre not sure what youre looking for, let your local dealer do it.
OldSchoolin86
10-22-2002, 05:00 PM
Your manual won't tell you if it's worn out. Take the trike or the cylinder to a dealer to have it checked out.
ATC350X 85
10-23-2002, 07:48 AM
I know how to use a micrometer. The manual tells me the specifications :rolleyes:
TexasRex
02-09-2004, 02:24 PM
if its egg shaped, wouldnt there be signs of blow by?
KASEY
02-09-2004, 09:51 PM
LOL!!! 1 1/2 Year old post!!!!!! i think he has figured it out by now!!!!! :D :D :D :D
nitekrawler
02-09-2004, 10:41 PM
:D
We would hope :!: