Posts
1131
Joined
11/9/2014
Location
Costa Mesa, CA
US
Edited Date/Time
7/20/2020 4:25pm
Picking up a used 2017 FC250 with unknown hours (likely 100+).
I fully anticipate framing the bike, and at least replacing the piston, rings, cam chain, and tensioner.
It will most likely get a new oil pump gear, while I have motor out.
With regard to the crank, is it enough to check for run-out/wear by dial indicator, or just split it and replace the rod and bearings to be on the safe side?
If i use the run-out method, does anyone have some good specs for maximum allowable play.
I fully anticipate framing the bike, and at least replacing the piston, rings, cam chain, and tensioner.
It will most likely get a new oil pump gear, while I have motor out.
With regard to the crank, is it enough to check for run-out/wear by dial indicator, or just split it and replace the rod and bearings to be on the safe side?
If i use the run-out method, does anyone have some good specs for maximum allowable play.
If it were to be trail ridden I would of not rebuilt it for her .
Before disassembly it had run out of .0015 But the side to side clearance to thrust washers was a little loose
I dont recall the measurement. But .032 come to mind.
The cam chain & tensioner definitely need replacement. I also did a piston & rings at 75 hours. & during this rebuild also.
If this was ridden by a fast kid , Change it for piece of mind. FYI the KTM rod kits are pricey. It may make since to buy crank assembly if you cant rebuild it cheaply.
I would worry more about the rod breaking than the plain bearing going bad.
It was trued in V blocks I was just double checking in my lathe . Sometime the crank centers can be off from the bearing surfaces
The Shop
Bike has 170hrs and I don't have any reason to doubt it.
It was owned by a Mexican guy in country California who ran it up and down the flat farm roads. There are no trails in his area, and he had no way to bring the bike to tracks or even connect to trails. Fortunately the guy was mostly scared of it after a couple of decent crashes.
The front tire was completely bald from riding on hard/asphalt roads. So yes, the motor will have a full restore, although it sounds amazing tight. My previous 2013 350 KTM made tons of topend noise (cam chain, tensioner) at 100 hours and this bike is amazingly quite compared to that.
Everything external needs some love (tires, levers suspension, chain sprockets, bars), so I think some preventative maintenance will go a long ways.
Considering what I paid for the bike, I can afford to drop $1500 on it and still be doing ok. Should be a fun little project and thanks again.
If things don’t look good, it will be parted out/flipped in short order. Been Around too long to get too attached to something that will be outdated in 5years. But it does have a classic look that has me reading those cerrakote Ti and carbon build threads on vital wishing I had more time and money to sink into her
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