No compression situation figured out

Rider_02 · November 22nd, 2020, 09:12 PM

So I was out for my first ride on my new to me 2009 FE570 on Saturday. 20 minutes into the ride the bike just dies and has no compression. I figured out today that the intake valve rocker seized onto the shaft, I’m guessing from lack of oil. Apparently this is a fairly common issue unfortunately.

Rider_02 · November 22nd, 2020, 09:30 PM

Was tough to pull out, didn’t do too much damage

Taffy · November 23rd, 2020, 02:07 AM

thanks for the heads up. Good of you to share.

Taffy

Rider_02 · November 23rd, 2020, 05:12 AM

Does anyone know if there is a good modification to prevent this from happening again? My understanding is KTM released an updated version of the shaft with a little flat on the top side for the 500EXC motors that use the same head. I don’t know if it would make a difference on the 70 degree ‘Berg because of the head angle (the flat would be at the wrong spot)
From the reading I did, it was caused by clogged oil screens (there are 2 of them in the system), I will investigate if that was my issue as well. According to the last owner Oil and filter were just changed and new clutch installed. I will take the screens and filter out to see if they are plugged. One other person had his screens plug off with clutch fibres after a clutch change.

cambo · November 24th, 2020, 04:25 AM

Do you know how many hours / miles were on the bike ? Are the parts still available to repair it ? hope it’s back on the trails quickly

Rider_02 · November 24th, 2020, 05:45 AM

It has 32 hours on the motor. A recluse clutch was installed just before I bought it with zero hours on it. I found the oil screen was plugged with a black gritty material that feels like shaved hard plastic, I wonder if it is from the cam chain slider because it has a manual chain tensioner installed instead of the stock hydraulic one. If it was set up too tight, would the chain shave down the guide? I don’t know. I don’t know where else this type of material would come from. The oil looked new and I took apart the oil filter, it was clean.

Rider_02 · November 24th, 2020, 05:48 AM

Luckily the head is the same as the one used on KTM 500 EXC/XC-W, so yes parts are readily available. I am going to put fresh oil in it, run it for 5-10 minutes and drain it again, then check the screens and see if there is still this mystery stuff coming out

Rainerio · November 24th, 2020, 10:18 AM

There's still another screen at head. Did you clean/replace it. Each time you change the oil check/clean the screens and of course replace the oil filler

Rider_02 · November 24th, 2020, 11:12 AM

Thanks, yes the screen at the head was clean, I am still trying to figure out what was plugging the lower screen.