250f engine noise, can anyone diagnose?

munch
Profile picture for user munch
Posts
48
Joined
5/4/2014
Location
GB
munch
Picked up an rmz 250 2008 for cheap, it had an engine noise. First thing I did was drop the oil, check all filters and valve clearances. 3 valves were on the loose side and one tight, all sorted and in spec now.

Below are 3 videos of the bike, before I dive any deeper I would just like the opinion on others as it could be something simple...
https://www.youtube.com/watch?v=AUw3QZzl7Z8
https://www.youtube.com/watch?v=druA_vu2bzI
https://www.youtube.com/watch?v=L4zkQSk6bxc
|
ktm-5
Profile picture for user ktm-5
Posts
555
Joined
2/17/2017
Location
Ravenna, MI US
ktm-5 10/27/2017 5:01pm
10/27/2017 5:01pm
I would replace the cam chain or adjust it. Sounds like it's loose
Acidreamer
Profile picture for user Acidreamer
Posts
1794
Joined
8/25/2015
Location
Mansfield, OH US
Acidreamer 10/27/2017 5:10pm
10/27/2017 5:10pm
Check cam chain and tensioner and guides. If that checks out okay id pull the head off and see what the internals look like. Definitely wouldnt run it till you find it.
walent215
Profile picture for user walent215
Posts
2417
Joined
12/6/2014
Location
Ridgecrest, CA US
walent215 10/28/2017 4:59am
10/28/2017 4:59am
Might be something simple but my opinion would be to tear it down immediately ....we had an 09 crf250 and it developed a slight noise , not as bad as yours, but ended up needing complete rebuild including bottom end...a rebuild at this point wont be too bad since it hasnt grenaded . You mentioned you picked it up cheap...i would just plan on a rebuild and now you can start with a clean slate and be comfortable knowing whats been done to it. When you get to that point, pm me, i will save you some $$ on parts.
TrailDigger 10/28/2017 6:24am
10/28/2017 6:24am
Any idea when the last top end was done? Replace the cam chain and reset the tensioner; your bike sounds like my friend's sxf250 that grenaded shortly after. The cam chain had jumped because he didn't replace the chain or reset the tensioner. Dropped a valve and that was it for that motor haha

The Shop

See All »
munch
Profile picture for user munch
Posts
48
Joined
5/4/2014
Location
GB
munch 10/28/2017 3:52pm
10/28/2017 3:52pm Edited Date/Time 10/28/2017 3:56pm
Thanks for all the replies, I decided to dive into it today and just strip everything so I'm sure.

Crank is spot on, no play anywhere
Right side casing is all fine including clutch / primary gear ect
Piston looks good considering I do not know the history I would be happy to continue using it (I'm planning to sell the bike on anyways!)
Cam chain guides look ok, I don't think they are too worn.

The timing chance to me seems quite loose! It hasn't jumped since I've owned it (test rode for approx 2minutes) and had a lot of start/stop and revving trying to diagnose issue but has not been lapped around a track or anything.

I have a video of the chain here: https://www.youtube.com/watch?v=pCis-1_oHqI&feature=youtu.be

That is with the tensioner installed, the tensioner seems to operate fine how would I know if the tensioner is bad?

What is everyones opinion on the chain and how loose it is? Also can I re-use the base/head gaskets or will I definitely need new?
Paw Paw
Profile picture for user Paw Paw
Posts
679
Joined
12/24/2011
Location
Benton, LA US
Paw Paw 10/28/2017 7:13pm
10/28/2017 7:13pm
Put the engine at TDC and see where the cam gear marks line up. That will give an idea about the cam chain.
I would replace it as you are not sure of it's history or age. The same with the piston and rings. Yes you will need new head and base gaskets.

Paw Paw
RCF
Profile picture for user RCF
Posts
546
Joined
4/1/2008
Location
PA US
RCF 10/30/2017 4:07pm
10/30/2017 4:07pm
The chain should not have that much playing in it. Could be the chain is stretched and tensioner is fully extended and not put enough pressure on it also don't reuse the gaskets.

Post a reply to: 250f engine noise, can anyone diagnose?