Mr Tea Posted August 25 Report Share Posted August 25 juniors 125 fired up as normal , warmed up and out but with in to laps he is in saying it’s not right . Sure enough I could fill hat is best described as a knock on the run down in revs in neutral. ran up the gears normal . checked over and changed the plug as a starting point , nothing else found amiss. Parked up and he too the 250 out for the rest of the day. got it home, can feel it also do it on the increase in revs. Every now and again , a solid knock . No vibration. Is it detonation ? Was fine up until today . Weather is normal , fuel and oils the same, everything is the same just this. what say clever 2 smoke people ? Quote Link to comment Share on other sites More sharing options...
Timbo S2 Posted August 25 Report Share Posted August 25 (edited) No idea. Buy my 250 as a cheap spare whilst you investigate. Edited August 25 by Timbo S2 3 Quote Link to comment Share on other sites More sharing options...
TLRS Posted August 25 Report Share Posted August 25 Can detonation occur on a shut throttle? Quote Link to comment Share on other sites More sharing options...
Superdunc Posted August 28 Report Share Posted August 28 Sounds like a big end. 1 Quote Link to comment Share on other sites More sharing options...
dab33 Posted August 28 Report Share Posted August 28 Take the barrel off and have a look, can't imagine it's difficult to do. 1 Quote Link to comment Share on other sites More sharing options...
DougW Posted September 2 Report Share Posted September 2 Quick checks. Take the ignition rotor cover off and check for play in the mains. Take the exhaust pipe off and CAREFULLY insert a finger into the port , rocking the piston backwards and forward over TDC by CAREFULLY turning the flywheel with a finger pressed against the piston can show up play in the big end. I did this a few weeks ago after a friends KTM developed a knock and it showed the big end had play, I still have all my digits but don`t blame me for any unwanted amputation, I did say CAREFULLY 3 Quote Link to comment Share on other sites More sharing options...
Mr Tea Posted September 3 Author Report Share Posted September 3 Went to strip it down and it had snapped two of the four studs that holds on the barrel. Mark at gear 4ktm has never seen that before . We couldn’t find anything else on the top half wrong so instead of a £1200 strip and rebuild of the bottom I’ve ordered some news studs and together with a new pistons and bits we’ll see what that does. 8 Quote Link to comment Share on other sites More sharing options...
Timbo S2 Posted September 4 Report Share Posted September 4 13 hours ago, Mr Tea said: Went to strip it down and it had snapped two of the four studs that holds on the barrel. Mark at gear 4ktm has never seen that before . We couldn’t find anything else on the top half wrong so instead of a £1200 strip and rebuild of the bottom I’ve ordered some news studs and together with a new pistons and bits we’ll see what that does. Nice cheap fix. Winning. Quote Link to comment Share on other sites More sharing options...
Mr Tea Posted September 8 Author Report Share Posted September 8 On 9/4/2024 at 9:58 AM, Timbo S2 said: Nice cheap fix. Winning. Took the bike out today and after a session to give the new top end a gentle break in it was all good to go and fuck me I don’t know what extra I’ve done but the lad says it’s a lot better than even before it played up. Junior thinks I’m some engine genius. 6 4 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.