tmoloney Posted January 24, 2016 Report Share Posted January 24, 2016 Hi, Not sure this is where I should post this, but I guess someone will tell me if I got it wrong. I am new to trials (and two strokes), having bought a used Sherco 2012 290 ST 3 months ago. I live in Vanuatu where there is no Sherco dealer or any good motorbike shops, so the small riding fraternity here has to do all our own servicing. Today I cleaned out the fuel tank and also cleaned the carby, as I suspected there may have been some dirt in the tank (correct). Put it all back together, and it started almost first kick. HOWEVER, I had re-routed the throttle cable incorrectly and so it was on full power, so when the bike started it revved to the max for about 5 seconds before I could stop it. I mean it screamed! After stopping the bike I easily rerouted the throttle cable and expected all to be ok - not so. Since then I have been unable to start it with the kickstart. Compression seemed down, so I measured it and it was 72psi, but have no idea what it should be. I finally towed the bike behind a car and got it to start, but the power seemed down and it would not idle consistently. When it stopped I was unable to restart it with the kick start again. A couple of questions if there is anyone that can help. I have looked hard but been unable to find a service manual for this bike - does one exist? Could the over-revving have damaged the rings?, reed-valves?, hence causing the starting and idling problem? Any other thoughts? Many thanks Terry (The riding we normally do ) Quote Link to comment Share on other sites More sharing options...
lineaway Posted January 24, 2016 Report Share Posted January 24, 2016 You nicked the piston. If you remove the front pipe, you will probably be able to see the rings are now stuck. If you are lucky you might be able to clean it up. If you have aluminum stuck on the cylinder walls, use muriatic acid with a small brush. It will dissolve the stuck pieces. Keep us posted. Quote Link to comment Share on other sites More sharing options...
lineaway Posted January 24, 2016 Report Share Posted January 24, 2016 (edited) It is called a cold seizure. A warm engine might have survived. Remember to always check for the clunk of the slide closing completely when working on any bike. http://www.shercousa.com/pdfs/sherco_top_end_maintenance_manual.pdf Edited January 24, 2016 by lineaway Quote Link to comment Share on other sites More sharing options...
tmoloney Posted January 25, 2016 Author Report Share Posted January 25, 2016 Thanks everyone, got up early this morning, saw all your posts, and decided to strip the bike down. Yes, definitely looks like "cold seizure", although must admit I have never heard of this before. Well that was one expensive mistake! Really appreciate the prompt and accurate help. Does anyone know of a service manual or repair manual for this bike? Terry Quote Link to comment Share on other sites More sharing options...
pauls320 Posted January 25, 2016 Report Share Posted January 25, 2016 Check out lewisportusa website, they have all the brands info on there, hope you get her fixed up okay.. Quote Link to comment Share on other sites More sharing options...
2stroke4stroke Posted January 25, 2016 Report Share Posted January 25, 2016 I'd say a lot of that looks like old damage. I bet it had a healthy rattle before? Quote Link to comment Share on other sites More sharing options...
micm Posted January 25, 2016 Report Share Posted January 25, 2016 I guess you might have inhaled a bit of grit off that mountain of volcanic dust methinks! Quote Link to comment Share on other sites More sharing options...
cascao Posted January 26, 2016 Report Share Posted January 26, 2016 This black carbon deposits around wear markings indicate that this damage isn't new.... For shure you will have a much more stronger engine after new top end. Quote Link to comment Share on other sites More sharing options...
tmoloney Posted January 26, 2016 Author Report Share Posted January 26, 2016 I feel somewhat better knowing it may have been a pre-existing condition, and would have needed doing regardless of my small f__up. Thanks again to all -looking forward to what should feel like a new bike! Quote Link to comment Share on other sites More sharing options...
lineaway Posted January 26, 2016 Report Share Posted January 26, 2016 Sure you had a little blow by. That happened at full throttle with a cold motor. Remember you can do a 250 or a 290. The 250 Rev`s better especially at low elevations. Quote Link to comment Share on other sites More sharing options...
lineaway Posted January 26, 2016 Report Share Posted January 26, 2016 My son last weekend. 1 Quote Link to comment Share on other sites More sharing options...
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