August 16, 20206 yr Hi Guys, I hope you can help this newbie. I have just purchased my first classic trials a montesa mh200.. it is in good condition and had a lot of money spent by the previous owner. We took it out yesterday to put it through it paces and although it has started first kick every time up to now it ceased to run mid way through our session. I had a look today and it seems the plug was very wet and not sparking. I cleaned the plug and it briefly fires then its soaking wet again. I have stripped the carb 4 times today to double check there is no blocked jets etc and the float needle seems to be working correctly. I feel it could be ignition related as the spark never looks that strong. The coil looks new as does the points. I also am struggling for info on the net to check stator and coil. Help please.
August 16, 20206 yr Have you had the flywheel off & checked the woodruff key ? I had one of those years ago & the key sheared progressively, initially just altering the timing a little before shearing fully & then killing it completely. A quick removal of flywheel revealed the culprit, a few pence worth of key ! Only happened once, always ran fine before & after. I think I remember setting timing with a tool in the plug hole to measure a number of millimetres before TDC. Hope that helps.
August 16, 20206 yr Good luck, let us know how it goes. Do you have the tdc timing tool ? If I remember it was like a pencil type gauge which screwed into the plug hole with a plunger with mm scale on it. Manual specked the distance before tdc.
August 16, 20206 yr Author No I don't have any guage but I will have to find one or make one.Thanks for your help.
August 16, 20206 yr That looks like the one I had, not sure what the setting should be though, maybe in motion can advise or someone else on here ?
August 17, 20206 yr Author I have removed the flywheel and the woodruff key was fine. I am going to empty the fuel and re fill with a different oil and new plug ?
August 17, 20206 yr Author It seems its the crank shift seals its just chucked all the gearbox oil out on the floor ?
September 6, 20205 yr So not so well prepared by previous owner. Change that plug while you are at it as it will now be a constant issue fouling. When you time the ignition make sure the piston is coming up towards TDC and not travelling down the bore, a simple easy mistake to make if you don’t work on engines much.
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.