berkshireduncan Posted February 16, 2015 Report Share Posted February 16, 2015 Does anyone have a spec, or known-to-work setting? .. I'm guessing the timing's set in mm of piston stroke BTDC, rather than degrees BTDC on a crank dial gauge? Thanks Quote Link to comment Share on other sites More sharing options...
kingscorpion Posted February 16, 2015 Report Share Posted February 16, 2015 1,8 mm or 17º30' Quote Link to comment Share on other sites More sharing options...
berkshireduncan Posted February 19, 2015 Author Report Share Posted February 19, 2015 Thanks, Kingscorpion (Rookie?) question.. when you're setting the timing against piston position BTDC with an old school 'drop in' TDC gauge, how the heck do you accurately adjust in increments of as little as 0.2mm when the gauge scale is 1:1 with the piston? Quote Link to comment Share on other sites More sharing options...
feetupfun Posted February 19, 2015 Report Share Posted February 19, 2015 You use that gauge to find TDC, then make a TDC mark on the flywheel in line with something on the casing. Then measure from the mark to the position you want the points to open (either using a degree wheel, or by using geometry and measuring around the circumference) and make a timing mark. You then only have to be looking at the timing mark on the flywheel instead of having to read that tiny scale on the TDC tool 1 Quote Link to comment Share on other sites More sharing options...
berkshireduncan Posted February 19, 2015 Author Report Share Posted February 19, 2015 Thanks Feetup.. that makes perfect sense. P.O. did a (Motoplat) Electronic upgrade, so it's just a case of working out / marking up the flywheel at 17.30 degrees BTDC as you say, then lining up the stator behind with a drill bit through the timing hole in the flywheel. 1 Quote Link to comment Share on other sites More sharing options...
feetupfun Posted February 20, 2015 Report Share Posted February 20, 2015 If you want to check that your timing is right after setting it, you can use a strobe type timing light on your timing mark. Its a bit of a pain with the 348 though because it means either bump-starting the motor, or taking the flywheel cover off after kickstarting it. Quote Link to comment Share on other sites More sharing options...
berkshireduncan Posted February 22, 2015 Author Report Share Posted February 22, 2015 Thanks, feetup. I had my stator repaired by Steve at Bradford Ignitions, and followed your guide for re-timing. The bike's now starting and running well, so I'm back in business. Interestingly, the timing had been set pretty well advanced at maybe 2.2 - 2.6mm BTDC, so it'll be good to see how the bike feels and rides now. Thanks again all. Quote Link to comment Share on other sites More sharing options...
borderlord Posted August 14, 2015 Report Share Posted August 14, 2015 Have just been reading this topic. I have a 1967 250cc Montesa Impala....Motoplat Electronic...... Would you have any idea what the timing setting is for this engine...... Many Thanks Borderlord............ Quote Link to comment Share on other sites More sharing options...
merv Posted September 22, 2018 Report Share Posted September 22, 2018 Hi all, I have a montesa 349 with a problem, when the points are open the piston has gone halfway back down the barrel, am I right in thinking this must be a broken woodruff key? Quote Link to comment Share on other sites More sharing options...
feetupfun Posted September 22, 2018 Report Share Posted September 22, 2018 The points stay open for a while. The important thing is where the piston is when the points start to open. Quote Link to comment Share on other sites More sharing options...
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