Joined Nov 2001
17K Posts | 774+
Ely, England
Just thought I'd share this one with you as it was my first full on days on the tools for a while. I've had to cover for another "mechanic" who had to go and had two jobs booked in.
they were both 1998 bikes. one a 426 that I helped make up out of two broken engines for a CZ customer from Kent. the other a 501.
the first one was a pretty bike - the 501 - that the owner had checked out thoroughly and instead of trying to start it I did my usual which is to check through the tappets. I then checked for a spark and dried up the plug before trying to start the bike by foot. I fitted a sparks stator in a spare cover and swopped covers and fitted that and still it wouldn't start.
so i decided it was the carb. I found a huge MJ in there, no CD1 jet, a worn atomiser and even though cleaned out it did look grimey. firstly, I spotted that it needed blowing BACKWARDS and out the front. a piece of grit hit me on the cheek. this is how I always blow out a carb so that all air and debris hits me on the cheek. fuel valve, check the slide really is a "/50", smaller PJ, smaller choke, put it together.
Refitted it all. It would start and scream its tits off and then if I put the choke in it would stall. so I raised the tickover until it didn't, adjusted the fuel screw and then was able to lower the tickover considerably. next I did the ignition timing with the strobe and this again helped.
alas everytime I revved it the bike had a bad missfire. at this point I was told this was a regular thing so I had a deep think about this. I then started the bike up and revved it up really hard for 3-4 minutes, I mean HARD!
perfect idle, perfectly clean revving, starts first kick. I was absolutely chuffed as I'd pretty much homed straight in on the problem and wasted little or no time. refitted the customers stator and timed that. all was well. cheerio!
.........
the one I had in yesterday was the Chech bike. My mechanic of last Spring 'Jason' had built just the engine on the bench and so I set too! tappets first and they were also fine. spark was a little iffy but the reading off the stator was fine.
the bike was hard to start so I pulled the rubber boot to get to the carb and what do I see but a pool of oil! turns out the bike has been on its side.... so I strip the carb which we did a year ago and blow it all out, I fit a new gasket and two fibre washers as well as a new fuel valve. something we wouldn't have done a year ago.
I get it to start and it runs poorly, I fit the strobe and just getting it running again is bloody hard! anyway, it was yet again, like the day before, one of those where the stator could have been positioned anywhere! I start with 24d BTDC and the mark is only 1mm to the left of centre. Now what do I do? so now I try it central and it is a little better. the engine is now running but with glowing headers.... it's great at tickover but crap afterwards. something makes me press down on the carb....the bike stops immediately.
so I remove the inlet rubber and silicon the front face with some wurth RTV - just to get us going. first time I've ever 'bodged' with this but instantly it starts OK (as usual by now) but it doesn't run well at all. I change the idle setting and then like the day before I rev the tits off it for 3-4 minutes, you know GP style: wooha-wooha-wooha!
now suddenly it is running beautifully, starts first kick, tickover is great, revs cleanly.
alas we still have an oil problem coming down the frame spine so I need to get this sorted. that old 95mm ring problem again!
I tell you these things because it is all experience and I must have been faced with stark choices perhaps a dozen times on each bike.
I have to say that they both look beautiful. why I think they're so pretty I'm not so sure? maybe it is the silver frame and the functionality of them.
regards
Taffy
they were both 1998 bikes. one a 426 that I helped make up out of two broken engines for a CZ customer from Kent. the other a 501.
the first one was a pretty bike - the 501 - that the owner had checked out thoroughly and instead of trying to start it I did my usual which is to check through the tappets. I then checked for a spark and dried up the plug before trying to start the bike by foot. I fitted a sparks stator in a spare cover and swopped covers and fitted that and still it wouldn't start.
so i decided it was the carb. I found a huge MJ in there, no CD1 jet, a worn atomiser and even though cleaned out it did look grimey. firstly, I spotted that it needed blowing BACKWARDS and out the front. a piece of grit hit me on the cheek. this is how I always blow out a carb so that all air and debris hits me on the cheek. fuel valve, check the slide really is a "/50", smaller PJ, smaller choke, put it together.
Refitted it all. It would start and scream its tits off and then if I put the choke in it would stall. so I raised the tickover until it didn't, adjusted the fuel screw and then was able to lower the tickover considerably. next I did the ignition timing with the strobe and this again helped.
alas everytime I revved it the bike had a bad missfire. at this point I was told this was a regular thing so I had a deep think about this. I then started the bike up and revved it up really hard for 3-4 minutes, I mean HARD!
perfect idle, perfectly clean revving, starts first kick. I was absolutely chuffed as I'd pretty much homed straight in on the problem and wasted little or no time. refitted the customers stator and timed that. all was well. cheerio!
.........
the one I had in yesterday was the Chech bike. My mechanic of last Spring 'Jason' had built just the engine on the bench and so I set too! tappets first and they were also fine. spark was a little iffy but the reading off the stator was fine.
the bike was hard to start so I pulled the rubber boot to get to the carb and what do I see but a pool of oil! turns out the bike has been on its side.... so I strip the carb which we did a year ago and blow it all out, I fit a new gasket and two fibre washers as well as a new fuel valve. something we wouldn't have done a year ago.
I get it to start and it runs poorly, I fit the strobe and just getting it running again is bloody hard! anyway, it was yet again, like the day before, one of those where the stator could have been positioned anywhere! I start with 24d BTDC and the mark is only 1mm to the left of centre. Now what do I do? so now I try it central and it is a little better. the engine is now running but with glowing headers.... it's great at tickover but crap afterwards. something makes me press down on the carb....the bike stops immediately.
so I remove the inlet rubber and silicon the front face with some wurth RTV - just to get us going. first time I've ever 'bodged' with this but instantly it starts OK (as usual by now) but it doesn't run well at all. I change the idle setting and then like the day before I rev the tits off it for 3-4 minutes, you know GP style: wooha-wooha-wooha!
now suddenly it is running beautifully, starts first kick, tickover is great, revs cleanly.
alas we still have an oil problem coming down the frame spine so I need to get this sorted. that old 95mm ring problem again!
I tell you these things because it is all experience and I must have been faced with stark choices perhaps a dozen times on each bike.
I have to say that they both look beautiful. why I think they're so pretty I'm not so sure? maybe it is the silver frame and the functionality of them.
regards
Taffy
