Hi All, About 6 months ago I picked up a badly cared for MC22, I Have rebuilt the bike apart from a major engine strip, has anyone had an issue where as the bike won’t start after the following: Now has 4 good sparks Good compression Fuel good too But won’t start Question I have is; can you have 4 good sparks and still have a faulty pulse generator? IE I believe its firing at the wrong time? The online available service manuals do not discuss in detail the pulse coil in enough details for me to understand it’s interface with the CDI unit Cheers Richard
Do u have the leads in the correct order? https://www.2fiftycc.com/index.php?...eads-spark-plug-configuration-inline-4s.8176/
Hi there, Thanks for the speedy reply, yes they are connected correctly, as per the workshop manual It’s the N model I’m still thinking its the timing of the spark? Which I believe is sychonized by the pulse generator/cam ?
Do an ohms reading on your pulse coil , just unplug from your harness and measure between the 2 wires
Yes I had checked it and found to be 420 ohms, so looks good I found a good article on the pulse generator so checking the physical set up , just drained the oil to get at it I’ve answered one of my original questions, you do not get a spark if it’s faulty, proved this by disconnecting it Thanks for your help I will be taking the left side cover later today, and will know more then
Yep must have checked 20 times or so Plus made up a new set of NGK plugs and leads all new, New Iridium plugs, 4 heathy sparks too You hear it blow back through the exhaust but won’t fire up
Yep about 3 times now Cleaned jets, new insulators New clips and sealed New air filter, new needle valves in case Of leakage Done a compression test but then not cold 180 170 170 182 So no differential of more than 15 psi what they s would equate to warmed up not sure but suffice to start? Cheers
Have you tried starting it with the tank off, Block the vaccum hose on cyl 1 and use an aux tank, your petcock may be shagged/ blocked so this may help rule it out Your comp readings are pretty good. When you cleaned the carbs, did you remove adjust the air fuel mixture screws ? If so, how many turns do you have them set to ?
Yep running Aux tank suspended over the bike with inline filter so you can see the fuel Yep set the mixture screws @1 3/4 turns out plus new o rings
Any tips on staying logged in yep have ticked the stay logged in box or do you have to be a premium member ? Cheers
Hmm, you should stay logged in if you tick the box , back to your bike, do you know what year it was made ? If yours is 94 onwards (cbr250rr r ) then the carbs should be set at 2 and 1/4 turns out You can your frame number against this list
Hi there, No I tick the box every time and still have to log in (Iphone 6) Back to the bike Found bike carbs 1 2 3 on 1 1/2 and 4 completely wound in? Yep that’s how I found them These are the settings taken from 2fiftycc; CBR250(F) + CBR250R(H): 2Ѕ screws CBR250R(J+K) : 1 5/8 screws CBR250RR(L+N) : 1 3/4 screws CBR250RR® : 2 1/8 screws So I set as 1 3/4 as standard and am running standard jets So not sure where you got the 2 1/4 turns out? I have now removed the side cover and all is well, pulse generator is set correctly So I’m now left with perhaps the cdi unit? So about to do some reading to see what in the past owners fault issues for changing Cheers for your help much appreciated
Have you got the wires going to the coils on the right coils? Swap them over and give it a try (don't ask how I found this out).
Yes all correct, also the loom for the left coil does not reach to the right coil, and checked by the WSM Thanks for your input
Apart from getting a voltage peak adaptor to totally confirm the pulse generator .91v and the ignition coils 178v all looks well with the CDI unit, have no way of confirming the timing of the sparks discharged without another CDI unit to swap out that is So going to spend some time rechecking the amount of fuel getting to the compression chambers The weird thing is the way in which it pops back through the exhaust, it’s not a proper bang misfire it’s almost like like a mortar being launched then sound like it runs back up the exhaust? Odd