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Post by growntree on Oct 23, 2022 19:17:18 GMT
the figures for the stator test sound ok if the temperature was a bit below 20 degrees celsius? the system delivers a 'pulse' to the cdi every 360 degrees of engine rotation, so you get a spark on both cylinders for each rotation of the engine. only one cylinder is on the firing stroke at this time and the other cylinder's spark is 'wasted' a known good spark plug is quite useful as you can just plug it into the plug caps one at a time (making sure its earthed) and check you have a spark that way Cheers muchly for the info. I'm told it was 16 degrees, so hopefully that'll account for the discrepancy. Ah yes, good point on the pulse, that'll be 35rpm then if the frequency counter on my multimeter is OK, although it still seems a bit low. I'll try the new spark plugs on the gl500 or the bandit and if they're working, I'll try a gl500 or bandit coil on the superdream to see if there's any sign of a spark. I might try the superdream coil on the gl500 or bandit as well. Lots of things to try, lol. One thing I forgot to mention on the previous post is that the cdi isn't sealed fully at the back, so that might be something to look at if the coil and spark plugs are OK.
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Post by buster on Oct 23, 2022 20:28:46 GMT
I'd check the primary resistance rating of any coil your going to try, the superdream's run a very low resistance coil. I'm not 100% sure what effect a higher resistance coil would have on a component like the cdi
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Post by growntree on Oct 23, 2022 20:40:38 GMT
I'd check the primary resistance rating of any coil your going to try, the superdream's run a very low resistance coil. I'm not 100% sure what effect a higher resistance coil would have on a component like the cdi Ah, cheers, useful to know.
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Post by growntree on Nov 27, 2022 21:00:17 GMT
Been a while since my last update, so here we go. The stator tests seemed to be ok and the coil had some sort of resistance at both ends, so I thought I'd just get a replacement cdi unit and after grafting on a connector from the old cdi to replace the missing connector on the new one, it was all connected up. And I managed to get a rather weak looking spark, so I connected a battery and put some petrol in the carbs and one of the wires to the primary of the coil melted. So off with the coil and some replacement wires donated by an old mains cable later... And it runs. Not very well though, so the carbs have gone off to a friend with an ultrasonic cleaner. I've got a video of it running rather badly, but imgbb won't let me upload it. Since then I've got a replacement oil pressure switch as the original doesn't work, although after the first run of about 5 seconds, I popped the valve cover off and found it to be swimming in oil so there is oil pressure. I've also ordered replacement rubber covers for the oil pressure switch and the neutral switch as I might as well change the cover as well as the switch. I thought I'd be able to get away with lying the bike on its side to change the switch so the oil doesn't escape. I've rebuilt the brake caliper and had to get a replacement master cylinder as the original was seized and said yamaha on it. The replacement isn't seized, but isn't pushing any brake fluid either, so a rebuild kit is on the way.
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Post by growntree on Dec 18, 2022 21:31:49 GMT
I've now sorted out the front brakes after rebuilding the caliper and master cylinder. The brakes really didn't want to bleed, so had to invest in a brake bleeding gadget. DHA Brake Bleeding Kit, Hand-Held... www.amazon.co.uk/dp/B07YDRSQG9?ref=ppx_pop_mob_ap_shareWhich connects to the bleed nipple and sucks the brake fluid through. The various reviews said the bleed nipple adapters were rubbish, which they are, but using it with just the tube and no adapter seemed to work quite well and the brakes were bled in only a couple of minutes. My son flattened the battery on his vt125 and had to get a replacement, which gave me the idea to look at the battery I got with the superdream. I could just about read cb12a-a on the side of it, but after being in a back garden for years remarkably it still had a charge of just over 3v in it. The battery acid is still between the high and low marks, so I've plugged it into the optimate and it has lit up the save light attempting to ressurect it, so I guess I'll see how it goes.
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Post by johnjones on Dec 18, 2022 23:34:23 GMT
Brakes reluctant to bleed.....
"Suction bleeding".....
Be weary of the brakes being reluctant to release......
A simple check, with a lubed new caliper piston and seals and m/cylinder res cap off, it should be possible to push the caliper piston fully home with strong thumb pressure, and see fluid rise from the tiny hole, the counter sunk one, on the m/cylinder/resevoir floor.
If you have weak thumbs, a gentle use of a g clamp suitabley protected will surfice, but with only very light screw action.
If you have to use lots of pressure and/or the caliper piston will not push home, then the tiny hole is blocked or there is a problem with the caliper piston/seal/bore.
If that tiny hole is blocked, it can be difficult/impossible to bleed the brakes. A suction method can draw fluid past the main pressure seal.
If that tiny hole is blocked the brakes will be reluctant to release, getting worse as heat intensifies, ending up being locked on !
When brakes applied you will see the caliper piston move out a bit clamping the pads to the disc. Let go of the brakes, you should see the caliper piston return inwards slightly due to the haudraulic seal "recovering" from being deformed slightly, pulling the piston back in.
Note, some repair kits supply the wrong 400 piston and bleed nipple in the 250 kits. Was the piston in your kit the right one, same diameter yes, but length as well ? Bleed nipples can have the wrong size and thread.
Be warned.
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Post by johnjones on Dec 18, 2022 23:41:04 GMT
Sometimes batteries can recover. Sometimes granville bat aid pills actually work. They used to be inexpensive so we're worth the "risk". These days they are a bit toooo expensive. These days offers are out there for reasonably priced ordinary lead acid batteries. I don't use the more expensive "wonder batteries", I stick with the cheaper and just as good lead acid batteries. M and p was where I got the last batch from, carriage free, including acid for under £30. Long gaurantee as well.dry charged so long shelf life.
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Post by growntree on Dec 19, 2022 0:25:41 GMT
Brakes reluctant to bleed..... "Suction bleeding"..... Be weary of the brakes being reluctant to release...... A simple check, with a lubed new caliper piston and seals and m/cylinder res cap off, it should be possible to push the caliper piston fully home with strong thumb pressure, and see fluid rise from the tiny hole, the counter sunk one, on the m/cylinder/resevoir floor. If you have weak thumbs, a gentle use of a g clamp suitabley protected will surfice, but with only very light screw action. If you have to use lots of pressure and/or the caliper piston will not push home, then the tiny hole is blocked or there is a problem with the caliper piston/seal/bore. If that tiny hole is blocked, it can be difficult/impossible to bleed the brakes. A suction method can draw fluid past the main pressure seal. If that tiny hole is blocked the brakes will be reluctant to release, getting worse as heat intensifies, ending up being locked on ! When brakes applied you will see the caliper piston move out a bit clamping the pads to the disc. Let go of the brakes, you should see the caliper piston return inwards slightly due to the haudraulic seal "recovering" from being deformed slightly, pulling the piston back in. Note, some repair kits supply the wrong 400 piston and bleed nipple in the 250 kits. Was the piston in your kit the right one, same diameter yes, but length as well ? Bleed nipples can have the wrong size and thread. Be warned. Thank you. I'll give it a go.
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Post by growntree on Dec 19, 2022 0:32:18 GMT
Sometimes batteries can recover. Sometimes granville bat aid pills actually work. They used to be inexpensive so we're worth the "risk". These days they are a bit toooo expensive. These days offers are out there for reasonably priced ordinary lead acid batteries. I don't use the more expensive "wonder batteries", I stick with the cheaper and just as good lead acid batteries. M and p was where I got the last batch from, carriage free, including acid for under £30. Long gaurantee as well.dry charged so long shelf life. The rebuild is still quite a way off, so I thought I'd see how it goes, but thank you for the tip on which batteries to go for.
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Post by growntree on Jan 7, 2023 18:59:23 GMT
First update of the new year and I've done a few things recently. Firstly, I acquired forks and brakes for a 400, so now I've got twin discs at the front. Today I've had the bike on its side again to figure out why the oil pressure switch hasn't been working and it seems I just hadn't tightened it up enough and now the oil pressure light goes out when the bike starts. I noticed the post the other day about the sluggish rev counter, which mine also has, so I thought I'd give it a squirt of wd40. I kept the gauge upright and just squirted up the bulb hole. Seems to be less sluggish now. I've fitted all the gaskets for the exhaust and started it up, oil pressure light went out and it idled quite nicely about 1000rpm. Rev counter was behaving itself and it revved quite happily before I let it idle again for about a minute before it suddenly stopped and now won't turn over as if it has locked up. I guess I need to look at the engine again.
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Post by duffer on Jan 7, 2023 20:58:19 GMT
Frustrating, but well done so far. Crack on. 👍
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Post by growntree on Jan 7, 2023 21:52:09 GMT
Frustrating, but well done so far. Crack on. 👍 I just tried turning it over with a socket and ratchet spanner. There's a point it won't go past, so possibly a stuck valve? I'll have to take the top cover off tomorrow for a look.
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Post by BritPete on Jan 19, 2023 16:52:24 GMT
Hello all, I thought I'd start a build thread rather than updating the hello thread, so as a reminder here are some collection shots of the bike. Fancy doing a tractor next
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Post by growntree on Jan 20, 2023 18:34:31 GMT
Hello all, I thought I'd start a build thread rather than updating the hello thread, so as a reminder here are some collection shots of the bike. Fancy doing a tractor next That sounds like fun. Might wait until the weather is a bit warmer though.
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