Gentlemen, having completed the CB77 resto, its been stored at the back of the workshop with several others, but every now & again, they are all pulled out & fired up in an attempt to keep them 'healthy'.
So, yesterday out she came, fuel & choke on, 1 kick, ign on, another kick & shes up & running, so far so good.
About 5 mins in & she starts 'popping' on 1 side, gets worse then all the time, plugs out & the sparks seem to come & go when they feel like it, & i'm of the opinion that the condensers ( which are original) may be breaking down, SO, finally my question, new seem very expensive & rare, so do they HAVE to be for the 77 or will 'ordinary' (read cheaper) variants fit/work??
After all, its only a smoothing capacitor right?? Or am I way off.
Failing that, I've just about committed to buying a complete electronic system, but have failed to get anywhere with the guys in the US, are they still producing?
Found the German system & might go for that if all else fails.
I'm using Boyer & Pazon on other bikes with great success, but neither do them for the 77s, any others out there?
condensers
condensersGSX1400 Red/silver
GSX1400 Blue GS1000G Brockhouse Corgi CB77 CA77 T140 BSA 250 I DO have to grow old, I DO NOT have to grow up.
Re: condensersWhy do you think they have failed? Testing them requires equipment that few people have. However, it is reasonable to see what replacing them does. Any automotive/motorcycle condenser should work, at least well enough to give you an answer. In a way it is but not really. There's a short explanation on Wikipedia.
Update,
well, I soldered in a brand-new pair of condensers for the GS1000 a similar 12v coil system to the Honda, 2nd kick & she was running fine, so at least it seems that other units (condensers) will work on these bikes!! HOWEVER, there's always a 'however' right?? After about 10 mins or so, it started misfiring on l/side, just as before so I assume the old condensers were ok & it must be something else. Pulled the plug & it was wet, fitted another & it again ran ok, tried the old plug again & no spark, dud plug right?? Well as I was cranking & watching 'no spark' as I pulled it away from the fins there was a MASSIVE 1/4 inch spark from the plug threads to the engine, ( how can there be no spark across a small electrode-gap & yet jump a many-times greater distance from the body, so again, I assume the coils & condensers to be operating correctly?? Is it possible that brand-new plugs don't spark? GSX1400 Red/silver
GSX1400 Blue GS1000G Brockhouse Corgi CB77 CA77 T140 BSA 250 I DO have to grow old, I DO NOT have to grow up. Try cutting a short length off each plug wire and/or trying some new plug caps. Check both ends of HT leads. Swap leads left to right and watch where the fault goes.
Heat might be affecting the plug caps or coils. You should be fine with any type of condenser. Just a thing to snub out the sparks at the points. G
'60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160 '66 Matchless 350 '67 CL77 '67 S90 '77 CB400F But it wasn't a brand new plug was it. You had run it until the engine cut out at which point it was fouled.
You put in another pug and it ran OK, also produced as MASSIVE spark with the old plug so it appears that your ignition system is OK. The fouled plug is passing current through to ground OK, hence the massive spark when you moved it away from the cylinder head. It's simply not producing a spark on the electrode where it should, classic fouled plug. You need to figure out why a perfectly good new? plug should foul so quickly, unless you damaged the insulator putting it in which might produce the same symptoms. Suggest that you look at the carburettor.
I should have mentioned that everything was new with the exception of the condensers & coils, new plugs, leads & caps.
New pistons, rings & liners etc. It the new plug that seems to be playing up, the old one works!! Don't look fouled, I've had plugs all furred up with 'growth' & they still sparked!! Carbs are very good & fitted with all new jets & o-rings etc. I balanced the slides by placing 2mm rod in the slide-gap & observing them drop together as the throttle was opened, They were set up according to info from this site, but having sead that, they do look to be too black rather than the expected neutral browny-beige , maybe I should drop the needle a notch? Starts easily, runs smooth, responsive, & each cylinder runs the same when the opposite plug lead is removed, so I don't think its far out GSX1400 Red/silver
GSX1400 Blue GS1000G Brockhouse Corgi CB77 CA77 T140 BSA 250 I DO have to grow old, I DO NOT have to grow up.
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