If the pickup coil measures good it's good, nothing tricky about that one. The magnet is probably good. I hear what you're talking about in the video. I didn't follow the GN ignition but I'm fairly confident it's a work in progress and the box is probably being used a little out of spec. I doubt it is seeing exactly what it expects to see on the input side. So that is the problem, not defective GN boxes or something stock on the bike. The "bad" GN boxes would probably work fine on the bike they were intended for, unless you read that they don't. But you could treat it like a bad magnet and the bad magnet remedies you read on here might make the box happier.
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81 Special fuel level drops with rpms
- Thread starter ckahleer
- Start date
I didn't see that video, but if you still have the vacuum petcock just about anything would be possible. A real bad vacuum leak would do it, or the equivalent to that internally would do it.
Setting it to "prime" would bypass any problems with the fuel flow short of a big clog, if you want to try that.
ckahleer
XS650 Addict
This morning I put in the origional yamaha ignition box and unplugged the regulator/rectifier to run on battery power only.
Same thing. breaks up on acceleration. I'm out of ideas on electrical. May be time to go back to looking at fuel delivery. I'm not using a vacuum petcock or fuel filter. Swiching to res did not help.
Same thing. breaks up on acceleration. I'm out of ideas on electrical. May be time to go back to looking at fuel delivery. I'm not using a vacuum petcock or fuel filter. Swiching to res did not help.
Additional comment: the choke plungers are often overlooked as source of problems. On the BS 34, they're actually open to the diaphragm chamber too, so in addition to affecting mixture, they can mess with slide ops.
ckahleer
XS650 Addict
One more test I did today was to ride the bike with the left spark disconnected, and dangled an old plug from the cap. I used steel wire to ground the plug threads to the engine. Ran the bike in 2nd gear to 8K rpm with only a slight hint of a miss. Then did the same to right side. It ran like crap. would start breaking up above 3K rpm.
Choke plungers move in unison and both are all the way in when closed. I'm thinking more the problem is fuel delivery related. I have the float height set to 22mm as recommended in my Haynes manual. But a clear tube fuel level check is showing 4mm below float bowl gasket. The manual recommends 1mm. I will ignore the 22mm float height and adjust float tabs to get fuel level to within 1mm of bowl gasket.
Choke plungers move in unison and both are all the way in when closed. I'm thinking more the problem is fuel delivery related. I have the float height set to 22mm as recommended in my Haynes manual. But a clear tube fuel level check is showing 4mm below float bowl gasket. The manual recommends 1mm. I will ignore the 22mm float height and adjust float tabs to get fuel level to within 1mm of bowl gasket.
I think the scenario you describe is pretty wild - kudos on your creativity.
Re choke plungers: they may move in unison, that don't mean they seal in unison. I'm not suggesting that is your problem though. If typical stuff doesn't result in progress, I wouldn't discount it.
Re choke plungers: they may move in unison, that don't mean they seal in unison. I'm not suggesting that is your problem though. If typical stuff doesn't result in progress, I wouldn't discount it.
