View Full Version : '73 Bonneville sputtering

05-19-2012, 1:38 PM
Been working on this bike for ages and like most, it'll go great for a while but then a new problem rears up every couple of weeks.

Two weeks ago after rewiring everything (along with new points, coils, condensers but keeping my old Tymp) and running strong for a while, the charging system went to shit.

I went to Torch's Classic Cycles (thanks again!) and picked up a new Wassell rotor. Put it in, everything seemed to be going fine. Getting the proper voltage readings, etc. Ran good for a bit, but now it sputters and has generally poor performance whenever I throttle. It still idles fine and sounds good when I rev in neutral, but as soon as it's rolling it's another story.

Do you guys think this could be a problem with the charging system still? Maybe I screwed up the stator when I put it back on? As far as I can tell, there's the right amount of clearance between rotor and stator and everything else seems to be okay. I'm stumped.

Thanks in advance.

05-19-2012, 5:03 PM
Can't say what the problem is but I'm on a T140 forum in the Uk and nobody really uses wassell for engine parts becasue they consistantly fail and can't seem to be relied upon. Other may ahve had sucess with their kit but I'm just voicing an opinion.

05-19-2012, 8:46 PM
did you ever check the clearance between the stator and rotor?

05-20-2012, 1:20 PM
Yeah, Torch. I stuck a 0.08 feeler in there and was able to get it around the whole rotor...but not 100% freely. Should I be able to get it around without pinching it at all?

Might be a stupid question on my part...

And thanks for the input, Olly. It's a brand new rotor, so I'm certain (I hope!) that that's not the issue.

05-20-2012, 4:41 PM
duct tape a fully charged battery on the bike and see if it runs better, that way you can tell if it's a ignition or charging issue.

05-20-2012, 5:09 PM
Torch, not sure if I'm following you correctly. Should I take out the battery I'm using, which is fully charged and in good condition (reading 12.7 with the ignition off and holding up good under load), and try running the bike with a new one?

05-20-2012, 6:40 PM
no, I didn't know you had a battery.
If you have a good battery you don't even need and alternator it should run great for as long as the battery lasts, so it ain't the charging system.
start looking at other things that are common to both cylinders and don't overlook the head gasket.

05-21-2012, 12:34 PM
Fair enough. Thanks again for the advice, Torch. I'll start going through everything tonight and see what I can find, although after this I'm finally ready to get it over with and go no-battery.