Archived Posts

[Admin]

Last summer, without warning, the starter on my 550 quit working. If you hit the start button, it was like it had a dead short. The headlight dimmed, and the starter didn't even make a noise. I used the kick start the rest of the summer, since the bike normally starts on the first kick. I had planned on pulling it over the winter and replace it with a spare I have, but never got around to it.

Today I forgot about the dead short and hit the start button out of habit. It worked fine!! Time after time after time.

Anybody got ideas besides electrical gremlins??

Kevin

[Admin]

Today I took a pressure washer to the bike. When I was done it would not start, no spark. Checked a bunch of the wiring trying to find a worn wire that was grounding out because of the water.

Then pulled the points cover off, and water ran out. Come to find out when I put the cover on, a small spot of gasket was inside the points area, not between the points cover and the clutch cover, leaving a gap that let water get in. I was aggravated at first, and then thought, this was the best that could happen. Instead of standing in rain by the side of the road trying to figure things out, I was in the front yard, on a sunny day, with a beer in one hand. I may have to try trouble shooing this way more often.

:^):^)

Kevin

[Admin]

Sounds like a short somewhere. I'd ignore it until it happened again.

Good luck - Arne

[Admin]

Or a dead/weak spot on the commutator.

[Admin]

That's a good catch for a Monday afternoon. CONGRATS!


Lane

[Admin]

I checked all the carb boots and throttle cables and took the bike out again today. It ran great (stop and go for 9 miles) and did not have the high idle problem until I adjusted the throttle stop adjustment screw. After that the problem came back, but it does n't always consistantly idle high.
The bike now seems like it has sufficient low end, and I don't think the idle issue is related.
This bike requires a careful hand, I pulled away from a stop and turned left with the bike leaned over, it hit the power band and the rear tire slid out, this thing is more squirrely than the H2 I used to have.

[Admin]

I say short is probable.

I wouldn't ignore it.

If it kills your electronics (simple as they may be), will your bike kick start with a completely dead battery?

I'd hunt it down.

[Admin]

It might be as simple as dirty contacts on your starter button. I'd look for the cause, just to be sure.


Lane

[Admin]

If your bike is a 75 GT750, the pilot screw (close to the cylinders), which is really a fuel screw, not air, should be set at 3/4-turn out, I believe. It's really a small setting. Each carb has to to be set roughly before running (on the bench, by the book), then the main idle screw is set. Follow the procedure in the manual (available on the resource page), and it should work.

If you can't find it, let me know; I have an addendum that will help.


Lane

[Admin]

Thanks Lane I'll check it out.
(The bike is actually a 76, but with 75 grey tank and side panels)

[Admin]

I was thinking this the other day and maybe im wrong but it seems when you install pod filters alot of the support is gone.The factory air box keeps the carbs stable.Would the extra bouncing cause needle and seats,floats,and such to wear more rapidly?

[Admin]

Its a pain cleaning any vintage bike.I usually only pressure wash the wheels and under the motor. I use meguiars cleaner wax on the rest.Theres too many nooks and crannies for water to get.Good it happened in the driveway with a beer in hand though!

[Admin]

Smokie,

I guess that if the rubber boots were really really soft, that might potentially be an issue, but they are actually quite stiff. Even new "soft" ones are very stiff, so I don't think that's really an issue.

More of an issue is the intake noise and getting the carburation right.

[Admin]

"Blued" pipes are considered normal on a Norton. Mine, and virtually all I've seen including "show bikes" seem to be this way.
Ed
GT550A
71 Commando
Bul Frontera 370

Nortons and all other Brit bikes of that era had single wall pipes. Bluing in the bend near the heads was normal and usually occurred during the first hundred miles. Two strokes shouldn't blue the pipes.

Stu

[Admin]

yeh but cant see anything on how to check restistance etc in the charging system.
mmmm#
is this it?
http://www.ozebook.com/compendium/pei011.jpg

No, that isn't it. That's for the charging coils on the GT500 with PEI ignition. Your bike doesn't have PEI, and your stator is different. And the manuals make no mention of resistance readings on the earlier bikes that had ignition points. But the readings you got are similar to those on two coils that I have.

Hook a voltmeter across your battery terminals and note the reading. Then rev the engine to 5k briefly with the headlamp on and note the reading. It should be at least one volt higher than before you started the engine, and not less than 14 volts. If not, and if you're sure the battery is good, I'd suggest testing the regulator and rectifier, even though you say they're okay.

Stu