Rebuilt carbs, bike won't start now.

[retiredgentleman]

Yes, its almost certainly timing related.

 

[NewestOnTheBlock]

Yes, its almost certainly timing related.

Thanks retiredgentleman. Could you help clarify this? I'm reading this thread.....

http://www.xs650.com/forum/showthread.php?t=6645

And read this, posted by gggGary....

" If you have a TCI bike the timing is not adjustable and you don't need a timing light."

So since my bike is a 1980, has TCI. How would I go about addressing the timing issue?

 

[retiredgentleman]

Thanks retiredgentleman. Could you help clarify this? I'm reading this thread.....

http://www.xs650.com/forum/showthread.php?t=6645

And read this, posted by gggGary....

" If you have a TCI bike the timing is not adjustable and you don't need a timing light."

So since my bike is a 1980, has TCI. How would I go about addressing the timing issue?

Yes, the timing is not adjustable, because the pick-up coils are fixed and can't normally be moved.

What I mean by timing related is this:

The TCI black box gets its timing signals from the pick-up coils mounted on the alternator frame. As long as the small trigger magnet embedded in the rotor is strong, it has the ability to pulse the 2 pick-up coils. As the small trigger magnet gets weaker, it can no longer overcome the strong magnetic field the the rotor uses to generate alternator current. The result is the pick-up coils may miss seeing the magnet go by. If its intermittant, the pulses sent to the TCI black box get all mixed up, and the ignition coil fires at the wrong time.

Unplugging the rec/reg removes the strong magnetic field on the rotor. Therefore it will allow the weakened trigger magnet to reliably do its job.

 

[NewestOnTheBlock]

Gotcha. I gave it a try, sadly, the problem still exists.

 

[NewestOnTheBlock]

I'm going to take the carbs apart and do a overnight carb soak.

I don't know what the issue could be.

I keep thinking that a week ago I had no problem starting the bike. I didn't have this backfire issue, only the random high revs.

But now that i've rebuilt it...the problem(s) are way worse. So with theory, it has to be something I did to the carbs....

 

[retiredgentleman]

I'm going to take the carbs apart and do a overnight carb soak.

I don't know what the issue could be.

I keep thinking that a week ago I had no problem starting the bike. I didn't have this backfire issue, only the random high revs.

But now that i've rebuilt it...the problem(s) are way worse. So with theory, it has to be something I did to the carbs....

Don't soak any carb rubber parts in harsh chemicals (throttle shaft seals etc).

In post #10 you said you set float levels at 22 mm. If your bike is an 1980 with brass floats, it should be set at 27 mm.

I still think your main problem is electrical/ignition related.

If your bike still has the original 4 position fuse panel, with glass fuses, it can cause lots of electrical gremlins. Replace with new automotive blade type fuse holders.

Check resistance of ignition coil: primary: 2.5 ohms, secondary: 13k ohms

Check pick-up coils: 2 coils each at about 700 ohms.

Last..............the TCI black box may be defective. Have you opened it up? Some lads have found water inside.

 

[NewestOnTheBlock]

Right. I've soaked only the metal pieces and have set aside all rubbers....

Bike is a 1980, but I have plastic floats.

I feel like it is electrical too, but I want to eliminate the carb since it was what started it all. Once I get the carbs rebuilt tomorrow, I will be testing the electrics...

 

[XSLeo]

When you bebuilt the carbs, did you buy rebuild kits and use the jets and needles that came in the kit? If so put the stock parts back in the carbs. The kits don't come with the right parts. Usually the gaskets and float valves are ok. The rest seldom is.
Leo

 

[NewestOnTheBlock]

When you bebuilt the carbs, did you buy rebuild kits and use the jets and needles that came in the kit? If so put the stock parts back in the carbs. The kits don't come with the right parts. Usually the gaskets and float valves are ok. The rest seldom is.
Leo

Nah I just replaced all rubber/plastic parts, bought it all from mikes xs. I kept the original gasket seals though.

 

[NewestOnTheBlock]

UPDATE

After letting it soak overnight, I reassembled the carbs. Made sure I rinsed every piece, as well as blew compressed air through everything. I took my time with this as I didn't want to miss anything.

I followed the steps in post #4 in this thread, before I put them on the bike.

http://www.xs650.com/forum/showthread.php?t=17794

I also put on pipe tighteners on my carb boots as the tighteners that we're on there we're old and breaking. I also took the spark plugs out and brushed them off to make sure I had a good chance of starting.

It fired right up, I still had the spitting/puffing issue. But I think because I had betters carb boot clamps, the carbs didn't pop out. At one point the revs shot up to 3-4000, And I unscrewed the idle screw to lower it. Thats when I noticed the spitting/puffing either stopped or diminished.....Eventually after a few minutes of warming the bike up, there was no more spitting/puffing.

I decided to try and give the dead cylinder method a go. Like before I couldn't get the left cylinder to fire, but had no trouble with the right. I switched plugs to see, and the right was still fine. I then switched the spark plug in the left cylinder with 2 other ones I had (they we're used though, and we're kept for testing purposes). So I had tried 3 diffrent spark plugs in the left with no luck. I then took the right spark plug and put it in the left, and it fired right up.

So obviously I need a new pair of spark plugs. I currently have NGK BP7ES.

But other than that, so far...the bike is running again. Even though I know i have some issues with the bike to work out, I can't help but smile from ear to ear to hear it fire back up.

 

[NewestOnTheBlock]

A big thank you to everyone for the help. I'm glad to say that after 4+ weeks and plenty of replacement parts, the bike now operates and no longer has the random high idle issue.

Went on a 30minute ride today, pulled the plugs and its black. Running rich, but compared to before this is no problem.