top end rebuilt; won't start

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coffee_brake
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#11 Unread post by coffee_brake »

Johnj wrote:The old coils wired backwards trick. +1 for your buddy. Did he use to work on Triumphs?
He works on anything. He's the only one in this whole city who will touch an old Triumph or any vintage Japanese bike. Heck he prefers points to electronic ignition!

Thanks a lot everybody especially Wrider and Buzz for the help and advice, I rode the bike a whole lot this morning and it's doing OK. The smoking has stopped, so has the tapping in the valves. #1 is still not firing consistently, it's fuel-fouled, so that looks like carbs. And carbs is old territory. I'm trying very hard to NOT take off that carb rack again. Lots of seafoam...
Jenn S.
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2005 Concours
2001 Vmax
1992 CB750

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coffee_brake
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#12 Unread post by coffee_brake »

Back again with this one, I'd love some ideas from folks who have been here...sorry it's long....

I'm still having troubles with the #1 cylinder. It is firing, it does have fuel.
It is carbon-fouling the plugs...so it's not getting enough fuel right?
I can ride the bike, but only on 3 cylinders. If I rev it pretty high while riding, the #1 cylinder kicks in but within a few seconds it kicks back out again. There's good spark and plenty of fuel and changing/re-gapping plugs doesn't help. Stock pipes. This is a carb issue, I'm prety sure.

I'm doing everything I can possibly think of before I pull those #$@& carbs again. I'm trying to synch the carbs, but either something more is going on, or they are so far out of synch it's just scary. I did #2 to #1 and it was way off, and I had to set the idle screw lower. Then I did #2 to #3, and it idled so high I couldn't get the idle any lower. I'm not pushing with the screwdriver to get a false high idle (did that before), what else could be going on?
No jets were clogged when I put the carbs back together, everything was very clean. The #1 diaphragm looks great. The needle jet had a spot of carbon on it near the base where it touches the slide; is it not seating correctly?
The stock pilot screw caps are in place and all of them look to be adjusted the same. These cannot be adjusted on the bike, not without a very special tool from Honda (I tried every short or offset screwdriver out there, trust me).

So...it idles on 3 cylinders and runs on 3 cylinders, and will briefly when revved high run on all four. Then as the revs drop it goes back to three.

I'd appreciate any ideas, it takes me hours and hours to get the carbs out and back in. And I'll do that of course, but only if I have to. I'd like to try anything feasible before I do it, though.

Suggestions?
Jenn S.
AMA #658162
2005 Concours
2001 Vmax
1992 CB750

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#13 Unread post by Wrider »

Sounds like it's adjusted too rich. If it was too lean your plugs would look white, not black.

When you rev it high while riding it kicks in the #1 cylinder you said. Does that happen when you rev it quickly? Or slowly?

Honestly the only thing I can think of at the moment could be that the coil going to the #1 cylinder isn't strong enough. Sometimes when it's not strong enough the bike will show spark but in the pressure of the combustion chamber it won't actually be sparking or will be so weak it won't set off the mixture. Worked on a DR400 like that.
Have owned - 2001 Suzuki Volusia
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coffee_brake
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#14 Unread post by coffee_brake »

Swapped coils with the running bike, same problem.

OK, maybe it's not ever running on #1. All the plugs are black and sooty. I can't synch the carbs, the idle keeps changing. I can't find an intake leak anywhere. I sprayed half a can of carb cleaner everywhere around there and the idle never picked up; I don't think there's an intake leak.

Occasionally either #1 or #2 overflows fuel; can't tell which one it is. Or why.

Definately carbs; I'm ready to take them off again but I need to know why. I don't know why #1 won't run and I don't know why the idle keeps changing, and I don't know why sometimes they're pouring fuel, but not always.

Anybody got anything on this? I really appreciate all the suggestions already, too. I'm lost in these carbs.
Jenn S.
AMA #658162
2005 Concours
2001 Vmax
1992 CB750

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coffee_brake
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#15 Unread post by coffee_brake »

Nevermind. New float needles and a bench sync, and all is well with the Honda. Starts right up and fires on all four, rides and shifts slick as can be. Tank is up for bodywork and paint, and then it's a finished, road-ready bike brought back from a bucket-o-parts.


:jumpy:
Jenn S.
AMA #658162
2005 Concours
2001 Vmax
1992 CB750

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#16 Unread post by Johnj »

:clapping:
People say I'm stupid and apathetic. I don't know what that means, and I don't care.
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#17 Unread post by coffee_brake »

:mrgreen: :mrgreen: :mrgreen:

I'm tickled pink about it. Usually folks don't go back to the places they asked questions and tell what finally happened. In this case, the thing would still be in pieces, possibly parted out already, without the riders here telling me stuff about what I should do next. So I was just making it known what happened, happy ending and all that.

But....my free motorcycle is running great!!!! And I learned TONS about it!

:mrgreen: :mrgreen: :mrgreen:
Jenn S.
AMA #658162
2005 Concours
2001 Vmax
1992 CB750

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#18 Unread post by Wrider »

YAY!!!!! Congratulations on getting her all started up and running great! :mrgreen:
Have owned - 2001 Suzuki Volusia
Current bike - 2005 Kawasaki Z750S
MMI Graduation date January 9th, 2009. Factory Certifications in Suzuki and Yamaha

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