[BonesG9162]

So I have recently been experiencing problems with my motorcycle. General description: the bike bogs and backfires (out of the carburetor) when too much throttle is given within a short amount of time... My father and I have ruled out the carburetor, A/F mixture screw, plugs, plug wires, ignition coils, ignition module wires (the green and black wires everybody suggests investigating), exhaust gaskets/proper exhaust pipe seal and the fuel/vacuum line has excellent integrity. This is what my father and I are now hypothesizing ( he is very experienced with engines and motorcycles alike): the front cylinder valves are not seated properly or may have been worn down to a point that is now affecting the engine performance. Our supportive evidence is: when we put our hands at the ends of the pipes, the front (lower pipe) cylinder has very little exhaust ejection out of the end whereas the rear (upper pipe) cylinder has a very strong exhaust ejection and also the fact that fire shoots out of the carburetor intermittently when the engine begins to bog heavily.
The proposed solution: we are going to check the valve seat positioning as well as the valves themselves as well as readjust or replace any damaged valve(s).
Admitting I am not mechanically inclined, nor experienced, I seek aid from any that may be willing to give tips, advise, wisdom, links/website referrals and personal experiences to us as we try and rectify this irritating issue.

Thank you for your time and caring effort!

-Garrett

 

[Hiramsaint]

How many miles does it have? Hopefully an adjustment is all you need so stash away a couple of hours. As much as I love my bike, the valves are the hardest valves I have done on any of my past vehicles. I do hear it goes quicker the more you do it.

 

[mjklaser]

What brand/model of pipes do you have? Many have a 'crossover' that mixes the output of both cylinders - you can look behind the shields and see the crossover on most. Adjusting valves to spec, I certainly agree, but... Jeez, before you go start replacing valves, why not start by telling us if it is a stock or aftermarket/modified airbox? Has the carb been re-jetted or is it stock? How long have you owned this bike? When did it start behaving this way? There are many things that can cause such behavior... How did you rule out the things you said you ruled out? If you want us to advise, help, and share experience, then you have a ton of information and backstory that you are leaving out!! More input, please!

atriot:

 

[mjklaser]

Besides answering the questions and complete backstory requested above , please consider this for example: if any of the four bandclamps that attach the intake manifold to the cylinder heads and to the carb are loose and leaking air, then you could experience the exact same symptoms that you describe - your resolution might be as simple as tightening 4 clamps - "I'm just sayin'...":

 

[TUGG]

You say you have ruled things out, but you might want to ask some questions here and let some people experienced with the bike say if they agree with you.

As for your statement about " too much throttle in a short amount of time"..... If you are twisting the throttle like it was a fuel injected bike and expecting it not to bog or backfire, your problem is exactly what you typed, you are giving it too much throttle in a short amount of time. That is a characteristic of the 1300. They do that. You have to roll into it a little bit. There was a thread on this exact thing not too long ago.

Like others said, we need more info on your bike to be able to help you.

 

[FRNKCAT]

Besides answering the questions and complete backstory requested above , please consider this for example: if any of the four bandclamps that attach the intake manifold to the cylinder heads and to the carb are loose and leaking air, then you could experience the exact same symptoms that you describe - your resolution might be as simple as tightening 4 clamps - "I'm just sayin'...":

Exactly... Sure would save an engine removal & head removal to check valves...

KISS......



.

 

[arby]

You say you have ruled things out, but you might want to ask some questions here and let some people experienced with the bike say if they agree with you.

As for your statement about " too much throttle in a short amount of time"..... If you are twisting the throttle like it was a fuel injected bike and expecting it not to bog or backfire, your problem is exactly what you typed, you are giving it too much throttle in a short amount of time. That is a characteristic of the 1300. They do that. You have to roll into it a little bit. There was a thread on this exact thing not too long ago.

Like others said, we need more info on your bike to be able to help you.

I respectfully disagree. I have never had an issue with bogging on my 1300. No matter what gear I'm in, I twist the throttle and it goes. (Of course, going 25mph in 5th, it bogs.

As long as you're in the correct gear for the mph you're traveling, there shouldn't be a problem.

EDIT to Ask..

How many miles on the bike, & when was the last time the valves were checked?

 

[TUGG]

I respectfully disagree. I have never had an issue with bogging on my 1300. No matter what gear I'm in, I twist the throttle and it goes. (Of course, going 25mph in 5th, it bogs.

As long as you're in the correct gear for the mph you're traveling, there shouldn't be a problem.

EDIT to Ask..

How many miles on the bike, & when was the last time the valves were checked?

I assumed he meant while in neutral.

Want to add that if a valve was bad, it would be a constant issue, not just when revving quickly.

 

[arby]

I assumed he meant while in neutral.

Want to add that if a valve was bad, it would be a constant issue, not just when revving quickly.

Good points.:icon_redf