Triumphrat

Coocha

I'm sorry if I'm duplicating a previous discussion, but I've browsed the topics and I think this problem may be unique.

So I've been riding my new (to me) '99 T-bird very little since I haven't gotten the title to register it yet. However, today I tried to open her up on a straightaway, and I began to experience sputtering at about 4000 RPM. I'm not sure if this is a misfire or not, but basically the bike refuses to exceed 4000 RPM. This is not a static issue: in second gear, I can get up to 5000 RPM before sputtering occurs, and at 3rd and 4th, it seems to occur at 4000.

The interesting thing is, this sputter does not occur at all in neutral or with the clutch in. I'm hoping this is just a carb jetting issue, and isn't indicative of something more serious. Anyone had any similar experiences who could shed some light on the subject? I look forward to hearing some thoughts. Please keep in mind that I'm a newbie to motorcycling, but have done some carb work before on two-barrel auto carbs, so if you can reference me to a previous topic, please do

trypcil

Sounds electrical! :razz:

__________________
http://www.triumphrat.net/photogalle...m794/album346/

The owl of Minerva spreads its wings only with
the falling of the dusk.” - G.W.F. Hegel, Philosophy of Right (1820), "Preface".

jimmyj900

That says it's a load-related problem since you're probably not opening the venturi in neutral or with the clutch in.

That suggests that it's a carb or air intake problem.

Have you checked the air box and filter box for critter nests?

Have you had any backfiring through the carbs prior to this problem? That could cause a diaphragm rupture what would prevent the slide(s) from operating properly.

Check for critters first, though -- highest probability.


Jim

__________________
http://s279.photobucket.com/albums/k...0Head%20Stuff/

Coocha

I agree that the problem is load-related. And since I'm from the school of 'cheapest fix first' I'll examine the airbox, replace the air filter, and see if that does the trick.

The most daunting thing to me regarding the carbs is synching all three after any sort of cleaning or rebuild. I've read a little about it, but have no experience w/that, so hopefully I'll be able to avoid it.

MickMaguire

dont avoid it, carpe diem!

Buy a twinmax carb balancer from aerostitch it's a cynch to use and you will transform your bike.

__________________
Mick...

Just remember; an awful lot of the free advice you will get on forums is worth exactly what you paid for it. There will always be somebody trying to convince you to do something really stupid, just because they did it or want to do it.

MickMaguire

FWIW I would be checking the petcock and carb filter screens for a buildup of crud, which woudl be reducing the flow of gas into the carbs. It could well be that you are starving the bike of gas at higher RPM because you cant get enough into the float bowls.

__________________
Mick...

Just remember; an awful lot of the free advice you will get on forums is worth exactly what you paid for it. There will always be somebody trying to convince you to do something really stupid, just because they did it or want to do it.

Coocha

Well Jimmy, when you mentioned 'critters', I thought you were being facetious and was just referring to any gunk that might have accumulated in the airbox. Hah. Turns out there was a NEST inside the airbox, along with a hole that had been gnawed out of the bottom of it. So I removed the airbox and cleaned it out...

Seems like the nest continues on into the air filter enclosure (which straddles a piece of the frame, underneath the tank... I'm kind of confused on how to remove it b/c the tech manual I ordered hasn't come in yet). I'm going to surf the forums tonight and try to figure out how to take the air filter enclosure out.

But here's another question: I know some people drill holes in their airbox, but they also re-jet the carbs to account for the added air. Will this little hole that the rodent gnawed out screw up my performance with stock jetting? it's only about 1.25 square inches in area, and lies at the bottom of the airbox.

Thanks again for the suggestion. You were spot-on.

Coocha

Well Jimmy, when you mentioned 'critters', I thought you were being facetious and was just referring to any gunk that might have accumulated in the airbox. Hah. Turns out there was a NEST inside the airbox, along with a hole that had been gnawed out of the bottom of it. So I removed the airbox and cleaned it out...

Seems like the nest continues on into the air filter enclosure (which straddles a piece of the frame, underneath the tank... I'm kind of confused on how to remove it b/c the tech manual I ordered hasn't come in yet). I'm going to surf the forums tonight and try to figure out how to take the air filter enclosure out.

But here's another question: I know some people drill holes in their airbox, but they also re-jet the carbs to account for the added air. Will this little hole that the rodent gnawed out screw up my performance with stock jetting? it's only about 1.25 square inches in area, and lies at the bottom of the airbox.

Thanks again for the suggestion. You were spot-on.

MickMaguire

you get the air filter housing (actually that's what's normally called the airbox) out by removing the carbs, you then pull it forward off the frame. Removal of the carbs involves disconnecting the gas line and choke cable, then undoing all the clamps, you can the push the airbox back out of the way pull the carbs back off the head rubbers ans slide them out to the side. If you want to remove them completely then disconnect the throttle cable at the bars and pull it through with the carbs. Otherwise you just need to support them while you take out the airbox.

You shoudlnt desperately need to plug the hole in the secondary airbox really, but it wouldnt hurt to cover it with some duct tape.

__________________
Mick...

Just remember; an awful lot of the free advice you will get on forums is worth exactly what you paid for it. There will always be somebody trying to convince you to do something really stupid, just because they did it or want to do it.

MickMaguire

you get the air filter housing (actually that's what's normally called the airbox) out by removing the carbs, you then pull it forward off the frame. Removal of the carbs involves disconnecting the gas line and choke cable, then undoing all the clamps, you can the push the airbox back out of the way pull the carbs back off the head rubbers ans slide them out to the side. If you want to remove them completely then disconnect the throttle cable at the bars and pull it through with the carbs. Otherwise you just need to support them while you take out the airbox.

You shoudlnt desperately need to plug the hole in the secondary airbox really, but it wouldnt hurt to cover it with some duct tape.

__________________
Mick...

Just remember; an awful lot of the free advice you will get on forums is worth exactly what you paid for it. There will always be somebody trying to convince you to do something really stupid, just because they did it or want to do it.