[Sankar]

BBlost,
First check the plugs, just a bad plug can cause this. Also try a different spark plug cap.. yes this could create such an issue.

See the plug to know if it's running too rich or lean. Adjust if necessary.

Check and clean the carb main jet and emulsion tube if required.

Check float level and flow of petrol from the tap to the carb.

If your bike is a TCI ignition then battery could play a part in this. If your bike has a CDI ignition (like some early tbirds) the battery will not effect this behaviour.

If you do all this and still the bike does this then it's time to come to these things:

Plug wire, ignition coil, CDI/TCI unit. In that order.

Also look for loose connections near the CDI and the ignition coils.

The bike will not show such behavior in a zero load situation like when revving in neutral.

[jkdas]

Originally Posted by Sankar

BBlost,
First check the plugs, just a bad plug can cause this. Also try a different spark plug cap.. yes this could create such an issue.

See the plug to know if it's running too rich or lean. Adjust if necessary.

Check and clean the carb main jet and emulsion tube if required.

Check float level and flow of petrol from the tap to the carb.

If your bike is a TCI ignition then battery could play a part in this. If your bike has a CDI ignition (like some early tbirds) the battery will not effect this behaviour.

If you do all this and still the bike does this then it's time to come to these things:

Plug wire, ignition coil, CDI/TCI unit. In that order.

Also look for loose connections near the CDI and the ignition coils.

The bike will not show such behavior in a zero load situation like when revving in neutral.

The bike guru said it.

The above said process is called a through check-up

[the_trooper]

Originally Posted by bblost

My July 2003 ThunderBird with about 65k done has a slightly weird issue.

If I gun the engine heavy, then she starts to stutter in the power climb.
Its like, she is On now Off and this cycle continues with power coming in jerks.

However if I accelerate linear with an easy throtle action, building speed,
there is no problem and she goes fast.

Also there is no jerking when raising power in neutral.

The bike is completly stock, clean air filter, good oil and in good shape.

This jerky power delivery is driving me crazy.

any tips on what might be wrong.

July 2003 would be a CDI model. So the bike is not dependant on the battery.

Get your clutch, sprocket and associated rubbers checked. It could be a case of your clutch nut being loose or clutch bell rubbers being worn out.

Does the magneto make a hissing/rubbing noise when the light is switched on.

[bblost]

Thank you everyone.

A visual inspection showed a couple of thin cracks on the rubber manifold.
The length of one of the cracks was almost a centimeter.

I am getting this replaced asap.
Was unable to get it at the RE spares shop (Delhi Motors at Afzaljung)
Will try other outlets shortly.

The clutch is very clean. Had it inspected less than 1000 kms back.
The petrol tank is clean and I had tested the quality of petrol coming out by putting bike in reserve and letting the fuel flow out into a bottle after vigorous shaking of the bike.
The spark plug is still the original one, and its clean. No carbon deposit or anything.
Will check the gap level again.

I will first replace the manifold.
If the issue persists will go thru everything mentioned by Sankar.
Thanks a lot, everyone.

[abhi]

What you can try is to run the bike with the choke open. If it solves the problem, your Carb needs a clean and tune up. It should not stutter under acceleration. Since you've already changed manifolds, this should sort it out.
How much mileage do you get?

[bblost]

I have no idea what my bike's kmpl is.

The odo was removed long back. I fill her up when the reserve is touched and ride.

Its my idea of fill it, shut it, forget it.

Will update tomorrow, have confirmed that the manifold is available at an outlet.
mechanic visit due tomorrow or maybe will do it myself.

[bblost]

Thank you very much
I had the manifest replaced and the problem has not recurred so far.

Today morning went to Commercial motors at Ranigunj.
Bought the manifest for 95/-.
Went to over my mechanic and had it fixed.

There was a small problem with the manifest.
The new tBirds have a catalytic converter to which a pipe from the manifest is connected.
My bike has no such thing, so this nipple had to be closed.

My mechanic used a file to make it shorter and then plugged it with a blunt aluminium nail.

The bike's tone has now changed at high speeds.
Its now got a more fuller beat coming thru.

I will update if the problem recurs.

However I did do a close inspection of the old manifest.
The inner wall did not show any cracks on it.

fingers crossed, will update after my weekend ride.
thanks

[redfire]

The new bulls have got their pancake airfilter in the RHS tool box and a hose / rubber manifold running from it to the carb. They always tend to cut / shrink which results the above mentioned problem. If you are not against a slight mod, throw that damn thing out and put a neat K&N or Green conical filter, enjoy the intake growl and the extra space in the tool box can be used for tools / raincoat. This was my first mod on my 500 after this problem.

[shldn]

Cheers , Ride Safe.

[bblost]

[quote=redfire;765273]The new bulls have got their pancake airfilter in the RHS tool box and a hose / rubber manifold running from it to the carb. quote]

@Redfire: I changed the hose connecting the carb to the engine. Not the airfilter to the carb.

But yes, I did notice that this hose also has a couple of cracks on it.
Will replace this as well.

The reason I don't want to go for a conical filter is simple.
I don't want a FFE.
If she inhales more, she would need exhale more as well.

[susan3004]

Originally Posted by redfire

The new bulls have got their pancake airfilter in the RHS tool box and a hose / rubber manifold running from it to the carb. They always tend to cut / shrink which results the above mentioned problem. If you are not against a slight mod, throw that damn thing out and put a neat K&N or Green conical filter, enjoy the intake growl and the extra space in the tool box can be used for tools / raincoat. This was my first mod on my 500 after this problem.

Hi,
I have the new Bullet 500, just done about 1400kms on it.
Can you give me the specifications of K&N fitted to the bike. And does it look very different from the original after the fitment??

[Sankar]

Originally Posted by bblost

Thank you very much
I had the manifest replaced and the problem has not recurred so far.

Today morning went to Commercial motors at Ranigunj.
Bought the manifest for 95/-.
Went to over my mechanic and had it fixed.

No offence but this reminds me of the "socket-jober" & "jacob sir" thread
It's called a manifold.

There was a small problem with the manifest.
The new tBirds have a catalytic converter to which a pipe from the manifest is connected.
My bike has no such thing, so this nipple had to be closed.

My mechanic used a file to make it shorter and then plugged it with a blunt aluminium nail.

Have u used some kind of glue or sealant with the nail? You should've used a bit of glue like araldite or a dab of RTV sealant alongwith the nail to make the seal 100% air tight. No problems this can be done if it starts leaking.

However I did do a close inspection of the old manifest.
The inner wall did not show any cracks on it.

The manifold expands and contracts due to the suction cycle while the engine is running. So cracks might still be there, which will let air in, even if you can't see the cracks.

[Sankar]

Originally Posted by redfire

The new bulls have got their pancake airfilter in the RHS tool box and a hose / rubber manifold running from it to the carb. They always tend to cut / shrink which results the above mentioned problem. If you are not against a slight mod, throw that damn thing out and put a neat K&N or Green conical filter, enjoy the intake growl and the extra space in the tool box can be used for tools / raincoat. This was my first mod on my 500 after this problem.

Yes that rubber pipe is known to create problems when it gets out of shape. It will restrict the air flow.

Or if you don't want to use a K&N or Green you can use an older original type air filter box, this is only for Bullets and Machismo's. TB's cant use the original type air filter box. This is any day better than the pancake crap fitted in the side box.

Originally Posted by bblost

The reason I don't want to go for a conical filter is simple.
I don't want a FFE.
If she inhales more, she would need exhale more as well.

Thats not true. You can use a K&N even if you don't put a freer flowing muffler. Just keep in mind to upjet after the K&N.

[Psycho]

Your jetting is too lean you ought to either up the jetting and the tuning or move the metering rod one step up to solve the problem. easier would be to turn the air screw in by 1.5 turns

[Sankar]

Originally Posted by Psycho

Your jetting is too lean you ought to either up the jetting and the tuning or move the metering rod one step up to solve the problem. easier would be to turn the air screw in by 1.5 turns

Psycho he has a Thunderbird, it has a BS carb. With the BS carb if you screw in then the mixture becomes lean because it's a fuel screw and not the air screw.

Yeah you can lift the needle up. It's a bit complicated than doing with a normal carb but you can you have to be careful not to lose the tiny spring and washer. There are three slots on the needle (in the case of BS) and the clip would be in the top slot as default.

@Psycho i've sent you a PM. Please check.