Triumphrat

justducks

My 05 t100 is surging under load, any load. in neutral it revs out just fine. but even at steady throttle on the highway it surges. Any ideas I have already done the normal stuff.(check for Vac leaks, cleaned the carbs, plugs, air filter.)

MIKE

RonD

sounds like your breathing vent might be blocked.it could be incorrect float level in carby ,it could be your pick up coil or ignition coil breaking down under load ,plugs break down under load have you fitted new ones?
air leaks and blocked air filters do this stuff, is your main jet fouled ,have you had bad fuel ,have you got a blockage in your fuel tap,is your throttle vave opening fully.

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Regards Ron
Hurricane pictured(Harry)

TCL

What kind of mods have you done to it?

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Death or Glory

Rides a 2007 T-100

bmetz99

Since most carbureted motorcycles come set up from the factory with very lean jetting (good for emissions, not for performance) some lean surge is not particularly unusual.

Your bike is running on the midrange circuit (mixture controlled by the needle position) at normal cruising throttle settings (it runs on the idle jet & mixture screws at idle, and on the main jet at full throttle). I've had good luck getting rid of steady-throttle surging by simply placing a single shim under each needle. In the case of the Bonneville, a #4 washer from the hardware store generally fits nicely. You'll do well to bring along a dial caliper or micrometer in order to select a pair of washers that are within .001 or .002 of each other. These generally run in the area of .020 to .032 thick. Since the old adjustable needles had slots in them that were 1mm (.039 inches) apart, a single washer is usually a good place to start.

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\"A motorcycle is a tool, not a fashion accessory"

My Bobber

sweatmachine

the needle suggestion is a good one, you might also try enriching your idle mixture a 1/4 turn or so by using the D tool from Newbonneville.

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Who says being a tool is a bad thing? I have more use for my tools than I do for most people.


Click for a picture of my slightly modified Bonnie

justducks

I have changed the main one up from stock, k/n air filter, one .020 washer under the needle, nology wires and coil, drilled the hole on the slide, new plugs. The problem started a few months ago and has been getting worse. I think i may have to replace the diaphragms in the carbs i am going to try that next.

MIKE

justducks

oh yeah and adjustable needles,from new bonni.

MIKe

TCL

Ducks, I know you said you went up a jet size, but you may need to go up more. When my bike was lean, I'd give it hard gas and it would surge at the top like my hand was stuck on the throttle. New jets are alot cheaper than carb diaphragms, which I would not think would cause this anyway. As long as there are not visible tears, I'd rule out the diaphragm theory. Maybe dump out the cruddy gas in the bottom of the carb bowl that comes out when you rejet.

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Death or Glory

Rides a 2007 T-100

sweatmachine

I really don't think it's a diaphragm issue, besides, if they're torn you can repair them with rubber cement instead of replacing them.

__________________
Who says being a tool is a bad thing? I have more use for my tools than I do for most people.


Click for a picture of my slightly modified Bonnie