TLR200 off idle stumble advice please

[spud99]

Hi all, I've a new to me 86 TLR200 with a severe off idle stumble when I whack the throttle. So far I've set the valves (new timing chain also), set the decompression cable and throttle free play, cleaned and regasketed the carb including cleaning all jets and orifices, and set the float level to 24mm.

Relative to carb adjustments the air screw is at 1 3/4 turns out, and I've shimmed the needle by 1/16 inch spacer.

The problem is two fold:

1. on idle it doesn't return to a low idle quickly when warm. When cool (1 minute idle) with the choke off, idle is good.

2. as the engine warms the off idle stumble gets worse. I believe it to be a too lean condition as if I open the air box a little (using a wedge and tape on the air box cover) the stumble is worse.

I have read about the xr100 carb swap and drilling the jets but these two solutions would be a last resort for me. Any advise?

[t-shock 250]

"whacking the throttle" on a TLR will result in a hesitation/cough/stall so try not to do it.

Also using a higher idle speed helps alot, though yours does sound something else isn't quite right there.

[max1956bikes]

Hi all, I've a new to me 86 TLR200 with a severe off idle stumble when I whack the throttle. So far I've set the valves (new timing chain also), set the decompression cable and throttle free play, cleaned and regasketed the carb including cleaning all jets and orifices, and set the float level to 24mm.

Relative to carb adjustments the air screw is at 1 3/4 turns out, and I've shimmed the needle by 1/16 inch spacer.

The problem is two fold:

1. on idle it doesn't return to a low idle quickly when warm. When cool (1 minute idle) with the choke off, idle is good.

2. as the engine warms the off idle stumble gets worse. I believe it to be a too lean condition as if I open the air box a little (using a wedge and tape on the air box cover) the stumble is worse.

I have read about the xr100 carb swap and drilling the jets but these two solutions would be a last resort for me. Any advise?

[max1956bikes]

throw spacer away under needle.put clip second position from top.open throttle slowly.problem fixed

[spud99]

Thanks for the advice. This is a North American (Reflex) and doesn't have the needle with the adjustable needle settings. I'll try to take it easy on the throttle opening.

[4stroke]

You may find that most of your problems stem from a worn carb slide.

Air leaking past a badly fitting slide causes poor tickover and mixture setup.

[scooterspal]

"whacking the throttle" on a TLR will result in a hesitation/cough/stall so try not to do it.

Also using a higher idle speed helps alot, though yours does sound something else isn't quite right there.

I solved this problem on my TLR200. I posted my results, here:

http://www.trialscentral.com/forums/topic/31606-going-for-the-brown/

Get to know your spark plug intimately! You can tell most everything about your engines operation by just reading the plug.

Edited October 3, 2010 by scooterspal

[spud99]

I think I've got it. I went up one size on both main and slow jets (38 to 42 and 93 to 98). My local supplier had both. I also shimmed the needle (NA spec bike) with a 1/8" rivet backing, and set the float so that the bike just slightly raises idle speed just before running out of fuel with the fuel cock closed. Air screw set at 1 3/4 turns.

When I cleaned the carb to make sure the orifices were clear I took a piece of monofilament fishing line, the largest you can pass through the jet, tie a knot in the mono and pull it through the jet. If it is too big of a knot the mono will break. This also works for the vent lines and tubes. Works a treat.

Next is the replacement of the wiring loom. The PO went wild with the cutters and connections.