LT2 won't take throttle

yflyer · Posted: Mon Nov 15, 2010 10:14 am Post subject: LT2 won't take throttle

I've just about got my 1972 LT2 back to life. I just had the carb professionally cleaned. It starts right up (1st or 2nd kick)
it idles just fine but doesn't take hard throttle. Any Ideas?

Thanks

Yflyer

MR.CHocko · Posted: Mon Nov 15, 2010 3:42 pm Post subject:

What type of cable are you running on it? Is it a newer type with a rubberized coating? Or the older type without it? If it is the older type I would suggest you lubricate your cable by useing dri slide or WD40. You will have to disconnect it. If you did lubricate it all ready check and see how it is mounted on to the carb or the cable maybe broken somewhere.

Steve Searles · Posted: Mon Nov 15, 2010 8:25 pm Post subject:

I have had that happen. Make sure you have the stock airbox and filter on first.

lostdrifter240 · Posted: Mon Nov 15, 2010 11:25 pm Post subject:

sounds like stupid idea but check and make sure choke is off b4 juicing it. mabey choke is stuck. that and make sure its warmed up good. good luck

rdaystrom · Posted: Tue Nov 16, 2010 10:45 pm Post subject:

Bogging or the inability of your bike to take any throttle above idle indicates a lean condition. It could be caused by several things. Start by checking the air filter. Old foam type air filters deteriorate, fall apart, and get sucked into the engine. Many times I see them with all the foam gone. Other than some potential wear from that junk going into the engine most of the time it just goes away without causing any damage. The main problem is the air/fuel mixture without an air filter is considerably leaner. That alone can cause your problem. Next I would confirm that the fuel supply is clean fresh gas. Most likely that old tank had some gunk in it and it may have gone straight into your carb. Even though you had it cleaned it could still be the problem. After confirming an adequate clean gas flow to the carb you must confirm that the main jet and pilot jet are open and the carb bowl is filling up. (requires carb removal and disassembly). Other factors could be an intake leak around the cylinder base gasket or a crank seal leak. Those are less common. Be sure the autolube tube is on it's fitting. These bikes don't run perfect until they are warmed up somewhat and even then you cannot snap the throttle open and expect instant response. Although it shouldn't bog out unless you are lugging in too high of a gear. These engines don't have constant velocity carbs that can help prevent that bogging problem. The bike should run well after a minute or so if everything is functioning right. While you're at it put a new spark plug in it if you have not done so already. Not being able to hear the bike I must also say that a plugged exhaust baffle can cause an engine to not take throttle although it sounds totally different. You can diagnose that by removing the exhaust baffle and running the bike to check for improvement in the way it runs.