This might be an easy one for your guys who are more experienced. I'm still new to the whole turning of the wrench thing.

Anyway, I've been working an 1987 LS650 for far too long. Here is what I've got so far.

1. The bike starts up fine and idles perfectly.

2. When I drop it into 1st gear the RPM's drop to almost nothing and the bike eventually shuts down.

3. Carb. Tried 2 and 3 washers on the needle. 52.5 and 150 jet. It runs very rich. 1 turn on the adjustor screw at the moment. Actually, I've tried all the jets I've got in different combinations and I still get the same 1st gear low RPM problem. Cone filter.

4. Exhaust - 18" muffler with a 13" baffle. Stock header.

5. Swapped out the spark plug, just in case.

6. Battery is about a year old and fully charged as of last week.

7. Adjusted the valves with a new feeler gauge from Harbor Freight.

8. I've got a 2nd carb. It may need a gasket. It's next on my To-Do list.

9. I got ahold of a 36mm Mikuni round slide carb. Thought I might try for the upgrade with the UFO, but I wanted to make sure there wasn't something else I've missed. All I have is the carb at the moment.

10. Thought I might have some bad fuel. Ran to the gas station and got some fresh 91 octain.

11. Swapped out the O Ring on the Intake Manifold.

12. Petcock. Bought the Raptor 660. Tested it yesterday. Flows like a river. Bought a 2nd petcock just in case. I haven't installed it yet.

12. Replaced the metal gasket on the header pipe.

13. Heat wrap on the header. I've rechecked the entire exhaust. Can't find any leaks.

I haven't looked at the kickstand switch, but I've read on here that it can be a problem, although I don't think the symptoms are the same as mine.

That's it. That's my brain dump. I just want to ride. Is that so wrong?!?!

Yes, it does roll forward when in gear.

Two weeks ago I was able to drive it around the block. It was backfiring badly. I had flames shooting out the exhaust. It wouldn't go over 20 mph.

When it is in gear, while I have the clutch pulled in, I try to give it gas and it, I don't know how to describe it, gasping and wheezing? Like it's not getting enough air or fuel, or both. I can't tell which.

I have repeatedly checked the floats. The seem fine, but maybe I need to take a closer look. I checked the float needle and little filter. There is no obstructions of any kind.

Dave 's advice is along the same thoughts I had.I'm wondering why you've jetted the carb 52.5/150  the stock jetting for the big carb( 86-87)being 47.5/155. I think the 52.5 pilot jet may be to big ,I'd try a 50 .I also think Dave may be right about the cone filter,you could try removal (for a test ) .you need to look at the clutch adjustment it shouldn't be grabbing.If it were the kickstand switch the bike would die immediately ,It wouldn't slow and then die.

I ran it without the cone filter. No change.

I didn't have a 50 Pilot Jet, so I used the 47.5. I checked the floats again and made some small adjustments. It made absolutely no difference. I still get the exact same symptoms.

I did notice the headlight dims by almost 50% when I kick it into 1st gear. It gets a bit brighter, but thats when the RPM's bottom out. It's still gasping when I turn the throttle.

I'm going to borrow a volt meter from work and test the battery. I bought the battery in November. The ignition coil is brand new but that doesn't always mean it's good. The spark plug is new and I gapped it according to Clymers.

At this point I'm thinking it's NOT the carb. It's electrical.

If it's trying to walk you need to adjust the clutch.

Your idea of Idling Great might not be what it likes, it needs to be around 1100 rpm.

Sounds like you're headed in the right direction.
I'd stand it up, play with the gas, and drop it in gear just as I goosed it, if you can get it to rev up in neutral.
The clutch safety must be okay, and the sidestand is maybe not.. If that thing is messing up it Could, possibly, be killing it without just shutting it off like a switch, have you tried putting it up before dropping in gear?

You might try adjusting the clutch (less free play). And also raising the idle speed a little. It isn't supposed to idle like a Harley but faster at 1100 rpm. You could also adjust the idle mixture screw. It shouldn't be rocket science.

Ok. I've tested the battery. At Rest, it measures 12 volts. With the motor running and in 1st gear, it measures 11.33 volts. Withing seconds of shutting down the bike it immediately goes back to 12 volts.

Sidestand Switch - It looks like the previous owner already took care of that one. It was already looped back on the wiring harness.

I guess that leaves the Clutch Switch which I will look at tonight.

I may need to purchase some new controls because the hand brake lever doesn't activate the brake light. If there is a problem with the clutch switch it may need to be replaced.