Running problems with my 94' FC600

Howdy, I previously posted about a non-starting 94' FC600 I bought and my troubles with starting it. Since then, I have made alot of progress, but I am still far from a functioning bike. In order for me to get this bike to start originally, I had to adjust the valves, thoroughly clean the carburetor, and adjust the decomp lever. After I did all that, I got the bike running pretty great for one day and did a little riding.
Since then I have been plagued by the same persistent problem. Now, I can easily start the bike, usually with minimal choke, and get it idling and running great...for about a minute or too until the engine warms. When it warms up, it always starts surging crazily within about a minute until it finally dies at idle. In order to restart it, I must turn the choke all the way up, and even then it will only badly idle and immediately die if I barely touch the throttle. It won't give me as much a backfire without the choke.
This all seems backwards to my rudimentary carb logic; I figured I was running a little rich at start from cold, because I could usually start it with minimal choke. But when the engine warms, the mixture is clearly getting out of balance. However, I had the understanding that it should run richer as the engine warms because the fuel is better atomized before burning? However, if this were the case, then why can I only barely start it with choke when its warm, leading me to believe that it is running lean? Since this point, I have recleaned the carb, and installed a fuel filter. Also, I noticed that my headers were very loose and poorly sealed, so I removed them, cleaned the mating surfaces, and reapplied high temp silicone to no avail.
Additional info: this bike is equipped with a Dellorto VHSB 38 (less common) carb with (air?) screw turned out 1.5-2 turns and the idle screw out 5.5 turns(best settings I've found). I will get the jet sizes and such tomorrow, but I believe that they should be adequate because the guy a bought a from(he's trustworthy) says that it was running fine when it was parked last season, and he was riding in the same climate/altitudes.

Any Ideas?

TLDR: Bike starts easily but starts surging and always dies when it warms up. Then, it will only idle with full choke applied, and will die instantly with any throttle.

Taffy said:

as I said before fella

you need fresh parts in that carb and you should start with the fuel valve.

regards

Taffy

Click to expand...

Yeeeaaaah, I know. I've been putting off spending a bunch of money on carb parts until I knew that was the problem, I'm tight on cash and want to be sure it will work, but I guess the time has come. Sooo:

By the fuel valve, do you mean the needle valve controlled by the float?

I was also planning on replacing the choke lever(the bottom is broken so I have to wedge something under it to get full choke), getting a few pilot jets and main jets the play around with, and buying the gasket replacement kit.

Should I replace the the needle, atomizer, and choke jet? What other parts should I replace?

Also, the plastic cap has slightly cracked and chipped away where it meets the tube that holds the throttle cable? First, do you think this is something to worry about? Should I replace the plastic cap?

I know you sell some but not all of these parts, but I'm always up for doing business with a fellow rider/forum contributor. However, I do live in Oregon and you live in England so I feel like shipping might be prohibitively expensive.

Also, How do I know if my slide bore is worn out? I hear that if this happens the carb is basically dead?

All these rebuild parts also begs the question; Would it be worth me replacing the whole carb with a more common carb with more readily available and economic parts, and a bigger base of support in the community. I looked at FCR's but they seem prohibitively expensive.

Any chance I could throw the Keihin CVK40 from my KLR650 on there and make it work?!?

Taffy, did I offend you in some way? Sorry if I'm not completely sure on my next course of action, but I am new to Husabergs and was just looking to find a little friendly advise.

Yes, I do have a limited budget, but yes, I think it would be worth while to buy a few extra jets to find the proper setting.

Yes, I would like to fix my existing carb, but I also would consider getting a new one if this would mean more support and better results. It seems like the VHSB's are uncommon and do not have much experience around here.

I desire very much to fix this bike, but I cannot just start dumping money into it. I would like to gain a better degree of certainty that any investments I make into this machine will be worth while and will work towards me owning a functional motorcycle.

Regards,
Rewsiffer