Motorcycle Repair: 1976 shovelhead, harley davidson shovelhead, steady speed

Question
hi mike i have a 1976 harley davidson shovelhead that is giving me a headache. the bike was rebuilt completely and was running strong when i got it, but know it feels like something is wrong. the engine and all seems to be fine, but when im in any of the 4 gears its doing some kind of jerking motion back and forth. if i give it more throttle i can get passed it. it only does this when im running at steady speed in any gear, except for high speed in forth.  and i have one other problem. i cant seem to keep the chain tight enough. every time i adjust it and go riding, at the end of the day its just as loose as before i adjusted it. i love the bike, it rides good but i need help.  please tell me what to do. this is what ive been told, clutch needs adjusting, need new chain, and probably needs a tune up.   help me please. chris bradshaw

Answer
I would go ahead and do the tuneup and check the primary chain to see if its to loose. Check the clutch to make sure its not to tight.
As to the rear chain. If youa re having a problem like you described then its time to replace it. I would suggest also to replace the sprockets sinc ethe chain is that wore. Changing the sprockets will make the chain last alot longer. Also get a o-ring chain. They last abut twice as long as a regular chain.
Good luck and happy riding
Mike