I have a 1991 Honda Nighthawk CB750. I have just replaced the stock handlebars with new drag-bars and replaced the stock chain with a Volar high-performance chain. The bike shifted fine until I replaced the handlebars and chain, now, it will only shift into 1st, neutral, and 2nd. The clutch is engaging and disengaging fine from what I can tell. I am at a loss for what the issue could be. I had to take off the shift lever to remove the cover plate when I put the new chain on, and I also had to tighten the clutch cable when I put shorter bars on. I figured I put the shifter on wrong but I adjusted it every way possible with no change. Occasionally when I move the bike forward and then try to shift, it will go through 1st-5th with out any issue, but it wont stay that way for long. Any ideas where I went wrong or what could be the problem?