Chain drive XJ's, surging and you..

I realize many models of XJ's are shaft, this thread is for those of you with chain drive.

I've been trying to resolve a cruise 'surge' for 2 summers. Tachometer would flicker around a couple hundred rpm at street speeds and bike would have minor surging. I've done carb work, valve adjustments, replaced brake pads, checked clutch, etc. All these needed to be done, anyway, but the slight surge remained. I also thought tachometer needed work.

Since my chain was nearly adjusted all the way out this spring, I replaced chain and sprockets today (shout out to chacal for parts). Took about 2 hours and all went well.

Fyi - Old chain was O ring with about 15k miles. I admit I had been negligent in cleaning it properly . I know this because I put it on 25 years ago. From the factory it came with standard chain.

Holy crap it runs, accelerates and decelerates smooother. Surging seems gone. Less 'rubberbanding' and vibration, quieter too.

Behold, my tachometer really does work and is much steadier!

Hope this helps someone else.

 

Today was the real test, took a highway cruise today since it rained the last few days...big smile....this is not my bike, someone left a new one in my garage the night I changed the chain and sprockets.

The new chain really smoothed her out.

 

yup new sprockets take the play out of the chain to sprocket fitment.
I am thinking what you were feeling is the chain sliding back and forth on the sprocket. worn teeth and roller outer diameter would make the sprocket tooth pitch wider with a smaller diameter roller adding to the play

 

Its funny I haven't seen more on 'chain surge' here, but then most XJ owners on this site probably have shaft drive.

 

When I first put mine on the road it surged to, I had checked my sprockets and was assured it had the right chain even though it didn't look right to me, so I changed the chain and voila new improved bike, I showed the difference to my uncle who was the original owner and he was happy I fixed it but wasn't happy when he learned he had been taken by the guy who used to fix it for him.... Love the chain drive, if it breaks we fix it on the road just need to carry a spare, shaft dies...well ya know....