Powerband question

Alright guys been putting a few miles on the bike after got it all safe and sound. I hadn't really opened it up until last night and I was getting it in 3rd gear. I hit about 7800 rpms and bam it was at 9000. My question is that the powerband kicking in? It did it so fast that the engine actually sounded like I had pulled the clutch in. Does this sound right to you guys? Any opinions are greatly appreciated. Thanks

 

It sounds like the clutch slipped when it hit the powerband. Springs getting weak, fibers getting worn.

 

Well, it could be the clutch slipping.

It could also just be the motor, the XJs do go from 7,000 to 10,000 pretty quickly.

Were there any other symptoms, such as a surge of 1500rpms without the acceleration to go along with it?

Have you checked the clutch plates recently?
What type of oil are you using?

 

No I haven't checked any of that. It didn't act like the clutch because I was still gaining speed and it seems to do it at the exact same rpms everytime. It also doesn't matter if I'm going uphill on flat or going down hill. 20/50 motorcycle oil

 

my bike needs a new clutch as we speak and when i get to a certain rpm and the motor is pulling pretty hard i can feel the clutch start slipping. when that happens you can feel it happen, the power seems to die a little and the rpms shoot up a little. its hard to explain. that could be your problem. you say this is your first bike? that being the case you might just be getting into the rpms where the bike really comes alive ( powerband ). when you get to this rpm and are giving the bike a good bit of throttle the bike will take off in a sense. inline 4 cylinder engines usually dont have alot of power at lower rpms but when u get to the higher rpms they start to pull alot harder. this could be what you are experiencing. how many miles are on your bike?

 

It feels exactly like you. It makes me feel like I want to hold on a bit tighter. Bike has 8200 miles are sa

 

Next step would be to do an adjustment on the clutch cable, just to double check, then take it for another spin.

It sounds like you're just getting to the "fun zone". Like I said, these things go from 7k to redline pretty quick, and yes if you haven't experienced it before it will definitely make you tense up a bit.

But if it were me, I'd still check those clutch plates out so I knew for sure it wasn't the problem.

 

You're getting into the power band above 6K. That is where the clutch will slip if it's going to. Your speedometer should move up with the tach, if it isn't your clutch is slipping.

 

Right on thanks for the tip.

 

Here's another: with 8200 miles on the motor, if you haven't checked your valve clearances and properly serviced/adjusted the carbs, I wouldn't be running it to redline unless you're trying to blow it up.

 

Thanks fits I have already done all of the recommended maintenance that you all said that should be done. Valve clearances Carb cleaning brakes front and rear, tires, plugs, fluid changes even fork seals. The whole works.

 

Pull the plugs.
Make certain that you are NOT running "Critically Lean".

XJ-Bikes love to put-on the power when Lean.
But, ... too lean can trash a power plant fast.

 

What will the plugs look like if it's running critically lean?

 

If it runs lean it will be too hot.

 

Thanks ecologito. I will pull them and post pics probably sometime over the weekend.

 

Also, if you pull the clutch cover off and look at your steel plates in the clutch they should be nice shinny metal. If they are discolored (blue from heat or brown from glazing) clean then with a scuff pad and brake clean. Now if the steel is warped from heat, replace them. While you have it apart check the thickness spec of the fiber and the length spec of your springs.

 

Thirty year old petrified friction plates don't work well, even if they aren't worn beyond spec. They were oil-soaked, and when the bike sat (and they all did) they dried out. Soaking them in new oil won't fix that, they simply need to be replaced.

Steels that have been burnt blue shouldn't be re-used, even if they aren't warped.

The thirty year old springs should simply be replaced as well.

 

Excellent advice!

I've seen low mileage XJs where everything in the clutch measured in spec and they slipped like they were made of ice.

 

Agreed, if it's original you may as well replace them, however, if the clutch is somewhat new and the PO didn't know how to shift properly a cleaning couldn't hurt. It's amazing how simple these machines are and after some TLC they are just about bulletproof.