Random High Revs During Accelleration??

I was thinking maybe a stuck Butterfly or Venturi ( i think thtas what its called right? the 'flap' that the butterfly screws open?) But I'm not 1 hundred precent sure.
Lets say I'm in third or fourth and I'm speeding up cause the road jsut went from 35 to 45. That initial pull of the throttle to speed up makes my tach rise by about 1000 rpms. You can hear the bike jump up, working hard, and then I release the throttle a bit for a sec and pull it back up and she's at the RPM range she needs to be.
My other thought was, Clutch Slip???
That'd be the worst case I think.
What do you guys think?

 

SL, I would say your clutch is slipping a little.

 

Clutch sounds right. What oil ya running?

 

20w50 actually. Valvoline 4 stroke

 

Try doing the clutch adjustment on the bike. 9K shouldn't create a bad clutch. Oil seems correct along as it doesn't have a lot of additives for "friction reducing".

 

+1 for clutch.. measure the plates for thickness if you end up busting it open.. Clean and resurface (sandpaper) the friction material... clean very well.. then soak in oil.

I added a few washers to shim my new clutch and its working well.


First time doing a clutch on a bike... i think it took me an hour.. its not hard at all... got used EBC plates on ebay that were well within spec for 10 bucks

 

Cool, so this shouldnt be too bad. I've read a little about clutch adjustments KT, how should I go about doing this? Where shall I start?
-SLK

 

Sounds like clutch slip to me too. Regardless of the 9K miles, the friction plates may be garbage just from sitting. The little friction pads become saturated with oil and then dry out and crumble. Remember they're just teeny-tiny brake pads.

You could try pulling the clutch apart and flushing the friction plates with brake cleaner to see if you can "unsaturate" them but they may be toast. If they crumble as you clean them then replace them.

I know it's a heartbreaker to have to replace unworn parts, I feel your pain; I had to replace a clutch with only 7K miles on it that was deteriorated from sitting.

 

Well, not too concerned about having to replace unworn parts. I jsut want her to run good for years to come. So if I gotta replace something and its not too expensive and not too tough to do and I can do it on my own then I have no problem doing it.
Is there a How To on what I should do now?
Flushing Plates? Replacing Plates?
-SLK

 

I saw a write up by one of the GURUs on here the other day for clutch adjustment, but can't find it right now. Also a clutch replacement, but surely you have the manual, right?

 

Sadly.. No.. But I jsut saw one pop up on Ebay for the first time since I've had Maxine. Its a Factory Service Manual. I'll bid. Hopefully I'll win.
Till then, if anyone finds that post on How To do a Friction Plate Removal/Installation, that would be fantastic.
-SLKid

 

The clutch is actually quite simple. Once the cover is off, you simply remove the six pressure-plate screws and springs and lift the pressure plate off. Then the "guts" come out: a friction plate, a plain plate; a friction plate, a plain plate, until you've got the whole stack out.

Take the friction plates and flush them with brake cleaner, and inspect. I can pretty much predict what you'll find: the little friction "pads" themselves will most likely be all hard/slick and crumbling at the edges. If NOT, and the brake cleaner manages to "unsaturate" them for you, they will be more like litttle thin brake pads.

Reassembly is the reverse of disassembly. The dot on the hub lines up with the mark on the pressure plate.

I've got parts on the way from chacal to rebuid the (21K) clutch on my '81 550 Seca; I can do a photo how-to but it will be a couple of weeks before I get it posted.

 

Oh cool! Thats about what I figure Fitz. I have been looking at Diagrams for it and surmized the same process you descibed. Thanks a lot! I think I'm going to check on that within the next couple days. Doesnt sound too hard
-SLK

 

measure your springs they're probley good but I just did mine last month and the old springs were almost a 1/4" shorter than my new ones. Mine also has 35k miles on it though. I'll grab my book tomarow and post the specs for the friction plates, steels, and springs

 

sorry i forgot my book at the shop

 

ok have the book
xj650 40.1mm (1.579")
service limit 39.1mm (1.539")
xj750 41.2mm (1.622")
service limit 40.2mm (1.583")
hope this helps

 

Buy the XJ CD.

 

Clutch parts arrived. DAMN that was quick, I think Len drove 'em up here.

I'll get into it most likely this weekend as I too am beginning to experience "random high revs during acceleration."

 

I really noticed it last night coming home from work. We hit a 45 to 55 zone on a two mile stretch close to my house, and the car in front of me was going 40..
So i passed him
But it took me forever cause I'd pull the throttle hard to jump up speed and my rpms would jump up instead of my bike.
Release throttle quickly, rpm jump down, pull throttle, Repeat, till i got enough to pass him.. Sucks..
Lemme know how it goes fitz! I'd love to solve this performace problem. Its robbing me of Maxines full potential
-StreetLegalKid