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trans issues?

3K views 18 replies 6 participants last post by  Canty 
#1 ·
Today I went for a ride with my buddy. Shifting was solid, 1st, 2nd, 3rd, and 4th seemed OK. Pulled hard. However, it seemed that 5th and 6th reved normal but did not accelerate correctly. On the way home, after I left my friend so it was just my bike I could hear, I was in 5th and grabbed a wrist full of throttle. Rev'd to 8k but only hit 83mph. I don't know guys, it just seems wrong. Anyone have anything similar?
Matt
 
#2 ·
Sounds like your clutch is slipping based on the symptoms you are experiencing (lack of acceleration while in high gear). How old is the engine oil and what type of oil are you using btw ?
 
#3 ·
2004, 3k miles, Mobil 1 I think, is there an additive that would be good? I will do a change and see if that helps. Oh, one more symptom. While in neutral, with the clutch pulled its smooth, but if I release the clutch I can feel a vibration. But I have felt that since I first time I got the bike started.
 
#5 ·
Just to clarify, was that automotive grade Mobil 1 or is it the motorcycle specific Mobil 1 oil that you are using?

Skip using any additives.

I take it you have a 2004 model year bike with 3000 miles on the odometer, yes?

What I was trying to get at is when was the engine oil last changed and how many miles have you ran on said oil (?).

Reason being, if it is fairly "old," it's possible to get some funky shifting/clutch behavior, especially if the oil that was in there was not very friendly with the wet clutch system of bikes.

Starting with a fresh oil change and getting a "baseline" for the shifting behavior will hopefully reveal more about your clutch/shifting behavior; report back and let us know how it goes.
 
#6 ·
Mobil 1, if it's car oil - will make your clutch slip and isn't formulated to work with a gearbox & wet clutch. Doesn't do the engine any harm (My VFR750 ran on Mobil 1 for 10's of thousands of miles, but I needed to put in beefier clutch springs because the clutch slipped).
I don't know if it'll stop slipping if you put in a decent performance bike oil now (probably would, eventually is my guess), if not - either new clutch discs, or stronger springs.... standard clutch on an RC51 is pretty heavy as standard though...
 
#8 ·
On the surface, it sounds like your plates are worn, or your clutch springs are sacked out.

I'd suggest inspecting and measuring the clutch plate thickness and replacing if below spec or glazed.
Also check length of each clutch spring.
If any of the clutch springs is below spec, it won't apply sufficient engagement pressure, or unequal pressure.

Most likely, it's just the friction plates worn, and possibly glazed as well.

Be sure and note the three types of plates used on an SP2 clutch that uses the judder spring and seat.
The special inner plate, the middle plates, and the special outer plate (that sits in the shallow groove).
 
#15 ·
It's all in the service manual.
An electronic caliper (Harbor Freight, Northern Tool) to measure plate thickness and spring length, and a 1/4" torque wrench to properly torque the clutch spring bolts and cover bolts to spec (and not over-tighten).
And a set of metric sockets if you don't have any.
 
#10 ·
Mobil1 motorcycle oil is well known to cause clutch slippage in motorcycles lots of stories over the years from BMW Adventure riders etc, but of all the motorcycles I have owned the only one that had a premature clutch slip problem was my Erion built 900RR when I put in Mobil1 Racing 4T. I don't know if it has Molybdenum in it which is well known to not work properly with many different versions of Honda organic clutch disks or if the stuff is just too slick to do the job, but there is definitely a correlation between honda clutches slipping and Mobil1 oil.
 
#13 ·
That is bad! OK, guess I will be opening the clutch after I replace the brakes on my Dually. Thanks again guys. Oh, one more question along the same topic. Air in the line could not make this issue correct? I have developed a small leak in my master cylinder. Not bad, just enough to show some moisture on the lever. I want to replace it, OEM is fine with me but I would like to find levers that are not OEM. What brand makes levers work with OEM or is the Brembo MC the only real option?
 
#16 ·
OK, so I finally got around to doing the clutch. I was prereading the manual and it shows tear down all the way to the main shaft. In reality all I need to do is tear down to the clutches and steels and replace them then put the bike back together. Is that correct?
Canty
 
#17 ·
Yes, just remove the clutch cover (not the right crankcase cover) and remove the drive and friction plates.
The clutch cover uses an o-ring style gasket. If it sticks to the cover, just carefully fit it back into clutch cover grooves. It's held by little nibs on the cover.
Be sure to install the judder spring and seat, plus the special inner and outer friction plates along with friction plates in order.
The special outer friction plate fits in the half slots.
 
#19 ·
So, I am looking at the Barnett Clutch discs and I can clearly see the one that goes on the inside. Its inside diameter is larger then the rest just like the manual said. However, all the rest are identical. I do not see any difference at all. Does that mean that any of them can be the outside disc? I was going to call the company but they are closed on Saturdays.
Canty
 
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