I'd mentioned to my service guy my clutch seemed to feel like it was sometimes slipping under power in 4th and 5th gear. He said he had the right tools and procedures to adjust the clutch correctly. Its better maybe, but not completely. It can also be harder than usual to shift out of 4th and into 5th under hard power.

Now I read in an Aussie H-D Magazine the later models are suffering gearbox failures from premature selector fork wear. The filings from the wearing forks is contaminating the bearings, but the worn forks are allowing the 4th and 5th gears to slide in and out of mesh under power and riders think it feels like the clutch slipping. The mag goes on to say its more of a problem with power modified engines and for those who use the stock box behind 103, 110 and 120R motors.

Who knows anything about this please?

My bike's done around 22,000 Kilometers now, (13,750Mi) Mechanic didn't comment on apparent oil contamination on the two changes he's done for me since 14,000km when i bought it.

cheers & Thanks

Gordon

 

Where to start? Helical cut gear sets have what is known as "axial thrust" where the main and counter shafts actually push away from each other.When this happens the main shaft goes one way and the counter shaft the other. The bearings in the bearing door are retained by snap rings and the axial thrust actually forces the bearings and snap rings in and out of the bearing door. Put the bike in 3rd gear and pull the clutch about half way in you can feel the clutch moving in and out in your hand, that is the bearings moving in and out of the trap door and the clutch push rod having play and then none. The axial thrust condition combined with a loose overall stack height have led to a number of shifting issues as well as perceived clutch problems.Replacing the forks and fork rod will help for a little while but the problem will rear it's ugly head again.Check your primary chain tension as well, it could be too tight and pulling on your mainshaft. If that is the case you should put a run out gauge on the portion of the mainshaft that is exposed once the inner primary is removed and make sure the shaft is not bent it that area. You want no more than .002 run out. It would be much more difficult to disassemble the whole gear set to check for run out on other places of the mainshaft but at least measuring the exposed portion will give you some idea. If I keep going this will become a novel and Harley lawyers will be knocking at my door with paper work for a slander case. When all else fails give me call and we will get you into a DD7, until then ride and repair it till the band aids quit working.

 

Wouldn't the larger bearings in the F6F provide the same fix? As I understand it excessive axial movement can result in the clutch to become slightly disengaged under power - giving the impression of a slipping clutch problem. The transmission is constant mesh - a worn shift fork would allow the gears to become out of mesh?

 

'Constant mesh' means the full width of each mating pair of gears are fully engaged at all times. The selector fork is much narrower, so there is no way that wear on a selector will allow the gears to come out of mesh.

I did think that Mark's suggestion of a DD7 was a bit over the top!

 

The F6F will help, not just the larger bearings but we also retain those bearings with a steel plate to make sure they can't move.