2012 RT V-Twin howling at hi revs under load - Any thoughts on cause/remedy?

[Peter Aawen]

Hi All Spyder Ryders/Owners/Wrenchers who are still interested in sharing their knowledge of the V-Twins & SE5's, I'm trying to help our local (non-dealer) Spyder Tech fix an interesting one here....

It's a 2012 RT, only done about 35,000 miles but it's been ridden & used hard in rural Oz, including lots of two-up riding, towing, and dirt roads... So it's got a few other wear/use issues that aren't really an issue; the owner's aware of them and all of them will sort/fix OK, so we're not really concerned about them here, but we are a bit stumped by this - it has a real 'gear type' howl at revs/load under WoT... It'll do it in any gear, if you can wring its neck/accel hard enough, doesn't do it at all under 'normal/gentle' riding, and it's not induction noise. It sorta sounds like it might be clutch related, but there's no slip, rev flare, or any other clutch type symptoms. There is no abnormal rotational movement in either pulley, altho the front pulley & output shaft does move in & out about 1/4"-1/2" from the casing if you push/pull (doesn't take much effort!) and there was a sliver of about 1/3rd of a circle of what looked like a part of a 1"-1.5" dia shim, wave spring, or circlip along with a small amount of other metallic filings/fur evident on the magnet plug when draining the oil (immediate thought/worry... where's the rest of it?! ) Otherwise, the oil looked, smelt, & felt pretty good... and it's apparently had regular oil & filter changes per the schedule using a quality m/cycle oil too...

The only other issue that it has which we feel might be related to this is the belt & pulley issues the bike has - the belt has been running too loose for quite a while (of course my Krikit has stopped clicking atm so I couldn't measure the tension properly, but both on the ground & in the air I could twist the belt thru about 170° by hand midway between the pulleys, rather than just the expected 90° ) so the belt HAS been skipping under WoT for at least the last couple of thousand miles - it sounds like a machine gun under hard accel & it's been doing it for so long that it's worn 'flats' on the driving/load faces of the belt teeth where it's been skipping so often, with a little matching wear on the rear pulley, plus it's polished all of the front pulley teeth to a mirror sheen!

I'm reasonably sure that tightening the belt up to somewhere near the general consensus of 'OK' for the V-Twins will get rid of the belt skip issues, but we are both a little concerned about doing that knowing that there's a shim/spring/circlip missing in there somewhere, and that the output shaft has all that in/out movement - if the bits in the oil were part of something holding the trans internals in place/within acceptable tolerances, could tightening the belt put undue lateral pressure on the output shaft &/or the gears and rapidly create a catastrophic failure?

So there it is - anyone have an insight or thoughts?? I've searched thru all the early V-Twin threads and haven't really found anything that seems to specifically relate, so I'm tossing it out there to the brains trust & those more experienced with engine/trans internals to see if anyone can add insight, comment, or help... Thanks in Advance.

Ps: A couple of other things just came to mind - the rear casing support/alignment rubbers look a bit thin/worn, but there's no perceptible movement/other abnormalities; and the rear tire, which otherwise appears to be aligned properly, is marginally more worn on the Left hand side (drive sprocket side) The extra wear isn't all that obvious, and I didn't have any of my tread tools on hand, so I'm only guessing at it being maybe 0.75mm more wear on the outermost block edges, scaling back fairly evenly across the rest of the tread face.... The Drive Belt appears to be well aligned & running true tho?!

[Bfromla]

Not a gear head by NO means, any howling def inspection of air box filter & intakes. Coming from tranny test of oil if not just good change fully synthetic. If enough of the circ clip to measure diameter(or compare with new part kits) maybe experience tech can give couple idea /possibilities

[Mikey]

Given what you have said, I was thinking to myself output bearing, then you mentioned it in your post! A belt that is not aligned would have a squeal, but it being in the shape it's in, and the shape of the sprockets, it would be different!

[BLUEKNIGHT911]

" more wear on the left side of the REAR tire ", IMHO this is not normal ...... Over the years, I have used Five or Six rear tires on three different Spyders None have had this type of wear. WHY this is occurring on that Spyder I can't say .... good luck ... Mike

[Snowbelt Spyder]

Well Peter, study the gearbox section in your manual. Look at all of the things that have to fail for the main output shaft to move that far and that easily. There are 4 snap clips, plus a number of thrust washers, just on the main shaft alone. Plus, the engine is making metal, and that will continue to circulate and get into everything until this is fixed. Think of all of the bearings getting awash in shavings. You could pull and cut open the engine oil filter just for giggles, and see how much aluminum you have there. You could even have some metal to metal contact going on inside the gearbox making that noise, too. The gearbox is toast. Looks like a good winter project.

[BajaRon]

If the output shaft moves that much. It's going to give you some serious belt alignment issues. But I think you're probably looking at an output shaft bearing problem. There is no way the output shaft should move that much or that easily.

[Peter Aawen]

Thanks all.

Everyone's saying what we were fearing, pretty much reinforcing the 'worst case' scenario thoughts that we had here, so I guess there's no way to avoid the inevitable; the gearbox hasta be pulled apart, and I 'spose the silver lining is that it means the 'pull the whole engine/trans assy out & put it on the bench to work on it' job also means that all the other things (which would've cost time & $ anyway) become 'fixed in the overall process' things, cos there's no way it's worth fixing the gearbox & then putting it all back in the frame with the worn bushes or dodgy drive belt etc, is there now!?!

Ahh well, as said, it'll make a good wintertime project! But now it's time for me to make the phone call no Spyder Owner wants to be on the receiving end of....