Terrible Sounding Tiger (help?)

[Sinnergy]

Hi folks; relative newbie around here, and I'm hoping to pick the brains of the local gurus.

The bike:
'96 885 bought at 30K miles after a hard lay-down. Resurrected with now re-welded subframe, Rhino-Coat bodywork, and almost 50K miles on JB-Welded clutch cover. Total mileage now 82,335 miles. Corbin Seat, and Yosh exhausts make up what has been a spectacular ratbike all over the US and Canada.

The issue:
Over the last 10K miles or so, the front of the motor has gotten progressively louder--but only at low RPM. As soon as I have it above 1500 RPM, it is as smooth and (it was always somewhere between my VFRs and BMW for noise) quiet as ever.

A few weeks ago, I tore into the motor and replaced the cam chain, tensioner, and main rubber. There was no significant difference (though there was a lot of wear on the rubber, and the chain was stretched by a full .45 inches). I came to the conclusion that the trouble must be in the balancer, and tore that apart as well. There is a significant amount of play between the gears. There is almost .03 inch wear on the endshaft where the 51T gear rides, there is .04 inch wear inside the 51T gear (presuming that there was .00 clearance originally, though I'm sure there must have been some--I just don't have specs on the part). The rider bushing is obviously worn, and the spring bushing is probably worn (again I don't have any specs). The main gear looks OK, and the bearings don't have any play that I can measure.

So, I wondered if even with more vibration, I could just run this thing without the balancer installed.  After some chats on one of the UK based forums, I went ahead and buttoned the case back up, filled it with oil, and tried it.  The sound is different, but it is still noisy.  While if I'd had more forethought, I would have recorded before AND after, I did post up a half minute video so that you can hear the motor run without the balance shaft at .

Now I'm wondering what else it could be.  The reality is that this bike just isn't worth putting $1200 to $1500 into it to rebuild the whole motor, or replace it with what they want for them on e-overpay.

Many thanks,

Sinn'

[nightrunner]

When you say the bearings have no play do you mean the rod bearings?   I'm thinking after 82K, they might be getting a bit loose.  And a rod bearing will tend to rattle down low and smooth out as oil pressure goes up.    And/or the wrist pin bearings may be getting loose too.

Have you considered looking around for a used motor?  Maybe find a parts bike with lower miles.

[abruzzi]

Did you check the alternator drive shaft? 9 times out of 10 that is the cause.  Look up "DAR" or "damn alternator rattle."

Geof

[Sinnergy]

Scott; the bearings that I was talking about are the end support bearings on the balance shaft.  I haven't pulled the sump (yet), but I figure by the time I do that, it'll be beyond reasonable hope.

Geof; That was a thought that I only came across in the last day or so... Cachgeo hinted at it, and I'm hoping that someone that has heard it first hand (Mustang?  Beuller?  Beuller?) will be able to make some comparisons there for me.

I'm definitely on the watch for a replacement motor, but they seem to be a bit scarce here in the states.  Since looking (about two months, now), I've found exactly two--both on e-overpay, and both well over $1K shipped here.  As much as I like the bike, it just isn't worth that right now.

If you hear of one that I could get out here in the $500 range, PLEASE pass it along.

Thanks,

Sinn'

[coachgeo]

because of the scarcity maybe.... Im not sure.. but the suggestion I got when gathering info about the value of my not so good running engines was 4-500 for .... not so good running engines to close to 1000 for a good one.


But.... keep in mind.... a good running engine.... at a 1000 and well  maintained after is cheaper than a new bike!

Or for about 5-6000 you can put in a Diesel Diahatsu it could end up costing like some idiot I know with the initials of Coach George something close to that.

[Mustang]

The issue:
Over the last 10K miles or so, the front of the motor has gotten progressively louder--but only at low RPM. As soon as I have it above 1500 RPM, it is as smooth and (it was always somewhere between my VFRs and BMW for noise) quiet as ever.

sure has the symptoms of alternator rattle., if the noise goes away above 2k or so check the alternator first .

So, I wondered if even with more vibration, I could just run this thing without the balancer installed.  

Sinn'

hook the balancer back up it's there for a reason  :shock:

[abruzzi]

Geof; That was a thought that I only came across in the last day or so... Cachgeo hinted at it, and I'm hoping that someone that has heard it first hand (Mustang?  Beuller?  Beuller?) will be able to make some comparisons there for me.

the check is very simple.  Pull the alternator.  If the bolt is sheared on the alt side, you'll see it right there.  If the alt side is fine, wiggle the shaft in and out. WARNING - never pull it further than a tiny bit, a centimiter should be safe.  If there is noticeable in/out play, then the bolt is sheared on the clutch side  Fix is relatively simple, and about $150.

Geof

[nightrunner]

Did you check the alternator drive shaft? 9 times out of 10 that is the cause.  Look up "DAR" or "damn alternator rattle."

Geof

That was my first thought too but he said the front of the motor, and the youtube vid did not really sound like DAR.  Sounded a bit deeper and more internal than DAR.  But like you said its an easy easy thing to check.

[nightrunner]

Scott; the bearings that I was talking about are the end support bearings on the balance shaft.  I haven't pulled the sump (yet), but I figure by the time I do that, it'll be beyond reasonable hope.

Of course nothing is impossible for the man who does not have to do it himself.  BUT FWIW, if you can pull the motor and dismantle yourself, the rods, mains, and wrist pins should not cost too much.  Check Bike Bandit or other site rather than pay TR shop prices.  If the journals are badly scored, you can have the crank turned at a machine shop for what should be a reasonable price.    This may take longer than you had planned but you could  likely get away with not too much cost.  But like I said, it ain't me so its easy to preach   :)   But do check for DAR first.

[Sinnergy]

Mustang (thanks for the reply), Nightrunner (1): I'll certainly look at it soon.  I'll probably pull the alternator on Saturday (looks like a nice rainy day for it here in the Great North-Wet), and I'll let you know what I find, but it really does sound 'deeper' than I'd expect from the descriptions that I hear.  Bikebandit claims to have shipped the new 51T gear and washers today.  I'll put the balancer back in as well.

Remember; this puppy has 82K of not-babied miles on it, a branded title, and half my riding over four years.  I'm what we refer to as 'self-unemployed' and cash is always at a bit of a premium.  While I like the argument about it being less than a new bike; I still have a very nice VFR in the stable along with five or six other lesser machines that would still haul my but around the country if I asked nicely.  The new-bike comparison isn't going to cut it with my wife.

Cashgeo: I'll be in SoCal in about two weeks if there is anything I can do to be helpful, but it'll probably be August (the best part of the year for that part of the country) before I make another ride to the Great State again, and I'll probably be on two wheels--not able to haul a lot.

Nightrunner (2): I consider myself a fair hand with a spanner, but I've apparently got a curse.  I've rebuilt six engines over the last three decades, and out of those... six have had rod bearing problems when I was done.  I can do pretty much anything else, and am not afraid to tackle much.  I run a small manufacturing company, and have most tools at my disposal, but like the calculus that I flunked three times in college, rod bearings just don't fit into my skillset.

All info is appreciated,

Sinn'

[Sinnergy]

Well I (finally) got the anti-backlash gear, and two washers in yesterday, and put it all together today.  As long as I had it apart, I also pulled the alternator and checked the endpiece for play.  I also pulled the clutch cover and checked that end as well.

Nothing.

I could tell as I was putting the balancer back in that there was almost exactly the same amount of 'slop' that there was with the original gear on it.

Apparently the bike had suffered alternator rattle somewhere in its first incarnation, because there was an extra aircraft-grade lockwasher under the screw.  There was some minor wear on the cush rubbers, but nothing that felt like a problem.  The shaft in the motor felt solid as well with just a little rotational play (about the same as crankshaft to balance shaft--this may be standard in this motor).

Everything looks ship-shape under the clutch cover as well, though I suspect that I may be getting close to needing a new set of discs.  I can see wear in the basket where it used to sit a little 'shallower', but clutch grip is not part of my problem.

I've PMed Coachgeo (sorry about the previous misspellings, I was reading it wrong), but any other leads on a solid replacement motor would be appreciated.

Thanks in advance,

Sinn'