Rear end noise

STsam41 · Apr 24, 2016

So just finished replacing my steering head bearings and while doing some other maintenance specifically oil/filter and rear differential fluid change. Bike is on lift and on center stand. I clamped front wheel and started bike then shifted to first and let bike run to warm up both engine oil and rear differential fluid. I notice (both before and after rear fluid change) a knock or rattle from rear end seems to be loudest near the forward end of the final drive case. If I tip the throttle it seems to disappears. I haven't noticed any issues or noise while driving the bike at all.

KTD1911 · Apr 24, 2016

as far as i know that shoud be a "no load" drive lash mine will make a slight noise if i run it in gear on center stand

STsam41 · Apr 24, 2016

Kinda wondering if it's normal. It's not rhythmic-sort of sporadic but still constant. I was wondering if there's a throttle balance performed on these bikes. I have a carb tune somewhere that I've used to balance throttle plates on my brothers BMW R1100 RT but that's a twin. Is there a similar procedure for the ST?

dduelin · Apr 25, 2016

Some erratic noise is normal. The 1261cc V4 is a long bang motor with pause between cylinders 2 and 3 and 4 and 1 so the crankshaft is accelerating and decelerating slightly at idle and with no load on the drive train it manifests some noise through gear lash. If you drag a little rear brake does the noise go away? If the noise is constant or doesn't go away with a slight load I would look further.

There is a throttle body synch procedure that can be done but the Honda V4 is a much different from the boxer in how this affects performance. The Honda's only affects idle and off-idle speed while the R1100s can affect performance across it's entire rev range.

BakerBoy · Apr 25, 2016

It is likely normal--there's a lot of parts that mesh and have slight clearances, therefore noticeable backlash with the drivetrain unloaded like that. Drag rear brake to verify it greatly diminishes.

STsam41 · Apr 25, 2016

dduelin said:
Some erratic noise is normal. The 1261cc V4 is a long bang motor with pause between cylinders 2 and 3 and 4 and 1 so the crankshaft is accelerating and decelerating slightly at idle and with no load on the drive train it manifests some noise through gear lash. If you drag a little rear brake does the noise go away? If the noise is constant or doesn't go away with a slight load I would look further.

There is a throttle body synch procedure that can be done but the Honda V4 is a much different from the boxer in how this affects performance. The Honda's only affects idle and off-idle speed while the R1100s can affect performance across it's entire rev range.

I will check regarding the brake load but I'm guessing that it will make the noise go away. I do believe the throttle sync will alter this somewhat and the problem only exists at idle as far as I can tell. I found the sync in the maintenance manual and an old post with pics online so going to try that. I will post results.
thanks

dduelin · Apr 25, 2016

Also check the twin bearings inside the driven flange. These can go bad with no other symptoms except some clunking/rattling noise when idling in gear. I can't believe I forgot that in the earlier post. Mine were bad at 96,000 miles but many owners replaced them much earlier. Honda P/N 91052-KZ4-J21 or aftermarket 6905RS.

STsam41 · Apr 25, 2016

Well just confirmed that noise does go away dragging rear brake or during high idle. Mines an '06 with only about 35,000 on the clock.

jmcarruth · Apr 26, 2016

Normal behavior for a ST1300.

Rear end noise

STsam41

KTD1911

R.I.P. - 2020/10/13

STsam41

dduelin

Tune my heart to sing Thy grace

BakerBoy

It's all small stuff.

STsam41

dduelin

Tune my heart to sing Thy grace

STsam41

jmcarruth