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STRANGE CLUNKS -> ALTITUDE ADJUSTMENTS -> BEST USED BIKES -> STICKING CLUTCH -> TOOL TIME

K-LUNKING BEEMER

Q: I love my 2012 BMW K1600GT.

Best bike I’ve ever owned. But it has one major flaw that BMW Motorrad U.S. seems to be ignoring: a very loud clunk that occurs when the bike is shifted into first gear. This is the third big BMW I have owned, and I have never experienced this problem until now. There is also a considerable amount of driveline lash in first gear, which makes very slow speeds extremely difficult. If you look at the various sites and blogs that contain comments from K1600GT owners, you will find literally hundreds of similar “clunk” comments, yet BMW seems to be turning a deaf ear.

¡USTIND. PARKS NORWALK, CONNECTICUT

The clunking sound you hear is the rotating gear dogs on one gear meshing with the stationary gear slots in the corresponding gear when they are moved into position by the shift fork. Additionally, the stack-up of tolerances in each segment of the final drive is taken up as well, resulting in the driveline lash.

We don’t know which BMWs you previously owned, but the opposed-Twin Boxers use an automotive-style, singleplate dry clutch, while the Ki6oos have a multi-plate wet clutch. The latter type is a more ideal fit for across-the-frame engines like the 1600’s inline-Six, but it also tends to produce a tiny bit of drag, whereas the automotive type does not. That drag usually is not noticeable when the transmission is in gear. But when the clutch is disengaged in neutral, fluid friction caused by the oil between the drive and driven plates creates just enough drag to keep all the plates and the transmission input shaft rotating; and when first gear is engaged, the input shaft and the driven plates are instantly slammed to a stop, causing the clunk you hear.

What’s more, BMW Boxers have considerably more flywheel inertia than the K1600 models, and that tends to make driveline lash on those opposed-Twins a little more manageable than it is on the light-flywheeled, quicker-revving inlineSixes. As you have found out by reading other K1600GT owners’ experiences, that clunk and lash are clearly characteristics of this motorcycle, but many other bikes also exhibit the same attributes.

DE-CALIFORNICATION

I have a 1994 Honda Shadow VT1100C that I bought used ® some years ago. On numerous occasions, after long storage, I’ve had to remove its carburetors for cleaning. Judging from all the extra hoses, valves and the charcoal canister, I’m guessing it’s a California model. Now, I’m no professional mechanic, but it seems like a real hassle to work around all that extra gear when I don’t even live in the U.S. To save myself some trouble and also out of sheer curiosity, is it possible or even reasonable to remove or modify any of this evaporative equipment?

KENT MILLS RAMSTEIN, GERMANY

Alt’s possible and, in most instances, reasonable to remove some * emissions equipment, but don’t do so unless you have a trained technician either advising you or performing the work. The de-Californication of your Shadow might not be legal in Germany, so you should check into the matter before proceeding.

It is relatively easy to remove the Evaporative Emissions Charcoal Canister (CC). Vapors from the fuel tank are routed into the canister and then back into the intake tracts. There is a line with a one-way valve between the fuel tank and canister that can be removed from the CC and vented to atmosphere without any issue. Consider this a drain line and run it toward the ground, bypassing the rear tire, the exhaust or any other heat sources while also avoiding any spots where fluid can pool. To prevent air leaks, any connection between the CC and the intake needs to be blocked, either with a rubber plug and clamp or a bolt and a crush washer.

ATTITUDE AT ALTITUDE

This year, my three riding buddies and I spent a week in Colorado camping in Durango and Gunnison. We were all riding 2008 and newer H-D Road Kings, which are fuel injected. In the higher elevations, we got crazy (increased) fuel mileage. We experienced 60-plus more miles per tank and no loss in performance. Why is this?

I have been in higher elevations on my 1987 H-D Softail (S&S Super E carburetor) many times and experienced coughing, sputtering and lackluster performance. I assume the electronics of the fuel injection is the reason, but I don’t know why.

¿%G0T A MECHANICAL OR TECHNICAL PROBLEM with your beloved ride? Perhaps we can help. Contact us at cwservice@cycleworld.com with your questions. We cannot guarantee a reply to every inquiry.

KEITH HASWELL DALLAS, TEXAS

A Modern are remarkably fuel-injection well adapted systems to working at different altitudes.

With Electronic Control Units (ECU), the rise from sea level to 10,000 feet or higher is hardly noticeable. As we climb, air becomes less dense, but a carburetor continues to meter about the same amount of fuel no matter the elevation, causing excessive mixture richness. The EFI on your H-D, however, constantly compensates for the reduction in air density and reduces the amount of fuel accordingly. With less fuel needed, overall efficiency is increased, improving fuel mileage. A fuel-injected bike’s full-throttle acceleration at high altitudes would be noticeably slower than it is at sea level due to the lower air density, but during casual, non-aggressive riding, you wouldn’t notice much difference.

FRICTION STICTION

QB 4600 I have miles. a 2012 Yesterday, GSX-R750 on with my about ® way home from work, I noticed

something rather unsettling. When preparing to slow and downshift, I pulled in the clutch lever, and the clutch did not disengage for almost two seconds! This scary behavior was repeated—only when downshifting but not with too percent consistency—for the rest of my short ride home. It almost always happened between second and first gear when coming to a stop. I recently had the 4000-mile service performed. I have read that using a lowergrade oil (have been using Amsoil) could affect the clutch, which runs in the oil.

I cannot vouch that the service place put Amsoil back in, although I asked for it. Could this be the culprit?

CHRIS LAMB DAYTON, OHIO

Because this condition only emerged after your last oil change, you might consider changing the oil and filter again with the same grade of Amsoil you were using before the problem arose. Better yet, switch to one of the brands and weights of oil recommended in your GSX-R’s owner’s manual. If you can’t trust the previous shop to use the specified oil, take your Gixxer somewhere else to have the work done.

If that doesn’t fix the problem, you’ll need to ensure that the clutch cable and lever are moving freely and that the clutch

is properly adjusted. All newer GSX-Rs have clutch adjusters at both ends of the cable plus one inside the clutch cover on the right side of the engine. This last adjuster, beneath a small access cover, is crucial to proper clutch actuation. Since you are not a mechanic, it’s best to have the entire clutch system adjusted by a Suzuki Certified Technician. Or, if you have a friend with mechanical skills, have him follow the directions in the service manual for your bike. Please note that many model years of GSX-Rs have different adjustment schemes. What might work on a 2010 isn’t necessarily right for a 2012.

OLD HONDA RUBBER

I have had my Honda CB450 since 1969. It was my only ride ® until 1988. Since then, it has been garaged. I’ve finally started working on restoring it but have run into problems obtaining some odd rubber parts. Last year,

I did find a source but lost the web link when my computer crashed. Since then, I have Googled and eBayed and forumed to no avail. Thanks for your help.

]AY KAKNES DANVILLE, NEW HAMPSHIRE

A David Silver Spares of England (davidsilverspares.co.uk) is an excellent resource for older Honda parts.