Tech Questions & Answers

Clutching at Answers
Mark, I got one for you that even the shop guys cannot answer definitively. I have a 1986 Triumph T-bird with a dragging clutch. Friction and steel plates are in excellent condition, as are inner and outer baskets. I measured the throw distance of the pressure plate and it was a mere 2 mm, which seems a bit short as I was expecting at least double that considering there are about 17 plates that need to be separated. Do you have any idea what the spec'd throw distance is? Even the official Triumph manual is silent on that measurement.
Pat Duff
Via e-mail

I hate to disappoint you but I can't find that answer anywhere, it's simply not listed in the shop manuals. Here's a way to figure it out, though. First measure the installed height of a new clutch spring, then measure its compressed, coil-bound length; the difference between the two dimensions will be the approximate lift of the pressure plate.

Once you have that dimension you can determine if your drag problem is being caused by worn clutch plates, a worn-out lift mechanism, or improper adjustment.

According to my Honda Common Service Manual, the rear drive shaft splines should be lubricated with molybdenum disulfide grease, where they enter the U-Joint; however no mention is made when it comes to the final drive/wheel spline connection, which is what I assume you're referring to. You could use a moly lubricant, like Anti-Seize, there as well, but I prefer to use an EP-rated grease, which resists shock loadings better than Anti-Seize in that application. In fact, the best stuff I've found is CRC 3303-STA Lube, which is actually synthetic brake grease that's often used in heavy equipment shops to lubricate things like hydraulic pump splines.

Hold on Hoss
I have what may be a dumb question. I noticed on my Harley that many of the fasteners are Torx or hex/Allen head screws and bolts, and was wondering why. I read in another motorcycle mag that they are considered less likely to strip out than slot head or Phillips head screws. It also said they are in harder-to-reach locations-this could explain some of it. I didn't know if this is the sole reason or if they have better holding strength than other fasteners. Even some of the socket head bolts look like they are 12-pointers. What is your take on this?
Hoss
Via e-mail

Actually, Hoss, it's an extremely good question. You're right, there's a more positive engagement between the fastener and the tool, and both Torx and Allen heads are less likely to strip than slotted or Phillips head screws. This makes them easier to torque, especially in hard to reach locations and it also makes them more suitable for assembly line installation methods; you can load the air tool and zip them in without worrying about the bit slipping and rounding out the fastener head. Torx and Allens are also a bit more attractive, at least in my opinion.

As a side note, tamper-proof Torx screws, which require a unique socket, are often used to-you guessed it-prevent tampering. For example, many throttle position sensors are held in place with tamper-proof Torx to prevent shade tree mechanics from futzing around with them. As far as holding power goes, neither Torx nor Allen holds an inherent advantage over any other type of screw; that's determined by the screw's tensile strength and threading. However, as noted, because a Torx or Allen key is less likely to slip, the screws can be torqued with greater accuracy, which gives them a substantial advantage.

Gauge of Success
Got to start by saying that I 've gotten some good tips from you regarding repairs and maintenance. The reason for writing is my 2004 V-Star 1100 Classic. As with most bikes built in the last 10 years, mine has the instrument cluster a top of the fuel tank-WHICH I HATE. I have to take my eyes off the road to see my speed. 40 years ago, my Hondas had the speedo (and tach) above the handlebars. If memory serves, it also told me what gear I was in. It was a perfect spot for them as you only had to glance down to see speed and RPMS. My question is; is it possible to adapt a gauge set-up from an old Yamaha to my bike?
Tony Valerio
Marlborough, Ma.

It is possible Tony, but it won't be easy. For starters, most of the old bikes used cable driven, mechanical gauges; unless I miss my guess, your bike uses solid-state gauges that are triggered electrically. While it could be done, installing a gauge set from , say an early 80's Virago, would be way more trouble than it's worth. Of course, you could always adapt something from a latter model or maybe a sport bike, but it would involve a fair amount of rewiring and probably the addition of a speedometer correction device like a Speedo Healer to get the speedometer to work properly.

I think a far easier solution would be contact one of the aftermarket instrument suppliers like Dakota Digital. They have a line of handlebar-mounted gauges, including a gear position indicator, that should be just what you're looking for, and will be far easier to install and wire.
www.dakotadigital.com