Speedo- It's not the cable!

[louis_holtz]

Hi all,

Had the wonderful experience of stripping all the panels (well almost all) of the @ last night to replace the speedo cable, just to find that the original cable is still in working. After replacing the " old working" cable with a new one the speedo & trip meter still doesn't work? So it's definitely not the cable.

Do any of you know if there is something else that might have broken or will I be needing a complete new speedo?

It's a RD07A with about 30 000 miles on the clock.

Many thanks

Louis

[africatijn]

Must be one of the gears inside the speedo housing then. This is a known weak point.

Unfortunately you have to remove the front wheel to check this.

Gdluck.
T.

[Lord Stig]

Tijn's right - probably the nylon worm gear. Do a search, there's lots about it here. You can easily check it without taking the wheel off if you can get the wheel off the ground. Just undo the screw holding the cable on the wheel end, pull the cable out and then turn the wheel by hand. there is a steel blade-like thing visible in the speedo-gearbox that locates on the wheel end of the inner cable - if the speedo gearbox is fine it will turn as you turn the wheel, if not it will be stationary.

Hope that helps, and do please search this site - there are some useful tips here.

Stig

[icenian]

Must be one of the gears inside the speedo housing then. This is a known weak point.

Unfortunately you have to remove the front wheel to check this.

Gdluck.
T.

This happened to me. Strangely, with the cable disconnected, is you spun the front wheel you could see the gearbox (thingy on front wheel that the cable connects to) was working. Must have been the extra bit of load from the cable that made it slip...

If you want to confirm, you could try testing the speedo itself by putting an electric drill on the end of the cable. If the speedo moves (but expect only a few MPH from a normnal drill) then you know it is OK, and so it must be the gearbox...

There are two likely points of failure in the gearbox. Theres the tabbed washer that sits next to the wheel bearing, which is really cheap; I'd replace that anyway as if it is a bit worn and starts to slip it will probably destroy the nylon gear. The nylon gear (in the gearbox itself) costs nearer 20 pounds. Neither of these looked too bad on my bike, but obviously they were worn enough to stop working even so. Don't enquire about the price of a whole new gearbox, at least not without a stiff drink to hand...

[louis_holtz]

Thanks a lot guys, will give it another go this weekend.

Happy riding!

[Chad]

i had this problem with mine. take off the front wheel and check the gearing. the two tabs were slightly bent where the previous owner must have forced the half that the cable goes on . i gave them a little tweek with some long nosed pliers and its been working fine since.
good luck

[eugen1]

I'll give that a try myself, mine hasn't been working for a while, it used to happen all the time on my transalp. Priced it today, 17£ something, didn't get it even tho they had it in stock.

[louis_holtz]

Hi all,

I did the "turn the front wheel test" this weekend and the "blade" shape thing didn't move therefore I found my problem. I'm taking the bike to a shop to get it sorted (only because I haven't got the stuff at home to do it myself). I want to buy all the stuff I'll be needing beforehand.

Can any of you tell me if it's worthwile getting a new "gear" or just the two washers? As far as could see on the microfisches that all that goes into that section.

If there's anything else I need to get please let me know.

Many thanks

Louis

[icenian]

I'm taking the bike to a shop to get it sorted ...
Can any of you tell me if it's worthwile getting a new "gear" or just the two washers?

Always fit a new washer at least - it's cheap, and a worn washer may knacker a new (and much more expensive) nylon gear. I doubt a worn nylon gear would damage a steel washer, and it wouldn't be a disaster to destroy a cheap washer anyway.

If you're paying a bike shop to do it, I'd change the lot. That could be a waste of up to about 20 pounds, but that's better than having to go back to the shop again if you reused a slightly worn part and it broke shortly afterwards.

Strictly speaking you ought to be able to tell the shop to just replace what's needed; if you pay a professional mechanic they should diagnose the problem. But they might replace the tabbed washer, see that it works, and give you the bike back. And it may go again 2 weeks later because the nylon gear was worn but it wasn't immediately apparent. Of course, a good shop shouldn't charge you if you come back after a problem recurs because they failed to spot a worn part...

[africatijn]

And make sure you'll get the "old" parts they replaced. Just a little check to see if they really do what they say... (Dunno how reliable your garage is...)

T.