Trip meter gear slipping

[Barry]

The last two times I've used the bike it has recorded fewer miles than actually ridden. 24 miles instead of 28 and 4 miles instead of 8.

The usual cause is well known, a pot metal gear wheel inside the speedo slips on the shaft.  I noted that on both occasions the bike had been stood in the sun for sometime so perhaps there is a differential expansion issue.  I'm busy with other projects at the moment so it will be some time before I can tackle the problem as I want to do it right. My question is what has anyone used successfully as a permanent fix for the problem - epoxy, loctite or is there something else ? 

Pic courtesy of Querty123 in a previous thread.

[Barry]

Rode the bike to work today and made sure to park up in a spot that would be in shade all day. Sure enough the trip meter recorded the miles accurate to a tenth so the gear musn't have slipped when kept reasonably cool.  I'll still need to fix it though.

[ged in oz]

I’m watching this with interest Barry. My odo isn’t working and it’s a pain in the butt trying to monitor mileage.

I’ve fitted my spare R45 speedo which gives me time to find the right solution for the original clock but I’m keen to hear how others have tackled it.

I’m thinking of a degrease of the relevant area and some gel superglue?

It seems very common so it’s obviously a design fault.

[Barry]

I’m thinking of a degrease of the relevant area and some gel superglue?

I've heard that superglue will work  Ged.

Besides the securing the gear wheel there is the little matter of uncrimping and re-crimping the bezel while causing minimum distortion. That's the main reason why I want to do it once and do it right.

[ged in oz]

So, I finally got around to looking at this issue Barry. I used a toothpick to get a dob of gel superglue onto the shaft/gear wheel and it seems to have worked ok.

My speedo has the trip meter reset button protruding through the front glass and this obviously allows water into the instrument and there was plenty of corrosion and oxidisation going on.... i cleaned the rust away from the joint as best I could before I glued it and after the superglue had set, I gave everything a good soak in WD and freed it all up as much as possible.

The only advice I can offer in terms of the crimped cover is to insert a really fine screwdriver blade under the crimp and then try and work it around between the crimp and the case rather than levering it repeatedly the whole way. The less you can distort the (very soft) crimped metal, the better I think.  I still used a smear of silicone when I resealed it though to make sure it stays sealed.

I ran it for 30klms or so yesterday and both trip and odo worked fine and the disassembly and cleaning has stopped the needle dancing around and the speed seems to be reading pretty accurately.

[Bob_Roller]

Where do you put the adhesive, is it visible in your pictures ??

[ged in oz]

Hi Bob, no I didn’t get a photo of the glued joint. I should have....

I put a drop of superglue on the point where the grey metal gear wheel sits on the rusty spindle with the tapered end. The gear wheel was slipping on the spindle, which is what causes the problem.

I scrapped away as much of the rust as I could before glueing, and then lubed it all as much as possible to free everything else up again.

The following link describes the process for an R100 clock, but they are apparently the same mechanism once you’re in there, so it is still pretty handy.

https://pbase.com/dwerbil/image/14562002

[Barry]

Is this where you put the glue.

Mine hasn't slipped again since I started parking it out of the hot sun but I will get around to it eventually.

[ged in oz]

Thanks Barry! Yes. That’s exactly the correct spot.

I was expecting the internals to be covered in grease, (and therefore difficult to glue) but as you can see it’s all very rusty and dry of any lubricant.

I think you might be onto it with the differential expansion explanation. I guess it must have been an interference fit from new and it’s obviously inadequate with the regularity of failures.