Speedo Fluctuations After Chain & Sprocket Relacement

[PlentyMech]

Hi, I just replaced my C&S on my Gen6 VFR (went to 15/43 525). No dramas but it did take a while to get the sprocket cover back on for some reason. Took it for a test run around the streets and the speedo is fluctuating when holding it at a steady speed. Uploaded a short video to demonstrate. It'll be 45kph then suddenly 35 then back again.

 

I also noticed towards the end of the 10 min ride that there was a very slight feeling of drag and release if that makes sense when normally it would just be smooth, a bit like if you had an insane tight spot. When I checked the chain after it was pretty hot as was the sprocket cover and clutch slave mounted on it. I can't recall if this would be hot after a normal ride anyway. I've changed over 50 C&S over the years but this the first time on this bike. Chain also has a slight tight spot just after this ride which is unusual as normally it just requires a slight adjustment after the first good ride and tight spots come much much later after some use. 

 

Anyone has anything similar happen to them or just advise how hot your chain and sprocket cover is after a short ride? 

 

Thanks all.

 

 

[TheLimey]

This seems a common occurrence. More than likely the little nylon hex drive that couples the speed sensor on the sprocket cover to the front sprocket bolt head has got pushed down on its shaft a little too far. This means it's not quite seating on the front sprocket bolt fully and gives erratic speed readings. 

 

You just need to whip the sprocket cover off and pull the nylon hex drive up on its shaft a little and then remount it. 

[bmart]

winner winner chicken dinner. Many Hondas do this. 

[Grum]

Did you remove the speed sensor before removing the sprocket cover. Makes is easier to properly align the speed sensor coupling after the sprocket cover has been re-installed.

Only remove the speed sensor not the whole cover to inspect its coupling.

 

Chain issue. Have you fully tightened the pinch bolt? Didn't overtighten your new chain by any chance? Have you purchased a top quality chain?

[PlentyMech]

On 1/18/2022 at 12:37 PM, TheLimey said:

This seems a common occurrence. More than likely the little nylon hex drive that couples the speed sensor on the sprocket cover to the front sprocket bolt head has got pushed down on its shaft a little too far. This means it's not quite seating on the front sprocket bolt fully and gives erratic speed readings. 

 

You just need to whip the sprocket cover off and pull the nylon hex drive up on its shaft a little and then remount it. 

 

That was exactly it thank you! I'd have never pushed it up a bit as it looked fine and it didn't want to move willingly. 

 

[PlentyMech]

On 1/18/2022 at 6:01 PM, Grum said:

Did you remove the speed sensor before removing the sprocket cover. Makes is easier to properly align the speed sensor coupling after the sprocket cover has been re-installed.

Only remove the speed sensor not the whole cover to inspect its coupling.

 

Chain issue. Have you fully tightened the pinch bolt? Didn't overtighten your new chain by any chance? Have you purchased a top quality chain?

 

Thanks for pointing that out. Not removing it initially is probably where it went wrong as wasn't aligned and then I go tighten the sprocket cover. Much easier to remove it as you say. Got a feeling the friction of it slipping was creating the heat as well as was cool as a cucumber after the same length test ride albeit it's not like Darwin here today.

Pinch bolt fully tightened. Only thing slightly different this time was the tool I had available made hard work rounding the rivets on the master link but I measured them and the master link and compared to the other links and was fine. On the 2nd test ride I couldn't feel anything though. Will give it a few runs but think it's actually OK. Chain is a X.A.M AX. Something new but the dealer swore by them and at the time I was having issues tracking down a 525 15T front cog and chain without long lead times.