My tach seems sluggish Video!!!

[photojon]

Here is the link to the video. Click Here


The bike in question is a 1980 XS650 G.
It has 3.1 original miles. It sat in a garage in Wisconsin for 31 years. It was not properly broken in. We cleaned the carbs, put on a junk tank so I can save the original.

To the problem, as you can see it acts like the tach cable is not spinning correctly. but it does. Which leads me to believe that it has to be in the tach that is not working properly. Does anyone know of similar problems, solutions?

 

[xjwmx]

The easiest solution is to ride it awhile and see if it frees itself up. They often do. There's no geared connection between the needle and the cable inside the tach, just magnetic influence. So if the needle is a little sticky....

 

[shotgunjoe]

I had this problem on another bike. My assumption was a sticky cable... lubed it up real good and no change. Swapped out the tach, and never looked back. Lots of guys pulling their tachs off on their bobbers... Might find one real cheap

 

[nezzer]

Well I wouldn't recommend putting much stress on the engine in this state. The tach and the oil pump run off the same gear. If the tach is sluggish, the oil pump may be as well. Presumably there is some issue with the tachometer itself, meaning the oil pump is working fine. Pull the line off at the tachometer and see if the little square line seems to be spinning at the correct rate, well really is it spinning faster when it should? If so, then everything in the engine case including the oil pump is good, and the tach itself is bad.

If its not, then I am at a loss as to what could be wrong.

 

[shotgunjoe]

Easy way to test the tach itself is the chuck up the tach cable in a drill and spin up the drill, if the tach isn't moving as fast as it should thats your problem...

 

[Shadow24v]

Theres a writeup on 650rider about sluggish tachs. The grease on the needle's bearing gets nasty with age causing the tach to read VERY slow. I did this on my 78, pulled the tach apart, cleaned the old grease off and lubed it with machine oil. Tach works REALLY well now.

 

[pamcopete]

photojon,

Just ride it and it will free up on its own. I wouldn't mess with anything on a bike with 3.1 miles.

Nezzer, you need to study up on how the engine works. There is no way for the oil pump to be "sluggish". It is geared to the engine, like, with gears.......can't think of an easier way to say it...

 

[Sundie]

Nezzer, you need to study up on how the engine works. There is no way for the oil pump to be "sluggish". It is geared to the engine, like, with gears.......can't think of an easier way to say it...

+1 on the .

+1 on the "just ride it - on a nice hot day the grease will ease up and start working properly again"

 

[nezzer]

Agreed it is driven right off the crank. Main idea was not to push it if there is a chance the oil pump might not be pumping like it should. Who knows, maybe the woodruff key was missing or the gear was cracked, however unlikely its not worth taking the risk when a simple inspection of the tach cable would cut it.

 

[pamcopete]

nezzer,

I hate to admit it, but you are right. If the woodruff key was missing, the pump would probably still work but in fact it could be "sluggish" due to the gear slipping on the shaft. Just not likely in a bike with 3.1 miles on it from the factory.

 

[nezzer]

I got so excited to watch the video I didn't read the rest of the original post. I see photojon already checked the cable. Disregard my post. My bad.

Super cool on finding a bike with 3 miles on it. I wonder what set of circumstances lead the original owner to buy it, drive it around the block a couple times, then store it for 31 years. Crazy.