Gauges arrived....as I feared

My new gauges just arrived and as I feared, the tach is infact cable driven.

I love the look but I'm not sure how to proceed. Do I run just the speedometer and deal with having no tach, try and make a new housing for the old tach and use that, or just sell them both and accept that I can't make them work.

*sigh*

Pics!




Here's the backside of the tach...not what I wanted to see

 

Could you not do some sort of coil induction... simular to doing a timing light from a spark plug?

 

Sorry scratch that...

I was thinknig of the reverse problem.

 

Where did you get those gauges Hessen? they look pretty awesome

 

Return them! Companies expense.

 

I ordered them from www.mikesxs.com

Returning them is a bit of a gray area, their return policy if fairly strict by the looks of it. I'm waiting on an email back from them.

If there was some way to modify something to make it work, I'd be keenly interested to know

Being as next weekend is offically "fiberglass weekend" for me, I'm thinking of using the new speedo, old tach, and making a fancy little housing that will bolt to my upper yolk and screw to the small "dash" area on my fairing. Hopefully at the same time I can give my wiring harness a new home

I'm pretty sure I can even make a new face for the old tach so it matches the speedo. Not sure how I feel about having a huge tach and a teeny speedo though.

Updates as they develop.

If by chance anyone would be interested in buying them, I'd go 90$ on the pair, with the mounting brackets. Thats a couple bucks less then buying em new off teh webs.

 

What would the implications of rigging my bike with a mechanical tach be?

How is the sensor on the engine that reads the RPMs different between cable / electronic?

 

On the electronic side, for Secas anyway, the tach takes the input from the right side coil (grey/black I think, maybe grey/red) and converts it to pulses that you can read on your tach. Basicly, the + to the tach is constant, and the wire from the TCI to the coil is a -/0. When the tachometer gets a "ground" from that grey wire, it causes power to flow to the unit causing a jump. The normally closed circuit becomes open and it produces a blip on the tach. The amount of "blips" indicate the RPMs of the engine.

Mechanical is a little hazy. I've owned a few, but the last one I had was on a CB360, and it used a cable and gear driven by the camshaft. I honestly don't remember any more than that. It's been years since I had that thing.

My suggestion: Unless you absolutly LOVE that new tach, dump it and find an electronic one. Even if you find some XJ with a mechanical tachometer (I don't know if they exist or not) the gearing could still be off and give you a false reading.

 

Thanks for the tip. I'm going to try and run just a speedo for a day or two, see how I like it.

I've been trying to find some info on the net but I'm coming up dry.

 

The maxim 650 is a mechanical tach... above and between the two rightmost cylanders...

You can also add marks to the speedo to denote redline in each gear.

 

On that 650, Where is that located exactly? between the exaust ports, intake ports, or around the valve covers? Crankcase maybe?
Let me know and I'll go check my 750 for a place to modify it

 

Now thats not a bad idea...just marking the speedo face.

Might be my best solution

 

I would just look around for a electric tach. You should be able to find one that will be a close match to the speedo. I know Drag Specialties makes an electronic tach that looks close.

 

Looks like a pretty close match!

Another 85$ is a bit of a pain. If i can manage to sell the other tach (or return it) and maybe I'll go for it.

 

I'm suprised to hear that the tach issue occured. Perhaps you could talk the nice folks into swapping you for an electronic unit or determine if an adaptor exists. Bummer there buddy. They look very nice too. Moding your bike is a very difficult proposition as you would have to have the head machined to accept the mechanical gear that would normally mate up with the matching gear on the cam. I'm not up on 750 Maxes but there might be a model out there with a donor head and cams for you. Good luck.

 

Until just now, I had NO idea that there was such a thing as a mechanical tach. I just assumed they all used the coil impulse, as that's all I've ever had to deal with.

 

While not particularily helpful - in this picture I'm tightening the tach cable.

http://xjbikes.com/coppermine/displayim ... pos=4.html

I'll look through my photos for a better angle later

 

Actually the later Max 650's went to an electric tach too. Not sure what year they started, but my '82 originally had an electric tach, but now that it has an '80 motor in it, I'll be switching over to full-manual.

 

Hess man those guages are real nice and all...... but kinda like some girls...(no offence E.P.)
what you see aint always what you get!!
and some times the pretty ones arent worth the hassle!

I'd sell them on e-bay or somewhere and count my losses (unless you make money) and go get a new set that works the way you wanted.

Are you looking for smaller, shinier, ?

Hi revin engine needs a tach just to keep you from..... you know!!

Happy Huntin
Mike
_____________________________________
I'll keep my eyes peeled for you

 

At the time I was going for smaller but with the way the old box looks under the fairing the smaller ones just don't work for it.

I'm going to attempt to make a "dash" that will bolt the the inside of my fairing, down to the upper yoke and set the gagues into that. There's a set of XJ750max gagues on ebay I'm keeping my eye on. The LCD is cracked but, according to the sell, the guagues are still in working order. If they don't go over 20$, I'm going to pick em up.

I want to get that one to dismantle, just incase I screw something up.

I've got the tiney chrome ones posted here and on craigslist.

I'll give it a week or so then turn to Ebay.

 

Best of Luck!

 

I might just be interested in those gauges, I am pretty sure my tach is electrical (I traced the wire from the tach down to the headlight bezel), but I'm not sure how to tell without any uncertaintly

Any help?

Thanks,
Shawn

 

If you have a mechanical tach you will have a cable quite the same as a speedometer cable. I f you dont then no doubt your tach is electrical.

 

Yeah, the back of the tach will look like the back of the speedo, with the place for screwing the cable in.

 

OK, Im confused. These are both electric gauges?

 

You tell him Hess
The tach is mechanical (cable driven) as is the speedometer.

 

HVN is correct, both are cable driven. (analog, mechanical...etc etc)

The backlit faces and LEDs, are, of course, electric though.

 

The exhaust cam still has the tacho gear driver on mine so i gather the the bit that goes onto it is actually a hole in the cyl head , wizz to the wreckers and check it out maybe?...nice gauges too....