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2-cylinder shop tachometer?

lmo1131

New member
Slash 5 owner here. My tachometer is basically useless under about 2,000 rpm. I'm not even sure it is accurate at that speed.

But try to synchronize carburetors to anything remotely near 1,050 rpm is virtual guess work.

Is anyone familiar with a tachometer capable of working with a 2-cylinder engine? I don't want to mount it, just have it in the shop.

"Ear-balling" just isn't working for me....
 
I know that the TinyTac product works reasonable well on /2 models. However, the update rate might not be sufficient to really be accurate down that low. There are probably tachs that are used for Harley's might work.

What about something like this? I used this to synch the carbs on my R69S, which has no tach...made a big improvement.

http://www.dealparts.com/product/43-5712-0.html

Jeff Dean shows them in use on his bike on this page:

http://bmwdean.com/personal_challenges.htm
 
I have a Twin-Max and have to say, it's been a disappointment. Too "delicate" in it's adjustment... at least I find it to be.

I was just getting set to build the $4 synch tube, but it still left me with "no tach".

The Harmonizer looks like a complete package.
 
Twin-Max

My big issue with the Twin-Max is that it's really easy to hit the zero knob. I tried on at a tech day and i kept hitting the zero knob, forcing me to start over again.
 
My big issue with the Twin-Max is that it's really easy to hit the zero knob. I tried on at a tech day and i kept hitting the zero knob, forcing me to start over again.

Same experience.

It's just too sensitive ... it seems to lose it's set point just being strapped down to the seat while I'm using it. I'm no EE, but I would have thought that they could have selected a potentiometer that wasn't sooooo sensitive.
 
Just ordered the Harmonizer... incredible feedback on it and especially on it's developer on advrider.

We'll see.... the lowest price tach is could find was hovering around $60, so I figured a replacement for my Twin-Max, AND a tach. Win.
 
My big issue with the Twin-Max is that it's really easy to hit the zero knob. I tried on at a tech day and i kept hitting the zero knob, forcing me to start over again.

A second issue with the twinmax is that sometimes you could appear to get things in balance, but if you swapped the vacuum tubes to verify it would show up as out of balance. :bluduh I got rid of my twinmax long ago.

The Harmonizer is very nice. Not only for the tach feature, but because it tells you how much out of balance you are. The spec for my '05 GS is anything less than 25 mbar at idle is OK. Since the only way to sync that bike at idle is to re-adjust the valves knowing the actual out-of-balance amount is important. Last service the Harmonizer told me there was a 14 mbar difference. No worries!
 
My Harmonizer showed up this morning.

A bit surprised that no instructions were included... but it looks like the first page on a advrider link will suffice.

Smaller than I thought it would be.
 
A bit surprised that no instructions were included... but it looks like the first page on a advrider link will suffice.

The label attend to the front has most of the instruction you usually need. Yesterday I found that it also works quite well with my R69S that had vacuum nipples added. The bike was running nice. It's now running nicer.

Looks like my Morgan Carbtune is no longer needed.
 
WOOO HOOOO!!!! that Harmonizer is absofreakin'lutely the simplest, coolestest... mostest accurate-est tool I have!!!

I'm going to balance everything again tomorrow just cause it's so much fun!!!

Thanks for turning me on to guys!


edit -


Thanks for turning me on to guys!

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I'd gotta pay more attention to proof-reading.. . . .
 
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