Tachometer reading high

[sambow]

I'm having a minor problem with the tachometer reading incorrectly on my 1988 V-Max with 56k on it. I just bought it this week so I don't know a ton about it yet. The tach reads about 1500 idling and about 7k going 70, so its obviously way off. I don't have a ton of time to work on the bike this week, but I'm hoping someone will say, "Ahah! Same thing happened to my bike! Do x y and z."

I also realize that the tach is not a huge deal (I'm not going to be redlining it anytime soon), and if its a complicated fix I'll leave it for now...

Thanks guys!

-Sambow

 

[naughtyG]

ok I know these are a little on the obvious side, but:

- it's very easy to adjust the idle too high, the adjusting screw is on the left in between the two carbs just below the slides covers. Normal idle is 1000 +-50 rpm

- 7000 @ 70mph could be just right for 4th gear - are you sure you're in 5th?

 

[sambow]

Don't worry about being to obvious, I'm new to this bike so I won't be insulted That being said, the previous owner informed me of the problem before I bought it, and I was definitely in 5th.

 

[naughtyG]

ok! some peeps here will tell you the OEM tacho is a bit crap - on my '86 it's always been fine so I dunno.

It's easy to swap and there's usually a bunch of gauges pods on fleabay going for cheap, so you'll have no problem fixing it.
Here's one going for just $10, altho the shipping's a bit steep at $30. Comes from Canada though, which explains it.
http://cgi.ebay.com/ebaymotors/2001...020QQitemZ300306226551QQrdZ1QQsspagenameZWDVW

As far as the idle's concerned, just remember that the Max likes its carbs sync'd regularly and that this will help both with running smooth and a good idle.

 

[lankeeyankee]

I have plenty of the OEM VMAX tach assemblies (10+).. send me 20.00 and you can have one. I am located in TN.. avg 3 day shipping by USPS. Send me a message for further info on payment arrangments if your interested.

Most likely its a resistor that is burnt out.

 

[sambow]

It idles smooth as silk so I'm pretty sure its just the tach reading incorrectly.

Do you think replacing it would fix it? I wondered if it might be a chaffed wire or something... If the consensus is that replacing it would fix it then yeah, I'll definitely pick one up from you yankee.

 

[gamorg02]

It idles smooth as silk so I'm pretty sure its just the tach reading incorrectly.

Do you think replacing it would fix it? I wondered if it might be a chaffed wire or something... If the consensus is that replacing it would fix it then yeah, I'll definitely pick one up from you yankee.

you could go down to autozone or whatever and pick up a cheapo tach. wire it into your existing tach and see if there is a discrepancy. if there is, return it and order one from lankee (pretty damn good deal if you ask me) You should also check out his custom gauges..

anyways if the tach's are equal then start into the eletrical (ugh...) but i bet its a tach issue.

 

[sambow]

Good idea, I'll probably give that a shot today. Thanks for the prompt responses!

 

[gamorg02]

Good idea, I'll probably give that a shot today. Thanks for the prompt responses!

should be pretty easy, altho fyi, i think the tach has to be 2 cylinder capable!

if you haven't been in the instrument panel its kind of a bitch to unplug it and plug it back in so your best bet, honestly, might be to leave the pigtails plugged in and just flip it and unscrew everything that way. i bet you'll be able to tell pretty quick. definitely post your results, and even better, if you could get a vid of the tach's running side by side that'd be money.

good luck man

-g

 

[sambow]

Hmm, read the previous post a bit too late... I got a 4 cyl tach and plugged it in and it was reading below zero rpms, but it was moving. If I blipped the throttle I could get it above 0 rpms but not by much. I didn't see any 2 cyl tachs at autozone so I guess I need to go looking around. Now that I've got it opened up (surprisingly easy) I may as well go find a 2 cyl tach and get to the bottom of this! I'll post a vid of the two once things are up and running.

-Sam

 

[sambow]

Hmm, I'm having a hard time finding a 2 cyl tach... I've called advanced auto and autozone, neither carry one. There are a few motorcycle shops around but I'd like to avoid buying and returning at a small business... Any tips, I'm in Lansing, MI.

 

[gamorg02]

two thoughts...

1. someone who knows the ignition timing stuff better than me... if you set a 4 cylinder tach up, wouldn't it just show 1/2 the actual reading? or is it different than that..

when you were blipping the throttle, what did the new tach say vs the stock one?

2. goto harlan-engineering and order a shift light. those are 2 cylinder programable and you can set it pretty easily for 2k - 10k in 200 rpm increments to test it out. thats gonna be a few days though...

hmm as far as that goes... i'm not sure what other types of local stores would sell 2 cylinder capable tach's. i thought most came with a 2/4/6/8 setting...
plus u'd have a nice shift light for the bike once its up and running...

 

[gamorg02]

and if you are going to have to order something, might as well just get it from lankee for $20. if you can't find something local w/out too much of a headache, u know u'll have that w/in a few days...

 

[sambow]

All of the tachs seem to be 4, 6, 8 Anyways, I've come to the same conclusion, it can't really be the wiring since a tach should run off any wire in the electrical system (along with grounding it), right? So I PM'd yankee to grab one from him, for $20 I may as well just get this taken care of. Thanks for everyones help!

 

[Redbone]

I would check with Lankee Yankee, he does some nice work retofitting the gauge pod, a plug-n-play mod. He stands behind his products too. It sounds like he has some used gauges if that's the route your going. Here is a link to his gauge mod, there is a nice picture of Lankee's completed gauge cluster in post #29.

 

[KJShover]

Hmm, read the previous post a bit too late... I got a 4 cyl tach and plugged it in and it was reading below zero rpms, but it was moving. If I blipped the throttle I could get it above 0 rpms but not by much. I didn't see any 2 cyl tachs at autozone so I guess I need to go looking around. Now that I've got it opened up (surprisingly easy) I may as well go find a 2 cyl tach and get to the bottom of this! I'll post a vid of the two once things are up and running.

-Sam

You can still use a 4cyl tach, just make yourself a T-boost type setup and instead of running the wire to your Vboost controller use it as a feed for your tach.

 

[sambow]

Thanks, but I already returned the 4 cyl tach, I'm going to order an OEM tach from yankee.

 

[lankeeyankee]

Sambow I sent ya a message with payment information and options.

Thanks

 

[gamorg02]

good choice overall... $20 plus maybe a bit more to ship it quicker i think is the best choice just to see.


i wonder if you could leave them both hooked up momentarily to see if there is a discrepancy, or if the resistance in one would throw off the other reading in the system....

everyone that's dealt w/lankee's products and selling i've heard nothing but great things as well...

 

[lankeeyankee]

everyone that's dealt w/lankee's products and selling i've heard nothing but great things as well...

Thanks man you posted that comment and I didnt think you would, ok ok you won how do you want to be paid?