Newbie, with no tacho, need help

[Silageman]

Howdy folks,

I've just bought an AT -RD04, from a friend who has had it garaged for a couple of years, we charged the battery up and it started first time, so I thought 'that's the very fellow for me', and bought it there and then. It passed the MOT today no probs and no advisories, so far I've only ridden about 10 [city] miles, and it runs pretty smooth, expected fuel problems as it had stood for so long unused, but seems ok, haven't opened it up yet [till I get it legal first], the only thing not working is the Rev counter[needle does not move at all]. The guy I got it from knew this had stopped working last time he used it and was told by a mechanic it would be a faulty CDI unit. I cant find much info on the cdi units [not sure what it does], but I'm not convinced it would effect the Rev counter, still I'm new to AT's and wondered if anyone out there could offer advice, or know anywhere to take the bike to have it checked, thanks in advance to anyone who can help.
Bob

[BobA]

Bob


Welcome to the forum and AT ownership, you'll love both.

With regard to the rev counter, I doubt very much if it's the (expensive and hard to get) CDI if the bike is running OK.

I would suspect a wiring problem, and the easiest way to check is to remove the screen (a few screws) for easy access to the rear of the tacho (rev clock). You should see three wires coming out of it, and these will have a connector a few inches from the clock. I believe there is one other wire that will run on it's own across to the connectors in front of the speedo. Check all these first, it will take you minutes and cost nothing.

Rev clocks have been known to become victims of rec/regs that fail, but I'd check all the obvious connections before spending any money.

If it was a fault with the CDI, the bike would not run correctly, or would run on one cylinder. The rev clock takes a parallel feed from a feed to one of the coils.

Let us know how you get on.



Good Luck


BobA

[AlanH]

If yours is the one without the trip computer above the clocks, I've got a spare RD04 rev counter. If that's what it turns out to be, it's yours for £12 plus postage.

As BobA says, they only usually go if a regulator has blown at some point and the excess voltage has killed them so check that out carefully.

[RodYork]

Alans offer seems the best way, but have a read of this article- you might derive some help from it

Tacho fix

personally, I would
a/subscribe to the forum (£10 well spent)
b/take up the Alan offer

Welcome!

[Silageman]

Cheers Boba,
Thanks for the advice, I will investigate the Tacho wires at the weekend, I've just taken the bike for a good 120 mile run, it's running quite smooth at low speeds, but at fast acceleration, and over 60 mph, it does splutter a bit, I'm thinking perhaps carbs need balancing, or there is a problem in the ignition system, or perhaps CDI unit is faulty,
But on the whole it's a great bike to ride, well balanced handling, but the seat is a bit hard to sit on after 60 miles I had to get off with a numb arse. Will search for some kind of Gel seat cover to fit, would'nt like to tackle a proper long distance on it as it is.
But overall ...top bike, and I do like this forum [yes, just subscribed, I know it makes sense.]

[AlanH]

When it was left standing, were the fuel taps turned off? Even if they were, if the carbs weren't drained, the old fuel in the carbs will have evaporated and left varnish in the main jet and emulsion tube. I'd bet that stripping the carbs and cleaning all the jets thoroughly would help. If it's at higher rpm and gets worse as it warms up, the chokes may not be closing too so check out the plungers and choke cable.

CDI failures tend to have a permanent effect on one or both cylinders in that you will not get a spark on an affected cylinder. A CDI failure can cause the tacho to stop working if it's the circuit for the cylinder that the tacho is wired into but idf this was the cause in your case, the bike would very obviously be running on one cylinder.

So here's your homework...
1) Strip and clean the carbs thoroughly.
2) Check all the cables and choke plungers
3) Bung the carbs back on and get it running again
4) Get a voltmeter and check the voltage across the battery at 5000rpm
5) Report back with your findings

Have fun

[Wingnut]

Silageman

Welcome and enjoy both. Ive a RD04 as well doing a strip and rebuild . Post some pictures give us all a look. Speedo gave me trouble - still not fixed . It has a mechanical problem . The gear that engages the cable at the wheel hub is worn away. I'm starting from zero but have to say it would be allot harder if I wasn't subscribed to this forum. Id like to know what your problem is and how you fixed it .

Jonny

[AlanH]

The gear that engages the cable at the wheel hub is worn away

I've got a spare one of those too - a full speedo drive. You can get the plastic gear from David Silver Spares but clean the drive out thoroughly before you fit a new gear otherwise it'll break again very quickly.

[Wingnut]

I've got a spare one of those too - a full speedo drive. You can get the plastic gear from David Silver Spares but clean the drive out thoroughly before you fit a new gear otherwise it'll break again very quickly.

Alan H

Thats what exactly what happened and within 30 miles of fitting. The cable seems free enough but may be it should have been replaced as well. By the way Al are you an RD04 owner ? I'm only asking cos I'm trying to get a feel for the numbers on the forum who are riding RD04'S .

Jonny

[Wingnut]

Home work
Use to do allot of my home work in the back of the bus on the way in to school in the morning .

Think I'm going to follow up on the carb clean section.

Jonny