Tachometer not working after Regulator replacement

[Larry Biskit]

Hi all.

Just went on hols to french/swiss alps, regulator failed on the way down. The bulbs blew and battery chucked all its water out, the Tacho stopped all of a sudden and 2 mins later the bike stopped running. Got down to top of the alps during daylight whilst topping up the battery 3 times to get to a workshop. The parts came and all got fixed and is good as gold, except the tachometer. Its totally dead and has been since just before the first time the bike stopped. Any ideas on wether the CDI is ok or now faulty or is it a tacho prob, I figure its not impossible that something happened to the wiring but would be big coincidence perhaps. Like I said the bike is all good and did another 1200 miles on our way up and over and back. Checked all fuses and took tacho off and checked conections etc... Also where does the wiring go to, I mean where do i check connections at the CDI. Cheers.

[robelst]

Just a wild guess, but I remember my tacho stopped working when I disconnected the fuel-pump relay. Maybe the overload has damaged this relay as well (it's a cut-off relay, which means that the pump will probably still work with the relay broken).
Good luck!

[Larry Biskit]

Ok, That sounds good, I hoped that the expensive CDI was ok cos the bike runs fine... and one of the other things attached to that part of the wiring was the fuel pump cut off relay. Is it a case of buying a new one, cheap/expensive? from honda? Sorry for all the questions, had the Bike 4 months, love it, always wanted one, but theres plenty to learn. Cheers again. Oh yeah its an RD04 1990/91. Thanks.

[robelst]

These relays cost 30+ quid, so quite expensive (give David Silver spares a bell, or look at www.davidsilverspares.co.uk ). I am not sure if a similar relay can be bought from a car-part supplier, they tend to charge pennies what OE bike-parts cost in pounds and are often better quality as a bonus
First thing would be to check that relay to make sure it actually causes the problem.

Good luck!

[North Thai Biker]

The same thing happened to my friend's '94 AT. He blew the rectifier and all the lights went and the battery. His tach is still out. I think they are an expensive part. Joe

[Larry Biskit]

Ok, I found a replacement relay at www.davidsilverspares.co.uk for £35.48 Thanks for the info, but first will check the potentially dodgy relay on the bike.... How do you test a relay (multimeter?) , also I havnt looked yet but where would it be on a L model RD04? I can trace the wiring back from the fuel pump I spose. Also if I take it off for testing will it damage other wiring or pump if the bike is started without the relay...? Cheers guys

[Larry Biskit]

Still looking into this problem and after trying another relay, to no avail, I figured the prob lies in the tacho itself or the CDI unit.

So pulled the tacho gently apart and found a scorch mark on the plastic housing the electronic board, so pulled that apart. The soldered wires had, in a few places along one side of the board, melted, dribbled and bridged over to another part of the circuit.

Got the soldering iron on the job and cleaned up and re-soldered the dodgy looking wires and joins. Put it togther and crossed my fingers. The tacho now works... but... there's been lots of buts... now it'll work when the revs are low, up to 3 to 4000 rpm's. When it shows 4000 rpm Im wringing the Sh** out of the engine, should show 7 or 8 ( or 15 by the sound of it) at least...

I checked the signal from the cdi/rr coil and it seems ( vaguely) fine. I mucked around with the multimeter and on DC it showed that the voltage went up and down, whilst reving the engine up etc and looked like it was sending more than the Tacho showed. Havnt had the multimeter long so not sure what to do with it really, so may have tested wrongly.

I pulled the tacho apart again and made an pretty thorough clean up and re-soldered any average looking spots where diodes etc joined onto the green board. Will try again tomorrow and see if its any healthier now. Dont hold much hope after the cooking its had tho.


Anyone had this prob and solved it before??

Does anyone know where I can try/buy a tacho for ( cheap, new ones are £236 ) an RD04 or any good Breaker who might be worth a try.

Thanks all.

[Northy]

I had the same problem (RD07) th the recfictier that cooked the battery and blew the some lights ........ the bad news is I bet the is tacho shot, burn't out or over loaded the electrics/doides?
I was getting a pluse from the coil/cdi unit but the tacho would only get about 1500 -2000 that its, even pulled my tacho apart but no luck.

Had to buy a 2nd hand tacho , which once fitted , sorted the problem out.

Northy

[Larry Biskit]

Nice one Northy, ta for that info, albeit reinforcing the need to spend some dosh.

The tacho didnt work properly after the second fix up so if anyone has a tacho or knows where to get one please please tell me.

Ive tried many many breakers with no luck. I hoped to keep the price down so dont want to go the Honda or other parts suppliers as they are mega expensive. Yep Im a tight ar%*. Well, just poor more like.

Right, off to see if the low rev range helps my miles to the Gallon.

[GSPD750]

I've said it before (and I'll say it again) but the following link to a Dyna Charge Monitor can save alot of grief on the road. People can whine about the price of this gadget for what you get but it will probably save your ass one day.
You can pay the man now...or later.

http://www.xrv.org.uk/phpBB2/viewtop...highlight=dyna