84 RZ 350 No more power from my battery bike still starts

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motoman353
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84 RZ 350 No more power from my battery bike still starts

#1 Post by motoman353 » Tue May 29, 2018 12:09 am

I went for a ride the other night and the fuse for my headlight blew. I replaced it and was good to go or so it seemed. I took the bike out today for quick ride and the bike sputtered and acted funny. It would clean up and run normal then start sputtering again. I

It became apparent that it's an electrical issue when I stopped to get gas. When I went to fire the bike back up there were no lights, turn signals didn't work, and no neutral light however the bike would still fire up. Once it fired up it was obviously running off of the stator. If I used a turn signal sometimes the signal would go off and the bike would sputter again but only under a load. It revs free when in neutral or not under a load.

It continued to act up on and off but once I got home the bike was no longer getting any juice from the battery. Turn the key and nothing, no power valve cleaning cycle, no lights, no nothing but the bike will still fire up and then everything comes on again.

I've tested the battery and it's fine so I don't know what's failing. I pulled the seat, gas tank, and headlight to check all of the connections. I was thinking maybe it was some sort of short or grounding issue but I don't see anything sticking out at me. The stock wiring harness isn't pretty in some spots but again I don't see anything sticking out at me that seems to indicate an obvious issue.

Is there an electrical component directly related or should I pull the whole wiring harness and check the whole thing over? It's very frustrating to say the least and I'm grateful to any help anyone might provide.

This bike sat off of the road since late 1985 with barely 3000 miles on it in a horse barn. I picked it up 3 years ago and it was rough from sitting. I took it all the way down to the frame and put it back together. I've done the 28mm Keihin setup, vforce 4 reeeds, and old school toomeys. There were a few spots in the wiring harness that were questionable but I repaired them before reassembling the bike. I've put less than 1,000 miles on it since.

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RZed
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Re: 84 RZ 350 No more power from my battery bike still start

#2 Post by RZed » Tue May 29, 2018 12:51 am

I'm not sure what the issue is. But if you're concerned about the wiring harness, I replaced mine with one of these reproduction wiring harnesses from Economy Cycle. https://www.economycycle.com/shop/yamah ... n-harness/
I think it is money well spent as it was a pretty easy install. Just take your time and pre-label the connectors to make it easier. I ended up redoing my whole electrical system because of a bad stator. Now I have the peace of mind that all the wiring is good to go for another 30 years!! :smt023

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Charlie
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hondaror
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Re: 84 RZ 350 No more power from my battery bike still start

#3 Post by hondaror » Tue May 29, 2018 2:03 am

Sounds to me like a ground issue.
Rory
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kjellz
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Re: 84 RZ 350 No more power from my battery bike still start

#4 Post by kjellz » Tue May 29, 2018 12:32 pm

Agree with Rory here.
Also could be a bad connection between rectifier output and battery. Ignition runs off its own circuit and is thus independant of the battery and charging system.
Check all ground points and if any wires near the stearing bend area is bad. Measure batt voltage, then start and see if charging raises voltage at battery when revving. Should be 13.5+ and indicates reg = ok. Measure dc putput at regulator. If way high it means regulator has bad connections and are unable to "dump" excess charge current. Check terminals for health at ignition switch too.

Good luck.
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RD350 YPVS 1990
F2 converted to N2 Red/white 1986 - Figaroli pipes

motoman353
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Re: 84 RZ 350 No more power from my battery bike still start

#5 Post by motoman353 » Tue May 29, 2018 1:44 pm

Thank you to everyone for the suggestions. As I've said I didn't see any failed connections or loose grounds but it does present like a grounding issue. Before I go pulling the harness I'll look over the grounds again and then check the components kjellz suggested. I come from a motocross background so the electronics there are minimal in comparison. Hopefully I find some answers.

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Re: 84 RZ 350 No more power from my battery bike still start

#6 Post by kjellz » Tue May 29, 2018 2:32 pm

If you report back your findings, there will be even more to go on and perhaps more tips to follow up.

By the way, you did mention the headlight fuse failed! -That actually points to short circuit somewhere, unless the unlikely even occurred that the failing bulb caused this. Is that cleared out as possible fault?

Tried moving the steering from side to side when checking headlights and charging voltage?

Or try runing things with head lights off and simply see if problems comes and goes with using headlight, or with or without battery etc.


Cheers
Kjell
----------------------------------
RD350 YPVS 1990
F2 converted to N2 Red/white 1986 - Figaroli pipes

MK
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Re: 84 RZ 350 No more power from my battery bike still start

#7 Post by MK » Tue May 29, 2018 3:49 pm

Usually the fuse box is pretty rotten and fuses have bad contact.

Start measuring voltage against ground at the regulator output (red).
Then check fuse in and out. If that all has about the same voltage than the battery plus side, check other locations with that method.

What you look for is spots that show significant voltage drop along the supply line.

Btw: I assume you checked the fuses BEFORE you take any other measures.
Bye
Martin

motoman353
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Re: 84 RZ 350 No more power from my battery bike still start

#8 Post by motoman353 » Tue May 29, 2018 10:23 pm

I checked all of the fuses before I started any of this. I've shook the bike and turned the bars to the stops in each direction to no avail. Unfortunately I just seem to have come down with some nasty cold so the bike will sit for a few days until I feel well enough to do some of the test suggested above. I'm sincerely greatful for all of the suggestions and I will definitely report back with my findings

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kpke
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Re: 84 RZ 350 No more power from my battery bike still start

#9 Post by kpke » Wed May 30, 2018 11:06 am

Smart suggestions up there. Keep at it and it will rear its ugly head.

The fuse block can be a big problem. I have swapped out 4 of the factory fuse blocks for automotive type.

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Re: 84 RZ 350 No more power from my battery bike still start

#10 Post by MK » Wed May 30, 2018 1:06 pm

Almost forgot it: First check with such issues is

- resistance on the stator white against white and against ground.
Each of the 3 white wires should show a low value (0.3 ... 0.6 Ohm) against white and no connection against ground.
- rev the engine to 4500 rpm and measure DC voltage at the battery poles. That should be 14.5 V. If its significantly higher, the regulator is blown. If it's much lower it'll point to the stator.
A cross check would be to measure AC voltage at the poles. It should show a low value of 0.05 - 0.15 V AC. If it's much more you have another clue for a blown regulator.
Bye
Martin

motoman353
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Re: 84 RZ 350 No more power from my battery bike still start

#11 Post by motoman353 » Wed May 30, 2018 11:49 pm

KPKE,

What automotive fuse box are you using there? I've looked ar some but they're all seemingly to high to fit under the seat especially with the cover on.

MK thanks for more suggestions. This cold is pissing me off because I can't get put to the garage to check the suggestions provided by everyone here.

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kpke
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Re: 84 RZ 350 No more power from my battery bike still start

#12 Post by kpke » Thu May 31, 2018 11:04 am

I believe that fuse block came from O'Reilly's (auto parts store). Less than $10 I'm sure.

It is waterproof, not that that matters to me, with an O ring in the lid.

motoman353
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Re: 84 RZ 350 No more power from my battery bike still start

#13 Post by motoman353 » Fri Jun 01, 2018 10:20 am

I had about 2 minutes worth of energy yesterday and I checked voltage at the main fuse, with the bike off, and had only 9.5 volts on either side and as soon as the key is switched on the voltage goes to zero. The battery is a steady 12.75 with nothing running. I'm hopeful to feel well enough to really get into it this weekend. What would cause voltage loss like that at the fuse block?

motoman353
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Re: 84 RZ 350 No more power from my battery bike still start

#14 Post by motoman353 » Fri Jun 01, 2018 9:32 pm

I ran through a series of tests this evening, from everyone's suggestions, and after completing several and still scratching my head I found the culprit. I went from regulator to rectifier to stator and back and it was a simple broken connector in the old fuse box. The lost voltage was somehow coincidental which led me astray... I'm simultaneously happy and angry that something that pathetic eluded me when I'm capable of much more complex work. Oh well at least it's an easy fix

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Evans Ward
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Re: 84 RZ 350 No more power from my battery bike still start

#15 Post by Evans Ward » Fri Jun 01, 2018 9:41 pm

Glad you found it! May want to consider the automotive fuse box upgrade with soldered connectors- good preventative maintainence!
84 RZ350-Toomeys,SCR milled head, stk 26 carbs,300 M, 35 P, stock regrooved needles AS 2.5 turns out,stk air box,Banshee reeds Zeel non-progr CDI,TSRL Program YPVS,alum rad,R6 shock,GV emulators w/RT springs,fork brace,Shindy steering damper.

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