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Author Topic: 1975 RV90(M) - oiling and electrical system questions  (Read 513 times)

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Offline Bacdef

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1975 RV90(M) - oiling and electrical system questions
« on: June 26, 2017, 11:25:51 AM »
Hello all

This is my first post here, I hope you are all well.

I am in the process of bringing a 1975 RV90(M) out of retirement and putting it back on the roads/fields/beaches/trails/rooftops.  I do not intend to go full-scale complete teardown restoration here; my intent is to get it running, ride it in the summer and progressively clean up and fix everything in the winter as the years go by.  I got it in 2009  in  a kind-of-runs state and promptly stashed it because of a lack of free time.  Now is the time of the unstashing.  The bike looks to be mostly unmodified and rather complete.  I am currently missing one OEM mirror and, of course, the air pump.  Cracked plastics (fender and frame cover) will need to be taken care of but in general it looks pretty good under the accumulated dirt and goop.  Someone in the past was not careful filling up with 2-stroke oil and the area around and below the oil tank is caked with oily accumulated dirt, including the wiring harness, bleh.

I was able to get one test ride out of it before parking it and I remember it was very hard to start, seemed to have low power and would not idle without full choke.
 2ST oil was leaking from the bike the whole time it was parked.   This week I took off the left covers, flywheel and stator and found a loose banjo bolt near the left crank bearing as well as a bad crank oil seal.  This explains the leaking oil and possibly the hard start/low power I experienced when I test rode.  I have a new oil seal ready to install and the banjo bolts have been tightened.

First question :  when I removed the crank seal some 2ST oil poured out, say half a teaspoon.  That event, plus the fact it has been leaking while parked indicates there seems to be a constant trickle of oil from the tank to the bearing.  Of course if I kick the engine over a few times oil appears at the bearing as this actuates the pump but is it normal for the lube system on the RV90 to be 'constant-drip' even when the bike is inactive or should I look for a problem with the oiling system ?

Second question is electrical.  My 1975(M) seems to have a slightly different electrical system than those referenced in the various wiring diagrams I can find on the internet.  The system features three coils on the stator (2 lighting, 1 ignition), an actual voltage regulator and a two position ignition switch (ON and OFF compared to OFF-DAY-NIGHT).  The system features and always-on headlamp and that might be due to Canadian legislation. Wires coming from the coils are Yellow, Yellow/Red and Black (no green).  Has anyone here seen a wiring diagram for this system ?  I've found similar alternator arrangements on German wiring diagrams for the RV90 but they all feature the three position switch.

Attached is a pic of the partly disassembled RV currently in a secret underground location.
Thanks for reading!

Offline Bacdef

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Re: 1975 RV90(M) - oiling and electrical system questions
« Reply #1 on: June 28, 2017, 11:25:59 AM »
Hello again !
I have some good news to report regarding the wiring diagram.  A gentleman posted elsewhere the diagram for the 1977 RV90(B) and after a quick check against my 75 it looks like I have a match!  I can confirm that the diagram, like my bike, features three coils at the stator and a two position ignition switch.  I have yet to crack the headlamp open but I was able to quickly compare the diagram with the easily accessible components and so far the color code matches at the alternator, battery, rectifier, ReGuLaToR, turn signal relay, horn and all rear lamps.  Diagram has an extra, unconnected, G/W wire from the alternator absent on my bike.

Looking at the diagram it looks like one coil services ignition, one is regulated and feeds the headlamp and instrument lighting with AC and the last one is on battery duty.  The battery looks to be there to ensure the tail/brake lamps and flashers stay usable at low RPM.

Diagram is attached to this post in case someone needs it.  Looks to be applicable at least on the 75,76,77 RV90 sold on the North-American market.
File is a low-resolution JPG but is usable once printed on a US Letter sheet if you squint hard enough.

Still in the dark regarding the constant oil flow from the CCI if anyone knows about that.

Offline Old Okie

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Re: 1975 RV90(M) - oiling and electrical system questions
« Reply #2 on: July 12, 2017, 08:35:16 AM »
Sounds like you are making progress. These bikes are fun bikes, my grandson rides it everyday.
We got it at a garage sale for $50.00. The head gasket was blown and the rear brake was worn out.
The front brake was probably never used. The bike is complete with all parts and a split front fender.
Ours is a '72 model and starts on first kick nearly every time.

Good luck on your project and keep posting your progress so we can all enjoy your bike.
An old guy with a motorcycle habit.
Currently have several big bikes and a Suzuki RV90.

Offline Bacdef

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Re: 1975 RV90(M) - oiling and electrical system questions
« Reply #3 on: July 12, 2017, 11:35:56 AM »
Thank you for your interest Old Okie.

I might start a thread in the projects section where progress could be reported, although I would need to take a lot more pictures to support that.  Right now I am still disassembling, bagging and tagging.  Still mulling how far I will go with this.  I intend for the bike to be a runner so a 'show and shine' restoration is out of the question.  I am aiming for a stock look with all original parts but I will be keeping most dings and major scratches with adequate repairs made as long as the parts are serviceable.

As she stands now the seat, bodywork, left cover, instruments, battery box and all electrics are off.  Here is a fresh pic.

The question about the oiling system's trickle flow to the bearing is stil open if anyone knows.

Offline Acolytus

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Re: 1975 RV90(M) - oiling and electrical system questions
« Reply #4 on: July 20, 2017, 02:27:23 PM »
I do believe the oil system is supposed to have a constant drip to ensure that the engine keeps getting oil, even when inactive. Would not be a bad idea to check for any oil leaks and also check the oil pump to see if it still works. You don't want to risk running the bike with an oil injection system that does not work.

I have always thought the RV90s were cool. Nice bike and good look with the project!
'77 Honda XL75; '80 Honda XL125 (w/ 200cc motor); '85 Honda XR80R

'75 Kawasaki MC1-M Cafe Racer; '79 Kawasaki KE100

'70 Suzuki A50 Maverick; '74 Suzuki TS125; '95 Suzuki RM80

'72 Yamaha RT2; '74 Yamaha GT80; '74 Yamaha DT175; '75 Yamaha DT100; '75 Yamaha DT400; '81 Yamaha XT250

Offline Bacdef

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Re: 1975 RV90(M) - oiling and electrical system questions
« Reply #5 on: July 25, 2017, 09:11:33 AM »
Thank you for your comment Acolytus.

I'm beginning to think some pump flow-by at rest might be normal, be it by design or not.  I was concerned a bit because the bike has been sitting for years and I was thinking since there is no seal between the bearing and bottom-end that oil might have pooled at the bottom of the engine, reducing the internal volume.  I was afraid of hydro-lock or blowing a crank shaft seal off if I tried to turn the engine over but then I remembered since my magneto crank seal was bad and the bike was leaned to the magneto side on the kick stand it actually LEAKED all that oil instead of pooling it, which was not that much in the end.  First start, whenever that occurs, will use mixed gas as an added safety measure until I can confirm the pump operates as it should but I did see oil at the bearing from kicking it over when the seal was off so it looks promising.

The way things are right now I can set aside about 2 hours per week to fiddle with the RV so progress is super slow, but I'll see this through.  This week's highlight:  a compression test, done on a cold engine,  showing 150 PSI after 4 good kicks.  Not the most telling of tests but again, allows me to be somewhat optimistic regarding the general condition of the top-end at least.

I'm going to start taking more pics so I can create a project thread, probably when winter comes along, so I can tell the story in a more timely manner instead of posting once every other week to report the removal of a single component.