Fuel Tank

RZ-RD-RZV.... and everything in between

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silverstrom
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Fuel Tank

#1 Post by silverstrom » Thu Nov 06, 2014 10:17 pm

Why do some fuel tanks have vents on the bottom? I've only seen this on some RD500 tanks. I've seen several on eBay Germany in the past and just noticed that an RD500 tank I have here has a vent on the bottom. It is identical to the RZ500 tanks I have here other than that vent on the underside.

Twinsport
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Re: Fuel Tank

#2 Post by Twinsport » Fri Nov 07, 2014 3:37 am

Hi,

I have only seen the tanks without vents. Can you post a picture of how it looks?

/Steen
If I had a signature, it would be good.

silverstrom
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Re: Fuel Tank

#3 Post by silverstrom » Fri Nov 07, 2014 9:12 pm

This is the RD tank I have. I'll get a pic of the bottom of showing the vent tomorrow.

On the bottom of some tanks there is a round flat spot. On some tanks there is a threaded boss there with one way vent valve attached.

I've seen it on a few tanks, but all German RD500 tanks and never anywhere else. I'm wondering if it was perhaps a German TUV requirement late in the production run.

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Speed Freak
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Re: Fuel Tank

#4 Post by Speed Freak » Sat Nov 08, 2014 5:23 am

I checked the parts manual, but there is no special German version for the 85 1GE.
Just some modifications like different headlight lense, some reflectors, sidestand modifications etc. for Austria, Sweden, Denmark...

If you show me the picture i can check my 2 fuel tanks, one should be the standard european 1GE, the second one is an Austrian version.
My bikes:
RD500 YPVS 1GE
RD350 YPVS 31K 1985
Honda CBR 1000 RR SC57
Yamaha R1 RN04

silverstrom
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Re: Fuel Tank

#5 Post by silverstrom » Sat Nov 08, 2014 7:11 pm

Ok, here are 2 tanks side by side. The red/white is an RD500LC tank from Germany. The dark one is an RZ500 tank from Canada.

From here they look identical

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Image

From the bottom they look the same as well, but if you look closely you'll see the vent valve and also a small white vertical post near it. You can see the valve resting against the post. That post is about 2 cm long and I have no idea why it would be there. It is a factory application.

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Image
Image

The tanks are different inside as well. On the dark RZ tank you can see there is a baffle/support about 4 inches wide with a hole cut in it. On the Rd tank all you see is a narrow vertical beam. Also, the internal collar around the opening of the RD tank is only half as long as it is on the RZ tank.

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When you see the bottom of the tank you'll also notice there is a flat round area on the RD tank where the valve is located. The RZ tank doesn't have this. I found another RD500 tank online and it has that round area, but no valve.

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So, there you have it. Why are the tanks different? I measured them and they are identical in all directions. Why are the internal supports different? Why do some tanks have the round spot on the bottom but others don't? Why do some have vent valves and some don't? I've only ever seen 2 tanks with the valves and both were German. The red and white one I bought, the other was Faraway Blue and that was only a few months ago. Why does mine have a valve? Pre-production? Or perhaps a tank sold by Yamaha as a replacement many years later? How about a tank with a higher purpose in life? Whatever the case, the valve is definitely a factory fitment.

Perhaps out anorak Steve has the answer?

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kpke
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Re: Fuel Tank

#6 Post by kpke » Sun Nov 09, 2014 12:02 pm

This may be of no value but...

The fuel tank on the RZ350 85 1/2 NCII Kommifornia only model has what I think is that same fitting.

It connects to the carbon canister here via rubber hose

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It is California only smog equipment.

I did not take any pics of the fitting on the tank. It is still there on my bike. I believe the bike also has a "special" CA only fuel cap with "special" venting. It's possible your tank may require a special fuel cap???

It's hard to believe your 500 tank would have the same story. Perhaps one of our super smart CA politicians move to Germany when they were designing their RD500 and wised them up on global warming. To save the planet "You must install this useless plastic piece of sh!t on your gas tank or the polar ice caps will melt down thus killing all the polar bears and..."
Ken's Garage YouTube Channel :smt023
https://www.youtube.com/c/KensGarage1

1985 RZ500 (R6 suspension & body work)

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Speed Freak
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Re: Fuel Tank

#7 Post by Speed Freak » Sun Nov 09, 2014 1:20 pm

I know that Switzerland often used "special" models compared to the rest of europe.
As example, my NSR125 was restricted to 11hp and there were a lot of other funny things in it.
I also know from the bandit 600 that the models from end of the 90`s had some emission control stuff in it - german models not.

Austria also used this "Swiss only" models.
My bikes:
RD500 YPVS 1GE
RD350 YPVS 31K 1985
Honda CBR 1000 RR SC57
Yamaha R1 RN04

silverstrom
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Re: Fuel Tank

#8 Post by silverstrom » Sun Nov 09, 2014 4:09 pm

None of the fiches show a vent valve for any country. That doesn't mean some countries don't require the valve. It could just be that Yamaha doesn't show it. Whatever the case, it isn't a common occurrence as I've only seen a couple and most haven't seen any. There were enough bikes sold in Europe that you would think this type of take would show up at least occasionally if the valve was a specific requirement. If it is pollution related, we should have at least seen more about that side of it at some point.

It isn't just matter of sticking a valve in a tank. The tanks are physically different. Why are the internal supports different? Why do we see at least 3 different tank bottoms?

Not important, but given all that we know about these bikes after 30 years I find it interesting when something new comes along.

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Speed Freak
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Re: Fuel Tank

#9 Post by Speed Freak » Sun Nov 09, 2014 5:52 pm

Checked both they have no valve, but the flat round area is pressed into the bottom of the tank.

Both bikes sold in Austria, both registered in 1988 (but i think built in 1985).
First one has no special parts, just standard european bike (frame number 1GE...~1600)
Second one is an Austrian bike with all reflectors etc. (frame number 1GE...~3500)
My bikes:
RD500 YPVS 1GE
RD350 YPVS 31K 1985
Honda CBR 1000 RR SC57
Yamaha R1 RN04

silverstrom
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Re: Fuel Tank

#10 Post by silverstrom » Sun Nov 09, 2014 10:26 pm

Hopefully we'll hear from more people. I'm really curious about it now.

Twinsport
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Re: Fuel Tank

#11 Post by Twinsport » Mon Nov 10, 2014 4:14 am

Checked my two tanks. One German and one Danish. No valves, but both have the round spot..

God knows where the "Danish" bikes were meant to be sold. Since only 8 bikes were sold here, we surely do not have any special models for our little market..

/Steen
If I had a signature, it would be good.

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Speed Freak
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Re: Fuel Tank

#12 Post by Speed Freak » Mon Nov 10, 2014 10:00 am

I think there was something in the 85 1GE parts manual about "Denmark only" parts.
I can check at home :grin:
My bikes:
RD500 YPVS 1GE
RD350 YPVS 31K 1985
Honda CBR 1000 RR SC57
Yamaha R1 RN04

silverstrom
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Re: Fuel Tank

#13 Post by silverstrom » Mon Nov 10, 2014 11:57 am

Sweden, Norway, Finland, Denmark, Austria.....I've checked them all and it doesn't show it.

Denmark shows just side stand and headlight changes.

It just occurred to me that I've been to all of those countries....Lol

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Re: Fuel Tank

#14 Post by jackson.40 » Mon Nov 10, 2014 1:00 pm

silverstrom wrote

Perhaps out anorak Steve has the answer?





Are you ready for the answer now? :grin:

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Speed Freak
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Re: Fuel Tank

#15 Post by Speed Freak » Mon Nov 10, 2014 3:11 pm

Image

:smile:
My bikes:
RD500 YPVS 1GE
RD350 YPVS 31K 1985
Honda CBR 1000 RR SC57
Yamaha R1 RN04

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