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 Post subject: Oil injection pump o-ring part number
PostPosted: Thu Apr 20, 2017 1:20 am 
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Joined: Sat Aug 04, 2012 2:01 am
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Location: Ventura, California
After reviewing the parts fiche, I have not been able to identify the oil injection pump o-ring that "seals" the pump when installed into the engine case. Can someone help me out with the correct part number for this o-ring or show me where on the fiche it is displayed?

http://www.rzrd500.com/500phpBB3/download/file.php?id=558

Thank you!


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 Post subject: Re: Oil injection pump o-ring part number
PostPosted: Thu Apr 20, 2017 3:10 am 
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There is no part number for the o ring :sad:

Steve


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 Post subject: Re: Oil injection pump o-ring part number
PostPosted: Thu Apr 20, 2017 8:07 am 
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I can try to find out the original size of this o-ring.
I think in the US it should be easy to get them in Japanese standard size.

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 Post subject: Re: Oil injection pump o-ring part number
PostPosted: Thu Apr 20, 2017 3:29 pm 
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Maybe JIS S20 (19,5x1,5mm), it`s the closest match I can find in the Japanese standards.
But the dimension of the groove doesn`t really fit as the O-ring should be stretched ~10% in length around the inner groove diameter which is 19,45mm.

Something like 19x1,6mm should fit, material NBR70

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My bikes:
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Honda NS400R NC19
Honda CBR 1000 RR SC57
Yamaha R1 RN04


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 Post subject: Re: Oil injection pump o-ring part number
PostPosted: Thu Apr 20, 2017 9:32 pm 
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Location: Ventura, California
Ok, good - I am not loosing my mind... nice to know the o-ring for the 2T pump doesn't exist in the fiche.

I will have a go with an online Google search for a 19mm x 1,6mm NBR o-ring. If anyone has a cross reference to a Yamaha part number or has replaced this o-ring with a Yamaha part number that worked correctly, please let me know.

Thanks to all who have contributed to this part search!!


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 Post subject: Re: Oil injection pump o-ring part number
PostPosted: Thu Apr 20, 2017 9:45 pm 
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I checked my RZ350 and TZR spares hoping to find an o-ring that would work, but no luck. I know I've seen something that will work, but just where is the question. Surely there is an o-ring used somewhere else that will fit.

There is this place in the US http://www.o-rings.com/

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1987 TZR250
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2014 Triumph Thruxton Modified
1979 Pontiac Trans Am with modified 1969 Olds 455 (7.5 L) 400++ HP, 500++ Ft/Lbs


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 Post subject: Re: Oil injection pump o-ring part number
PostPosted: Thu Apr 20, 2017 10:54 pm 
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I bought a CNC machined oil pump block off plate years ago, it came with an o-ring. I wish I could remember the vendor.

*edit*

Here we go.

http://www.ebay.com/itm/Yamaha-RZ500-bi ... 2d&vxp=mtr

Would this o-ring do the trick?

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 Post subject: Re: Oil injection pump o-ring part number
PostPosted: Fri Apr 21, 2017 12:42 am 
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It looks like that o-ring will only fit his block off plate. The pump o-ring is much thinner.

_________________
1985 RZ500
1985 RZ500 Project Bike
1986 RG500 ATR
1986 NS400R
1987 TZR250
1988 Honda RC31
2007 DL650 VStrom
2014 Triumph Thruxton Modified
1979 Pontiac Trans Am with modified 1969 Olds 455 (7.5 L) 400++ HP, 500++ Ft/Lbs


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 Post subject: Re: Oil injection pump o-ring part number
PostPosted: Fri Apr 21, 2017 5:47 am 
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I have measured the groove and calculated te size with the Trelleborg O-ring calculator (account requireed):
http://www.tss.trelleborg.com/at/de/ser ... lator.html

JIS S20 should work, but it`s not 100% according to the design standards I`m using.

I don`t have access to the JIS documents but from what I can find they want groove width 2,1mm and depth 1,2mm for 1,5mm cord diameter rings.

Dimensions on the part: outer diameter (housing) 22mm, inner diameter groove 19,4mm, width ~2,1-2,2mm
Width is ok, depth of the groove is 1,3mm which leads to too less compression of the ring according to standards (for static sealing).
For dynamic sealing (slow rotating shaft) it would fit as the compression needs to be lower as for static sealing.

Anyway... it would work as it doesn`t seal high pressures.


To come to a solution...
http://www.theoringstore.com/index.php? ... s_id=40316
You can buy 50 of them for the same price you pay for one Yamaha O-ring.

NBR70 (or Buna N70) is suitable for fuel (not ethanol) and oil.
70 Shore A is standard hardness.

_________________
My bikes:
RD500 YPVS 1GE
RD350 YPVS 31K 1985
Honda NS400R NC19
Honda CBR 1000 RR SC57
Yamaha R1 RN04


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 Post subject: Re: Oil injection pump o-ring part number
PostPosted: Fri Apr 21, 2017 12:59 pm 
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Location: Ventura, California
Agreed - I will order the 19,1mm x 1,6mm NBR70, as the JIS S20 size spec (19,5mm x 1,5mm) ID seems to be a bit large and the CS (cross section) too small. Thanks for the link and I will get one ordered for a trial fitting.


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 Post subject: Re: Oil injection pump o-ring part number
PostPosted: Fri Apr 21, 2017 7:35 pm 
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OK, I have ordered both the JIS S20 (19,5mm x 1,5mm - 22,5mm OD) and the 19,1mm x 1,6mm (22.3mm OD) NBR70 o-rings. After reading all the fantastic technical info at the Trelleborg web site that Speed Freak offered:

http://www.tss.trelleborg.com/at/de/service/desing_support/oringcalculator_1/O-ringcalculator.html

I think the size to use will be the JIS S20, but I will test fit both sizes. My reasoning is as follows:

1) I find it doubtful that Yamaha would design an o-ring application using a 'bastard size' vs a JIS size.

2) The way the case is machined vs the pump groove makes me lean toward the larger OD (22,5mm vs 22,3mm) of the JIS S20 o-ring.

3) The existing o-ring that I removed measures appoximately 19,4mm ID, 22.2mm OD with the CS (cross section) measuring 1,4mm squished between the pump and the case, with a CS spread (in the width of the ring grove of the pump) of 1,6mm - yes, this o-ring has been in an assembled state for over 32 years.

4) The way oil flows into the cavity to lubricate the pump shaft (driven off the kickstart idler gear), under the o-ring, pressurizes the o-ring from the "outside".

Keep in mind that I am not an engineer and other folks my see problems with my logic, but I am open for further discussion. A test fit may not demonstrate which of the two o-ring options is best and I imagine either one will work to properly seal the pump to the case.

Once I receive the two o-ring samples, I will report back any assembly differences if they are detectable. In the mean time, feel free to add to the discussion and thanks to all who have offered possible solutions, additional references and further ideas on the subject.

Thanks again everyone!


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 Post subject: Re: Oil injection pump o-ring part number
PostPosted: Fri Apr 21, 2017 8:03 pm 
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Hi the oring measured 22mm on the pump and 1.5mm thick.
Cheers.

Image


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 Post subject: Re: Oil injection pump o-ring part number
PostPosted: Sat Apr 22, 2017 4:44 am 
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The problem with measurements on old O-rings is that they shrink or grow over time.
Also inner/outer diameter will never be the same as new.

My measurements are:
~19,3mm inner diameter
1,5mm in radial direction
1,7mm in axial direction

The only JIS size in this range is the S20, It`s also my opinion that this is what we need.
But also keep in mind, this part was designed in ~1980, there is also a possibility that the JIS has changed.

I have measured all O-rings I have bought new - there are some "bastard size", nothing is impossible.
It`s quite easy to make a new mould for O-rings.
I have also compared new to old...

Reason why this O-ring is not available from Yamaha is that they get this complete part from Mikuni pre assembled.
Maybe its possible to get original parts for the pump directly from mikuni as the pump design is also used on a lot of other more modern bikes like Aprilia RS125, scooters etc.
http://www.ebay.at/itm/ROTAX122-123-APR ... SwAPlXgg~q


@Bengt Weil: The pressure topic for O-rings is more valid for axial sealing (ring is between 2 flanges).
With outside pressure you stretch the ring over the smaller groove diameter, with inside pressure you compress the ring with the outer groove diameter.
You just need to imagine what happens when the pressure goes inside the groove.
If there is inside pressure and the ring is stretched over the inside groove diameter it has to grow until it`s pressed to the outside diameter to seal => not good as there is a lot of movement in the O-ring then and it will fail over time.
But I guess in 99% of the cases it will not fail even if the design of the groove is wrong...

For radial sealing you stretch it over the inner dimension when the groove is in the inner part and you compress it by the outer diameter when the groove is in the housing.
Simple reason for that is the assembly proess, you have to avoid that the ring starts to twist in the groove and will not be squeezed between the 2 parts while pushing together both parts.

Always lubricate the parts during assembly with the fluid it should seal.
NBR O-rings: engine oil
EPDM O-rings (cooling system): DON`T use engine oil! As far as I know silicone oil/grease is what you sould use.
For Brake parts (might be SBR material) I`m using this one: http://www.pinzgauer-techshop.ch/daten% ... spaste.JPG

As you can see - to buy an "o-ring kit" is more or less useless because there are so much different materials.
I like to use Yamaha parts because I know they are the correct material.
Interesting info to this topic, but it`s german...
http://www.o-ring-prueflabor.de/de/fach ... -versagen/

_________________
My bikes:
RD500 YPVS 1GE
RD350 YPVS 31K 1985
Honda NS400R NC19
Honda CBR 1000 RR SC57
Yamaha R1 RN04


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 Post subject: Re: Oil injection pump o-ring part number
PostPosted: Sat Apr 22, 2017 1:32 pm 
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Location: Ventura, California
Good stuff - Thanks Speed Freak.

Hadn't thought about the JIS standards having possibly changed over the last 35 years... good point. As well, makes sense that the o-ring is not on the fiche as you point out, the complete pump is sourced (with the o-ring) from Mikuni.

When I receive the two different size NBR70 o-rings, I will definitely lube with motor oil (gearbox lube) for assembly and get a feel which size fits best, without twisting, excessive stretch/compression or assembly pressure.

Your last link -

http://www.o-ring-prueflabor.de/

does have a tiny British flag in the upper right corner for the english translation - I will give it a read.

Thanks again for sharing all your feedback and knowledge!


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 Post subject: Re: Oil injection pump o-ring part number
PostPosted: Sat Apr 29, 2017 2:52 pm 
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Location: Ventura, California
I received the 2 different replacement oil pump NBR70 o-rings for the 2T pump -

1) 19,5mm ID x 1,5mm CS x 22,5mm OD (JIS S20)
2) 19,1mm ID x 1,6mm CS x 22.3mm OD

After lubricating the o-rings with gear oil and doing a trial installation on the pump, the JIS S20 (1) o-ring had a good feel with some resistance (squish) while installing the pump while the other o-ring (2) felt a bit tighter going in, requiring a little bit more push, twist and finesse to insert the pump into the case, almost like the o-ring wanted to roll rather than slide into position.

I'm sure either one would work, but I think that I'll opt to use the JIS S20 (1) o-ring as the assembly pressure "had a good feel" vs feeling just a bit too tight. (Worse case, if it ever leaks, it isn't too difficult to remove the pump and switch o-rings).

Thanks again to all that shared their feedback - it's always welcome! If anyone has any additional advice, I am all ears...


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