RD350 Oil Pump Question

[captainslow]

Hi,

Great forum and a wealth of knowledge and experience on 2 strokes here. Thanks for allowing me to post.

I am trying rebuild an oil pump that I got for my RD350. This is my first attempt, so please go easy on me.  After disassembling and cleaning up the pump and parts, during assembly I ran into a few questions.

1. I see that I have only one tiny spring for the 2 pins that go into either side of the gear. I assume I would need one spring for each of the pin. Is this correct? If so any idea where I can source one?



2. The pump also appears to be missing a pin (inserting picture of a pump found from eBay with the pin). I assume I need it. Where can I source this one from? Cannot find it on any parts list so don't know what to look or ask for?



3. I see this cover (402-13146-00) on some pumps listed for sale but mine didn't come with one. Do I need one? What is its purpose? And why do the pumps have it but I cannot find it on an exploded diagram on partzilla or elsewhere?



TIA
cheers

[so-cal-sdr200]

socal250 or Arrow to the yellow phone.....
 Finding the exact spring might be a problem.
 The roll pin, when you can find the diameter/length
 could be found at McMaster-Carr.
 I'll defer to the real experts here for more info.
 Cheers, Jeff

[1976RD400C]

Springs are available at Economy, Yambits and HVC, roll pin is a 3mm, I've never seen that cover piece on RDs.

[m in sc]

i have, the later ones had that cover. is it nec? no.

[RDnuTZ]

I believe the cover piece is supposed to keep the cable from coming out of the groove in the pulley.

[m in sc]

goes under the nut to keep the split pin from backing out.
ive run them with and without

hvc has a good pic of a pump w one on his site:

[captainslow]

Thanks for all the info.

1. If I understood correctly, I need 2 of the tiny springs? I can look up economy/hvc for it.
2. Can the pump be operated without the roll pin? This disassembly video shows that it is a screw type pin?

https://youtu.be/rcF8Ztn5zMY?t=147


From this exploded picture of the autolube from HVC, I think I need

1. Adjust Pulley Guide
2. Pin Return Spring

https://hvccycle.net/oil-injection-pin-return-spring-hvc200103-4/#gallery-2

[SoCal250]

Yes there are 2 dowel pins in the distributor under the worm wheel gear. Each pin has a spring. Are you certain that the spring is not stuck down inside the bore? Sometimes this can occur after the pins are removed, the spring can get kind of 'glued' into its bore with old oil and varnish.

You need the following parts:

1) PIN, SPRING - Yamaha 91608-20010-00
Part is NLA from Yamaha so you'll need to source a NOS one or find one from a hardware supplier. Size is M2x10.
It's press-fit roll pin. I think the reason the one shown in the YT video is threaded is because he's likely working on a Rajdoot not a Yamaha. Vintage Yamahas do not use a threaded pin to retain the pulley.
https://www.ebay.com/sch/i.html?_nkw=yamaha++91608-20010&_sacat=0&_from=R40&_trksid=p4432023.m570.l1313

2) SPRING, COMPRESSION - Yamaha 90501-02016-00
It is NLA from Yamaha so you'll need to source an NOS one or get it from Economy Cycle or HVC
https://www.ebay.com/itm/133088410324
https://www.economycycle.com/shop/yamaha-rd250350400r5ds6ds7-parts/engine-related/oil-pump/oil-pump-worm-gear-pins/

When reassembling, make sure you have the worm wheel gear oriented in the correct direction. Otherwise the clutching function will not work for the manual priming wheel and the worm drive from the engine will tear apart the inside of the pump. I ran into this a couple years ago when I acquired an RD350 that was worked on by a "factory trained shop with 25 years of experience". They obviously didn't know what they were doing because they rebuilt the pump backwards. I was fortunate that Mark (m in sc) had a spare worm gear for me so I was able to rebuild it correctly.

Out of curiosity, how many teeth are on your worm wheel?

Also if you have a newer pump you'll need the worm drive bushing on the end of the shaft.
WASHER PLATE - Yamaha 90201-08624-00
These are still available from Yamaha, and Economy stocks them as well.
If you look down into the well where the shaft goes and you see a pressed-in bushing like this, then the part is not needed.

[Economy Cycle John]

The 400's have the threaded bolt instead of the roll pin.

[SoCal250]

The 400's have the threaded bolt instead of the roll pin.

You're correct, my oversight. It's been a while since I worked on a 400 pump, the last 7 to 8 I've done have all been 1970-75 units.

[captainslow]

Yes there are 2 dowel pins in the distributor under the worm wheel gear. Each pin has a spring. Are you certain that the spring is not stuck down inside the bore? Sometimes this can occur after the pins are removed, the spring can get kind of 'glued' into its bore with old oil and varnish.

You need the following parts:

1) PIN, SPRING - Yamaha 91608-20010-00
Part is NLA from Yamaha so you'll need to source a NOS one or find one from a hardware supplier. Size is M2x10.
It's press-fit roll pin. I think the reason the one shown in the YT video is threaded is because he's likely working on a Rajdoot not a Yamaha. Vintage Yamahas do not use a threaded pin to retain the pulley.
https://www.ebay.com/sch/i.html?_nkw=yamaha++91608-20010&_sacat=0&_from=R40&_trksid=p4432023.m570.l1313

2) SPRING, COMPRESSION - Yamaha 90501-02016-00
It is NLA from Yamaha so you'll need to source an NOS one or get it from Economy Cycle or HVC
https://www.ebay.com/itm/133088410324
https://www.economycycle.com/shop/yamaha-rd250350400r5ds6ds7-parts/engine-related/oil-pump/oil-pump-worm-gear-pins/

When reassembling, make sure you have the worm wheel gear oriented in the correct direction. Otherwise the clutching function will not work for the manual priming wheel and the worm drive from the engine will tear apart the inside of the pump. I ran into this a couple years ago when I acquired an RD350 that was worked on by a "factory trained shop with 25 years of experience". They obviously didn't know what they were doing because they rebuilt the pump backwards. I was fortunate that Mark (m in sc) had a spare worm gear for me so I was able to rebuild it correctly.

Out of curiosity, how many teeth are on your worm wheel?

Also if you have a newer pump you'll need the worm drive bushing on the end of the shaft.
WASHER PLATE - Yamaha 90201-08624-00
These are still available from Yamaha, and Economy stocks them as well.
If you look down into the well where the shaft goes and you see a pressed-in bushing like this, then the part is not needed.

This is great info! Thank you!!!

If I may ask, how did you manage to find part numbers for items that are not listed in the parts catalogue?

Looking into the pump, the bushing is installed. So I don't need the washer plate. Thank you for this info.

[captainslow]

What is the recommendation on the hoses and clips? This is what my pump came with. I don't know what is the circle shaped thing at the of the pipe for? I assume they are inlets to push oil to the carbs but I cannot find them in the parts catalogue.

[m in sc]

thats a banjo bolt, and thats for an R5 or DS7

[m in sc]

question: do you have your original oul pump?

[captainslow]

question: do you have your original oul pump?

No I don't. I bought one off eBay and trying to rebuild it.