Autolube pump not pumping evenly between sides

[ElFuegoBlanco]

My RD400 autolube pump isn't acting the way I think it should. The right-side is barely putting out any oil. I mean barely barely. In fact, it wasn't enough output to push through the tube. I had to manually fill the tube for it to put out any oil at all. Left side seems fine.

It was much better last time I looked at it, when I installed it and bled it. I hoed it again but it didn't make any difference. I also rechecked the gap and increased it .1mm to be on the higher side. I don't know it that's the right direction to get more oil or not.

Any suggestions?

[Arrow]

Ok, so what is the gap set to now?

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[ElFuegoBlanco]

Ok, so what is the gap set to now?

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.25mm

[Arrow]

Some history as well please. Has the pump recently been rebuilt/taken apart, or not?

When you say the right hand side I'm presuming you mean the right outlet and not the top outlet. It matters not which outlet supplies which cylinder, but it does for diagnostic purposes. So its best to keep the plumbing as in the parts book, ie top outlet to left cylinder.

If the pump is drawing just a tiny bit of air in via any of the seals, it will show up first on the side (right) outlet, and obviously not pump any oil to that side. It also doesn't necessarily mean that you will see a leak anywhere.

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[Arrow]

Ok, so what is the gap set to now?

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.25mm

Good job you increased it by 0.1mm as that's on top end of standard now.

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[ElFuegoBlanco]

Some history as well please. Has the pump recently been rebuilt/taken apart, or not?

When you say the right hand side I'm presuming you mean the right outlet and not the top outlet. It matters not which outlet supplies which cylinder, but it does for diagnostic purposes. So its best to keep the plumbing as in the parts book, ie top outlet to left cylinder.

If the pump is drawing just a tiny bit of air in via any of the seals, it will show up first on the side (right) outlet, and obviously not pump any oil to that side. It also doesn't necessarily mean that you will see a leak anywhere.

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76 RD400 barn find. actually, the "parts bike" for a 76 with 150 miles on it. So basically, it sat in storage for the last 30something years. Maybe 40.

It hasn't been rebuilt to my knowledge. When I got it, the pump was on the bike but covered in a plastic bag. Unfortunately, I don't have any more history on it.

Yep, I mean the outside, not the top.

Ive seen there are services that do rebuild work. Is there anything that can be done in the home garage? I'll tighten it down, is there anything else that can be done for air issues?



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[Striker1423]

Outer seal replacement is possible with the kit from HVC, but it's highly recommended to use Yamaha seals. And in the winter, send it over to the UK for Arrow to rebuild it. :)

[ElFuegoBlanco]

Outer seal replacement is possible with the kit from HVC, but it's highly recommended to use Yamaha seals. And in the winter, send it over to the UK for Arrow to rebuild it. :)

It just hit me that he's the one who sold me the plastic pump gear. Really did me a solid on that one.

[Arrow]

Anyone can put a pump together. If it's done properly, that's PROPERLY, then it will be most reliable, and work totally as Yamaha intended. It may well need some extra parts swapping out, as well as the standard stuff.

I guarantee all my pumps for twenty years. If you want me to do it just let me know. I'll put you in the book and you can send it later on. Expected delivery December or January (I've caught up a lot).

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[ElFuegoBlanco]

Running premix to take this video. I'm guessing there should be more oil movement, but this is my first 2T.

https://imgur.com/a/2f6Um7E

https://imgur.com/a/EUyzmUG

Also, it looks like I was wrong about the 2 outlets being uneven. They appear to be the same.

Any insight would be greatly appreciated

Rob

[Striker1423]

It looks fine at idle. To speed up the process, hold the pump cam down to make the pump run at full stroke. You can also increase the idle a bit to achieve a faster rate. Make sure all the air is out of the lines and hook those suckers into the carb nozzles and rip it.

[Arrow]

That doesn't look too bad to me. Don't forget the bore size of that clear pipe compared to the 0.7mm (or so) oil exit hole drilled in the carb. The flow through the latter is much more under control.

Can you repeat the video, this time hold the pulley right down towards the main body of the pump so it's on maximum stroke.
And also include the pump stroking in the shot, as the first video.

Also, each line will only shift some 0.55cc for 200 turns of that wheel on the back of the pump (when its at minimum stroke). Check for this. At maximum stroke the spec. is 5.5cc. Both those values are in the middle of the spec. range.

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[NYSingh]

FYI there's a 'how to' on testing the autolube pump on the forum:  http://www.2strokeworld.net/forum/index.php?topic=1119.0

[ElFuegoBlanco]

That doesn't look too bad to me. Don't forget the bore size of that clear pipe compared to the 0.7mm (or so) oil exit hole drilled in the carb. The flow through the latter is much more under control.

Can you repeat the video, this time hold the pulley right down towards the main body of the pump so it's on maximum stroke.
And also include the pump stroking in the shot, as the first video.

Also, each line will only shift some 0.55cc for 200 turns of that wheel on the back of the pump (when its at minimum stroke). Check for this. At maximum stroke the spec. is 5.5cc. Both those values are in the middle of the spec. range.

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https://imgur.com/a/saA1ISL

[Arrow]

Looks good, but I didn't want you to turn the pulley, just hold it right down, (same thing).

I wanted to check something else and turning the pulley blocked my view!

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