Topic: CB750 Oil pump O Rings?

[Bailgang]

My bet is that the new shaft seal is causing the increased drag. I've rebuilt a couple of 750 oil pumps where I replaced that pesky shaft seal and both times the pumps were noticeably harder to turn when fully assembled even though the rotors were assembled in the same orientation as they were when I first took them apart. It wasn't notchy at all so I wasn't alarmed by it because I figured being that shaft seal was new and therefore sealing like it should was the cause of the drag and I haven't had any problems with either engine that the pumps were installed in. As Elan does point out there is an inconsistency on how the dots on the rotors face, the oil pump on my sons 73 750 had it's dots facing out while the pump on my F2 had one dot facing out and the other in.   

[Big Bob]

Disassembled the pump again. Checked out each part as it came off. Nothing odd aside from the fact that the dowels on the shaft are now magnetized. Had to use a magnetic pickup tool to grab them because I've got fingers the size of bratwurst.

Tried inserting the shaft through the seal without any other parts attached. Yeah, definitely some drag there. I'm thinking the tighter seal may be the culprit.

Reassemble again. And now the shaft won't turn at all. 10:13am here in Chicago. Is that too early to start drinking?

[mystic_1]

Is the new seal maybe sitting proud in the casting and therefore binding up when you put the side plates on?

mystic_1

[PeWe]

Inspiration before doing the CB750 oil pump
http://hackaweek.com/hacks/?p=1656

[Big Bob]

I solved the problem by using exceptional care when installing the three screws that hold the covers in place. Got to make sure you use an even amount of force. I was tightening them 1/8 turn at a time. Works fine now.

No, I didn't monster one screw in and then do the other two.

[edwardmorris]

Anyone here that have completed a Super kit restore,  documented it with photos and tools needed to make achive a successful result?

This would be very cool..

+1
I successfully replaced that inner seal on my kids K3 a few years ago but I think I got lucky more than anything else, there has got to be a better way.

Sorry I missed this earlier, the first time around I had the shop remove it, but for my current build, I followed the method described by Mark/Hondaman with trivial mods as I saw fit. Worked well, but I was too lazy to document it. But, Ron did!

http://forums.sohc4.net/index.php/topic,36459.msg1681203.html#msg1681203

[IVPeters]

Long-time SOHC forum lurker, first time poster - Just went through the oil pump from my 750 K7 engine and thought I'd share how I removed the pesky shaft seal with relative ease.

After scraping out the rubber leaving just the steel base, I Used a dremel high-speed cutter bit (I believe it's 199 to be exact) and made a groove in the inner wall of the steel - being careful not to cut through it completely, this was the most tedious part.
Then, using a blind bearing puller (the one I have has heads for 11mm ID min. to 32mm ID max. - I used the smallest head, fit perfect) I set the fingers of the puller head in the new groove, heated the pump body for a little thermal expansion and with a few slides it extracted cleanly.
All the pics I have are from after I got it out as I wasn't sure if it was going to work while I was doing it 

[espressokiller]

Hey Elan, I tried looking for your kit but couldn't find a working link. Are you able to send me a link so I can purchase a kit with a stopper and spring as well?

Cheers!

[70CB750]

Search for him under members and send him personal message. 

Hey Elan, I tried looking for your kit but couldn't find a working link. Are you able to send me a link so I can purchase a kit with a stopper and spring as well?

Cheers!

[NobleHops]

Lil' help for member Elan: I've installed two of his kits in the past 2 months, they are excellent, and a great value.

Here's a link to his eBay store: http://stores.ebay.com/Vital-Motor-Parts?_trksid=p2047675.l2563

If for whatever reason that link goes stale, just search eBay for "550 oil pump" and scroll down if needed and you will see kits by "Vital Motor Parts".

[PeWe]

I ordered my first set via this forum, 2:nd on eBay getting everything in a neat paper package. I guessed it was Elan.
I ordered the Oil pressure switch and oil pump strainer (mesh) too. Good shipping which affect the total.

[Elan]

Thanks all! I've not been able to make it onto the forum like I used to. New house with reno's and two kids under 4 will do that haha.  I'm now taking all orders through the link NobleHops posted (thanks!). I've hired my wife to take care of the order packaging- That's why they are more organized and on time now

Vital Motor Parts is now a Legit company (again, many thanks to my wife!) and we have more products on the horizon.  We're no Partzilla, but I truly love bringing back the hard to find/discontinued stuff for our bikes. We all have limited time and its best spent in the garage or on the road- not on google

 I do get your PM's as well, so never hesitate to reach out.

Thanks,

Elan

[NobleHops]

Thanks all! I've not been able to make it onto the forum like I used to. New house with reno's and two kids under 4 will do that haha.  I'm now taking all orders through the link NobleHops posted (thanks!). I've hired my wife to take care of the order packaging- That's why they are more organized and on time now

Vital Motor Parts is now a Legit company (again, many thanks to my wife!) and we have more products on the horizon.  We're no Partzilla, but I truly love bringing back the hard to find/discontinued stuff for our bikes. We all have limited time and its best spent in the garage or on the road- not on google

 I do get your PM's as well, so never hesitate to reach out.

Thanks,

Elan

Totally my pleasure. You and the other vendors that reproduce this stuff provide a super valuable service, and your products are a great value to boot.

Keep on rockin'!

Nils Menten

[PeWe]

Very convenient to get everything needed served on a silver tray...by paper.... good price and best shipping to Europe as well.

[Hotwheelbill]

I already have my rebuilt oil pump from CycleX, but it did not include the four outer O rings. Will these work?

https://www.amazon.com/dp/B005RUSK28/ref=biss_dp_t_asn