Topic: 1978 CB750K — Post 836 OIL PRESSURE - not good

[SKTP]

So it turns out there were 2 tach seals jammed in there. The inner one has baked right on and I spent about an hours trying to pick it out with a dentist pick...still needs more picked out to seat the new seal...fun times!



If anybody has this picture of how it looks clean, that'd be very helpful

[RAFster122s]

If it were a 550 I would almost be tempted to pull the top cover so you could get better access and be able to use some cleaners without worry of them washing out lubrication and be able to pull the gear so you could get the seat % seal opening spotless.  Just don't dig a groove in the side of the aluminum to give the seal a weap area to escape through.
If the gear were out I would use a synthetic  very fine steel wool to scour the seal pocket or use a brass brush in a dremel...just keep the rpms down below 15k rpm. I don't think the beveled portion is going to be cleaned with the dremel or brass brush unless you reshape typical brass brushes with plastic handles to bent the end to have bristles that can reach the end/tip. A brass bottle brush could work too, BTW, unless you didn't know...using steel or stainless steel brushes aren't recommended on aluminum parts...small pieces of the wire can break off in the aluminum and later rust...they tend to be too hard on aluminum and cause scratches in the aluminum.  I don't know if that applies to steel wool or not. I believe it is not advisable to use steel wool on aluminum to clean it or attempt to polish it some/give it a brushed like finish.

[Bonz55]

I apologize if I missed it but would you mind sharing what type of wheels / tire set up you have on this? It's beautiful.

Thanks

[SKTP]

Thanks

Lester mags. 19" front 18" rear. Powder coated black. And I want to say Dunlop D404s.

[754]

Is the ring of the seal still in there.?. Not sure if you have the frame cut, be easier with cover off. If you scratch the shaft, it will keep leaking.  If you could get two picks in you can pull more evenly.
I made a fixture to drill hole in the seal , then insert sheet metal screw to pull it out.

[SKTP]

What's actually in there? It seems like there's a the rotating shaft with the slot (and driver the cable)....then is there a flat metal circle that also spins? Right now I am working on the premise that I need to pick out all the semi-hard caked on rubber bits from the grooves and that the groove on the new seal slot into those when clean...there's not enough rubber in tact to drill anything it's just caked into the grooves (if you look at the top picture...the one on the left is the part that pulled out...the remaining parts of it or stuck in the grooves..the other seal was on top of all that crud...

[754]

The part on the left looks to me like the rubber portion (and maybe the metal flange ) pulled off of the ring portion of the seal...which should look like the one on the right which appears. To be intact
 If the outer ring stayed in it will be hard to get out .
Right now does the cable fit in and the screw goes in easily?

[SKTP]

No...it is not fitting with the seal...I CAN jam it in and screw the retainer screw in...but it's not seating like the picture RESTORATION FAN posted on the top of the previous page.

There's no metal in the picture of the mashed up rubber....is there a metal piece that could come out? I seems liek the bottom of the hole has a metal "washer" type thing in there that can spin...is that the case? Id the an exploded diagram of the tach drive anywhere?

[madmtnmotors]

Just keep working at it. Looks like there might be some silicone down in there, and you might find that there were actually three seals jammed in there. These seals usually don't fit extraordinarily tight, and I often use a more generic type of pick that is sturdier than the dental type of pick:

http://www.harborfreight.com/4-piece-pick-and-hook-set-66836.html

Keep at it, it will eventually come out.

[SKTP]

thanks everyone....I like the looks of those picks...

I put the good Motul engine oil in yesterday...need to get this thing leak-free...dare to dream

[madmtnmotors]

I seems liek the bottom of the hole has a metal "washer" type thing in there that can spin...is that the case?

The recess for the seal is bored into the valve cover. When you get to the bottom of the hole you will have solid aluminum. The tach drive shaft is inserted from the inside through the small hole in the center of this bore. I will often use a light coat of Permatex Anerobic sealer around the outer edge of the seal itself just in case the bore that the seal rests in has been gouged:

https://www.amazon.com/Permatex-51813-Anaerobic-Gasket-Maker/dp/B0002UEONM

Most auto parts stores carry it.

[SKTP]

I seems liek the bottom of the hole has a metal "washer" type thing in there that can spin...is that the case?

The recess for the seal is bored into the valve cover. When you get to the bottom of the hole you will have solid aluminum. The tach drive shaft is inserted from the inside through the small hole in the center of this bore. I will often use a light coat of Permatex Anerobic sealer around the outer edge of the seal itself just in case the bore that the seal rests in has been gouged:

https://www.amazon.com/Permatex-51813-Anaerobic-Gasket-Maker/dp/B0002UEONM

Most auto parts stores carry it.

Thanks...I think there might be something else jammed in there. I am praying this is the cause of my leak and it is not also my head gasket...but it is most likely both...I will get this thing not leaking!!! One leak at a time...side note: it's really fun to drive!

[754]

Someone get a caiiper measurement of the depth for him...if seal is in when measuring deduct seal height from that.
 If part of the seal housing is still in there and does not spin freely, you may have to chisel it out, i can tell you how to do that.

[SKTP]

Will be picking out cooked on 40 year old Tach seal again this weekend...anybody have a depth reading for the tach-hole? Or a seal-less image of the hole?

thanks

bookmarking http://jwebsterdesigns.com/portfolio-post/oil-pressure-gauge-adapter/

http://www.marshallinstruments.com/catalog/shockproof.cfm

[MCRider]

Will be picking out cooked on 40 year old Tach seal again this weekend...anybody have a depth reading for the tach-hole? Or a seal-less image of the hole?

thanks

bookmarking http://jwebsterdesigns.com/portfolio-post/oil-pressure-gauge-adapter/

http://www.marshallinstruments.com/catalog/shockproof.cfm

I've got a couple of cam covers sans seals. I'll measure the hole depth, tonight or tomorrow.  I'll snap a pic also.

[SKTP]

THANK YOU MCRider!!! Greatly appreciated

[flybox1]

...or, measure the thickness of the new seal, and add to it the length of the speedo cable end that should fit into the valve cover mound, giving your total depth needed
justa thought 

[SKTP]

Been way too busy..finally took her out this weekend...it had been almost a month!?

Still need to finish picking out that tach-seal pretty and I'm pretty sure I have a minor head-gasket leak that I will fix (or maybe crappy pucks?)...need to get the motivation to pull that engine one more time....

Finally got her up to 80mph...still need time to trust her and get brave...

[SOHC4 Cafe Racer Fan]

Been way too busy..finally took her out this weekend...it had been almost a month!?

Still need to finish picking out that tach-seal pretty and I'm pretty sure I have a minor head-gasket leak that I will fix (or maybe crappy pucks?)...need to get the motivation to pull that engine one more time....

Finally got her up to 80mph...still need time to trust her and get brave...

I can relate.  I've barely been able to break in my new bike.

Don't be too gingerly though.  Run your bike with some load and don't be afraid of making some revs.  Let it cool and then repeat. 

[Restoration Fan]

It's been a while since we mounted the tach cable into Stella.  But I do remember this:  when it pushes in, there is a metal "lip" edge on the front the pushes down into the slot.  You have to get that to go far enough down into the hole that, when it touches bottom, the retaining screw that goes down through the case will fit behind that "lip" and hold it tight against the bottom of the hole.  If your's won't go that far in, I would get some of those picks and start digging until you only have solid metal at the bottom.

Too bad you're not near Georgia or I'd gladly meet up with you to try & help out.  Keep at it.  You'll get it.  And the result is oh so very worth it.

[USMC5811]

Been way too busy..finally took her out this weekend...it had been almost a month!?

Still need to finish picking out that tach-seal pretty and I'm pretty sure I have a minor head-gasket leak that I will fix (or maybe crappy pucks?)...need to get the motivation to pull that engine one more time....

Finally got her up to 80mph...still need time to trust her and get brave...

LOVE those pipes!


Sent from my iPhone using Tapatalk

[SKTP]

OK...3rd time is a charm

After the rebuild I am still leaking and unacceptable amount. I am going to switch to a cosmetic gasket.

http://www.dynomanperformance.com/bikepages/sohc/gaskets-head.html

Emailing APE now to ask what thickness they recommend (they resurfaced my head). Going to double check my PUCKS in case they are leaking (but I doubt it is those. Used brand new OEM ans sealed following Hondaman's book).

I currently have an MLS gasket in there and the jugs surface was not resurfaced (only the head)...I guess I should have the jugs resurfaced as well? I am not doing this again or do you think that following Hondaman's book (using non-hardening sealer on the gasket in areas should be adequate). I am puttign the dowel-pins back in with the rubber o-rings. It did not leak at all originally...REBUILD #1-I DID NOT SEAL THE PUCKS REBUILD #2 - I used am MLS gasket with on 1 surface resurfaced.....I am learning very slowly

[MCRider]

THANK YOU MCRider!!! Greatly appreciated

Shoot. I forgot all about this. Still need the info?

[SKTP]

THANK YOU MCRider!!! Greatly appreciated

Shoot. I forgot all about this. Still need the info?

Couldn't hurt...but now that I am committed to pulling the engine again...I will have the cam cover off and hopefully have an easier time cleaning out the old crap in there

[SOHC4 Cafe Racer Fan]

Chris,
Are you using HD Cylinder Studs (APE, Kibblewhite or other)?