Author Topic: 3rd crank seal a charm NOW WITH PART NUMBERS Project 14.1 1971 CB750K (Read 5491 times)

fasturd · « **on:** May 30, 2010, 10:24:27 AM »

Hey guys,

Project 13 is pretty much done for now and I need to make some money to start a couple of other projects to I dragged Home "14.1" My buddy built "14"... Anyway...

It is a 71 CB750K With a factory replacement block. New tires some cafe bits and a bunch of extras.

As I was doing a once over while the bike was still in the van I noticed a switch set I have never seen.
Check out the pictures of the left hand control. There is an extra button. Is that high beam flasher? My '69 and my 72 do not have this set up. Is it from a later Honda?

If any of you know please let me in on the secret.

I will post more pics later.

Bob750 · « **Reply #1 on:** May 30, 2010, 06:14:52 PM »

Nitrous oxide boost button? Alternate Musical horn?

But seriously, can you tell if it's momentary or click on-click off? My K4 has the Hi-Lo Beam toggle to the right of the turn signal. I don't see that here, maybe it's for that as you suggested--well you suggested a Hi Beam flasher, but maybe it's related to the headlight. Can you turn the key and find out? Maybe the horn switch burned out and a PO simply added one that works. Not same color as rest of switch... Are there any strange appliances elsewhere on the bike?

fasturd · « **Reply #2 on:** May 31, 2010, 07:21:32 AM »

It is a factory switch mounted as original. Another forum user directed me to a link. This is SO not Honda but when they first added the turn signal beeper they also added this button...It silences the BEEPER!!!
SO you could have the beeper which isn't such a bad reminder but sucks to listen to sitting at a light or you could hold the button and quiet the damn thing when a cute girl was looking.

fasturd · « **Reply #3 on:** May 31, 2010, 07:25:18 AM »

Here are the first few pics... I can't get it out of the van because I hurt my knee and the bike has no brakes at the moment...LOL! Getting old sucks.

Lots of great bits came in the package. I really have no idea if it runs but P/O says it did. So I will go on that assumption...

More to come...

theofam · « **Reply #4 on:** May 31, 2010, 07:57:24 PM »

That van sure does come in handy!

Are you going to cafe 14.1? What are the plans?

fasturd · « **Reply #5 on:** June 01, 2010, 05:00:23 AM »

I would have bought a new van but I can't find a better one!

This one will be a cafe. Nothing here to save so not worried about originality. I will use the frame and motor as is. The body work will need to be re-done as it is a bad P/O rattle can...

It has new tires so I don't think I will change the wheels though I have been itching to use the Lesters or the DID alloys I have waiting around.

There are drag bars on it now but I am thinking of using my Dunstall clip ons or a set of clubmans on reversed pull backs. I am 6' 2" and I found out that if I use a set of bar backs to move the bars up and forward (instead of back) I get a lot more room on the bike.
Check out the pic below for how the bars will work. I built that one 2 years ago and it rode very well.

Not sure of color yet.

Remember this is the last 750 I did NOT 14.1...lol. We have a ways to go yet!

Details of the bar backs used the other way around. Gave me a lot more room on the bike. and they get rid of a bunch of tank/bar clearance issues.

Minnesota recently changed the Lisc. plate law we can no longer hang our plates sideways...

So 14.1 will be along this route most likely with a stock 750 tank. Not sure yet you know how it is, you put something on and take something off until it just looks right!

fasturd · « **Reply #6 on:** June 16, 2010, 05:37:34 AM »

14.1 update. I managed to move it around the garage a few times... Where does TIME GO!

fasturd · « **Reply #7 on:** July 29, 2010, 04:41:14 PM »

Holy cow. You get a wild hair and poof you get a bike. 14.1 sat around for a couple of months with no progress other than being pushed around the shop to get it out of the way... Well it is now a bike.

Lots of little issues that needed to be sorted out, Carbs, electrical, and just assorted crap to deal with.

So I dug through the boxes and started mocking it up. It has a so-so previous owner black paint job so it is going to be built with "patina" parts.

I wanted to simplify the bars so I switched out the switch gear and used an early CL single throttle right hand switch and a matching CL left switch. I added a set of chrome power levers to the rebuilt front master and the clutch. New throttle and clutch cables. I used clubmans and an upside down and reversed set of bar-backs to get the bars where I wanted them. I am 6' 2" so I need the extra knee room. Right now I am just running a tach I will probably add the speedo when it comes time to sell it.

No signals and the rear fender and tail light are stock. I didn't want to butcher the stock fender. I will get a later one and bob it instead. I cut up an old K front fender to get the shorty that is on the front. The seat is a eBay Guliari hardtail replica. The pipe is "unknown" but it sounds cool so it will stay.

All in all not a bad little bike. It will continue to get tweaked until the title shows up then I will decide if it stays or goes...Dang fun to ride though absolutely spanks project 13s ass!

fasturd · « **Reply #8 on:** July 29, 2010, 04:46:15 PM »

OK here are the pics that should have been attached...

I didn't document as much of this one as I was in a hurry...I promise I will do better on the next one!

fastbroshi · « **Reply #9 on:** July 29, 2010, 09:28:12 PM »

Interesting mounts for the bars you got there. Is that one of the repro Guliari seats on there?

fasturd · « **Reply #10 on:** July 30, 2010, 04:50:21 AM »

The seat is one of those eBay repros and really is a decent item. Some one was selling it cheap a while back and I got a pretty good deal on it. I know now that buying directly from the company will get you a pretty decent seat that fits and works well.

The reversed and turned upside down "bar backs" are from a GL1000 I parted out a few years ago. It looks a little Frankenstienish but it gets the bars forward where they need to be. Not the solution for everyone but I like the room it gives me. And this way I can save my Dunstall rearsets for a different project and still get some knee and gas tank to handle bar room.

fasturd · « **Reply #11 on:** July 31, 2010, 02:44:22 PM »

Hey guys.

I have a question regarding replacing the oil seal on the points side of the crank. This is the seal under the points plate. I seem to have a pretty decent boot wetting oil leak at this point. I removed the cover and the points plate and unfortunately cannot really see if it is the main crank seal or the oil o-ring at the bottom of the 6mm shaft. I will replace the o-ring regardless but I am wondering if the oil seal can be replaced without tearing down the motor? Is this one of the seals that can be removed from the outside?

Any suggestions would be greatly appreciated.

( if you look closely you will see the previous owner installed the seal backwards...Which also didnt help anything...)

THanks in advance,
Bill

fasturd · « **Reply #12 on:** August 04, 2010, 06:36:23 AM »

OK so in the process of dealing with the points "area" oil leak I found out a few things...

There are conflicting opinions on wether or not the seal can be replaced from the outside. However the reason some say it cannot be done is that the seal is supposedly flanged. Well I am going to get a stock seal and if it is flanged I am going to order a standard oil seal in the Honda dimensions with out the flange... One forum user stated that he removed the flanged and sealed it in place with the appropriate goo. My best builder buddy and I agree it is worth a try.

Before I go ahead with the crank seal I removed the 6mm shaft that carries the points and replaced the 6mm x 2.3 o-ring. I still have a small weep but it is better. I am still not sure where it is coming from as once you remove the points you can no longer run the engine to see the leak... Powder so far has not been helpful as oil gets misted everywhere and it show wet on the shaft and the seal...LOL.

Interestingly Honda saw fit to put a weep hole on the bottom of the case just under the points. Is that to let out accidental moisture or oil?

So on to the next item...

fasturd · « **Reply #13 on:** August 04, 2010, 06:43:57 AM »

After sealing the shaft I notice that I am still getting way too much oil under the bike. It turns out one or both of the oil lines are less than solid... My good friend was working on a set of oil lines and now was the time to see how they work. The following pictures are the trial fitment and install. Sorry for the dirty bike this is pre-cleaning. (might as well solve all the problems before I get it clean).

This is a nice fairly inexpensive set up. Synthetic rubber hose with a braided stainless cover. Just like brake lines they are going to be almost indestructable. We will probably make the lines just a bit longer next time. But I think the fitment looks good and the black and silver lines are pretty hot roddy!

3.7 quarts of oil and a filter later we are on the road again!

mrrch · « **Reply #14 on:** August 04, 2010, 07:40:44 AM »

Where did your friend source the parts to make up the oil lines?
I like the black fittings.

fasturd · « **Reply #15 on:** August 07, 2010, 01:48:51 PM »

My buddy Ross is a hot rod savant! He knows where to get all the good stuff. I can ask him for the info.

The oils lines solved "that" problem but it is still leaking under the points and I am pretty sure it is the crank seal. I ordered 2 new ones from honda and I am going to try the external cheater fix. If it goes well and even if it doesn't you will see the results right here!

fasturd · « **Reply #16 on:** August 18, 2010, 08:14:48 PM »

After reading up on all the opinions and doing a little asking around here is my conclusion.

The Honda Oil seal does have a very small flange, aprox. 1 mm. It sits in a groove cut into the case it is NOT on the inside of the crank case. I bought 2 factory oil seals (7.00 each) I did NOT cut the flange off the first one. I cleaned up the seal seat and coated the seal with Hondabond and tried to drive it home. The flange caught and tore the rubber coating. One seal down. Putting a little more thought into the next one as I only had one seal left for tonight. (I ordered 3 by dimension from a local seal jobber they do NOT have the Honda flange or the metal seal that the Honda item does.) I will eventually try them also if this last one fails.
We used a burnishing tool to cut a slight taper into the case, Then we cut off the lip of the seal. I lubed the area and the seal with WURTH HHS2000 a super slippery synthetic spray grease. I held the seal in place and drove it home with a large socket. It took a couple of good whacks but it is in place minus the factory flange. We reassembled the points plate and checked the timing and no leaks. We then saddled up and rode to the Quickie Mart to buy a lottery ticket as this may be our lucky night. When we got back I rolled it into the shop and so far NO oil. Before replacing the original seal, which by the way some BOOB had put in backwards there was a literal Triumph puddle everywhere I parked. I took off the points cover and it was still clean and dry.
Obviously the real test will be with a few hundred miles under its belt but so far so good and so dry.
I will have the other seals on hand if this one fails. They are more of a traditional seal but in the correct dimension to fit the crank and the case. They would save the trouble of cutting the flange off and they cost less than $2.00 each. I will post more on the subject if the Honda seal fails.

fasturd · « **Reply #17 on:** August 28, 2010, 07:18:35 AM »

Well, I was wrong. It WAS sealed...

After a nice highway drive to a local bike night everything was dry and dandy. On the way home I subjected her to a little more high RPM flogging and was rewarded with a wet foot... So seal number 2 also failed.

When I took it out to see what was up it was apparent that it was leaking around its base. Now remember this is a seal being driven in from the OUT SIDE. Not placed in properly as per Honda assembly instructions.

During this trial and error process I also sourced a few "spec" oil seals. That are similar dimension to the Honda seal but with out the small flange and secondary metal inner seal.

I pulled the factory seal back out and replaced it with the spec seal and a little Honda bond.

So far the spec seal has been holding up. These normal seals are meant to be driven into place so there was no modification needed to get the seal to fit.

Now there were a few other problems that seemed to pop up (mainly due to my taking the previous owners word that the bike had had some professional service done).

The Valve cover breather tube was vented into the oil tank. The crank case vent was vented to air and the spigot from the tank that was supposed to go back into the crank was plugged... So after getting the seal to hold I was now PUKING oil everywhere. I did a little reading of the factory manual and of course Honda routes its breather lines CORRECTLY and plugs the crank case hose in to the back of the tank. Nice, no more oil soaked back wheel!!! And no more BP sized oil spills everytime I come to a stop.

With everything buttoned back up, all hoses routed properly, the spec seal in place and a new o-ring on the points shaft I have no oil on my shoes, ground or tire.

Now it only has about 10 miles on it and I plan on pushing it this weekend to see if I can make it leak but (again) so far so good. IF the seal stays in place and doesnt leak I will post the part number incase any of you want to give it a try.

By the way the spec seals are less than $2.00 each!

fasturd · « **Reply #18 on:** September 04, 2010, 07:12:10 AM »

I got another ride in maybe 40 miles, the rear tire, my boot and the rest of the bike are dry! Nice change for $2.00. Still going to put a few more miles on before I post part numbers for the seal but I think I might have a soloution for those who don't want to tear apart an other wise good motor.

fasturd · « **Reply #19 on:** September 16, 2010, 03:12:04 PM »

Few more miles still dry...Let the beating begin!

tweakin · « **Reply #20 on:** September 16, 2010, 03:29:00 PM »

Great to hear... let her rip.

Quote from: fasturd on September 16, 2010, 03:12:04 PM

Few more miles still dry...Let the beating begin!

fasturd · « **Reply #21 on:** September 22, 2010, 12:24:32 PM »

80 more miles and still dry this may be the final fix.

Part number to follow in next post.

fasturd · « **Reply #22 on:** October 04, 2010, 08:12:15 PM »

OK. I have been flogging the rat for a while now and it is still dry as a bone.

I promised to list the seal I used so Here it is.

The factory crank seal for the right side is # 91201-300-003. This seal is intended to be installed with the cases APART. Some have suggested that it is possible to install the factory seal from the outside. I will not say that it cannot be done but I was not able to make the factory seal work WELL. The first one tore while being installed. The second one went in after I shaved the inner lip off BUT it seeped and the whole purpose was to have the bike be dry not kind of dry... So it may be able to be driven in from the out side but I was NOT able to do it with the stock HONDA seal.
The good thing is HONDA lists the dimensions of it's seals so I was able to take this info to my local bearing and seal supplier. The HONDA seal is 30X42X8 MMs. The vendor I found was able to supply me with a 30X42X7 MM standard oil seal. The Honda seal has an interesting metal washer inner seal. The standard seal does not. I am sure HONDA had a good reason for designing their seal the way it was designed I am in no way stating my seal is any better other than it lets you install a seal from the OUTSIDE.
The standard seal slipped into place with normal (minimal) effort. I had it and the case surface lightly coated with Yamabond ( I was out of Hondabond) and it pressed into place very nicely. While I was letting the bond cure I also replaced the little o-ring that is under the points stud as it was seeping as well. this o-ring is HONDA #91301-300-000 it is a 6X2.3 mm o-ring that seals the end of the actual crankshaft.
I replaced the points, re-timed and before I started my testing I also closed the automatic chain luber which I had forgotten my bike had... All the oil on the left side was from was from that genius device.
With everything in place I have been out for 3 tanks of gas and NO seeping, no dripping.

Is this repair for everyone? Maybe not. But if you have a right side crank seal that is leaking and you do NOT want to tear the bike down I think this is a great alternative.

Also, make sure your oil lines are routed properly. And that the vents can vent properly. Make sure all lines are connected. I usually check all this but on this one I didn't and it took me a while to find the valve cover vent hose was routed to the oil tank and the crank vent was routed to my back tire... Both are NOT good ideas...

So the seal that worked for me was from
International seal and packing co. Inc.
11 brookside Drive
Wilmington, DE 19804
800-651-2551
www.intersealpack.com

Seal 30X42X7AN

They cost me less than $3.00 each!

I know its cheating. And I am SURE HONDA'S seal is much better. This is just a cheap alternative that saves an engine teardown and or frustration trying to press the stock Honda seal into place (which is VERY difficult if not impossible)

Remember this is the RIGHT side crank seal under the points.

Good luck.

smpls70 · « **Reply #23 on:** October 04, 2010, 10:25:19 PM »

Nice work out if you !!!!..........I just might make it to my first first thursday ( oct.7 -10) ,fingers are crossed,...lets race around the block ,750-750

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Author Topic: 3rd crank seal a charm NOW WITH PART NUMBERS Project 14.1 1971 CB750K (Read 5491 times)