Topic: 1974 Rickman-Honda 750 CR replica/tribute

[754]

Get a hold of John Markwald, and find out about his old 836, it was quick , back in the Sturgis street racing days.   I think he still has a. CBX and puts on the drags at Buffalo Chip...
 Good luck with the project..

[kosmjon]

Get a hold of John Markwald, and find out about his old 836, it was quick , back in the Sturgis street racing days.   I think he still has a. CBX and puts on the drags at Buffalo Chip...
 Good luck with the project..

Thanks! I'll look him up.  An 836 kit is a likely option (why go 1st or 2nd oversize when you can jump to 836, right?)

[kosmjon]

Hey slikwilli420 seeing as how you have real honest-to-goodness parts available to see/touch/etc, would you be willing to take some measurements (length, diameters, and angles, etc.) for me when the time comes?  And perhaps even be persuaded to make poster-board templates of things such as the caliper carriers and send them USPS (postage paid by me of course.)  ?

[kosmjon]

Dunlop T100 tires are easy to find and are about ~$100 each.  Borrani America has the valanced 18-inch rims at a good price and I'm certain Buchanans can provide the spokes. But
I am not seeing anything that comes close to looking like the front and rear 6-bolt conical disc-brake wheel hubs.  Anyone have any ideas on who made those and where to find them or something that looks a lot like them ?  Thanks in advance.

[Zunspec]

Hi kosmjon,

I believe that those conical hubs were Rickman made and not a part sourced from one of the major manufacturers.  If you Google for the history of the CR I'm sure you might find more details. Within the classic race world there is sure to be someone producing replicas, but as with most stuff "classic" they won't be cheap.

Good luck

Geoff

[slikwilli420]

Hey slikwilli420 seeing as how you have real honest-to-goodness parts available to see/touch/etc, would you be willing to take some measurements (length, diameters, and angles, etc.) for me when the time comes?  And perhaps even be persuaded to make poster-board templates of things such as the caliper carriers and send them USPS (postage paid by me of course.)  ?

I would be happy to measure as well as help you make cretain parts if possible. I recently made a rear caliper hanger for another Rickman bike that turned out very well.

I'm becoming a really big Rickman fan so will go out of my way to help of I can.

I have been collecting parts for the last year or two and besides the frame I am only missing the top triple clamp and a few other small bits.

[kosmjon]

Thank you very much slikwilli420  I'll start making a list.

[kosmjon]

I guess you could call this the official start of the project. This past Monday I hit up Lowes looking for angle-iron and square tube to build a stand for working on the CB750 engine. I decided to check out the black iron pipe aisle just for kicks and came across these Structural Fittings  I found it funny that they were in the same aisle as the plumbing pipe since it is ERW structural tubing and clearly states it is not for plumbing use.  Anyways, as I looked at it I realized it could be used to make a simple rotisserie stand for CB750 (and other engines.)   I bought 6 fittings which ranged in price from $3 to $6 and a 10-foot length of the tubing for a total of $54.  I sawed two of the fittings in half and welded 3-inch pieces of 1-1/4-inch flat-bar with 7/16th holes drilled in them to each of the resulting 4 pieces.


Today, after about 3 more hours of cutting and welding, I had this:


and here it is with the CB750 engine installed into it.  I know it will be even more useful during reassembly of the engine.  Not bad for a total of 5 hours and $54 bucks, I say!

[palepainter]

Ya.  That looks solid and very useful.  Good job!

[scottly]

I took this pic of a Rickman in the parking lot at Laguna Seca in 1979:

[SOHC4 Cafe Racer Fan]

I like that you can rotate the engine in the stand, without having to have a larger-scape auto engine stand.

[MikeSimon]

Great job on the stand! I am a mechanical engineer, but I am always amazed about the ingenuity of guys out there!

Don't know whether this was the same bike as the "Laguna Seca" one above, but this was at AMA Vintage days for a couple of years in a row, for sale.

[kosmjon]

Thank you scottly and MikeSimon for the pics! Thanks palepainter, CB750 Cafe Racer Fan and MikeSimon for your appreciation of the engine stand.  Here is the engine turned so I could put the full force of my impact driver on the Counter shaft bearing holder.  What a bear that was to loosen those four screws!


Uh oh, looks like in the past someone had used some kind of shellac-like gasket sealer vs. Hondabond to seal the cases and that stuff let loose into the engine where the sump screen caught it.


Finally, the cases are split. I ordered a 20x1.5 mm rotor puller that hopefully will be here by Tuesday.

[kosmjon]

I am looking for opinions and sources on how create a refreshed, reliable engine with the least amount of $$.  The pistons appear in good shape and are already .50 oversize (there's a "50" on the side.)  The options I can think of are:

• Light hone and new .50 rings
• Overbore to 1.00 oversize with new pistons and rings
• Overbore to 836 kit
• 836 kit plus cam, valves, valve springs (CycleX "git-kit"?)

FYI, my local machine shop charges $40 a hole and I've done three engines with them so far and am very happy with the results.

So my questions are:

• what would ya'll recommend?
• Is is silly to do 1.00 overbore when you can go all the way to 836?
• Is is silly to go to 836 without also doing cam, valves, etc?
• Anyone used CycleX stuff?  Is it good stuff and a good value?
• What other brands/sources of piston kits to consider (or avoid)?

Thanks much in advance for any info/advice you can provide.

[slikwilli420]

An 836 from cruizinimage on eBay is supposed to be a nice mod, and is very inexpensive. I would add a cam and if you are really savvy, some port work. That will wake up the engine nicely without a huge cash investment and will not sacrifice reliability of other parts. If you are in that far, cam chain and tensioners would be a good idea too.

[SOHC4 Cafe Racer Fan]

It depends. 

You should see if the bores are in spec for the current .5 over. If so, new rings, hone and be on your way.  That is the cheapest, easiest route.

If not and need to overbore, it depends on whether you want future room for an 836 kit.  If you are not looking to up the performance, go with the 1.0 over. If you'd like a slight bump up, go with the cruzinimage 836 kit.

[Old Scrambler]

Nice Project   +1 on rings or C-I 836 .........clean up the valves and seats, add a mild cam aka F2-3.........electronic ignition and spend $$ on good parts. That 410 front tire may be a tight fit between the fender brace on standard forks.

[seanbarney41]

An 836 from cruizinimage on eBay is supposed to be a nice mod, and is very inexpensive. I would add a cam and if you are really savvy, some port work. That will wake up the engine nicely without a huge cash investment and will not sacrifice reliability of other parts. If you are in that far, cam chain and tensioners would be a good idea too.

+1 especially considering the stuff on your pickup screen is probably not gasket/case sealant...it is parts of your cam chain guide/rollers

[kosmjon]

An 836 from cruizinimage on eBay is supposed to be a nice mod, and is very inexpensive. I would add a cam and if you are really savvy, some port work. That will wake up the engine nicely without a huge cash investment and will not sacrifice reliability of other parts. If you are in that far, cam chain and tensioners would be a good idea too.

+1 especially considering the stuff on your pickup screen is probably not gasket/case sealant...it is parts of your cam chain guide/rollers

You are right. That is definitely chewed up cam chain guide. There were also some weird very flat chunks as well. I plan on thoroughly inspecting the bottom end, oil pump, etc.

[kosmjon]

Seeing this from C-I on ebay now: http://www.ebay.com/itm/69-76-HONDA-CB750K-836cc-65mm-BIGBORE-PISTONS-KIT-W-HEAD-GASKET-10-CB750KBB-/162293971812?vxp=mtr&hash=item25c9797b64  Listing says only up through 76, but will this work on my K7 1977 engine ?

[SOHC4 Cafe Racer Fan]

Seeing this from C-I on ebay now: http://www.ebay.com/itm/69-76-HONDA-CB750K-836cc-65mm-BIGBORE-PISTONS-KIT-W-HEAD-GASKET-10-CB750KBB-/162293971812?vxp=mtr&hash=item25c9797b64  Listing says only up through 76, but will this work on my K7 1977 engine ?

No, different kit.  He also sells the kits for your bike.

[kosmjon]

Thanks everyone for suggestions about the engine rebuild.  I've decided I will use C-I 836 kit for 77-88 motors with APE HD studs.
I have decided NOT to change the cam. I will replace:
clutch friction disks and springs
cam chain
cam chain guide rollers
and of course, gaskets, oil seals, o-rings.  If I missed anything important, please let me know.

I will get the cases cleaned up and assembled as a shell for use in mocking things up for all the frame mods I have planned.
I just sold my restored 1965 CB160 on ebay for a nice price and I now have $1500 (the rest went to debts) available to start buying stuff.  I need to get it up on wheels and I need to get the fenders, tank, fairing, DOM tubing, etc. so I can start major fabrication.  I will need a few tools such as a tubing notcher as well.

[slikwilli420]

What are your plans for frame mods? Really interested to see what you come up with.

[kosmjon]

What are your plans for frame mods? Really interested to see what you come up with.

Well... given that the basic goal is to have it look as much like a Rickman frame as possible. I am planning to take the stock frame:


and remove anything that does not look "Rickman":


and the use .120 DOM tubing in various OD sizes along with 1/8 and 3/16-inch plate to Rickman-ize it.


Note that I will not actually remove everything first and then add everything.  Rather, I will remove something and add its replacement, and continue to remove-add, remove-add while constantly checking frame for square-ness and using the engine shell to keep things lined up.

I agree with you the eccentric swingarm adjuster looks like a PITA, but in the interest of accuracy I think I'm going to buy a set of these


and make my own swingarm using the techniques illustrated here


I plan on adding some extra bracing hidden on the underside of the swingarm and will like use thicker wall than .120.  When all the fab work is done I plan on getting it powder-coated in a chrome-like finish.

So that is the basic plan.  First I'm going to use cheap electrical conduit in place of the $$ DOM tubing to mock it all up and verify the dimensions.  I need to get it up on 18-inch wheels and get all the of the body work parts in order to proceed so I will be able to compare it against the 5 pictures of the original bike I have to work with.

I know I'll be a lot of work, but does anyone see any major gotchas I am naively overlooking?

[slikwilli420]

For the frame, definitely stick with 0.065 DOM tubing. DOM is substantially stronger than regular ERW steel, and approaches non-normalized chromoly for strength. Its not quite there but closer to CrMo than it is to ERW. Its a solid choice for strength and ease of welding.

Not sure what diameter your swingarm tubing is, but on a Seeley swinger for instance, the tubing is pretty thin wall (like an 0.085-ish), but is like 1-3/8" or so, making it light and strong. The 0.120 is probably overkill, but you likely won't notice a real weight penalty, only a bit more stiffness, which isn't a bad thing.