Topic: The Hot Mess - 1975 CB550F1 Frame/1981 CB650 Engine

[calj737]

Did you ever re-weigh the stock hub? I'm curious what you find...

I just weighed my 750 hub (bearings and spacers on; rotor and speedo unit off) and it came in at 3 lb 4 oz = 52 oz = just less than 1.5 kg (on a Braun analogue kitchen scale). For what it's worth...

I be
I've that's about right compared with the 550 hub. That's why I said earlier that the Cognito hub is heavier, but much stronger. Compare it to a stock CB hub with dual rotors and I bet the Cognito hub comes in lower due to modern dual rotors.

[SOHC4 Cafe Racer Fan]

And a Cognito hub with modern floating rotors and an aluminum rim are likely much lighter than the stock hub mounted to the heavy stock steel rotor and steel rim.

[bwaller]

Oh, front hub....

[SOHC4 Cafe Racer Fan]

Well, even the crankcase from the 1982 donor motor have proven to be CRAP-OLA.  After clearing away the sludge/gravy on the top crank-case, what to my horror should appear?

This . . .

image_zpsjfha0gen by Donald Leonhardt, on Flickr

Which should look like this . . .

image_zpsg8wljctm by Donald Leonhardt, on Flickr

But, instead, looks like this . . .

image_zpsa2mcvhf9 by Donald Leonhardt, on Flickr

So let's recap, shall we.  Stripped threads on the head, minor scoring on the camshaft, a few bum rockers, cracked cylinder sleeve, and hole in the crankcase!!!

I know I could JB Weld it, but LUCKILY, I purchased a spare, clean 1981 matched set crankcase from Ebay just before I found the donor bike, and the bearing sizes match BBBB.  The only issue with the 1981 crankcase is that it has a stud/bolt broken off just a 1/4" or less from the crankcase.  It's being extracted by a machine shop and hot-tanked but then I should be okay to start anew.  DRAMA . . . averted!!

Oh and my cam chain guide has 3-4 width-wise cracks.  Honda Part No. 14611-426-010 is no longer made and I cannot find one anywhere.  Of course someone just sold a NOS one 2 months ago on Ebay for only $15!!  And then another NOS one in February for $8.  Now the NOS ones are unobtainium.  I'm in the hunt for a good condition used one. . . .

[riverfever]

So if I understand correctly...you're gonna combine the 81 with the 82 and then you should be ok? Sorry you're having so many issues right out of the gate Don. You'll get it sorted man. Hang in there.

[SOHC4 Cafe Racer Fan]

So yes, it's a combination of a 81 crankcase with 82 top end parts, crankshaft and transmission capped off with hard welded 82 camshaft and rockers.

[SOHC4 Cafe Racer Fan]

Great news on the cam chain guide.  On a recommendation from rb550four, I reached out to Tom Witt aka witttom on the CB650 forum.  He graciously offered a good condition used cam chain guide at a better-than-fair price.  So glad to get that sorted out.  The NOS ones are rarer than hen's teeth!

Now the wait for my order for NOS valve guides, cam/rockers to go out to Mike Rieck to Megacycle, the cam chain guide from Tom Witt and the machinist to remove the leftover bold from the crankcase. 

Things to do:
I am going to figure out what I want to cut off the frame, where to reinforce, and weld a frame hoop, rearset mounts, new tank mounts, etc. 

Here's what someone (can't remember who) suggested a ways back:

Framegussets_zps50735415 by Donald Leonhardt, on Flickr

And I also need to figure out what size 18" rim to buy for the front, and what do with the rear wheel.  I am thinking of adapting a 750F or newer rear disc brake.  I would welcome your thoughts on what rear disc brake adaptations people have made with the 550. 

[calj737]

The rear will fit a 150 comfortably. You'll need to think about clearance of the brake stay rod if you end up sticking with a drum brake.

What front end are you planning? GSXR? If so, I'd go up to the 18x3.50 for a 120-18 tire.

Why not grab new bronze valve guides from Dynoman?

[SOHC4 Cafe Racer Fan]

The rear will fit a 150 comfortably. You'll need to think about clearance of the brake stay rod if you end up sticking with a drum brake.

What front end are you planning? GSXR? If so, I'd go up to the 18x3.50 for a 120-18 tire.

Why not grab new bronze valve guides from Dynoman?

Good to know as to tire fitment. 

Yes, the front is a 2007 GSXR600 I might go with the 120/80-18 instead of the 110/70-18.

Unfortunately, the bronze valve guides from Dynoman do not fit the 650 (according to Buzz), only the 500/550.  Buzz says that the only compatible part he sells are the valve seals. 

[calj737]

Right! 650 head?.. 

[rb550four]

Only 4 left here
http://www.ebay.com/itm/HONDA-CB650-CBX650-POLICE-RC13-CB550-1983-1985-INLET-VALVE-GUIDE-12205-ME5-315-/271091714659?hash=item3f1e534a63&vxp=mtr
6 here
http://www.ebay.com/itm/1979-1982-Honda-CB-650-CB650C-Custom-Valve-Guide-NOS-12023-426-771-12023-426-000-/311264564639?fits=Model%3ACB650&hash=item4878d0559f&vxp=mtr
doesn't say ,don't no if there's a diff between exhaust and intake guide.
 There's a few on ebay... Honda has  upgraded part numbers on 500/550 , don't know which numbers supersede which for the same part,
just to let you know...that stuff goes on all the time.
 but there seems to be some out there.

[Retro Rocket]

The rear will fit a 150 comfortably. You'll need to think about clearance of the brake stay rod if you end up sticking with a drum brake.

What front end are you planning? GSXR? If so, I'd go up to the 18x3.50 for a 120-18 tire.

Why not grab new bronze valve guides from Dynoman?

Good to know as to tire fitment. 

Yes, the front is a 2007 GSXR600 I might go with the 120/80-18 instead of the 110/70-18.

Unfortunately, the bronze valve guides from Dynoman do not fit the 650 (according to Buzz), only the 500/550.  Buzz says that the only compatible part he sells are the valve seals. 

Stay with the 18 x 2.75 on the front Don, you'll only get a 4.25 rear rim for the rear so a 3.5 with a 120 is over tiring the front and unnecessary mate . Even my old 140HP GSXR1100J had a 2.75x18 front and a 4.5 x 18 rear, handled like a train on tracks and way faster than the 550 will ever aspire to...   Actually, my 3rd bike, the "money pit", is getting the very best of everything, it will wear 18x4.5 rear and 18 x 2.75 front, if i even thought there would be any benefit to running a bigger front tire on the street,  I'd be all over it, on our style of bike and with the geometry we have to deal with, a 110 is already a lot of tire for our bikes, Yes, I know the guys running 17 inch wheels run wider tires but 17's naturally steer faster due to their smaller size. Look at what the racers run....  

[SOHC4 Cafe Racer Fan]

Only 4 left here
http://www.ebay.com/itm/HONDA-CB650-CBX650-POLICE-RC13-CB550-1983-1985-INLET-VALVE-GUIDE-12205-ME5-315-/271091714659?hash=item3f1e534a63&vxp=mtr
6 here
http://www.ebay.com/itm/1979-1982-Honda-CB-650-CB650C-Custom-Valve-Guide-NOS-12023-426-771-12023-426-000-/311264564639?fits=Model%3ACB650&hash=item4878d0559f&vxp=mtr
doesn't say ,don't no if there's a diff between exhaust and intake guide.
 There's a few on ebay... Honda has  upgraded part numbers on 500/550 , don't know which numbers supersede which for the same part,
just to let you know...that stuff goes on all the time.
 but there seems to be some out there.

Hi rb550four,

There's no difference between the intake and exhaust valve guides.  They are all Honda Part No. 12204-KW1-405.  Unfortunately, the first listing is for the 1983-85 CB650.  I think the second listing may be compatible -- not sure.  I ended up getting them from www.partsfish.com  They are just not shipped yet.   

After trading messages with Cal and looking at it some more, I am going to source a 1975/1976 CB750F Super Sport Rear Wheel with sprocket, brake rotor, brake arm and caliper.  If anyone has one in good condition (preferably without the spokes and rim), PM me.  Cal confirmed this will fit fine into the TTR400 swingarm,  Then all I need to do is lace it to a new aluminum Sun Rim and BINGO, rear wheel done!

[SOHC4 Cafe Racer Fan]

The rear will fit a 150 comfortably. You'll need to think about clearance of the brake stay rod if you end up sticking with a drum brake.

What front end are you planning? GSXR? If so, I'd go up to the 18x3.50 for a 120-18 tire.

Why not grab new bronze valve guides from Dynoman?

Good to know as to tire fitment. 

Yes, the front is a 2007 GSXR600 I might go with the 120/80-18 instead of the 110/70-18.

Unfortunately, the bronze valve guides from Dynoman do not fit the 650 (according to Buzz), only the 500/550.  Buzz says that the only compatible part he sells are the valve seals. 

Stay with the 18 x 2.75 on the front Don, you'll only get a 4.25 rear rim for the rear so a 3.5 with a 120 is over tiring the front and unnecessary mate . Even my old 140HP GSXR1100J had a 2.75x18 front and a 4.5 x 18 rear, handled like a train on tracks and way faster than the 550 will ever aspire to...   Actually, my 3rd bike, the "money pit", is getting the very best of everything, it will wear 18x4.5 rear and 18 x 2.75 front, if i even thought there would be any benefit to running a bigger front tire on the street,  I'd be all over it, on our style of bike and with the geometry we have to deal with, a 110 is already a lot of tire for our bikes, Yes, I know the guys running 17 inch wheels run wider tires but 17's naturally steer faster due to their smaller size. Look at what the racers run....

Mick,

Thanks for the additional info on tires.  I will look into it some more before pulling the trigger on a new front rim.

[calj737]

Don - rear rim, 17 or 18? I'd think if you're planning on a 150, you'd want a 17". Me, I'd pair that with a 120 front notwithstanding the valid input from Retro. It's my opinion, that the width spread between the two is far more comparable to modern bikes even though normally the front is also a 17" when sprouting a 120 tire. So, 120/150 or I'd run 110/140 on a 18/17 setup. My €0.012

[Retro Rocket]

Don - rear rim, 17 or 18? I'd think if you're planning on a 150, you'd want a 17". Me, I'd pair that with a 120 front notwithstanding the valid input from Retro. It's my opinion, that the width spread between the two is far more comparable to modern bikes even though normally the front is also a 17" when sprouting a 120 tire. So, 120/150 or I'd run 110/140 on a 18/17 setup. My €0.012

Yeah, I was talking 18's only Cal...  As a comparison, the same year model GSXR750J {1988} originally came out with a 17x4.5 rear and a 17x 3.5 front    Personally, I think 18's are a better option on these older style bikes...

[SOHC4 Cafe Racer Fan]

I am planning on using 18" wheels on this bike.  Although the 17" wheel is the predominant sport bike diameter, I had the 45mm offset triples made especially for the 18" wheel and TTR400 swingarm.  Swapping to a 17" will alter the geometry and likely require new trees.  Plus, I think the 17" wheels would make the bike look almost like a supermotard (which I like if that's the purpose but not here).

[calj737]

So you want me to measure for a 150-18" rear tire then? Hmmm.... That might be close 

[SOHC4 Cafe Racer Fan]

So you want me to measure for a 150-18" rear tire then? Hmmm.... That might be close 

Well, it does NOT HAVE to be a 150, but I thought that would match well with a 120 or 110 front.

Bridgestone recommends a 4" rim for the 150/70 - 18 so its not like your typical 180/55-17 sportbike tire.

[calj737]

I agree, but I thought you'd keep the 18/17 ratio front to rear to mimick the 19/18 stock ratio.

So, 150-? Is your desire?

[SOHC4 Cafe Racer Fan]

I agree, but I thought you'd keep the 18/17 ratio front to rear to mimick the 19/18 stock ratio.

So, 150-? Is your desire?

Damn, Cal. Now my head is spinning with options.  My original thought was to stay with 18s both front and rear, but I suppose I could think about 18/17.  It's all in my head at the moment.

[calj737]

Well, I just polled Devin for some measurements off a bike in his stable equipped with 150-18. So I'll measure things up in the am and let know if there's ample room for it or a 17. Then you'll know what fits and decide as you will.

[SOHC4 Cafe Racer Fan]

Thanks, Cal!

[Retro Rocket]

A 160 will also fit a 4.25x18 rim Don, I wouldn't use a 160 on a 17 though, 150 would be a better fit..

I agree, but I thought you'd keep the 18/17 ratio front to rear to mimick the 19/18 stock ratio.

Cal, totally unnecessary bud, the swingarms we are using are designed to accomodate18 inch wheels, I have a 4.5x17 rim with a 180 slick on it and it fits in a stock arm, plenty of room in front of it for the 18, which is only half inch or less bigger in that area... Most classic race 500/550/750 run 18/18 combo, look at the continental road or race attack tires designed for these applications...

[SOHC4 Cafe Racer Fan]

More choices! The ContiRoad Attack 2CR tires have much more variety in the rear tires and are designed for classic motorcycles, just as the BT016 Pros are designed for 80's bikes.  I'm glad to have more rubber options.