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

[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.

[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).

[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.

[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.

[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.

[P.abrera]

Related to this, at what point in tire width on the stock 550 hub/swingarm do you have to start thinking of offset sprockets?


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[P.abrera]

Always ready with the info, cal. Thsnks

Theres always a lot of debate on how the different offset and angles a modern fork has will affect the steering behavior of the bike, wont a switch to a smaller wheel diameter also steepen steering angles and amplify the already quicker steering gsxr front end geometry? How did you compensate for that, Don? ...keeping notes for a future project


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[knottedknickers]

Theres always a lot of debate on how the different offset and angles a modern fork has will affect the steering behavior of the bike, wont a switch to a smaller wheel diameter also steepen steering angles and amplify the already quicker steering gsxr front end geometry? How did you compensate for that, Don?

I think you're correct that a smaller wheel will decrease rake ('steering angle') and trail. Increased offset will also decrease trail (though my understanding is that most sportbike forks have less offset (~ 30 mm)  than our CBs (~ 60 mm), which will increase trail). See http://www.autoevolution.com/news/a-quick-guide-to-motorcycle-rake-trail-and-offset-part-1-83482.html and http://bikearama.com/theory/motorcycle-rake-trail-explained/.

[SOHC4 Cafe Racer Fan]

Knotted.

I'm not sure which model CB uses 60mm offset.  550's use 45mm.  750's use 2 different offsets depending on the model and year.

Cal is correct.  I specifically ordered custom offset triples from Devin/Cognitomoto to compensate for the GSXR front end, the TTR400 swingarm and 18" wheels.

And yes, I am also using custom offset triples in my Bionic Mongrel CB750K2 build (with a 2008 CBR600RR front end).

[Retro Rocket]

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...

Yeah, I'm well aware of the road racers setup preference. Not sure what Don's intentions were though. And, he's not using a stock swing arm, so as a precaution I'll measure it for him as "his" swing arm is sitting on one of my bikes  I will say this. I've got a 130-16 on there now, and while I don't see any clearance issue to the frame of the arm, the stay rod (for drums) will be quite problematic without modification for a 150/160 tire.

As a reference, the dimensions I got from Devin was 13" radius from the CL of axle to peak of tmounted tire, and 5-5/8" for overall width at the peak. We all know that can differ slightly based upon which tire, but it should be close enough for local government work 

A 180 on a stock 750 arm? Hmmm, sounds "snug".

Have a look at the CycleX racer Cal, the F bike, it uses a stock swingarm with wide tires, not sure the exact size... Here's a pic of the 750 with a 180 race slick on a 4.5 inch x 17 wheel with stock swingarm, its tight, but it fits....Not the best pics but I still have the tire in the shop..

[Retro Rocket]

Knotted.

I'm not sure which model CB uses 60mm offset.  550's use 45mm.  750's use 2 different offsets depending on the model and year.

Cal is correct.  I specifically ordered custom offset triples from Devin/Cognitomoto to compensate for the GSXR front end, the TTR400 swingarm and 18" wheels.

And yes, I am also using custom offset triples in my Bionic Mongrel CB750K2 build (with a 2008 CBR600RR front end).

K0 to K6 use 60mm offset, F1 to F3 use 50mm offsett, I think K7 and K8 also use 50mm offset   

[P.abrera]

Cool. Lots to catch up on. Always an education hangin out with you guys

[knottedknickers]

Knotted.

I'm not sure which model CB uses 60mm offset.  550's use 45mm.  750's use 2 different offsets depending on the model and year.

Cal is correct.  I specifically ordered custom offset triples from Devin/Cognitomoto to compensate for the GSXR front end, the TTR400 swingarm and 18" wheels.

And yes, I am also using custom offset triples in my Bionic Mongrel CB750K2 build (with a 2008 CBR600RR front end).

K0 to K6 use 60mm offset, F1 to F3 use 50mm offsett, I think K7 and K8 also use 50mm offset   

Yeah, sorry--I should have been more specific about which bike I was referring to (my 750K6). Especially since I don't really know about 550 / 650s...

I snapped a few pictures of my 750K6 upper triple with my 1996 GSX-R750 lower, for what it's worth:





I'm sure you've probably seen Sam's Fork Chart, but just in case anyone else would benefit here's the link. Lots of good info there.

I'll just sit back and watch now...

[SOHC4 Cafe Racer Fan]

650 cam and rockers packed and ready to mail to Mike Rieck (to send back to Megacycle in CA) for hardwelding on rockers and new hardweld/grind cam.   

I might take one last crack at blaster soak and ULTRA heat to try to extract this bugger.  If not, off to the machinist it goes for removal. 

[flatlander]

what grind are you getting? one of their 550 ones?
bummer about that stud. good luck with it!

[SOHC4 Cafe Racer Fan]

Yes, Megacycle 126-20. 500/550/650 cam.

[SOHC4 Cafe Racer Fan]

Cal: Yes, that's definitely the intention!

IF anyone has a 1975 or 1976 rear CB750 Super Sport Wheel Hub & Brake they don't need  and that's in good condition, please PM me.  I reached out to Bill Benton (CB parts accumulator extraordinaire) but have not heard back yet.

[SOHC4 Cafe Racer Fan]

Stud soaking in penetrating oil.

Newest speed bump is trying to source a new output shaft seal. They are no longer made. Western Hills may have them.

91205-426-013   OIL SEAL (36X57X13)      

[bwaller]

Don, have a weldor weld a nut to the exposed stud. Spritzing a little water on the stud after welding will shrink the stud and help it back out of there. Safest bet man.