Topic: '73 500 - Subframe Fabrication

[calj737]

I hope to have that answer in late August as proved from a dyno. Going to take take a slightly different approach on this bike than originally planned: doing a frame modification next summer with rear brake changes, but going to put it on the road as quickly as possible this summer with standard geometry. Running our of time while college boy is home to perform all the customizations and mods.

[Tews19]

I think I am in the same boat as you Cal.... I have been debating on waiting on my frame mods and run a stock frame.

[calj737]

Tews - this bike is for my 20 year old college boy. He attends Trans Design school in downtown Detroit, and I've relented to altering this bike to suit his design. Problem is, that design changes slightly every few weeks! We know it will be a GSXR front end, we know it will be a mom shock rear, but the seat hoop, subframe and final geometry there keeps shifting. I'm not letting him decide those factors (meaning me cutting the frame) until he finalizes some drawings for his tank and seat.

Also, I'm not willing to cut the frame until I mock it up with the motor installed to insure the proper bracing, layout and position of the final components. Add to that, he's been working 14-16 hours a day all summer (luckily) and we don't get a lot of time together to hash through the decisions.

Recently, we discussed (over the phone, odd since we live together...) just sticking with the stock frame and geometry and putting the bike on the road by end of summer so he can ride it. With over $9.5k invested already, this seems a good idea. I told him we can phase the design changes in. It will add some extra negligee costs (twin shocks in lieu of a single mono, a temporary seat, and powder coating frame twice), but in the interests if time and progress, it seems to be the decision. I'll probably downstream the shocks from this bike to my 550 after the change, and I have a Benjies tank originally bought for the 550 that will go back on it, and the 550 tank to this bike. Since it's painted already and lined, and I can get an aftermarket seat to just plop right on. Easy squeezy!

Now I just gotta get the motor machined (jugs and lower end assembled) and installed in the frame. Then off to online shopping to complete the list of still to buy items and slap it all together. Then to dyno for proper tuning.

[SOHC4 Cafe Racer Fan]

Tews - this bike is for my 20 year old college boy. He attends Trans Design school in downtown Detroit, and I've relented to altering this bike to suit his design. Problem is, that design changes slightly every few weeks! We know it will be a GSXR front end, we know it will be a mom shock rear, but the seat hoop, subframe and final geometry there keeps shifting. I'm not letting him decide those factors (meaning me cutting the frame) until he finalizes some drawings for his tank and seat.

Also, I'm not willing to cut the frame until I mock it up with the motor installed to insure the proper bracing, layout and position of the final components. Add to that, he's been working 14-16 hours a day all summer (luckily) and we don't get a lot of time together to hash through the decisions.

Recently, we discussed (over the phone, odd since we live together...) just sticking with the stock frame and geometry and putting the bike on the road by end of summer so he can ride it. With over $9.5k invested already, this seems a good idea. I told him we can phase the design changes in. It will add some extra negligee costs (twin shocks in lieu of a single mono, a temporary seat, and powder coating frame twice), but in the interests if time and progress, it seems to be the decision. I'll probably downstream the shocks from this bike to my 550 after the change, and I have a Benjies tank originally bought for the 550 that will go back on it, and the 550 tank to this bike. Since it's painted already and lined, and I can get an aftermarket seat to just plop right on. Easy squeezy!

Now I just gotta get the motor machined (jugs and lower end assembled) and installed in the frame. Then off to online shopping to complete the list of still to buy items and slap it all together. Then to dyno for proper tuning.

Cal,

Your kid is lucky to have you as a dad.  Seriously.  My old man was cool, but he wouldn't have built or bought me a bike.  He would have helped out, as we did maintained some of the cars together, but nothing like this.

[calj737]

Kind words, Don. He is a great kid, I'm lucky. All my kids are great kids. They do well in school, in social situations, in sports. I've got little to complain about. I tell them all the time: You've got it pretty good, but you'll never have it easy with me. Sums up their life in my home. Work hard for it, earn it every day. I'll support you but never spoil you.

This bike is something I hope he retains for a long time not only as a remembrance of our efforts together, but as "his" first vehicle design. Cheaper than buying a new sport bike and 10x more value.

[Stev-o]

"Some time later after dinner, she sees me walking past and asks, "Is that your new camshaft in your pocket, or are you happy to see me?""

Hilarious!   Parts look fantastic.

[MRieck]

Cal,

With a 550, Honda claimed the stock motor produced 50 BHP, with the actual dyno numbers showing approximately 38 BHP.  I wonder what power this little beast will make! 

I am curious as this may drive whether I decide to bore out a 550 down the road or drop in a bored out 650.

Don

I find it interesting Don that Brent Waller's bike has approximately a 10% increase in displacement BUT makes almost 100% more HP.

[SOHC4 Cafe Racer Fan]

Cal,

With a 550, Honda claimed the stock motor produced 50 BHP, with the actual dyno numbers showing approximately 38 BHP.  I wonder what power this little beast will make! 

I am curious as this may drive whether I decide to bore out a 550 down the road or drop in a bored out 650.

Don

I find it interesting Don that Brent Waller's bike has approximately a 10% increase in displacement BUT makes almost 100% more HP.

You have my interest!  Wow!!

[bwaller]

Actually Mike it's only a 5% bore increase 544 vs 572cc.

Don I remember well a guy on here that had a fairly low mileage 550 he was going to bore to 61mm. He decided to dyno the bike before & after. The "before" engine produced 36.7rwhp and I don't remember ever seeing an update but actually watched for him a long time because I planned to build the same for my wife.

Honda's claim of 50 hp was measured at the crankshaft. (their figures were always optimistic) The difference between crankshaft & rear wheel horsepower obviously is drive line friction. (primary chain or gears, gearbox, drive chain friction losses) 

[calj737]

I am by no means an expert, hence the budget to Mike and the local shop. And I've heard the "no replacement for displacement" adage for, well, too many years admittedly. I think modern wisdom is that a properly configured, properly tuned smaller engine can equally perform and some times outperform larger displacement engines.

There's little likelihood of that being true if both were equal elsewhere, and one essentially had a properly tuned larger bore. But to revert to a 650 platform as the necessary change to get a fistful of throttle out of one these 500/550 engines is incomplete thinking in my book.

I over bored for a specific reason as my primary need: my jugs were shot! I upgraded the slugs to balance the new intake/valve train enhancements from Mike and Godferrey. No value in overwhelming the bottom end with an over the top, top end. But I certainly could have gone larger in the bore, but in my thinking with only very little benefit.

It would seem per Brent's experience, I may have been for the wrong or right reasons. But a healthy bottom end I think supports a much stronger top end than a stock top end can feed a stronger bottom end. The air/fuel performance is more critical than volume if you can't fill the volume and compress it.

At least, that's my rationale. Again, I could be "right" for the wrong reasoning, but I think this little bike will exceed my expectations 100% and certainly perform well enough to raise eyebrows from CBRs and larger bored bikes. Thanks largely due to Mike and Mr Banker!

[Tews19]

Bwaller do you happen to have a link to the thread on the other build?

Cal, my dad never spent that kind of money on me! Your boy is very lucky!

Now when do we start the paperwork for you to adopt me? I need funds to do Paulages 550/650/712 build!

[calj737]

Tews - I'm from the south, we work on handshakes here. My word is my deed, kind of stuff. Come on down! It's hotter than Kate Upton in sauna right now- but remember my caveat to them: you'll have it good, just not easy

 

[MRieck]

Actually Mike it's only a 5% bore increase 544 vs 572cc.

Don I remember well a guy on here that had a fairly low mileage 550 he was going to bore to 61mm. He decided to dyno the bike before & after. The "before" engine produced 36.7rwhp and I don't remember ever seeing an update but actually watched for him a long time because I planned to build the same for my wife.

Honda's claim of 50 hp was measured at the crankshaft. (their figures were always optimistic) The difference between crankshaft & rear wheel horsepower obviously is drive line friction. (primary chain or gears, gearbox, drive chain friction losses)

Even more impressive.

[bwaller]

Sorry Tews I can't remember the guys name. He was very thorough in his approach but I think he may not have returned here, don't know. It was several years ago.

I'm a 750 guy, when I worked in a Honda shop I always thought these bikes were slow & boring. Sorry but I only ever test rode stock bikes. It wasn't until I joined this forum that I decided to build a 550 based bike to replace my wife's 400F. From that experience I realised this engine (possibly more than any other of the sohc4's) is heavily restricted by the cylinder head. The bore can be increased, but without attention to the head any increase won't deliver to potential. I decided to build one to race instead of a 750 because the smaller model was a better handler. However I am surprised how much power can be coaxed out of them. It's all relative though, bang for the buck, most people want to make the bike their own and ride it on the street for what it is. There is often a modern bike in the garage!

So great, CB500/550's can be made to go especially when put on a diet. BUT honestly Cal, they are never a match for modern stuff. Don't go taunting any CBR's at a street light.   

I'll bet Mike wishes he had smaller fingers working on all these 500 heads!

 

[SOHC4 Cafe Racer Fan]

Sorry Tews I can't remember the guys name. He was very thorough in his approach but I think he may not have returned here, don't know. It was several years ago.

I'm a 750 guy, when I worked in a Honda shop I always thought these bikes were slow & boring. Sorry but I only ever test rode stock bikes. It wasn't until I joined this forum that I decided to build a 550 based bike to replace my wife's 400F. From that experience I realised this engine (possibly more than any other of the sohc4's) is heavily restricted by the cylinder head. The bore can be increased, but without attention to the head any increase won't deliver to potential. I decided to build one to race instead of a 750 because the smaller model was a better handler. However I am surprised how much power can be coaxed out of them. It's all relative though, bang for the buck, most people want to make the bike their own and ride it on the street for what it is. There is often a modern bike in the garage!

So great, CB500/550's can be made to go especially when put on a diet. BUT honestly Cal, they are never a match for modern stuff. Don't go taunting any CBR's at a street light.   

I'll bet Mike wishes he had smaller fingers working on all these 500 heads!

Brent,

Can you give us a quick break-down on your engine build specs and the hp/torque stats??

[bwaller]

I don't mind sharing if Cal doesn't mind the intrusion. I have told MRieck all the guys racing 550's that I've shared everything with.





60mm pistons (572cc) CR 1:11.4. Very tight squish & valve/piston clearances. Megacycle 126-20 cam, 1mm over valves. JMR porting. 9 degree inclined inlets, 29mm Mikuni smoothbores. Carrillo rods. All moving parts balanced to the lightest piece. Tsubaki camchain with stock tensioner, primary chain tensioner, 6 speed gearbox, eight plate clutch. CB650 oil pump & pan- 4 litre capacity with Setrab cooler. Modified Kerker 4-1.

[calj737]

Don't mind at all, actually intrigued by your mods. Certainly not the direction of this build, but I find it very informative how/where you modified and the results achieved. Intrude away!

[Tews19]

Hey Brent would you happen to have a video of your bike running?

Sorry not trying to hijack Cal.

[calj737]

Worry not, guys. Build progress is stalled, so this is all useful and interesting sidebars-

[bwaller]

http://forums.sohc4.net/index.php?topic=83871.0

On page 13 there's a vid of an early dyno session, and there are different race vids, one on page 19 from Mosport, and 21 from Laconia.  The audio is poor with the camera in a case. It's not loud even with a 2" comp. baffle, under 100db.

[SOHC4 Cafe Racer Fan]

http://forums.sohc4.net/index.php?topic=83871.0

On page 13 there's a vid of an early dyno session, and there are different race vids, one on page 19 from Mosport, and 21 from Laconia.  The audio is poor with the camera in a case. It's not loud even with a 2" comp. baffle, under 100db.

That is quite an exceptional 572cc CB550!! It really shows how much potential the 550 motor has IF you have the means to extract it.

[riverfever]

So another day of Xmas here in the mid-altantic. I came home today to a very large box, was expecting a tank from a member... Then, the darn thing was so heavy and had arrived so quickly, I was confused. A sharp knife and a wee bit of unpacking revealed-



That's the front 17x3.5 with Cognito hub on Sun rims. Geez, those guys at Buchanans do great work.

Side/side front and rear



Also, got my MotoGP back from ceramic coating. Did only the interior, leaving outside raw Stainless. Coated the collars as they will "attach" to the motor, be held permanently with 12pt nuts. Should look good-


Gee, I wonder what he'll bring me tomorrow!!

Heaven's to Mergatroid. I don't know if it's the pain killers or what but I just saw this picture of the exhaust again and I am sprung. Think I need a cigarette.

[calj737]

Why you on pain killers, Fever?

[riverfever]

Last night I was down in a remote canyon by myself fly fishing (I go there all the time) and I slipped and fell, got swept downstream a bit and my shin bashed into a boulder. I managed to get to the shore and hike out but it was a good enough hit to tear the waders and my shin was huge when I got home. Thought for sure I broke it. Was up all night in pain. Doc says it's just a nasty hematoma.

[SOHC4 Cafe Racer Fan]

Yikes!  I didn't know flyfishing could be so dangerous.  I've only been out a couple of times on the Platte River in your territory.  Once when it was minus 10.  Glad it wasn't a break but sounds like you took a serious bashing.