Topic: CB750F Supersport Build "No Replacement for Displacement"

[innovativems]

don't forget to get the dogbone mounts for the cb1100F engine. The 750F uses a different front engine mount than the 1100F if you are planning on just swapping engines.

It's part number 14 and 19 in this pic:
http://www.partsfish.com/oemparts/a/hon/506c7cd4f870023420a3c42a/frame-oil-cooler

Thank you Geeto!  You are a huge help on this!

[SOHC4 Cafe Racer Fan]

Looks like i may have a 1100 motor locked down for this bike.  This is going to be the "no replacement for displacement" bike.  Reached out to JES built for some suggestions and seeing about his parts.  This is going to be a fun one. 

I may be more excited about building this bike then my 74 h2 track/street bike.

Uf dah! That's a stout motor.

[Geeto67]

Looks like i may have a 1100 motor locked down for this bike.  This is going to be the "no replacement for displacement" bike.  Reached out to JES built for some suggestions and seeing about his parts.  This is going to be a fun one. 

I may be more excited about building this bike then my 74 h2 track/street bike.

Uf dah! That's a stout motor.

they are ok. They throw a lot of heat so you have to run an oil cooler with them and on at least one of my old cb1100F's I upgraded the stock one because I rode it in new orleans in summer. They make over 100hp and the magnesium engine covers are probably the coolest part. I always feel they need Kehin CR's to make their full potential. A beefier swingarm is needed if going into an earlier frame.

personally, of all the DOHC's I have owned and ridden, I like the 900F the best. it's just the better balanced bike of the two. It has all the power you miss in the 750F, but not as much heat as the 1100F. The 1100F is a freight train of a superbike, and a pretty good sport tourer, but not a sport bike.

[innovativems]

Looks like i may have a 1100 motor locked down for this bike.  This is going to be the "no replacement for displacement" bike.  Reached out to JES built for some suggestions and seeing about his parts.  This is going to be a fun one. 

I may be more excited about building this bike then my 74 h2 track/street bike.

Uf dah! That's a stout motor.

they are ok. They throw a lot of heat so you have to run an oil cooler with them and on at least one of my old cb1100F's I upgraded the stock one because I rode it in new orleans in summer. They make over 100hp and the magnesium engine covers are probably the coolest part. I always feel they need Kehin CR's to make their full potential. A beefier swingarm is needed if going into an earlier frame.

personally, of all the DOHC's I have owned and ridden, I like the 900F the best. it's just the better balanced bike of the two. It has all the power you miss in the 750F, but not as much heat as the 1100F. The 1100F is a freight train of a superbike, and a pretty good sport tourer, but not a sport bike.

My plan is brace the frame, run 17's and get some beffier forks, got a lead on a martin endurance swingarm in the uk and go to high compression pistons, mild porting, lighten the crank, ohlins shocks, and do some work on the forks.  But the motor is all tied on working out shipping or picking up that beast.  He's driving within 5 hrs of me soon, so trying to work that out.  I'm figure out a big ole motor will offset my cb400f. 

[SOHC4 Cafe Racer Fan]

Looks like i may have a 1100 motor locked down for this bike.  This is going to be the "no replacement for displacement" bike.  Reached out to JES built for some suggestions and seeing about his parts.  This is going to be a fun one. 

I may be more excited about building this bike then my 74 h2 track/street bike.

Uf dah! That's a stout motor.

they are ok. They throw a lot of heat so you have to run an oil cooler with them and on at least one of my old cb1100F's I upgraded the stock one because I rode it in new orleans in summer. They make over 100hp and the magnesium engine covers are probably the coolest part. I always feel they need Kehin CR's to make their full potential. A beefier swingarm is needed if going into an earlier frame.

personally, of all the DOHC's I have owned and ridden, I like the 900F the best. it's just the better balanced bike of the two. It has all the power you miss in the 750F, but not as much heat as the 1100F. The 1100F is a freight train of a superbike, and a pretty good sport tourer, but not a sport bike.

Are the frames identical between the 900 and the 1100?

[Geeto67]

Looks like i may have a 1100 motor locked down for this bike.  This is going to be the "no replacement for displacement" bike.  Reached out to JES built for some suggestions and seeing about his parts.  This is going to be a fun one. 

I may be more excited about building this bike then my 74 h2 track/street bike.

Uf dah! That's a stout motor.

they are ok. They throw a lot of heat so you have to run an oil cooler with them and on at least one of my old cb1100F's I upgraded the stock one because I rode it in new orleans in summer. They make over 100hp and the magnesium engine covers are probably the coolest part. I always feel they need Kehin CR's to make their full potential. A beefier swingarm is needed if going into an earlier frame.

personally, of all the DOHC's I have owned and ridden, I like the 900F the best. it's just the better balanced bike of the two. It has all the power you miss in the 750F, but not as much heat as the 1100F. The 1100F is a freight train of a superbike, and a pretty good sport tourer, but not a sport bike.

Are the frames identical between the 900 and the 1100?

Pretty close if not identical. The biggest difference is the swingarm, on the 900 it's the same tubular affair as the 750f, on the 1100f it is a more modern design box steel arm. It looks like aluminum because they painted it silver but it's a pretty heavy gauge box steel unit. Everything that bolts to a 900 will bolt to an 1100f and vice versa. The 1100f had special forks too, cast wheels instead of comstars, and an improved dashboard and fairing.

I think the 900f made something like 89hp at the crank while the 1100f made almost 110hp crank. There is a significant difference in the engines and you can see why they beefed up the suspension for it.

[MRieck]

Are the ports as rough as the SOHC castings?

They are small with the most lateral ports for 1 & 4 barely visible. Small valves. You can't do much with the guide boss because the area is thin and you don't want to compromise the valve spring seat area. You can work the floor and stretch the inside ports into a rectangular shape. The FJ1100/1200 head is a copy of the Honda DOHC head but the roof is thicker and the valves are larger.
 Brent Hyde has got good flow #'s (measured @28") but he uses custom intake pieces and centers the ports to the chamber and bigger valves (the primary restriction in any head). I assume he uses individual carbs like Lectrons etc.

[innovativems]

Been slowly rounding up parts for this build.  Been talking to JES built and the legend Brent Hyde.  I got a 900 motor located and found a set of 1100 rods.  The plan is to resleeve the 900 with 1100 sleeve and do the 1123 high compression pistons.  I'll tackle the primary chain, primary dampers, starter clutch, cam chain & adjusters from v&h. 

Locked in the JES build frame brace kit and his solid motor plug kit. 

On suspension i'm leaning towards boring my stock triples for some cbr600f2 forks.  And run the f2 wheels.  And probably use the modified gsxr swinger from JES with ohlins shocks. 

More to come!

[Geeto67]

Been slowly rounding up parts for this build.  Been talking to JES built and the legend Brent Hyde.  I got a 900 motor located and found a set of 1100 rods.  The plan is to resleeve the 900 with 1100 sleeve and do the 1123 high compression pistons.  I'll tackle the primary chain, primary dampers, starter clutch, cam chain & adjusters from v&h. 

Locked in the JES build frame brace kit and his solid motor plug kit. 

On suspension i'm leaning towards boring my stock triples for some cbr600f2 forks.  And run the f2 wheels.  And probably use the modified gsxr swinger from JES with ohlins shocks. 

More to come!

Why not just use a CBR hurricane 1000 front end. They are almost the same height as your stock forks, and the cbr f2 wheel will bolt up. I believe the trees just slide into the CBf neck but I haven't checked in a while. There are a bunch of threads on it on cb1100f.net if you can get logged in.

[innovativems]

the 600 forks was what jes built was saying he likes to run.  I'll dive into that front end.  Thanks!

[innovativems]

Picking up my 900 motor when I come back from texas next week.  Rods are shipping out today.  Might have a lead on a moto Martin swingarm in the U.K.  Once I nail down a swinger I'll start figuring out the front end


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[Geeto67]

Picking up my 900 motor when I come back from texas next week.  Rods are shipping out today.  Might have a lead on a moto Martin swingarm in the U.K.  Once I nail down a swinger I'll start figuring out the front end


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if the moto martin doesn't pan out, reach out to gpwerks. He's making all sorts of swingarms for bikes these days under the CalFab brand. I think he did DOHC swingers a while back, and may be doing some again in October.

[innovativems]

Picking up my 900 motor when I come back from texas next week.  Rods are shipping out today.  Might have a lead on a moto Martin swingarm in the U.K.  Once I nail down a swinger I'll start figuring out the front end


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if the moto martin doesn't pan out, reach out to gpwerks. He's making all sorts of swingarms for bikes these days under the CalFab brand. I think he did DOHC swingers a while back, and may be doing some again in October.

Thanks Getto!  I looked at using one of the calfab swingers back when i was building my 400, but the price was as much if not more then having Framecrafters build me one.  And Karsten's had alot more adjustability.  I couldn't get much of a solid price out of GP werks over the phone.  He wasn't the friendliest over the phone.  He does do great work though.  If things fall through on the moto martin one, i will probably do a JES built swinger or see what Framecrafters bandwidth is like.

[innovativems]

Alright my 1100 rods arrived and got a 1100 block found.  It's alittle rough but man it's hard to find 1100 parts. So plan with the motor, lighten the crank, 1000c trans gears, 1100 rods, 1123 pistons, webco cams, and a reworked 900 head.  This baby should move


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[innovativems]

Quick update (i'll start adding pictures soon).  I pick up my 900 motor next week.  My 1100 block will be here this week.  My JES frame brace kit will be done in next two weeks.  Got a pretty concrete plan on the motor. 

I'm still going back and forth on the suspension.  I'm leaning towards cbr900rr forks and thinking do a drop top clamp or getting some extended fork caps to get the length close to 800mm.  Then do 17" wheels probably f3 wheels.  I'm talking to a guy in the uk with a used metmachex swingarm from a 900f.  It's priced higher then i was hoping, so trying to get it where i think it's worth it vs getting one of the braced swingers from jes build. 

Then plan is ohlins shocks. 

Updates to follow

[innovativems]

Got a swingarm locked down out of the UK. 


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[innovativems]

1100 block and rods are here.



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[Geeto67]

have you started to hunt for lattice sport kit foot controls yet?

[innovativems]

have you started to hunt for lattice sport kit foot controls yet?

I started down that path and then i saw the nitro racing rearsets that even have a tandem option.  So probably will go that route and some high routed exhaust.  Thinking about the stainless JayGui System. 

[Geeto67]

have you started to hunt for lattice sport kit foot controls yet?

I started down that path and then i saw the nitro racing rearsets that even have a tandem option.  So probably will go that route and some high routed exhaust.  Thinking about the stainless JayGui System. 

the high price ($500+) has always kept me away from those rearsets. Glad to know someone is going to try them out.

I always like the Dekelvic systems for street bikes but the JayGUI systems look the full race part. If you are going full tilt high end I can see it making sense.

Are there any holes or massive dents in your current 4-1 exhaust setup? My brother is looking for a pipe because we just found a hole in his stock setup, and if you aren't going to use yours maybe we can work something out.

[innovativems]

have you started to hunt for lattice sport kit foot controls yet?

I started down that path and then i saw the nitro racing rearsets that even have a tandem option.  So probably will go that route and some high routed exhaust.  Thinking about the stainless JayGui System. 

the high price ($500+) has always kept me away from those rearsets. Glad to know someone is going to try them out.

I always like the Dekelvic systems for street bikes but the JayGUI systems look the full race part. If you are going full tilt high end I can see it making sense.

Are there any holes or massive dents in your current 4-1 exhaust setup? My brother is looking for a pipe because we just found a hole in his stock setup, and if you aren't going to use yours maybe we can work something out.

Ya I'm kinda thinking go all out on this bike and have some fun.  I'll message you some pictures of the exhaust.  It didn't look bad at all but I'll look it over good


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[innovativems]

My swinger has arrived!  I'll shave the chain guard brackets and polish it up at some point.  Going to get my forks and wheels coming so I can double check trail




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[innovativems]

Working out front end and wheels.  Have a lead on something very truck for a front end I'll share if it comes through.




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[innovativems]

Thanks to J-rod I now have a front end to use.




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[innovativems]

And some goodies from jes built showed up.  Frame brace kit, solid motor mount plugs, and aluminum mount plates


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