Author Topic: CB750 AHRMA Sportsman 750 Racer  (Read 171137 times)

0 Members and 2 Guests are viewing this topic.

Offline Rocketman

  • Hot Shot
  • ***
  • Posts: 391
Re: CB750 AHRMA Sportsman 750 Racer
« Reply #150 on: October 25, 2016, 06:18:57 PM »
Good to meet you at Barber.  Very impressed with your progress so far.  Looking like we will see you at the races next year.  While nothing beats track time, if you can work it in, good coaching can definitely shorten the learning curve. 

Offline Haybus

  • Enthusiast
  • **
  • Posts: 177
Re: CB750 AHRMA Sportsman 750 Racer
« Reply #151 on: October 25, 2016, 08:49:02 PM »
Awesome progress. That's an elaborate looking oil tank mount, but good to see you have it isolated with rubber mounts. Something I would have overlooked without the advice from an experienced racer (JohnN). Hopefully you have someone to teach you the finer parts of racing like Rocketman suggests. You seem to have the building part under control (my favorite part!!).

Alan
75 CB750
76 KZ900

Offline slikwilli420

  • Master of Disaster
  • Master
  • *****
  • Posts: 2,362
Re: CB750 AHRMA Sportsman 750 Racer
« Reply #152 on: October 26, 2016, 06:01:57 AM »
Good to meet you at Barber.  Very impressed with your progress so far.  Looking like we will see you at the races next year.  While nothing beats track time, if you can work it in, good coaching can definitely shorten the learning curve.

Thanks Rocketman! It was good to meet you too and thanks again for the rear tire! I will take the AHRMA class but I would also really like to find another road race class to take somewhere in the Midwest next year.

Awesome progress. That's an elaborate looking oil tank mount, but good to see you have it isolated with rubber mounts. Something I would have overlooked without the advice from an experienced racer (JohnN). Hopefully you have someone to teach you the finer parts of racing like Rocketman suggests. You seem to have the building part under control (my favorite part!!).

Alan

Thanks Alan. Its a bit more than I wanted to do with the oil tank mount, but it turned out really well and is rubber mounted which is one thing I knew I needed to do. Even with all that, it still weighs less than a stocker and should control heat better than the steel unit. The building part has proven to be a ton of fun, though I really look forward to lighting it up and pissing off the neighbors, then hopefully making a decent showing at the track next year.
All you gotta do is do what you gotta do.

Vintage Speed Parts Mashup: http://forums.sohc4.net/index.php?topic=133638.0
Rickman CR Parts Kit Refresh: http://forums.sohc4.net/index.php/topic,154837.0.html
AHRMA CB750 Racer: http://forums.sohc4.net/index.php/topic,158461.0.html
AHRMA Superbike Heavyweight Racer: http://forums.sohc4.net/index.php/topic,173120.0.html
'76F CB750 Patina Redemption: http://forums.sohc4.net/index.php/topic,174871.0.html

Offline slikwilli420

  • Master of Disaster
  • Master
  • *****
  • Posts: 2,362
Re: CB750 AHRMA Sportsman 750 Racer - Prep n Etch question
« Reply #153 on: October 28, 2016, 01:27:31 PM »
So I had my tank stripped and used prep n etch on the tank afterwards before priming. It looks like this:



Is this streaking normal? Did I do something wrong? It will scuff off with a green scotch brite pad. Can I paint over this or do I need to go over the whole surface again?
« Last Edit: July 10, 2017, 01:06:03 PM by slikwilli420 »
All you gotta do is do what you gotta do.

Vintage Speed Parts Mashup: http://forums.sohc4.net/index.php?topic=133638.0
Rickman CR Parts Kit Refresh: http://forums.sohc4.net/index.php/topic,154837.0.html
AHRMA CB750 Racer: http://forums.sohc4.net/index.php/topic,158461.0.html
AHRMA Superbike Heavyweight Racer: http://forums.sohc4.net/index.php/topic,173120.0.html
'76F CB750 Patina Redemption: http://forums.sohc4.net/index.php/topic,174871.0.html

Offline calj737

  • Really Old Timer ...
  • *******
  • Posts: 21,032
  • I refuse...
Re: CB750 AHRMA Sportsman 750 Racer - Prep n Etch question
« Reply #154 on: October 28, 2016, 01:32:39 PM »
Lightly sand it, prime it, then lightly sand before paint.
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline slikwilli420

  • Master of Disaster
  • Master
  • *****
  • Posts: 2,362
Re: CB750 AHRMA Sportsman 750 Racer - Prep n Etch question
« Reply #155 on: October 28, 2016, 01:44:39 PM »
Glad you chimed in Cal. Would a green scratchy work as well?
All you gotta do is do what you gotta do.

Vintage Speed Parts Mashup: http://forums.sohc4.net/index.php?topic=133638.0
Rickman CR Parts Kit Refresh: http://forums.sohc4.net/index.php/topic,154837.0.html
AHRMA CB750 Racer: http://forums.sohc4.net/index.php/topic,158461.0.html
AHRMA Superbike Heavyweight Racer: http://forums.sohc4.net/index.php/topic,173120.0.html
'76F CB750 Patina Redemption: http://forums.sohc4.net/index.php/topic,174871.0.html

Offline calj737

  • Really Old Timer ...
  • *******
  • Posts: 21,032
  • I refuse...
Re: CB750 AHRMA Sportsman 750 Racer - Prep n Etch question
« Reply #156 on: October 28, 2016, 01:49:58 PM »
More than coarse enough. A Red is probably sufficient. I never sand more than 320 from primer on. But a Green or Red to prep the metal for primer is good with me.
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline slikwilli420

  • Master of Disaster
  • Master
  • *****
  • Posts: 2,362
Re: CB750 AHRMA Sportsman 750 Racer - Prep n Etch question
« Reply #157 on: October 28, 2016, 01:56:55 PM »
Thanks Cal! Hopefully get this in primer this weekend.
All you gotta do is do what you gotta do.

Vintage Speed Parts Mashup: http://forums.sohc4.net/index.php?topic=133638.0
Rickman CR Parts Kit Refresh: http://forums.sohc4.net/index.php/topic,154837.0.html
AHRMA CB750 Racer: http://forums.sohc4.net/index.php/topic,158461.0.html
AHRMA Superbike Heavyweight Racer: http://forums.sohc4.net/index.php/topic,173120.0.html
'76F CB750 Patina Redemption: http://forums.sohc4.net/index.php/topic,174871.0.html

Offline slikwilli420

  • Master of Disaster
  • Master
  • *****
  • Posts: 2,362
Re: CB750 AHRMA Sportsman 750 Racer
« Reply #158 on: October 31, 2016, 08:38:59 AM »
Alright, so thanks to Cal I was able to get my tank project under control. After wiping with acetone, using Prep n Etch, then going over it all with a green scotchbrite, then acetone again, I was ready for primer. Of course this was not without its difficulties. I did manage to find 3 pinholes in the left rear of the tank which will need to be fixed. I still got the outside in primer for protection and now I think I will need to get it pressure tested, since I really only want to fix this tank once. I will line it with caswell's but might as well get it repaired first just to be safe.

Beyond that, I did get the rear wheel on and have a roller!! This is a big day and really puts me in a happy place. I need to make some chain adjusters and once I can get the rear wheel at mid adjustment, I can take more accurate measurements for trail and for shocks.

Speaking of trail, using 45mm offset clamps I was getting about 4.25" of trail. My rear wheel is off the ground about 1/2" and was not in the center of the adjustment, meaning once it sits on the ground and is adjusted properly, my rake will increase, giving me even more trail. I seem to remember reading that 90-100mm of trail was the sweet spot, so will need to play with offset to correct this. Retro Rocket, can you confirm this since you are a resident guru on such things?

Here are a few shots of the overall bike and the front brake setup:



« Last Edit: July 10, 2017, 01:06:58 PM by slikwilli420 »
All you gotta do is do what you gotta do.

Vintage Speed Parts Mashup: http://forums.sohc4.net/index.php?topic=133638.0
Rickman CR Parts Kit Refresh: http://forums.sohc4.net/index.php/topic,154837.0.html
AHRMA CB750 Racer: http://forums.sohc4.net/index.php/topic,158461.0.html
AHRMA Superbike Heavyweight Racer: http://forums.sohc4.net/index.php/topic,173120.0.html
'76F CB750 Patina Redemption: http://forums.sohc4.net/index.php/topic,174871.0.html

Offline turboguzzi

  • Old Timer
  • ******
  • Posts: 4,085
looks good! regarding geometry, take into account that there's a limit how much you can raise the rear (longer shocks) in order to reduce rake. that limit is when the top chain run ribs the top of the swingarm when in tension. youll have to mount at least the bottom of the engine with the sprocket shaft as well as the rear crown to see where you are
on trail, more like 100 than 90....

Offline slikwilli420

  • Master of Disaster
  • Master
  • *****
  • Posts: 2,362
My strut is 14" on the dot and that is a length that has been suggested by quite a few other racers. I hope it doesn't prove to bee TOO long. I may have to come up with a better slider for the top of the swing arm as well.
All you gotta do is do what you gotta do.

Vintage Speed Parts Mashup: http://forums.sohc4.net/index.php?topic=133638.0
Rickman CR Parts Kit Refresh: http://forums.sohc4.net/index.php/topic,154837.0.html
AHRMA CB750 Racer: http://forums.sohc4.net/index.php/topic,158461.0.html
AHRMA Superbike Heavyweight Racer: http://forums.sohc4.net/index.php/topic,173120.0.html
'76F CB750 Patina Redemption: http://forums.sohc4.net/index.php/topic,174871.0.html

Offline turboguzzi

  • Old Timer
  • ******
  • Posts: 4,085
that sounds about right length. kind of simplifies things as at this point you can only play with front end height :)


Offline slikwilli420

  • Master of Disaster
  • Master
  • *****
  • Posts: 2,362
Nice brake setup! Looks ace.

 8)

You guys made it happen! Thanks again from across the pond!!
All you gotta do is do what you gotta do.

Vintage Speed Parts Mashup: http://forums.sohc4.net/index.php?topic=133638.0
Rickman CR Parts Kit Refresh: http://forums.sohc4.net/index.php/topic,154837.0.html
AHRMA CB750 Racer: http://forums.sohc4.net/index.php/topic,158461.0.html
AHRMA Superbike Heavyweight Racer: http://forums.sohc4.net/index.php/topic,173120.0.html
'76F CB750 Patina Redemption: http://forums.sohc4.net/index.php/topic,174871.0.html

Offline slikwilli420

  • Master of Disaster
  • Master
  • *****
  • Posts: 2,362
Re: CB750 AHRMA Sportsman 750 Racer
« Reply #164 on: February 03, 2017, 08:21:34 AM »
Alright, this baby is still alive and kicking. Not sure if I will make it on the track this year yet but I'm putting pressure back on this one since I came into a couple extra bucks.

I am still focused on the frame/suspension which still needs the following:
- New springs/emulators for forks
- Race Tech rear shocks - still need to get the spec sheet filled out and send their way
- Triple trees - I am in the zone for offset to get the right trail, so a little more tweaking here will be needed before I commit
- Gas tank cleaned and painted/coat inside
- Mount oil tank/cooler and run lines - all of which I already have just needs to get done
- Mount seat
- Rear sets figured out - this will depend on what rear wheel I use. I already have the one set up for rear drum but its SOOO heavy. I have a flat track hub that I might use instead (entire hub weighs what the CB cush drive weighs) and get it laced up to a new WM5 raingutter rim from Borrani and use the same rear brake components Devin from Cognito Moto recommends for his rear disc conversions

That gets me a fair bit closer to a truly complete and finished roller. Then comes the fun part, the engine. Thats for another day although I do need to start thinking about a cam, thoughts?
All you gotta do is do what you gotta do.

Vintage Speed Parts Mashup: http://forums.sohc4.net/index.php?topic=133638.0
Rickman CR Parts Kit Refresh: http://forums.sohc4.net/index.php/topic,154837.0.html
AHRMA CB750 Racer: http://forums.sohc4.net/index.php/topic,158461.0.html
AHRMA Superbike Heavyweight Racer: http://forums.sohc4.net/index.php/topic,173120.0.html
'76F CB750 Patina Redemption: http://forums.sohc4.net/index.php/topic,174871.0.html

Offline calj737

  • Really Old Timer ...
  • *******
  • Posts: 21,032
  • I refuse...
Re: CB750 AHRMA Sportsman 750 Racer
« Reply #165 on: February 03, 2017, 09:21:11 AM »
Thats for another day although I do need to start thinking about a cam, thoughts?
Something resembling my wife; angry and lumpy would be my choice.
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline Roach Carver

  • Really Old Timer ...
  • *******
  • Posts: 6,725
Re: CB750 AHRMA Sportsman 750 Racer
« Reply #166 on: February 03, 2017, 09:26:10 AM »
Hahahahaha👍

Offline slikwilli420

  • Master of Disaster
  • Master
  • *****
  • Posts: 2,362
Re: CB750 AHRMA Sportsman 750 Racer
« Reply #167 on: February 03, 2017, 10:26:48 AM »
Thats for another day although I do need to start thinking about a cam, thoughts?
Something resembling my wife; angry and lumpy would be my choice.

I like the sound of that. Here is what I am looking at, remember I am going with the Dynoman 12.5:1 62mm pistons. Open to suggestions

Webcam 63a/b/c

Cycle X CX-4

Megacycle 125-60/70/x12

Some call for big bore as well, will that be an issue with the 62mm pistons, even though they are high compression?
All you gotta do is do what you gotta do.

Vintage Speed Parts Mashup: http://forums.sohc4.net/index.php?topic=133638.0
Rickman CR Parts Kit Refresh: http://forums.sohc4.net/index.php/topic,154837.0.html
AHRMA CB750 Racer: http://forums.sohc4.net/index.php/topic,158461.0.html
AHRMA Superbike Heavyweight Racer: http://forums.sohc4.net/index.php/topic,173120.0.html
'76F CB750 Patina Redemption: http://forums.sohc4.net/index.php/topic,174871.0.html

Offline innovativems

  • Expert
  • ****
  • Posts: 1,029
    • Innovative MotoSports
Re: CB750 AHRMA Sportsman 750 Racer
« Reply #168 on: February 03, 2017, 10:50:44 AM »
Don't know how I missed this bike!  Definitely following!


Sent from my iPhone using Tapatalk
2007 KTM 990 adv
2003 Honda RC51
2000 Yamaha YSR50
1978 Honda Express
1975 Honda CB400f
1974 Honda CB350f
1974 Kawi H2
1974 Honda CB550f
1971 Kawi h1
1973 Kawi h1
1974 gt 550
1974 gt550

Offline turboguzzi

  • Old Timer
  • ******
  • Posts: 4,085
Re: CB750 AHRMA Sportsman 750 Racer
« Reply #169 on: February 03, 2017, 11:57:26 AM »
Alright, this baby is still alive and kicking. Not sure if I will make it on the track this year yet but I'm putting pressure back on this one since I came into a couple extra bucks.

I am still focused on the frame/suspension which still needs the following:
- New springs/emulators for forks
- Race Tech rear shocks - still need to get the spec sheet filled out and send their way
- Triple trees - I am in the zone for offset to get the right trail, so a little more tweaking here will be needed before I commit
- Gas tank cleaned and painted/coat inside
- Mount oil tank/cooler and run lines - all of which I already have just needs to get done
- Mount seat
- Rear sets figured out - this will depend on what rear wheel I use. I already have the one set up for rear drum but its SOOO heavy. I have a flat track hub that I might use instead (entire hub weighs what the CB cush drive weighs) and get it laced up to a new WM5 raingutter rim from Borrani and use the same rear brake components Devin from Cognito Moto recommends for his rear disc conversions

That gets me a fair bit closer to a truly complete and finished roller. Then comes the fun part, the engine. Thats for another day although I do need to start thinking about a cam, thoughts?

you are getting there, just take a deep breath!
my rough assessment is that you need still 200-300 hours (no procrastination allowed),
so do effective 3 hours stints a day in the garage and you'll will hit the track in may.
I hope you find this useful rather than depressing info :)

Offline slikwilli420

  • Master of Disaster
  • Master
  • *****
  • Posts: 2,362
Re: CB750 AHRMA Sportsman 750 Racer
« Reply #170 on: February 03, 2017, 12:33:41 PM »
That's a tall order TG but I am putting my best effort forward. Time is tough to find these days but I do have a pretty understanding wife so that helps.
All you gotta do is do what you gotta do.

Vintage Speed Parts Mashup: http://forums.sohc4.net/index.php?topic=133638.0
Rickman CR Parts Kit Refresh: http://forums.sohc4.net/index.php/topic,154837.0.html
AHRMA CB750 Racer: http://forums.sohc4.net/index.php/topic,158461.0.html
AHRMA Superbike Heavyweight Racer: http://forums.sohc4.net/index.php/topic,173120.0.html
'76F CB750 Patina Redemption: http://forums.sohc4.net/index.php/topic,174871.0.html

Offline Old Scrambler

  • My CB750K3 has been in 39 States & 5 Provinces
  • Old Timer
  • ******
  • Posts: 3,808
Re: CB750 AHRMA Sportsman 750 Racer
« Reply #171 on: February 03, 2017, 06:58:03 PM »
Slick................take a look at track days at the Black Hawk facility near Rockford, Il...............Big Bob from Chi-town has set up a vintage track day in past years. There are classes and track-days offered at RA........but bring your wallet ;)

Nice progress on the build............getting close to motor time.
Dennis in Wisconsin
'64 Triumph Cub & '74 Honda CB750 Bonneville Salt Flats AMA Record Holder (6)
CB750 Classic Bonneville Racer thread - http://forums.sohc4.net/index.php/topic,135473.0.html
'63 CL72 Project(s)
'66 CL77 Red
'67 Triumph T100C
'73 750K3 Owned since New
'77 750F2 Cafe Project
2020 ROYAL ENFIELD Himalayan

Offline slikwilli420

  • Master of Disaster
  • Master
  • *****
  • Posts: 2,362
Re: CB750 AHRMA Sportsman 750 Racer
« Reply #172 on: February 04, 2017, 08:32:46 AM »
I'll keep that in mind Old Scrambler thanks for the heads up!

Talked to Ken over at Cycle X yesterday and they are gearing up to do a batch of cranks so I'll be sending my stripped crank and Cycle X super rods out to them for balancing and assembly.

I have never shipped a crank before so what does everyone suggest? I'll need to build it so there is enough room to ship it back with the rods installed. I'm thinking double/ triple wall cardboard but it might need to be even stronger. How does everyone else do it?
All you gotta do is do what you gotta do.

Vintage Speed Parts Mashup: http://forums.sohc4.net/index.php?topic=133638.0
Rickman CR Parts Kit Refresh: http://forums.sohc4.net/index.php/topic,154837.0.html
AHRMA CB750 Racer: http://forums.sohc4.net/index.php/topic,158461.0.html
AHRMA Superbike Heavyweight Racer: http://forums.sohc4.net/index.php/topic,173120.0.html
'76F CB750 Patina Redemption: http://forums.sohc4.net/index.php/topic,174871.0.html

Offline RAZZ

  • Enthusiast
  • **
  • Posts: 128
Re: CB750 AHRMA Sportsman 750 Racer - shipping my crank?
« Reply #173 on: February 04, 2017, 08:48:38 AM »
Take a look at This: http://www.aperaceparts.com/packaging.html


Sent from my iPhone using Tapatalk

Offline 754

  • Really Old Timer ...
  • *******
  • Posts: 29,058
Re: CB750 AHRMA Sportsman 750 Racer - shipping my crank?
« Reply #174 on: February 04, 2017, 10:21:11 AM »
Dont #$%* about, build a plywood box.... Then screw the top down.......reuseable..
 It will last you the rest of your life..

7 words I hate...I thought I packed it pretty good............
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way