Author Topic: CB750 AHRMA Sportsman 750 Racer  (Read 171907 times)

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Offline scottly

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Re: CB750 AHRMA Sportsman 750 Racer - prepping for Road America
« Reply #425 on: June 06, 2017, 07:50:33 PM »
I would still run the resistors with the 3.2 ohm coils. Good luck! 8)
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Offline slikwilli420

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Re: CB750 AHRMA Sportsman 750 Racer - prepping for Road America
« Reply #426 on: June 06, 2017, 08:03:50 PM »
I would still run the resistors with the 3.2 ohm coils. Good luck! 8)

Already installed! Just talked to Hondaman and he gave me the whole scoop. I should be all set now. Set of coils and ignition headed back to dyna after the weekend. Maybe they will let me get the 5 ohm coils instead?
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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
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Offline Kickstart

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Re: CB750 AHRMA Sportsman 750 Racer - prepping for Road America
« Reply #427 on: June 08, 2017, 07:31:21 PM »
Glad you've got the coil situation figured out.. I think we both wrenched more than we raced last weekend.  :)

Hey, BTW, congratulations on successfully completing the class and officially participating in the races.  You and your father really worked for it last weekend.. way to pull it off!

I'm looking forward to seeing you down at Barber.

Good luck this weekend!
- Chris
75' CB750F Orange flake (rider)
75' CB750F Blue (Project)
75' CB750F Painted black (Project)
No Reserve Racing #171 AHRMA

Offline slikwilli420

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Re: CB750 AHRMA Sportsman 750 Racer - prepping for Road America
« Reply #428 on: July 11, 2017, 08:53:20 AM »
Alright, after fixing all of the photobucket issues (I am now using direct links from Google Photos) I figured I would update my loyal followers (haha).

All of my oil lines have been rebuilt with crimp fittings instead of compression style fittings. I also discovered that the fittings to the oil cooler were vastly UNDER-torqued. They required 29.5ft/lb and I was doing it with a small wrench before now, so that is also fixed up.

The last piece is the tank, which is what plagued me at Road America. It was originally Kreemed, but that crap comes out with acetone, so it will get a Redkote treatment, and a bigger petcock (5/16" Pingel vs the 3/16" stock)

That should cover all of my gremlins at least for now. For those going, I'll see you at Barber in October!
« Last Edit: July 11, 2017, 09:59:02 AM 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
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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 Kickstart

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Re: CB750 AHRMA Sportsman 750 Racer
« Reply #429 on: July 11, 2017, 09:41:14 AM »
What year tank do you have, and what model Pingel petcock works with it?

I have a 77/78F tank and finding a good flowing petcock has been a real challenge for me, as the original OEM ones aren't available anymore.  I can get an OEM one that fits, but is not for the 750 and doesn't seem to flow as well... and aftermarket petcocks are all junk.  I'm positive I'm going lean on long straights

I might switch over to a K2 tank I have laying around to solve the problem.
- Chris
75' CB750F Orange flake (rider)
75' CB750F Blue (Project)
75' CB750F Painted black (Project)
No Reserve Racing #171 AHRMA

Offline slikwilli420

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Re: CB750 AHRMA Sportsman 750 Racer
« Reply #430 on: July 11, 2017, 10:02:46 AM »
One of two things you can do Chris. I also have a 77/78F model tank. The Pingel single output (or dual if you are keen on it) 5/16" will just fit into the tank bung. What I did was make an adapter to screw onto the tank and then the petcock will screw into the adapter. It moves the petcock down a little, but I still need to do some tweaking to get it just the way I want. If I didnt already have the single output Pingel, I would pop for the dual since you really can't have too much fuel.

The second option still involves an adapter at the bung, but I would simply use a 90 degree elbow to feed an auxiliary fuel valve. I thought about that but again, I already had the Pingel on the shelf so I figured I would try.
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 MRieck

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Re: CB750 AHRMA Sportsman 750 Racer
« Reply #431 on: July 11, 2017, 11:32:42 AM »
Install a good tank vent system with that Pingel.
Owner of the "Million Dollar CB"

Offline slikwilli420

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Re: CB750 AHRMA Sportsman 750 Racer
« Reply #432 on: July 11, 2017, 12:38:27 PM »
Install a good tank vent system with that Pingel.

Mike, talk to me about how good. I was fearing fuel issues at Road America and took my stock gas cap which has one 1/16" hole in the top and enlarged it to 1/8" as well as adding another. Meaning well over 8x the venting hole area of original. Do I need more?

PM incoming on a head I picked up.
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 754

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Re: CB750 AHRMA Sportsman 750 Racer
« Reply #433 on: July 21, 2017, 10:43:27 AM »
Aluminum is a third the weight of steel. Chro-No is same weight as any other steel.
.120 sounds thin but would have to check a modern axle to compare.
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Offline calj737

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Re: CB750 AHRMA Sportsman 750 Racer
« Reply #434 on: July 21, 2017, 11:01:39 AM »
Aluminum is a third the weight of steel. Chro-No is same weight as any other steel.
.120 sounds thin but would have to check a modern axle to compare.
Yes, it's the same weight, but stronger at the same weight. Thus, using a hollow axle should provide ample strength at less weight.

You can investigate some options here, Matt:
https://www.roguefab.com/tube-calculator/
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Offline slikwilli420

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Re: CB750 AHRMA Sportsman 750 Racer
« Reply #435 on: September 12, 2017, 06:13:23 AM »
Still alive and kicking and getting ready for a track day this Friday at a local track in South Haven, MI. I am familiar with this track so that takes some stress off and I can concentrate on technique and what the bike is telling me.

Only one pic to speak of, but its a big change. I received my tank from Air Tech, as getting the liner out of the old one was proving way too much headache and I would have changed to a glass tank anyway for next year. This is the Read Titan tank they make, Its a really nice piece, and about 9lb lighter than the stock steel tank, which is a plus in my book.

The tank has dual petcock bungs, but due to location, I will use NPT to barb elbows and run two inline shutoff valves along with a crossover which should totally rid me of fuel issues. The tank was coated by them and should last a lifetime with the non-ethanol gas I am using and the race gas I will use once my motor is built.

All of the other little odds and ends have been fixed as well, with new oil lines, a few changes to the wiring and a check of fasteners, oil, tire pressure, and chain.

If all goes well Friday, it will be pulled back into the garage, the gas drained, and aside from another wipe down and oil change, it will be ready for the big show at Barber.
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 seanbarney41

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Re: CB750 AHRMA Sportsman 750 Racer
« Reply #436 on: September 12, 2017, 09:43:16 AM »
What does Gingerman have to say about running vintage stuff at their track days?
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Offline slikwilli420

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Re: CB750 AHRMA Sportsman 750 Racer
« Reply #437 on: September 12, 2017, 10:19:27 AM »
Nothing whatsoever. 2-wheeled track days are handled by a place called Sporbike Track Time. This ended up turning into an event that will be an open format, meaning I get up to 3 hours of track time. Of course, by total loss ignition wouldn't have any of that so I figure 20-30 min on track and 30 min off to get battery charged up should be good.
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 seanbarney41

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Re: CB750 AHRMA Sportsman 750 Racer
« Reply #438 on: September 12, 2017, 10:39:50 AM »
So you have not contacted Sportbike Track Time to ask about potential problems they may have with you running a vintage bike?
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Offline slikwilli420

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Re: CB750 AHRMA Sportsman 750 Racer
« Reply #439 on: September 12, 2017, 10:50:02 AM »
Help me out here Sean. What issues are you talking about? I did talk to the guy promoting the event and a person at STT and both said it was no issue.
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 seanbarney41

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Re: CB750 AHRMA Sportsman 750 Racer
« Reply #440 on: September 12, 2017, 12:10:30 PM »
I'm not trying to grill you down, just curious as I would like to do some track days myself and the riders of modern bikes I have talked seemed hesitant to say that I would have no problems.
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Offline slikwilli420

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Re: CB750 AHRMA Sportsman 750 Racer
« Reply #441 on: September 12, 2017, 12:20:51 PM »
A running bike is a running bike, whether vintage or brand new. If your bike is sorted and runs well on the street with spirited riding, I would think you are nearly there. Knowing how much harder even a novice like me rides on a track, I would think about upgraded brake pads and tires at a minimum but beyond that, I don't see the difference.

Im sure I will get some shade from sport bike guys but as long as I don't do anything dumb, hopefully they accept me as bike guy, an nothing more.
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

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Re: CB750 AHRMA Sportsman 750 Racer
« Reply #442 on: September 12, 2017, 02:08:55 PM »
A running bike is a running bike, whether vintage or brand new. If your bike is sorted and runs well on the street with spirited riding, I would think you are nearly there. Knowing how much harder even a novice like me rides on a track, I would think about upgraded brake pads and tires at a minimum but beyond that, I don't see the difference.

Im sure I will get some shade from sport bike guys but as long as I don't do anything dumb, hopefully they accept me as bike guy, an nothing more.
And if you pass Tech Inspection, who gives a fart what you ride. Matt, you might just out-ride those sport bike wannabe jockeys  ;)
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"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 seanbarney41

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Re: CB750 AHRMA Sportsman 750 Racer
« Reply #443 on: September 12, 2017, 02:29:29 PM »
Was absolutely not questioning anyone's ability to ride track...only one specific organizations willingness to provide useful track time for vintage bikes.
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Offline slikwilli420

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Re: CB750 AHRMA Sportsman 750 Racer
« Reply #444 on: September 12, 2017, 06:45:51 PM »
A running bike is a running bike, whether vintage or brand new. If your bike is sorted and runs well on the street with spirited riding, I would think you are nearly there. Knowing how much harder even a novice like me rides on a track, I would think about upgraded brake pads and tires at a minimum but beyond that, I don't see the difference.

Im sure I will get some shade from sport bike guys but as long as I don't do anything dumb, hopefully they accept me as bike guy, an nothing more.
And if you pass Tech Inspection, who gives a fart what you ride. Matt, you might just out-ride those sport bike wannabe jockeys  ;)

I have heard that some of these guys really park it in the corners, likely because they aren't there for anything else to get street cred. That said, I am looking forward to riding with any and everyone whom wants to be safe and have a good time.

Sean, I would give STT a try next time and see. There is a public day coming up at Grattan in the next couple of weeks. Requirements to ride are very few so it's easy for anyone to get started.
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 seanbarney41

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Re: CB750 AHRMA Sportsman 750 Racer
« Reply #445 on: September 12, 2017, 07:17:20 PM »
Grattan!?...that track scares me just watching.  Do have vague plans to put an rd350 together for the track this winter.
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Offline Kickstart

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Re: CB750 AHRMA Sportsman 750 Racer
« Reply #446 on: September 13, 2017, 10:09:50 AM »
Looking good... and looking forward to seeing you at Barber in a few weeks.
Grattan is a great, technically challenging track... but it's really slippery if it rains, or if someone oils the track (they don't have a large support contingency for clean-ups).

And speaking of which... Some track day organizations are adverse to vintage or custom bikes.  Primarily for liquid containment concerns.  You're much more likely to see oil on the track at a vintage weekend (I'm pretty sure almost every AHRMA event has someone, at some point, spilling oil on the track).  The track day group I've ridden with a few times specifically states that if your bike is older than 20yo you need to contact them.  Fortunately, they are vintage friendly, and have staff that race vintages bikes so they know what to look for when tech-ing them.  Sounds like you already cleared it with your group, and your bike is already all safety wired and has a belly pan... so you should be good.







- Chris
75' CB750F Orange flake (rider)
75' CB750F Blue (Project)
75' CB750F Painted black (Project)
No Reserve Racing #171 AHRMA

Offline bwaller

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Re: CB750 AHRMA Sportsman 750 Racer
« Reply #447 on: September 13, 2017, 02:16:31 PM »
In these parts the trackday providers split the pack into three groups, novice, medium, and fast. Unless the vintage bike is relatively recent they must run in medium because of the potential closing speed difference. Unfortunately the medium group allows passing only after the apex or on any straights.

Even a poorly ridden R1 or similar will "make haste" after any apex. Any racer on an older or smaller displacement bike would need to be able to pass on the entrance to a corner. I always just went ahead and made my pass where I could and lived with the finger pointing.

For learning a new track it may be alright, but truth be known at some point street trackdays will not be the kind of time you need to hone racecraft. It's just too frustrating. Look for vintage race ass'n trackdays if you can find them.

Offline slikwilli420

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Re: CB750 AHRMA Sportsman 750 Racer
« Reply #448 on: September 13, 2017, 02:28:34 PM »
Brent, the usually break it into groups, but since this is a private event, it has been turned into a continuous 3 hours on track, where you can come and go as you please.

We'll see how others react to an older bike but if its not my cup of tea, I'll just move on. I need a track day before Barber to make sure some of my fixes from previous races can hold up for the full number of laps in racing conditions. I will need to look a bit more for vintage track days in the area but I am not aware of any.
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 bwaller

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Re: CB750 AHRMA Sportsman 750 Racer
« Reply #449 on: September 13, 2017, 04:05:20 PM »
We're registered for Barber.