Topic: CB750 AHRMA Superbike Heavyweight Racer

[754]

 Are you running  20mm rear axle ? I can sell some chain adjuster sideplates  if you wantvto make the middle parts. Like this.. if I can finish.. how thick is the swingarm ends?

[slikwilli420]

Are you running  20mm rear axle ? I can sell some chain adjuster sideplates  if you wantvto make the middle parts. Like this.. if I can finish.. how thick is the swingarm ends?

20mm front and rear. I'll need to check once I get the swing arm ready to put on. The adjusters it came with are steel which I won't be using.

[seanbarney41]

I had my f3 set up with a similar profile seat, and  renthal dirt bike bars, and man I could really throw that thing around...just needed rear sets to be perfect.  Riding position was really good for me, but you are a bit taller.  Hope the lower saddle does not make you too scrunched up.  It felt awesome  to be sitting more "in the bike" as opposed to "on".

...man, now you got me super excited to get that f3 engine rebuilt and back on the road!
DSCN0801 by Sean Barney, on Flickr

[slikwilli420]

Happy quarantine from Michigan! I have found a ton of time on my hands with the recent shutdown, and am in week 5 of being at home with my wife Ashley and 5 year old Jackson. That means I have time to work on bikes!

I have been slowly collecting parts and pieces for this one. When I last left off there was a frame with a few bits bolted to it and not much else. I came across a set of Astralite wheels hubs for the rear so the set is now complete.

Needless to say, the waterjet machine at the local machine shop has been busy. Brakes are mounted on custom brackets, spacers for the front wheel are done and I only need to turn them down some to shave some weight and make caliper bracket spacers for the other side, and it's a wrap. The rotors are custom ISR units that I ordered last March that showed up a few months ago.

The calfab swingarm install is all but finished as I am still playing with spacing for the pivot collar to get it just right so there is no play when tightened up. The axle adjusters are a 3 piece design bolted together and came out really good. They just need a bit of finish work then they can be installed and I can get chain alignment done properly, and finally make spacers for the rear wheel. The shocks are vintage Ohlins that were serviced by a place out in California. Pretty pissed they jerked me around for almost 14 months before they were done and returned to me, but they look great and I have the right one installed. This is a late F frame so the right shock mount is longer, putting the top out of alignment with the bottom, so some frame surgery is in order to fix that. I will fix that along with all the other frame bracing all in one go after I cut the tubes for braces and make up the oil cooler mount. With shutdown going on, I have no idea when I will be back to the welding shop to get it all burned together.

Items next up:
Finish rear wheel install, spacers, swingarm pivot and axle adjusters
Mount front fender
Oil cooler/number plate/headlight bucket mount
Cut down front axle to proper length
Mount a set of gutted gauges, block off speedo gauge and mount digital tach in other
Cut/fabricate frame braces for front down tubes, at the "V" above the swingarm and between tubes above swingarm
Spin-on oil filter adapter (refuse to pay $100 for one so will make my own)
Detab the entire frame
Start building the oil tank

[kap384@telus.net]

I had my f3 set up with a similar profile seat, and  renthal dirt bike bars, and man I could really throw that thing around...just needed rear sets to be perfect.  Riding position was really good for me, but you are a bit taller.  Hope the lower saddle does not make you too scrunched up.  It felt awesome  to be sitting more "in the bike" as opposed to "on".

...man, now you got me super excited to get that f3 engine rebuilt and back on the road!
DSCN0801 by Sean Barney, on Flickr

Sweet bike.  I'd like to see that! Start the rebuild!

[y2kc0wb0y]

Subscribed. Anyway to fix the old photo links?

[slikwilli420]

This one is still alive and well too!! I have been focusing on this one a bit lately until a few weeks ago when I needed to get really focused on my S750 bike for the upcoming season.

I have the frame all welded with gussets, frame kit, rear set bungs and all of the oil cooler/number plate stuff up front. Of course I had to blow it all apart from the first rough mockup to get there and now its time for the second and last mockup before things come down one more time for final assembly.

Started knocking up a new oil tank, similar to the one on my other bike, but deeper for more capacity:



Stock alternator cover and after cutting 30mm from it to narrow it:





Gauges from Speedhut fitted and ready to go. I used the Joker Machine rings to clamp it all back together. Very early superbike inspired if I do say so.



Working on the conversion of the left side engine lug to bolt on style. Why? Because I can and it looks badass.



Oil cooler/number plate mount made and tacked on, ready for final welding



Beautiful Auto crank ready to be sent off for some de-stroking work at Marine Crank



Lots more to come but it should be a badass ride.

[Ramrod_Racing]

Also, this is the Vintage Cup class for next year; so time to get crackin' 

[slikwilli420]

Also, this is the Vintage Cup class for next year; so time to get crackin' 

That lit a bit of fire under my butt for sure.

[slikwilli420]

Lord have mercy, its time for an update. So many things have happened since the last update that it will be hard to document everything but Ill try. Prepare yourself for a stream of consciousness post filled with pictures that may be out of order but it needs to be documented so here, we, go.

I am t-minus one week until I need to be loaded and headed for beautiful Southern New Jersey for the next round of AHRMA racing. This is the first time I will have 2 bikes to field and should be a really special event, as George will be there to bare witness to the whole thing.

Engine assembly and cam timing:








Finally in its home:



Oil tank finally complete (what a pain in the a$$ to make)



So, what the he11 is done:

Wiring
Oil lines
Engine assembly/install
Chassis all assembled and most everything that needs to be drilled for safety wire is
Bodywork painted and set up to be installed

What's left in the next 6 days:

Bleed brakes f/r
Install carbs and fuel lines/cables
Cut chain to length
Plumb breather/vent lines
Setup Dyna 2k ignition
1000 other little things I will get to when I see them

That's all for now but its still many hours of work, but I'll get there come he11 or high water!!

[Jerry Rxman Griffin aka MuthaF'er]

Oh yeah!!! 

[Old Scrambler]

Lots of Lube

Nice looking oil tank

[johno]

Man, Looking very sexy, that is one nice looking bike, well done and good luck with finishing off the project.
Your workshop is an encouraging environment to work in.
Cant wait to see how the new cam chain tensioner fares.
cheers johno

[turboguzzi]

all looks delicious! good luck putting it all together in time...  sounds like you have some all nighters ahead...

[gschuld]

Well I can say for sure that Matt has been busting his butt to get this bike ready.  And it’s chock full of custom pieces. 

George

[PeWe]

Very interesting reading with photos.
I look forward to see the dyno chart(s)
And result when riding the bike!

[gschuld]

I’ll let Matt give the details.  But I’m happy to announce the new bike is up and running, got broken in,  and made a successful lap or two around the block.  All signs are positive….

Good job Matt….and Ashley for being so supportive.

George

[Old Scrambler]

Very nice indeed

So sometime on Friday we should expect to hear the results of how it 'howeled' on on the dyno

[gschuld]

Yes, I suppose so.  Let’s not get hopes up too high here.  This engine is essentially a street bike engine perfectly capable of running pump gas and doing road trips being used on the track. 

The engine Kenny built for his superbike racer was FAR more of the full kill variety.

George

[PeWe]

100whp is expected if compression is enough?

[gschuld]

Well I’m hesitant to guess as dyno results regarding power numbers can be inconsistent between dynos depending on setting, corrective factors etc. 

We are primarily concerned with a nice air/fuel mixture through the range, and getting the timing dialed in for a nice even strong power curve that this layout of engine(and cam) is capable of.

I’m not sure how much time we will have on the dyno to fiddle with things beyond the basics.  The more time we have the more likely we will be able to get it closer to a ideal setting.

George

[Ramrod_Racing]

I only see one of the Hall bros on the pre-entry list, so not sure the dyno will be at NJMP this time.

[PeWe]

Yes, OK A/F mixture all over the throttle/rpm range is no. 1.

[gschuld]

I only see one of the Hall bros on the pre-entry list, so not sure the dyno will be at NJMP this time.

Not using Hall Bros at the track.  We have an appointment offsite:

https://www.xtrememachines.us/learn-about--factory-pro-dyno

[Ramrod_Racing]

I only see one of the Hall bros on the pre-entry list, so not sure the dyno will be at NJMP this time.

Not using Hall Bros at the track.  We have an appointment offsite:

https://www.xtrememachines.us/learn-about--factory-pro-dyno

Ahhh, y'all fancy huh?