1979 CB750F Tracker (maybe?)

jordandogtown said:
Not cheap by any means, but Cognito sure puts out some high quality parts. I'm going to drool over it a little longer then press it in and spend all weekend mashing parts together

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Ya, I bit the bullet and got mine for the GL500 a couple months ago. Beautiful piece and pressed in like butter

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Koëstum said:
Ya, I bit the bullet and got mine for the GL500 a couple months ago. Beautiful piece and pressed in like butter

Same here. As tight as all the tolerances are, the stem was a perfect match with the lower clamp. I couldn't have got a local shop to measure and mill a custom one any cheaper.
 
I ended up with a nice rainy Saturday that netted me plenty of shop time. So many parts of this build have been like one of those weird engineering time killing puzzles where all the pieces have to go together at exactly the same time. I couldn't trim the seat until the subframe was done. I couldn't work on the subframe until I knew where the tank would sit. I couldn't move the tank until I knew how the frame would end up. I wouldn't know how the frame would end up until the suspension was finalized (or close), and so on....

After a few months of scrounging eBay and saving money I feel like I'm finally making some tangible progress - other than all the doodles my wife so lovingly hangs up on the fridge.

With the stem pressed in and the forks loosely in place, I lowered the bike onto some lumber to account for the height of the tires. The rear sat a little high after making the move to a lower 17" front, but I've got the shock preload set at the highest, and am comfortable with the adjustment to continue.

Moving the tank was a breeze. The new position is almost identical to the stock position without the rubber mounts. I placed the rubbers in their new location relative to the OE mounts and traced/punched/drilled all the way through the gussets. Honda used this technique and then welded a single tube through the frame. I opted for a piece of solid round bar that I had laying around which happened to be the exact size

(Everything will get a final grinding/welding/love once the motor is out)

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I love the DOHC tanks, but understand why they get a bad rep. I think they shape is fine, but the stock placement doesn't flow and lacked a bit of aggression. By moving the front mounts just barely, and raising the rear a bit, the bike takes on a whole new persona. Sure, it looks a little muscle bike-esque, but I dig it. I like how the bottom of the tank seam more closely follows the top of the head, while the rear of the tank flows into the rear of the frame. The bottom bulge (decal portion) also create a near parallel line as well, giving it that SOHC tank feel that, IMO, sets the standard for motorcycle lines. The only downside is the emblem, which will be removed and probably replaced with a decal

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Looking good Jordan - nothing about the positioning of that tank that doesn't work. I like these DOHC tanks too, with a little finagling I really like their unconventional shape. No clearance issues?
 
The Jimbonaut said:
Looking good Jordan - nothing about the positioning of that tank that doesn't work. I like these DOHC tanks too, with a little finagling I really like their unconventional shape. No clearance issues?

None yet *knocks on wood*

The steering is shortened a little by the move as well as the gigantic GSXR upper tubes, so I guess my world's tightest slalom attempt will have to wait ;D

One great benefit, is that I now have a huge battery sized area opened up inside/under the rear of the tank. I should be able to fit a lithium battery in there without hanging below the frame rails at all. That will hopefully keep the electronics tray fairly compact under the seat
 
Nah mate, you'll be golden in the tight slalom - it's looking cool in front of the pump attendant trying to pull off a 12-point turn that'll really get you sweating 8)
 
Not saying it matters since they're 5 gallons, but you'll a half gallon or so of fuel capacity. Looks better though, I agree.
 
I really like that tank position Jordan. Gives the bike a real masculine statement and plenty of room to display those nice CR carbs and some shiny velocity stacks.
Look good!

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Could you fill the old tap hole and put either dual taps or a crossover down near the front of the tank to get back the capacity?
 
irk miller said:
Not saying it matters since they're 5 gallons, but you'll a half gallon or so of fuel capacity. Looks better though, I agree.

Maritime said:
Could you fill the old tap hole and put either dual taps or a crossover down near the front of the tank to get back the capacity?

Great points. I suppose it didn't matter too much in the stock position since the rear of the tank is so much smaller than the front, and hid away less gas. I think the regular "on" position of the petcock would be unchanged- but the "reserve" portion would definitely be reduced. Once I flip over to reserve I'll just have to ride a wheelie the rest of the way home 8)

To be honest, my back and knees (and the stereotypical café "seat" - but I won't admit it) keep me from riding more than ~50 miles or so at a time. I should be able to hop between gas stations without much issue.
 
With the tank sorted out, I'm on to the next puzzle piece. I made the final adjustments to the top subframe rails with a lot of patience and hand filing. I ended up with quite a bit of surface contact between the rails, so I'm feeling really good about the structural stability even with my subpar welding skills. Gussets will be added as well in addition to the main vertical(ish) supports. There is a ton of real estate behind the rear of the tank that will let me hide some bracing.

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Being pretty green to the art of tube notching, I am having a blast figuring it out. I was a little disappointed in the life of my $5 hole saw so I opted to finish the subframe by hand. The supports are roughly 3/4" OD so it wasn't too much of a chore. I used an angle grinder to remove the bulk of the material, then shaped and refined the curves with a hand file until they matched the frame. The compound angles were a little challenging but pretty satisfying once they lined up

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The Jimbonaut said:
Nah mate, you'll be golden in the tight slalom - it's looking cool in front of the pump attendant trying to pull off a 12-point turn that'll really get you sweating 8)

Oh no... I accompany my wife to a lot of events at her high school (she's the teacher, to be clear) and I can just hear the cool kids laughing now. I'm having flashbacks all over again
 
After tacking on the subframe, I could finally begin shaping and fitting the seat pan. I have no experience with fiberglass, so I just grabbed the angle grinder and went at it (theme of this whole build?) It cut super easy, and luckily I was just steady enough to not ruin it.

If you can remember back a few pages, I've had a "cut here" line painted on for months. After cutting along that line I thought I had made a terrible decision. The proportions were all way off, the lines didn't work together anymore, and I could just hear my hard earned money circling the toilet. After a quick snickers break, I started trimming the edges back little by little and eventually got it to a point where I really dig it. The bottom was also cut about 1/4" so it doesn't hang below the frame rails much. I still need to go back and refine/sand the edges, but I had my fill of fiberglass dust for the day, so it can wait.

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Onto the next puzzle piece; the battery. I knew I wanted to upgrade to lithium to save weight and space, but I really didn't want to mount it in the tail. I'm trying to keep that as empty as possible, with only a license plate and taillight. Moving the tank opened up a nice little cavity, but I still had to test it out before spending the money on the battery. After digging through some reviews, I began with the dimensions of the Shorai 12 cell that's so popular. After laughing at how comically small it looked, the mockup fit perfect inside the tunnel, tucked completely out of the way. I'll use some heat shielding and foam insulation (from heat as well as bumps) to protect the lil guy. Hopefully the remaining electronics will fit under the seat without hanging below the frame.

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jordandogtown said:
I accompany my wife to a lot of events at her high school...
Oh come on... you could have just left that there without qualifying it...


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jordandogtown said:
After tacking on the subframe, I could finally begin shaping and fitting the seat pan. I have no experience with fiberglass, so I just grabbed the angle grinder and went at it (theme of this whole build?) It cut super easy, and luckily I was just steady enough to not ruin it.

If you can remember back a few pages, I've had a "cut here" line painted on for months. After cutting along that line I thought I had made a terrible decision. The proportions were all way off, the lines didn't work together anymore, and I could just hear my hard earned money circling the toilet. After a quick snickers break, I started trimming the edges back little by little and eventually got it to a point where I really dig it. The bottom was also cut about 1/4" so it doesn't hang below the frame rails much. I still need to go back and refine/sand the edges, but I had my fill of fiberglass dust for the day, so it can wait.

106817-130319082635-50501981.png


Onto the next puzzle piece; the battery. I knew I wanted to upgrade to lithium to save weight and space, but I really didn't want to mount it in the tail. I'm trying to keep that as empty as possible, with only a license plate and taillight. Moving the tank opened up a nice little cavity, but I still had to test it out before spending the money on the battery. After digging through some reviews, I began with the dimensions of the Shorai 12 cell that's so popular. After laughing at how comically small it looked, the mockup fit perfect inside the tunnel, tucked completely out of the way. I'll use some heat shielding and foam insulation (from heat as well as bumps) to protect the lil guy. Hopefully the remaining electronics will fit under the seat without hanging below the frame.

106817-130319081139-50471873.jpeg


106817-130319081141-50482490.jpeg


106817-130319081141-504933.jpeg
The battery and wiring always a challenge on the Cafe and Brats. Hid a Gel battery in tail hump on my project. Reduced sized and CCA , flipped it sideways and used the OEM Honda battery holder trimmed down with OEM strap. Worked well. Changed all lights including Mini LED turn reduces amp draw.
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7aliveatlast7 said:
This is exactly what I’ve been struggling with, the compound angles! Got one perfect, but getting the other one to match was tricky.

It was definitely a test in patience and sanity, but so worth it. I caught a couple fingers on the top edge while filing and got some pretty good cuts from it. Now I can officially say "blood, sweat, and tears" went into it

The tears came from cutting a perfectly good motorcycle in half after I bought it :'(
 
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