eric2281's progress thread- '80 cb750k

[eric2281]

Now that I'm starting to make headway with my bike, I figured maybe it's time to make a thread on my progress. Unfortunately, I didn't take any pics of my bike when I first brought her home so envision a bone-stock cb750k with a windscreen and hondatech luggage rack.

Here's the earliest pics I have. In these pics, she already has euro bars & el cheapo blinkers~

Since then, aside from maintenance, I've added a new tail light, 4-1 mac exhaust, new grips, bobbed and painted the rear fender, painted front fender, installed mini gauges, removed 1" of seat foam, lowered headlight, and added bar end mirrors.

Future changes include: HID or halogen headlight. I'm undecided b/c I can't seem to find anyone who offers a proper 7" round HID projector & I don't want to burn out the retina's of other drivers. I've ran HID's in foglight housings on my car & they're INSANELY bright.

I'd like a cafe style seat but don't want to do any hacking. I want to be able to still use my current seat for occasional 2-up riding. I like the cafe seat that BCR offers for us DOHC's but it is super pricey. I'd also like to do rearsets but again, I'm undecided b/c of 2-up riding.

I may bob the front fender too but no solid plans right now. I'm going to need to re-spoke the wheels sooner than later and at that time, I'd like to paint the rims black.

Here's the most current pics I have. I'll try to get some better pics very soon~

Any advice/ critique is welcomed with open arms!

Thanks for looking!

-Eric

 

[KiwiTim]

Re: eric2281's build thread- '80 cb750k

Looking good, I'll be following this one. I'm about to try to cafe-ish my cb750 DOHC too. How do they gauges go? I'm looking at some the same. Do you know what the ratio is for the speedo and tach?

 

[eric2281]

Re: eric2281's build thread- '80 cb750k

Thanks Tim!

According to the DCC website, the speedometer ratio is 60MPH @ 2240RPM. I'm not entirely sure what this means but it is accurate on the cb750. I know this to be true b/c I had my wife pace me on the highway yesterday. The tach ratio is 4:1.

I mounted my gauges using the same mounts on the upper triple tree that the OE gauges mounted to. Mounting was super easy. The semi-hard part was the wiring but I think that was because the previous owner did some haywiring inside the headlight bucket. Having a circiut continuity tester will be a big plus. The color coded wires do not match up the the OE wire color codes so have a wiring diagram on hand. Look for my post on gauges in the 1-800-cafe-help section for more details on these gauges.

IMHO, the hardest part about cafe'ing a dohc is figuring out what to do about the seat. It obviously can be done. It's just not as easy as the sohc's.

 

[hurley209]

Re: eric2281's build thread- '80 cb750k

hey great bike dude!
i think youll get more responses though, if you put your build thread in the projects board (big arse) with the other build thread. i bet alot more of us will chime in for your build.
just thought id mention it.

 

[eric2281]

Re: eric2281's build thread- '80 cb750k

hey great bike dude!
i think youll get more responses though, if you put your build thread in the projects board (big arse) with the other build thread. i bet alot more of us will chime in for your build.
just thought id mention it.

You're right. I wasn't thinking. I guess I thought mine didn't qualify as a big project. The folks in there have complete teardowns and rebuilds. I just swapped out a few things. LOL.

Mods/ Admin: Can you please tow this to the Cafe racer section of Big Arse Projects?



Thanks in advance!

-Eric

 

[IndieSol]

Re: eric2281's build thread- '80 cb750k

The 2240:60 means that the front tire is doing 2240 revolutions per minute when the bike is going 60 mph. I have a Suzuki GS1100 and it uses the same ratio speedometer.

 

[eric2281]

Re: eric2281's build thread- '80 cb750k

The 2240:60 means that the front tire is doing 2240 revolutions per minute when the bike is going 60 mph. I have a Suzuki GS1100 and it uses the same ratio speedometer.

Ah, thanks! That makes sense b/c I knew it wasn't engine RPM. My gas mpg would be awesome if engine revs were that low @ 60mph. LOL

 

[eric2281]

I got my bump seat from Benjie last week. It's pretty sweet! It has a removable cowl for 2-up riding. Also my vanity plate came in. Unfortunately, DO THE TON don't fit. I'll be painting the bike pretty soon. I may get clip-ons if I can fab up rear sets that won't interfere with the passenger foot pegs.

 

[rrtec]

Looking great! Man I wish I had spokes... ALSO man after my own heart... I am a BMW guy myself...

 

[eric2281]

Thanks! It's getting new paint sometime over the winter, as well as a few minor changes & upgrades.

 

[Griff5268]

That seat is AWESOME. How much? Where can I get one? Thanks in advance.

 

[eric2281]

Thanks Griff, I hired Benjie from http://benjiescaferacer.com/ to build me the seat. He said it's the first 2-up cowl seat he's ever done for a dohc cb750. I paid out the nose for it ($6xx) Maybe he'd cut you a better deal since he's got the mold for it now. I don't know for sure though. I'm wishing maybe I went with the solo cowl seat but It's nice to have the option to take my kid out for rides still.

Overall, I'm pretty happy with the fit and finish. Padding is nearly non-existant though. May get it reupholstered some time down the line with a little more padding. Benjie is a super nice guy & good at responding to emails. The deadline was a bit stretched out though... I was told between a month - month and a half. It was closer to 90 days. May not be a big deal if your riding season is over.

 

[Griff5268]

Cool. It looks great.

 

[eric2281]

I have Tarozzi rearsets on order now. This means I'll be ditching the euro handlebars & going with clip-ons. I rebuilt the Mikuni carbs I bought & now need to mount them. Still haven't done ANY bodywork. I gotta get up off my rear and get it done soon. I think some of the lack of motivation comes from my dislike for the gas tank.

 

[Hoosier Daddy]

Found your thread linked in your sig line so I thought I'd follow along for gits-n-shiggles. 8)

 

[SoyBoySigh]

Great lookin' DOHC 'K. Haven't seen that Benjie-seat before. Is it really all that suitable for two-up riding? It looks hard as a board back there. Unless that's soft cushioning, in which case it looks like the stop-light would bend upwards when the pillion-personelle sat down. I've looked at Benjie's's site, and haven't seen this. Maybe it's just been that long.

Anyw which way, I sure like the 'K. I've spent, and I'm STILL spending a load of money just to swap out to wire wheels, AND eliminating the alloy plates where the foot-pegs are. Basically, getting a 'K model with some up-grades. And with spiral cylinder studs that are supposed to me much much stronger. Or so I am told.

The 'K is the better looking bike, it's too bad they didn't make bigger versions of it. I am working on some new side-covers for these things. I might just have to make a permanent mould, seeing how many people chuck the old ones away! Ha ha.

For your peg location issue, IF you don't wanna just drill new holes in the frame, I would just put a strip of steel down the
length of the bottom, bolted at each end at the stock peg locations, and paint it black to match the frame, then you'd need a hole or better yet a welded stud right where you want your pegs. But I think the best spot is just above and behind the pivot. IF you could put up with "race" shifting, you could just reverse the pedal, but there's stuff available.

The best rear-set supplier, maybe a bit expensive but they have a LOT of "universal" type controls in many different styles, is "Motocicli Veloci Milano". Lots of good clip-ons as well. One thing, if you wanna go with a much lower bar, heck even the superbike bars will affect this, you will need to get a "sport-kit" throttle and switch-pot, or it's equivalent, or else the cables will foul on the tank. Or you could try to drill and plasti-weld new threaded bosses on the switch-pots for forward pointing cables, that might give an extra stretch so that the cables aren't also too long. The OEM "sport-kit" fitment, lower bars and rear-set pegs, for the DOHC Super-Sport, came with shorter cables as well. It all adds up if you're gonna do this your-self. But cables can be shortened, and universal cable kits where you braze the end on the cable after you cut it to length have been in use for ever and ever. I guess this is one advantage of the new "fly by wire" throttle systems. Though, I've heard bad reviews of them, lagging response, stuff like that. Which is probably just due to poor set-up. Unless you can sense micro-seconds of delay, which I doubt. Maybe if you were a really really good drummer, or a classical orchestra conductor.... However you slice it, changing up bars and pegs isn't as simple as it SHOULD BE. Heck, look at the Honda Super-Hawk from the '60s, they had pegs with controls attached, that you could move from one location to another, and splined mated faces so that you could angle them right where you wanted 'em too. What the heck happened to THAT??? I have a few theories, but they don't reflect well on Honda, or on the DOHC or any other later era Hondas. And I won't elaborate too much here. Of course, they cheaped out on early Hondas too, with randomly fitted cranks and parts that often broke and needed re-calls to fix, stuff that would be unforgiveable in this day and age. I guess it's a good thing the old farts put up with that kind of crap back then. Ha ha. Maybe it was the state of the entire industry.... Anyway, I am really sick of these Dunstall copy-cat peg brackets, and I'll be going to a lot of trouble just to get my frame looking like a 'K frame.

In the mean-time, it's interesting to see all of the things the DOT crowd has done with the DOHC. Seems there hasn't been a lot of respect around here for 'em, no?

-S.

 

[eric2281]

Sorry for the late reply.

Define "suitable" LOL. The seat would not be comfortable for a passenger on a long ride. The one & only reason I went with the 2-up seat was so I could bring my daughter on short rides around the neighborhood or to the ice cream parlor. I'm guessing there's about 1/8 or 3/16 of foam in the seat so there's no issues with the stoplight. There's a bracket on the inside that the taillight affixes to firmly. I will be getting this reupholstered within the next 2 yrs for sure.

As for the rearsets, I'm still at a loss. I thinking the tarozzi mounts are for a dohc cb750 with that aluminum footpeg bracket, not my type. I'm thinking of having something fabbed but ticked b/c these were supposed to be bolt-on.

On a lighter note, I've been getting work done on it. Still waiting on the clip-ons from DCC. Maybe ride-able by early-mid june.

 

[Hoosier Daddy]

Yeah, I'm finding most of the DOHC CB750 performance parts are designed to fit the "F" model not the "K" or my lowly "C". :

 

[eric2281]

I found out that these rearsets are designed for European models. I guess they don't make rearsets for USA dohc cb750's. I'll do some research and figure out what sets the Euro models apart from US models.

 

[eric2281]

After over a year of getting nothing done, I finally devoted some time a few weeks ago to getting her finished rideable. The paint is Rustoleum rattle can Hunter green. I still need to wetsand the tank and hit it w/rubbing compound. I ditched the idea of clip ons and rearsets. I want to maintain a comfortable 2-up riding configuration. I also decided against the mikuni carbs. Future plans include possibly painting on the racing stripe or at least redoing the seat cowl with the leftover decal I still have. The motor stumbles above 6-6.5k under load so I'd really like to get that sorted out soon. I'd like to get proper velocity stacks rather than using the rubber inlets from the airbox. I still need breathers and lastly, I want to pick up one of those small battery packs and mount it under the seat cowl so I can ditch the big heavy acid battery. Long term plans would be a new/rebuilt motor and frame restoration.