Author Topic: AUXILIADORA 1981 HONDA CB750K BUILD  (Read 5743 times)

Online The Jimbonaut

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  • Posts: 1233
    • Lost Apostle
« Reply #50 on: Jun 17, 2018, 14:48:01 »
Looking great - really like Auxiliadora written like that on the tank too
« Last Edit: Jun 17, 2018, 14:51:07 by The Jimbonaut »
"I'm telling you Donnie, nuthin' but nuthin' but right"


  • Posts: 28
« Reply #51 on: Jun 20, 2018, 00:26:36 »
Looking great - really like Auxiliadora written like that on the tank too

Thanks man!

So literally just ordered some new cables (push/pull, clutch, and choke cable). The push and pull cables I ordered says they'll fit cb750's from 1969 to 1976 and not an 81 however I can't imagine them not still working with my carbs as the the length will work and the fittings on the end are the same as far as I can see. Once they come in that's when I'll go back to working on the bike.


  • Posts: 28
« Reply #52 on: Jul 02, 2018, 23:29:35 »
Small update!

So cables ended up working out. I only replaced the throttle cables and 1 of them is a little to short and needs a bit of modification to fit perfectly but functionally it works perfectly fine. In the process of removing the old throttle cables I found that one of the cables was actually broken which explains why the bike was revving so high in the video I posted in one of my last posts. After installing the new cables I proceeded to get the bike ready to turn on. Added some gas and she turned right on. Small adjustments need to be made to get the bike to idle some what well but more problems were ran into.

 The first problem was that the bike was running a little to rich. The fuel ratio screws were out 2.5 turns so I brought it down to 2.25 turns. I may even bring it down to 2 turns (Really don't want to buy more and more plugs due to fowling).

The second problem I faced was that the bike didn't run for long on its own at all. I should mention right off that bat that the battery I currently have installed in the bike isn't good. After one full charge it has the ability to turn the bike over once and then it's just to weak. Normally what
I'll do is boost the bike on, rev the engine with the throttle, use the idle adjustment screw to get the idle to a point where I don't have to rev the engine (typically pretty high idle), then I'll ride the bike for a block and it dies because the idle drops once it warms up and I can't start it again. I'm assuming this is due to the battery being weak as my charging system is in fact working but I'll have to update once I get a new battery and install it.

I'm sorry for my posts being some what short and not very interesting but I'm at that point where I'm getting tired of messing with things and just want the damn thing to run hahahah. I'll make sure the next time I post it's a bit more of an entertaining read!



  • Posts: 28
« Reply #53 on: Jul 29, 2018, 03:07:01 »
Time for a long over due update!

** You reading this **

Since last posting I've gotten a new bigger battery for the bike with approximately 230 CCA. It's the perfect amount to turn the engine over so now I no longer have to boost the bike or worry about it dying and being stranded in the middle of no where  8). (sorry for no pictures of the battery)

Aside from installing the new battery I also went about pulling the carbs off due to a rather large leak from the overflow on carbs 1 and 2 (I've mentioned this leak in the past). Long story short is that I would turn the fuel on and there would be a steady flow of gas out of the bottom of the carb bowls.Turns out after doing an inspection and some google searching that the problem was due to the float needles not sealing correctly. The fix for this was to use metal polish and a Q-tip to polish the needles seat. After doing this to every carb and reinstalling the fuel leak was almost completely fixed!! I still currently have a small drip from carb 1, however that actually tells me when I can start the bike so I don't mind the small drip.

Needle seats before:

Needle seats after:

Another thing that I got recently was my seat! I didn't make the seat myself because the process would have taken to long and I was having a hard time finding the right foam so I just got someone to make it professionally. Thankfully my dad knew someone whom did upholstery and I ended up getting the seat for only $75 CAD! The downside of me doing this however was that it was still a lengthy process and the amount of times I had to go  back and forth between the upholstery guy and my garage to test fit the seat was just annoying. Otherwise I think the seat came out pretty great!

Now the only thing I needed for this bike to technically be road legal is a speedo. I love motogadget products (as that's probably obvious) and I really love the gauges from them but I have a hard time justifying the price on them. I could get a decently cheap set of gauges but that involves more wiring which i'm kind of wanting to avoid so I thought I'd try something different.. aka a custom phone mount speedo. Now I already know some people aren't going to like this or think it looks good and that's fine but try and be open minded to the fact that this is a concept and IS REMOVABLE! I should also mention this set up cost me a total of $8 CAD so far.. I got the sheet metal for free, the phone is my girlfriends old phone that she gave to me for this, and i'm getting the welding done for free. The only thing I've had to pay for is a sim card adapter. If i stick with this set up the only other thing I'll need is a universal usb port that i can wire in easily to charge the phone.

It's big i know but be open minded.

Lastly, I'm in the process of test riding the bike every other day and have run into a bit of a running issue I wanted to run by some of you. So to break down my current set up, I have  4-1 aftermarket exhaust with a baffle in it, I've bench tuned my carbs, have large jets, and have the mixture screw at about 1.75 turns out. I've noticed that when the bike gets to operating temperature a couple odd things tend to happen:

1. When decelerating I often times here cracks and pops from the exhaust which to me implies that I still have to much fuel entering the combustion chamber and not being ignited. I've heard that this could potentially be bad?

2. When I pull in the clutch to shift gears my RPM spikes slightly between shifts and when I pull in the clutch when I'm coming to a stop my RPM rises and stays high as long as the clutch is in. When I'm at a stop i'll adjust my idle knob on the carbs to lower the idle and the RPM drops but then the bike basically comes close to dying/does die because the rpm is to low at that point.

if anyone has insight on what might be causing the RPM spike I'd really be thankful for some help because at this point it's the only thing causing me grief.

now to actually end this massive post with whats left on the list of things to do:

1. paint rear cowl black to match frame
2. redo my tank
3. lower front end slightly
4. Fix idle issue
5. Get insurance and RIDEEEEEEEEE

also... just to give you guys a bit of a sneak peak I just got these in from England.. but they'll be installed next summer if anything