Auxiliadora 1981 CB750 Build

PRIMEWORKS

New Member
Been a while since I've made a post but I've been enjoying the bike finally ! Here are a couple pictures from a recent cruise with some friends. Ill have some content to post in the near future as I have some parts I still need to add to the bike !
3be70b347bd93e00d0dd24c6a46f0856.jpg
4c2adcb2b53616ace6df51d62262ec9e.jpg
b9392e8332549763f2a17f081bb72f47.jpg


If you want to see m ore content that I might not post on here feel free to follow my bike instagram @auxgarage :)

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Jimbonaut

Over 1,000 Posts
DTT SUPPORTER
I really, really like what you made here mate - the silver engine sat below that bare tank looks great, with the black line working perfectly with the seat and cowl. Great eye man, lovely looking ride


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V10Pilot

Been Around the Block
PRIMEWORKS said:
Been a while since I've made a post but I've been enjoying the bike finally ! Here are a couple pictures from a recent cruise with some friends. Ill have some content to post in the near future as I have some parts I still need to add to the bike !
3be70b347bd93e00d0dd24c6a46f0856.jpg
4c2adcb2b53616ace6df51d62262ec9e.jpg
b9392e8332549763f2a17f081bb72f47.jpg


If you want to see m ore content that I might not post on here feel free to follow my bike instagram [instagram]9769718349[/instagram] :)

Sent from my Pixel 3 XL using Tapatalk
What’s the IG account name?


Sent from my iPhone using DO THE TON
 

PRIMEWORKS

New Member
I haven't posted here in a loooong time so I figured I'd give a life/bike update.

After 6 long years of school, I finally obtained my bachelor's in Mechanical Engineering so the bike hasn't gotten much attention. I have managed to go on rides here and there and have been riding it recently but have hit a bit of a wall with it. What I mean by that is, I'm not enjoying it as much as I once did and I'm on the fence about sinking more money into it versus selling it and getting something different.

Currently, there is a pretty significant oil leak at the front of the engine which would likely require me to remove it in order to seal it. Secondly, I have an incredibly annoying fork that constantly keeps leaking after attempting to replace the seal at least 2 or 3 times now. Thirdly, the bike lacks power or at least feels like it does (likely because of the pods).

At this point in time, I feel like I'm at a bit of a crossroads. There are a number of things I would like to do to the bike but I'm not sure if I would get much out of it. Ideally, I'd like to do the following:
1. Reseal and repaint the engine
2. Do a front fork swap to something like a GSXR front end while somehow managing to keep the stock front wheel (not sure if that's actually possible)
3. Redo the seat
4. Redo the wiring and organize it as I initially intended so it's nice and neat
5. Get new carbs
6. Incorporate new prototype parts. I'm currently starting a business designing new custom parts and this would likely be a good bike to start prototyping parts for (If you'd care to follow that you can follow me on Instagram @protolabs.aux)

With all that being said here are my other points that kind of go against doing any work to the bike:
1. I currently own a 1984 BMW R100 RS (a bike that's more desirable than the DOHC CB) that has been waiting to get my attention and could be my new vintage project bike
2. The idea of getting something newer like a Sportster 48, triumph bobber, Ducati sport classic, etc. Just something newer with more power and something more desirable seems attractive to me. Granted, maybe I would gain all of those things with the upgrades to the CB?

At this point, I'm not sure what to do and figured I'd see what everyone else's opinions might be. I've put enough money into this thing that by selling it I'd be losing money which is why I don't really want to let it go but I'd be throwing more money into it by keeping it lol.
 

Jimbonaut

Over 1,000 Posts
DTT SUPPORTER
I'm only kidding man, I'd love to get my hands on an old beemer but they're rare as hen's teeth here too. Plus I love these DOHC's so my vote was always going to be rigged.

If Auxiliadora was mine, I'd start by finding out where the oil leak's coming from. If it's base gasket you may get away with simply torquing down the head bolts a bit (no need to remove the engine for that). Or maybe the cam chain tensioner bolt on the front of the engine has stripped the threads from the head, or the bolt itself is missing its o-ring. If the threads are stripped you can fix that with a TimeSert or HeliCoil - also a job you can do without removing the engine from the frame. Check all your crankcase bolts of course to make sure they're tight, and also side covers etc. A jobber gasket on one of those side covers can create a leak really easily too.

Are you strapping your bike down a lot? Onto a work table, trailer, something like that? Over-tightening the straps on the front end of your bike can blow out those seals pretty well. Are you over-filling the forks with too much oil? That'll blow them too. Also, what state are your upper fork tubes? If they're pitted that'll cause a leak. It's always worth trying the quick fix of running some thin plastic (like a cut coke bottle or something - you can find the template online) and running that around the inside of the fork seal to dislodge any crap that's built up there.

Ditch the pods and run a stock airbox with those carbs. I'm sure you've heard that 100 times already. Your bike will run so much better with that set up. Or buy some Murray's Carbs for your bike (they come with pods) or CR 29's if you're feeling flush.

Stick some better shocks out back. Progressive, Hagons...lots of options that'll make the ride so much better.

Me, I'd definitely put some tracker bars on it too, but I'm a lot older than you. Clip-ons tick the style box for sure but you might enjoy the ride more in a more comfortable position. Judging by the above photos you don't much like the left clip-on anyway ;)

You've got a nice bike there mate.
 

PRIMEWORKS

New Member
So, which one do you think custom parts would sell well for?
Either bike would likely do well. Looking at production numbers and prices of CB's and how affordable they are. They would likely take the cake. My business isn't really about making custom parts for one type of bike though. Granted while I will be making my own custom parts to sell to the general public, the Business model really caters to people who want custom parts without the fuss of spending hours in the garage making something out of cardboard or foam. Using the knowledge and skills I've acquired through my post-secondary degree and own personal experience I would be offering CAD modelling, FEA analysis, and affordable physical prototyping through the use of additive manufacturing methods with the hopes of eventually getting my own CNC.

I'm only kidding man, I'd love to get my hands on an old beemer but they're rare as hen's teeth here too. Plus I love these DOHC's so my vote was always going to be rigged.

If Auxiliadora was mine, I'd start by finding out where the oil leak's coming from. If it's base gasket you may get away with simply torquing down the head bolts a bit (no need to remove the engine for that). Or maybe the cam chain tensioner bolt on the front of the engine has stripped the threads from the head, or the bolt itself is missing its o-ring. If the threads are stripped you can fix that with a TimeSert or HeliCoil - also a job you can do without removing the engine from the frame. Check all your crankcase bolts of course to make sure they're tight, and also side covers etc. A jobber gasket on one of those side covers can create a leak really easily too.

Are you strapping your bike down a lot? Onto a work table, trailer, something like that? Over-tightening the straps on the front end of your bike can blow out those seals pretty well. Are you over-filling the forks with too much oil? That'll blow them too. Also, what state are your upper fork tubes? If they're pitted that'll cause a leak. It's always worth trying the quick fix of running some thin plastic (like a cut coke bottle or something - you can find the template online) and running that around the inside of the fork seal to dislodge any crap that's built up there.

Ditch the pods and run a stock airbox with those carbs. I'm sure you've heard that 100 times already. Your bike will run so much better with that set up. Or buy some Murray's Carbs for your bike (they come with pods) or CR 29's if you're feeling flush.

Stick some better shocks out back. Progressive, Hagons...lots of options that'll make the ride so much better.

Me, I'd definitely put some tracker bars on it too, but I'm a lot older than you. Clip-ons tick the style box for sure but you might enjoy the ride more in a more comfortable position. Judging by the above photos you don't much like the left clip-on anyway ;)

You've got a nice bike there mate.
If I do any future work on the bike I'll likely go all out. Get new carbs and the works. But we'll see what happens.

My Engine leak is coming from the from this area on the bike. I've replaced the bolt in the hopes that it was just stripped and not tight. But I beleve its the actual gasket. Granted, tightening the head might also work...
1624936820664.png
 
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Jimbonaut

Over 1,000 Posts
DTT SUPPORTER
There should be a flared nut on that bolt. You can see it here on my engine rebuild -

gNurqwxh.jpg


That may help with the leak. Did you rebuild the engine? If so what base gasket did you use - jobber or OEM? I used a jobber the first time (along with jobber cylinder stud o-rings). Although the gasket seemed ok, the problem I had was with the o-rings, they were slightly too large which meant the cylinder didn't seat properly = oil leak. Had to tear the whole thing down again and switched out for OEM. Won't make that mistake again.
 

PRIMEWORKS

New Member
There should be a flared nut on that bolt. You can see it here on my engine rebuild -

gNurqwxh.jpg


That may help with the leak. Did you rebuild the engine? If so what base gasket did you use - jobber or OEM? I used a jobber the first time (along with jobber cylinder stud o-rings). Although the gasket seemed ok, the problem I had was with the o-rings, they were slightly too large which meant the cylinder didn't seat properly = oil leak. Had to tear the whole thing down again and switched out for OEM. Won't make that mistake again.
That picture is just an arbitrary one I found online! I don't believe I got an OEM gasket kit, I got it from 4into1.com. Any recommendations for where to get an OEM gasket kit?
 

Jimbonaut

Over 1,000 Posts
DTT SUPPORTER
So you do have a nut there? Hard to say what your problem may be if you post images of someone else's engine. Either way, make sure the nut there is tightened. I don't think you'll find an OEM gasket kit, you'll have to buy each gasket individually. I ordered mine from my local Honda dealership - it's not the cheapest route but it's the best in my experience if you've got the scratch.

By the way, I'm not suggesting you should do a full tear down by any means until you're sure it's your base gasket that's the problem.
 

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