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73' cb350g restoration for Off-road purpose....

4K views 52 replies 8 participants last post by  lamakina 
#1 · (Edited)
Hi everyone !

Getting ready to start my new adventure :)
I thought I would share it with Vintage Honda enthusiastic people !!
I've learned and enjoyed so much reading project logs from you guys so,
this is THE bike here...



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I will log some pictures and impressions, little by little, as the project progresses.
I've got a second exact same bike, so 2 full engines to work with :)
Everything is apart now.





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So.... I will do a bunch of cleaning, bead blasting,
inspecting and measuring parts specs....
Selecting and preparing the cylinder jug for over-sizing to 64.5mm.
(The bikes have been sitting outside for like 30+ years.
The engines were way stuck and the cylinder walls are pretty rusted...)



Pretty much all the obvious parts I'll need are on their way
(carb rebuild kit, bearings, seals, coils & points, and so on....)



My last rebuild went WAY too fast so I will go slowly on that one
unless my shop will turn into a bike warehouse and I won't be able
to move and actually work !!!
I will actually build a secondary shop/building to address
that "soon to be" obvious concern !!
Here is a picture and a link to a video of that last project... 73' CB450


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Along the way I will need help/recommendations concerning 1 thing... (at least !!!!!)

- I would like to try to have it running without a battery because there will be no flashers, lights, horn etc etc.... Only the ignition system... I started to read
about it and all I could figure is that I will probably need to replace the battery with a capacitor or something but that's all...
If some of you have successfully done that I'll be very happy to hear from you :)



GAME ON !!!




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#3 ·
Did a bunch of cleaning lately and painted a few elements related to the front and rear end....

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I like to start with having a frame, 2 wheels and suspension , a bench and a fuel tank put together first as it motivates me and looks nice every time I enter my garage... Im gonna get all my parts beginning of march and will reach that point soon after;)
Then it will be time to work on the engine !!

Lastly, I’ve decided to go more agressive with the tires and go for a trail and dirt road type bike !!

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Shinko SR241 :)

The next post will contain a very nice picture showing where Im heading I believe !!!
 
#6 ·
One thing I will never regret buying is my bead blasting unit !!!!!

BEFORE

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AFTER

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Unfortunately the cylinder rebore will have to wait as the machine shop is closed due to COVID-19 :(
Next is to paint the engine :)

Then cleaning the carbs.... I just bought a 30L ultrasonic cleaner and can't wait to try it !!!
It apparently does wonders !!!

Also working on rebuilding the air cleaners replacing the stock cardboard filters with UNI filter foam...
I will post a few pics... There is a good thread on that somewhere online and it really works well IMO.

Stay Healthy :)
 

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#13 ·
Replaced the air cleaner’s filter with some Uni foam....

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Here is the thread I mentioned earlier :

I added some rubber bands to keep the foam in place but I almost believe they are not necessary... if you cut the foam just wide enough so that it compresses On installation, it really snugs in !

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#14 ·
Get a really beat up front fender off ebay and at least use the Mounting bracket. That Bracket is the Front Fork Brace.
Riding Off Road on ANY surface hard packed dirt or not will torque & twist the fork tubes more than you would think.

Even people who go the cafe route for street use find that if they don't have that brace it can get really twitchy in the curves.
 
#16 ·
Oil pump question !!!

I figured it would be nice to make sure the oil pump was working properly...
Is there any test that I can do (that you guys know of) other than just measuring the plunger's diameter etc.
All is within specs and the plunger fits real nice in the cylinder...

I tried submerging the bottom part of the pump in oil and manually activate the plunger but no oil gets sucked up...
The bottom steel ball is moving freely.
If I prime the pump, manually activate the plunger, the oil exits where it should...

Is my test improper because I can't recreate the plunger in/out fast enough like the engine does ??

Thanks everyone
 
#17 ·
If the pump parts are in spec then it's virtually guaranteed to work correctly - the fact that you know the check ball is moving freely is about the only other thing that matters. It's a very simple design and though not the most efficient pump in the world, they rarely don't work properly. Once the engine is fully assembled, you can check the oil flow at this location when it's running - just have a rag handy as it can squirt out and make a mess
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#18 ·
Thank you very much Tom !!
Makes a lot of sense...
I will definitely check the witness bolt on start-up !!

May I ask another question....

Do you happen to know what those are for and if it is a big deal if one of them is broken off ??? Im sure they are there for something but I can’t figure ? Maybe catching some oil ??

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Thanks a thousand times...
I Never stop learning !!
Simon
 
#19 ·
Simon, I believe they are for the baffling function of the plate but I never really completely understood the design either. I can't say for sure, but I suspect it would be okay without one of them. Worst that could possibly happen is a bit more oil vapor in the usual blow-by gases that come out of the breather tube
 
#24 ·
Quick interrogation for which I could not find a straight answer on the web..
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One of my stud is missing that rubber part.... closest guess I could find is that it’s probably there for vibration reducing purpose ???

Question :

It does not seem like we can find some replacement, so are they 100% necessary ?? On my other “parts engine”, one is also missing and the other is ripped :( No luck !

Thanks
 
#27 ·
I've tried thinking thru why Honda did this. Best guess is vibration dampening, possibly those 2 studs suffer metallurgic stress failure over time.
I do have 1 new one left, used 2 new ones on my CL350. Took a couple of months searching to find them in France and bought all they had (3) because I knew someone would want the last one.
 
#37 · (Edited)
Too much time on my hands !!!
I thought I’d be done mid-summer !!

Engine painted (except the cylinder as it is currently being rebored).
I think I will eventually invest in a powder coating kit...

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Have you guys used the basic kit that sells for under 100$ ?? Any good ?
It seems to do the job ?

Bottom end closed...
Went real well... all is legit :)

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No electric starter...
Gonna work the head so Im ready when I get the cylinder...

Peace out :)
 
#40 ·
Yes I did index them :)
Thanks for the heads-up !

The ring gaps are right ON...

Cam chain tension is adjusted, valves also, and the ignition timing will wait until the engine is on the bike with 12V going through them !!

Im putting a single phase regulator/rectifier and will combine the two stator’s circuits (white and yellow wire).

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#41 ·
You can join those 2 wires together right after the stator plug and eliminate 2 wires from the rest of the harness, Of course that means re-wrapping the harness with nice new shiny electrical tape.
 
#42 ·
That’s exactly the plan !
Though the original harness is gone ;)

The coils will be the only electrical components on the bike... At first I thought of trying to run the bike without a battery but elected to not do so (seems unsure wether it would work reliably or not according to what I could read?)

I have plenty of room for a battery and an AGM 5ah is pretty cheap so.... Plus, if ever I wanna put a small tail light and beam, I’ll be all set!
 
#43 ·
A 5ah battery probably won't be sufficient, Honda calls for a 12ah for this model. The CB400T1 which doesn't have a starter calls for a 9ah battery. The points ignition coils draw a significant amount of power.
 
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