Topic: My 1ST ever K7 Build with 0% knowledge and 110% determination

[fiascoelment]

Hi Everybody!

So I have tackled something I shouldn't have but my stubbornness got the best of me. This is going to be a slow build also my FIRST ever build, I do not want to half ass anything. For the first year I am focusing more on the frame and suspension, wheels,  to have a complete roller but this time next year, and then after I will focus on the motor, gas tank, and renewing the electric systems (M-Unit Blue  maybe?) So below are details to what bike I am working with, and what I have done so far. Please, this is an open discussion and would like to hear from the community on what I maybe doing wrong and what I could do better.

So I picked up a 1977 CB750K for cheap on CL a few months back, in hopes in turning it into a neat cafe racer.
So far I have torn the bike down to the frame and have removed the frame tabs where the electrical were mounted since, I am planning to set up the electrical under the seat using the electrical tray I bought from Cognito Moto (https://cognitomoto.com/products/under-seat-electronics-tray-cb750)

I am holding off on removing the oil tank mounts on the right side of the frame until I buy the this bolt on oil tank to mount in front of the carbs (https://cognitomoto.com/collections/engine/products/bolt-on-cb750-oil-can)

I am also going to be sending my swing-arm to Hondaman, to be rebuild.

I have also grind off the seat mount to place a new rear loop and aluminum cowl also from Cognito Moto and Meyerbuilt Metal Works (https://cognitomoto.com/collections/frame/products/) (https://cognitomoto.com/collections/frame/products/?variant=32225554637)

I am currently waiting for the rear loop and cowl and now I have not done anything to this build for almost a month now, I am itching to working on it again but I do not know where to start since I do not have the rear loop and cowl yet. After I receive the loop and cowl and have welded it on the frame that is when I am going to have the frame sent to be powder coated.

I am open to suggestions on what I could be doing now, and or maybe in future. Below are some pictures of the bike and progress I have done

[fiascoelment]

Anyone knows how to add picture using the attachments button in this forum?

Also I want to add a bit more information:

That the bike is a non-runner, however I do not think that the motor was seized, since I was able to kick-it and hear the motor would try turning over.
Another thing is when I picked up the bike the rear wheel was stuck, according to the PO the bike was still in gear.

Now my question is would I still would have been able to put the bike in neutral, even if the bike was not on/running?

[fiascoelment]

Hey Calj,

Thanks, I hope so too, and with the help of this forum it seems more possible, even with a person with my knowledge of motorcycles, but I am willing to learn.

And as far as the swing arm swap, going to a 550 swing would this affect if I plan on swapping the rear drums to a disk brakes from a CB750F2?

Yes, now that you mentioned it, I think opt-in for a frame kit upgrade since, I had such a memorable time removing the engine (I was up till 5 AM and with work at 8 AM  )

More recently I have been looking into wheels and suspensions and braking, like mentioned earlier I would like to swap my K7 drum breaks for a F2 rear disc. Also My current wheels are both 16 F+R, Id like to go 17 granted it would not interfere or would need to fabricate anything on the swing arm also a wider rear wheel is preferable too.

As far as suspension goes for the front, I wanted a GSX-R conversion, or a GL1000 with dual disk but if the money is tight, I will still probably run stock forks with progressive springs. and for the rear shocks for now I was planning to get those "Vintage Japanese Rear Shock Set" from Cognito Moto,

Can anyone tell me the differences with getting a 12.8"(325mm), 13.4" (340mm), 14.4" (365mm) the pros and cons, the benefits of different measurements? What to look for when buying shocks?

Nonetheless, I am open to any suggestions, anything that can help me have a clean looking, reliable, comfortable bike when finished.

[Davez134]

Now my question is would I still would have been able to put the bike in neutral, even if the bike was not on/running?

Yes, you can/should be able to shift through the gears. I did on mine with the engine out of the bike after a fresh rebuild just to make sure everything was in order. The only issue you may have is if the clutch plates are stuck together from sitting?

+1 on the frame kit too. It has saved me many headaches.

[fiascoelment]

Well good thing I am also going to attempt doing a complete engine haul top and bottom read through this post many times 

http://forums.sohc4.net/?topic=29364.0

So if the clutch plates are stuck together Ill probably find that out once I get to the engine portion of my build, currently my motor is covered with a black thrash bag.
If I can spend the money, ill probably have a professional do it for me, anyone knows or can recommend someone I can send the motor to if I end up going that route?

[fiascoelment]

Trying with one picture at a time

[fiascoelment]

Here are more pictures

[fiascoelment]

Figured out a way!

[fiascoelment]

Here is how my bike sits today, took this picture on Monday for Cliff from Meyerbuilt Metalworks to measure my rear loop

[fiascoelment]

I have ridden a motorcycle before around a parking lot and what bothered me the most is the height, I was mostly on the tip of my toes and afraid of dropping the bike. I am 5'11"

What determines ride height?

Well I am currently eyeing a 750F2 around my area and hopefully I can pick it up by the first week September if it has not sold yet  , I may use the whole rear set up from the F2.

Got it thanks Cal! From Ikons would you suggest a specific shocks?

Added to my shopping list are:

Frame Kit

[fiascoelment]

Cal- Noted, once I am at that part of the build, which is I hope very soon I will contact Nils, thanks for pointing me his direction.

I have also inquired about Franks Frame kit, just waiting for his response.

Do you think I can use my current shocks to mock up tires under suspension compression when I am in the process of welding the rear loop?

[Davez134]

Your title says 110% determination. I believe with that attitude, you can/should try and tackle the motor yourself. With the knowledge of those on this forum and a few books, you can rebuild/freshen these motors with some pretty basic tools. Like you, I had never rebuilt a motor before, now I have done 2 for myself and 3 for others. They really are very simple as long as you pat attention to detail. You would save $$ and it is much more satisfying knowing you did it and things are done right. At the very least you may have to find a machine shop depending on the condition/wear of your cylinders. Just my thoughts/experience.

[Stev-o]

....but it may not even need an "overhaul"

[Davez134]

Yes, but too late to get into the get it running before you pull it discussion. Maybe a compression and leak down test?? But it's fun to take stuff apart 😜

[Stev-o]

Yes, but too late to get into the get it running before you pull it discussion. Maybe a compression and leak down test?? But it's fun to take stuff apart 😜

Leak down is a good idea.  It is fun to take stuff apart but how many baskets cases have we seen for sale from newby's that never get em back together?!

[fiascoelment]

cal- got it! granted I have stock shocks, the length should be 13" correct? Also I am located in New Jersey (North Jersey), US

Davez- I love tinkering, but sometimes there are battles I simply cannot defeat, having a "professional" contact (besides all you good people in this forums) that I can personally go to for help is a good insurance for me, last motor I worked on (helped) was a redtop S13 SR20DET to put in my 94' 240SX (oh the good times). One thing a love about the support in this community is that sources are endless, and with shops like vintageCB750, cognitomoto, MRcycles, and people like Hondaman (Mark), Dino (Hack-a-week), I don't think I would be tackling this project today.

Stev-o- I hope it doesn't, it is actually one of the first mistake I  made in this project was not trying to get the motor to start, I was to eager to tear down the bike (+1 fun=take stuff apart). How would I go about the compression and leak down test? The only thing I bought so far for my motor is a complete gasket set. My plans is to have a reliable motor that can get me to and from work (during the nice weather) , the weekend night outs, and sunday morning football/brunch  . Also to clean up, maybe going the vapor blast option (Restocycle) (I love that clean look!).

And last is I am trying not to be that type of newby. Not saying that I was never one of those newby, like mentioned before there were battles that has gotten the best of me (i.e. redtop S20DET), only reason to that is those type of project put me in a financial stress (college age mental stupidity), but few years, lessons, and experiences later has made me more financially responsible (well at least better than before). And I feel that this project is not a money pit like how my 240sx was. 

[Stev-o]

 How would I go about the leak down test?

Click here!

http://lmgtfy.com/?q=sohc4+CB750+leak+down+test

[fiascoelment]

okay i deserve that ! lol thanks stev-o

[Stev-o]

okay i deserve that ! lol thanks stev-o

My pleasure!

[fiascoelment]

So I am planning to start my engine rebuild this coming with weekend, first and foremost I will attempt to clean the motor first since I will be doing this rebuild in my bedroom (lack of space in the garage  ) So anyone have any pointers for me on how to make sure all the oil is drained out and to make the least amount of mess, I will be buying an engine stand this weekend from harbor freight (1000 lbs cap.) and the angle tabs to properly mount my engine on. also will have either a tarp or cardboard box under the stand to avoid oil spillage.

To clean the engine external I am planning to use a pressure washer, is there any other items solution I can use, I heard simple green works? My plan for the engine is to cover it with wrinkled black paint, is it worth having the covers vapor blasted then paint?

Also my plans for the frame is to have a smooth finished, therefore I decided to smoothed out some of the visible welds and I read that this is a bad idea . As you can see below pictures shows what I have done, the yellow dash is where I am going to cut the frame to install the rear loop.

So question is should I worry about the weld spots that I have smoothed out, is there anyway to remedy this? I read to properly smoothed out the frame I would have to go to the bondo way. I am planning to powdercoat my frame, will I run it to problem when using bondo?

[nvr2old]

Body filler will not stand up to the oven heat from powder coating.  You'll have to paint the frame if you want to go that route.  You can grind/smooth the welds out a bit, but you do risk losing a bit of strength if you go too far.  Problem is, you'll never get it perfectly smooth with just a grinder disk. It will show horribly under the powder coat.  I smoothed the frames on 3 of my bikes, used plastic filler for the final finish and then painted them.  They look nice, but it's a lot of work for something most people don't even see.

[seanbarney41]

the only way to smooth those welds is to remove metal...that is a no no.  These frames are not that strong to start with...VERY thin walled tubing.  It can be done by adding body filler, but thats a hack unless you are building a chopper.

Please don't misunderstand, I really understand your enthusiasm and determination...but you may want to learn how to ride on a stock motorcycle.  Then you will be able to better determine if changes are really an improvement or just the destruction of a cool old bike.

[fiascoelment]

nvr2old- I see, then I will consider the paint route, I may just turn to a body shop to do so.

seanbarney41- Noted. and no worries thank you for the advice, I completely understand what you are saying as I had a chance to snag a 77 CB750F2 to learn on, but that was sold. So for now until another deal like that pop-up then I will continue and thread lightly with this project.

Also for the engine rebuild, since not much is going on at work I decided to create an .xlsx file for its schematics, so far I have done the cylinder cover, and head. Please let me know if this has been done, or if I should continue to do the entirety of a CB750K7, my sources so far is CMSNL

[Stev-o]

Personally, I never use a pressure washer on my bikes, I dont like introducing water to them.

I use Gunk Foamy Engine cleaner and acetone to clean before paint.

No sense vapor blasting before paint [fairly expensive], bead blasting would be more cost effective.

[fiascoelment]

Finally got to touch my motor after sometime, my schedule has been hectic lately and last night I was able to get around to opening my motor. I got as far taking the off the Cylinder Head.

When I took of the Cylinder head cover, camshaft, rocker arms everything seems to be clean. Then when I got up to the point of taking of the 22 nuts and bolts for the Cylinder Head I noticed there was what it seems to be a spider web where the spark plug is located on cylinder 3.

When I finally took of the head I came across a very dark pistons and cylinder surface and what seems to be sand  and something that feels like sand, if any of this make sense, any one want to chime in

Also received my Cognito Moto Frame Loop and Cowl I have a picture of a mock up on my current frame

I have a long way to go but I am happy I can get back to this without losing interest. I won't be posting regularly but I will still keep this up and look for advice along the way

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[Maverick]

Every thing is looking great! And that black sandy stuff is carbon build up. No fun, but if you carefully clean it and check that your valves seat properly, it should be all right

[fiascoelment]

Thanks maverick ! Yeah since this is my first ever build I'm going try to be as thorough as possible here some more closer pictures of the Cylinder walls

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[fiascoelment]

+misc pictures

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[fiascoelment]

Hi Guys,

Im in need of your help. So I am trying to get the Cylinder Block separated from the case. Anyone know an efficient (non back breaking way) to get this off.
I have read the cotton rope in the cylinder trick, any one want to elaborate on that?

As much as possible I don't want use brute force.

Please let me know.

Thanks,

VT

[fiascoelment]

I was finally able to separate the block from the case here some pictures of my motor next im going to inspect the pistons and see if they are still good. I am getting closer to disassembling this thing down to the case! Any advice from here on?

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[fiascoelment]

Here are the cylinders, from the who are experienced can you tell the condition from there's pictures?

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[fiascoelment]

Hi guys,

I havent made much progress since I last posted but here I am still standing tall. I followed some of you guys here and got a harbor freight engine stand and fab up brackets to be able to mount them. Please let me know if I can get away with this mount without having the engine fall on me foot . I found it to be a little shaky maybe because of the lack of support on the other half of the engine.

I am now trying to split the case so I can inspect and maybe change the crank bearings, rod bolts and send the case for vapor blasting.

Any other things I should look out for to change or inspect while/when the case is split?

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[fiascoelment]

Can anyone also let me know if this bent on the shifter drum is normal? I noticed this while disassemble the shifter assembly

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