Markantenna

frankenbike

408 posts in this topic

so first time posting been lurking for the past 12 months or so. about the same time I joined tcu I picked up a 1978 cb

I bought my first cb400t 21 years ago for a highschool project rebuilt it and rode it everyday it is now in boxes in the shed awaiting resurrection.
this bike sat under my carport for about 4 months I dicked about with it made a battery eliminator and got it running ,in October we moved house and I scored a place with a decent workspace so I pulled the carbs and engine with the intention of a quick clean and getting it on the road.
I soon decided to do a complete rebuild so got a jet kit and rebuild kit for the carbs.
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so was not sure what direction to go with this bike at first I was thinking bobber then I thought café but then thought about the tcu motto chop what ya got and although it really isn't a chop I decided to use what I had so I ripped the front end off a 84 xl350 I had and chucked it on and thought it looked kind of cool.

so I pulled the bike down to bare frame and decided full rebuild and got inspired to do something a bit different that wouldn't break the bank.

I will have to get more photos but at the moment I have fitted the rear wheel from the xl to the bike and it fits ok . the neck stem on the xl is 26mm top and bottom and the original cb400 was 26mm top and 30mm bottom I had a mate turn a press fit bush on his lathe for the bottom of the xl stem to step it out to 30mm now it can bolt straight onto the cb400 frame.

will post some better pics of what I have donre and of the engine stand I have almost finished so I can start tearing into the engine.

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Edited by Markantenna

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I trimmed up the front and rear fenders a while back I will need to do more work on the rear and figure how to mount the front because the front on the 400 mounts to the front forks and the xl mounts to the under side of the triple clamp,so gonna have to figure how to mount to the forks of the xl if anyone has any ideas shoot.will post some pics soon.

I found with the wider front end the forks are now making contact with the tank so will be repositioning the tank I trimmed up the rear section of the tank and will be moving the tank mounts back a little.

I also cut out the rear seat support as it sits up and will be replacing it with some flat bar once it is welded in I will do the same to the front seat mount , the rear also acts as a fender mount so will be modifying the rear fender a bit more.here is how it looks as of today but I will post pics of earlier work.

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Edited by Markantenna

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Was thinking of removing the rear section and replacing with a hoop that kicks up a little at the back but now I'm not so sure I like how they look but you see a lot of bikes like that now I'm thinking I might just modify the existing rear section the stamped frame looks bad but I was thinking of trimming the pressed joins off and welding the seam then smoothing it out so it is not so chunky any thoughts

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If you can clean up the seams without compromising the integrity of the frame, I don't see any reason why you shouldn't.

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I might give it a go if it doesn't work out I can always lop it off and weld on a rear loop

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So I decided to leave the rear section as is for now. Just about buttoned up my engine stand so when that's ready will crack into rebuilding the engine. Hopefully that will motivate me to put more hours into this thing.

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been awhile since I posted I finally finished my engine stand.

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Edited by Markantenna

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so I stripped my engine and found my front cam chain guide was totally chewed up so found one on ebay, totally stripped the engine and ordered a gasket and seal kit.

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Edited by Markantenna

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having major issues with trying to update this post and upload photos here is a test run well that seems to have worked as you can see by the pic I was in the process of tearing down the engine.

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totally stripped the engine and stripped the head and found one of the exhaust valve guides was broken off in line with the head now I know why it was so smokey and running so rough.

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so the head is gonna get the works done to it at a shop close by that does custom head work ,it will be ported ,new valves seats and springs.

in one of the previous pics you can see all the crud in the bottom case that is what came off my chain guide.

I have the engine casings away getting soda blasted.when they get back I can start putting it back together.

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welded in a new flat seat support at the rear section today no pics yet , I will be cutting the forward support out and welding in a flat support to match the rear then I can start on my seat pan.i also played around with a spare frame to try and figure out how to get my tank to sit right and think I have come up with a solution pics to come .

and started to polish up my engine side covers,lots of work left forks to rebuild front and back wheels need rebuild if i thnk about it I start to freak out so one thing at a time I need to keep focused so once the engine is done I can look at it for motivation then I can do the rest of the frame mods then the list goes on.

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Edited by Markantenna

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Today my new swingarm arrived it's off a cb450 it's about an inch or so longer than the stock 400 swingarm will post some pics when I get it on the bike see how it looks

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Lookin' good there, pal... Don't let it overwhelm you... Maintain your focus like you are doing and you'll look up one day and see a finished bike. Looking forward to seeing fresh pix...

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I agree. You're off to a great start. Just keep plugging at it. Make lists. It not only keeps you organized. But it's also satisfying to cross things off as you finish.

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Hey thanks guys I value all comments and advice, I am picking up my engine cases and block today from the soda blaster can't wait to see how they look . I fitted a 450 swingarm the other day which is about 1.5 inch longer than stock also a little wider at the axle plates so will have to knock up some spacers will post some pics soon once again thanks for the input .

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So I gots a new fangled iphone 6 and I'm having a real hard time getting my photos off probably doesn't help that my laptop is steam powered. So quick update.i bit the bullet and successfully replaced the broken valve guide and I'm in the process of putting the head back together.

I received my new piston rings in the mail so the barrels back on so I would say another two weeks and the engine will be done hopefully I can post some pics by then.

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Ah shit I new I should have taken the head to the workshop to get it jazzed up the new guide required reaming so spent about 45 minutes on the interweb and found an original Honda new old stock exhaust valve guide ream now I gotta wait God knows how long for it to come from Canada to Australia faaaarrrrk but I suppose when it's done I will feel quite happy with myself

Edited by Markantenna

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Also picking up a sl350 tank on Saturday see how that looks will be posting pics soon

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Thanks dusty quick update ream arrived and guides reamed valves going in in the next couple of days I'm having two weeks off so will get some time post some pics and a few more updates

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