Topic: 1972 CB750 Steampunk(ish) Bobber Thing

[Noddy78]

And also thanks for the kind words guys, I'm totally chuffed with them too. I'm now getting onto the varnishing, hopefully I can get the finish I'm aiming for. I've also resigned myself to quite a while until I get my dream workshop so I spent the weekend converting our storage space into something workable so I can at least start tearing the engine down and see what the PO destroyed there...

[Riceman]

Well after making it to page 8,I decided it best to start at the last page
and go backwards......
Keep building and posting Noddy

Have you checked out Ron Young Patinas?
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CB4QFjAA&url=http%3A%2F%2Fwww.sculptnouveau.com%2F&ei=trZ4VMHhFcewogT3rYH4Bw&usg=AFQjCNE0VvlRVayJg1UCojp-Uiwv6Jp-Iw&sig2=2J4kxFNn6p1iOnAb9fxXXQ&bvm=bv.80642063,d.cGU

[Noddy78]

Well after making it to page 8,I decided it best to start at the last page
and go backwards......

Sage advice for anyone braving this thread...

Have you checked out Ron Young Patinas?

I have mate, I may end up utilising some of that too. Not sure as yet how "patina'ed" this one is going to end up being actually.

So.. engine tear-down over the weekend. Found just a little bit of metal in the engine...





The culprit:



It looks like the cam shaft had a blow out at some stage and the timing chain chewed up the valve cover... I can only assume the PO welded up the cam shaft and put it all back together (cam shaft was attached to the cam sprocket by only one bolt), including the stuffed valve cover and left all the bits of metal in the engine! But bugger it, that's what the oil filter is for, right!? ...



Luckily it looks like that did limit the damage, everything else actually looks OK. The only other suspect looking thing were these scratches on the upper crank case:



Thoughts?

So, I'm going to need lots of new bits! I'm thinkng 836 kit from Cycle X? What do you reckon?



I'm going to need about two thirds of all that anyway, might as well just go the whole hog...

[70CB750]

Auch! 

Is that a weld on the camshaft?

[martin99]

Looks like a PO just did a quick job to get it running and get it sold, without giving a shyte for whatever problems cropped up for the next owner. Gotta love some people

[flatlander]

ouch that looks painful.
might be an idea to warn other buyers of this #@*$-head.

[vfourfreak]

That motor must have made a fearful sound in it's last few minutes of running !! A camshaft lathe of sorts.

I'd go for the whole kit also !

Kev

[Noddy78]

I don't actually think the PO did anything maliciously, I'm pretty sure he was just incompetent. I have the Clymers manual he had with it, that's got all his notes etc in it (apart from "January 1992: Broom stick handle Frame Kit" and "June 2005: re-weld cam, shove it back in there without checking anything else"). He's evidently had the bike since at least 1984, and has tinkered pretty heavily with it. But that's ok, I bought it expecting to have to do almost everything, that was the point of getting this one... as I said way back when, before I got bagged out for destroying such a fine example of a CB750...

[Noddy78]

Is that a weld on the camshaft?

That is exactly what it is.

[Noddy78]

So, let's begin with the questions... Currently I measure the bore on my engine at a shade under 61mm (60.8mm), so basically stock. The cylinder sleeve walls measure roughly 3.5mm in thickness. So, if I'm looking at the 836 kit (which I believe is 65mm?) then I'm left with cylinder sleeve wall thickness of about 1.5mm or less. Now, this seems awfully thin to me... is this correct/what you would expect? Or do I have the dumb somehow?

Second question is, what cam do you think if I go the 836 kit? Cycle X have 1 through to 7 (http://www.cyclexchange.net/camshaftpage.htm) but I'm guessing I should be looking at 2 or 3, but which one? I'm not taking this thing to the race track or drag strip or anything, just after something reliable with a nice bit of poke. Thoughts?

[dave500]

dont ask questions just go the big kit man!,its a bit like re formatting a hard drive, it just wipes everything and starts fresh.

[Noddy78]

I bet you're just a riot at parties Dave...

[dave500]

only pirate parties ahh!ahh!ahh!just bore the whole thing over new cam etc in one hit,no point pussy footing around at this stage,just don't use wooden pistons!just run a basic cam,too many guys over cam any engine.

[calj737]

CX-1 is all you'll need to get a good "poke" out of it. Correction: Dave's a riot wherever he goes, pirate ship notwithstanding.

[Blackfin5]

Don't listen to Dave.....think bigger!  I hear JMR still has an 1000cc billet block available.  That will really make some steam.

[Syscrush]

I stopped clicking on this thread for a very long time.  I am glad I came back.  Those gauges are magnificent - good luck on getting that engine sorted out.

BTW - if you don't mind a suggestion about the wooden parts... If you apply some water-clear (refers to the color, not cleanup!) epoxy resin, you would have a very durable and chemical-resistant finish that can be treated the same as any other automotive surface like paint or chrome.

[Noddy78]

Glad you made it back too! I don't mind the suggestion at all, unfortunately I'm already half-way through the varnishing process. I wanted that wooden boat finish, so I went with a wooden boat spar varnish. Horrible stuff to work with, but it's starting to come together and look the way I want it to. Probably not as durable, but will hopefully do the job after 10-20 odd coats...

Also, this:

[Syscrush]

Second question is, what cam do you think if I go the 836 kit? Cycle X have 1 through to 7 (http://www.cyclexchange.net/camshaftpage.htm) but I'm guessing I should be looking at 2 or 3, but which one? I'm not taking this thing to the race track or drag strip or anything, just after something reliable with a nice bit of poke. Thoughts?

3 is out of stock - get a 2 and be happy.

[Noddy78]

Given how so far they're not answering any emails, it could be none at all...

[dave500]

youll be happy enough with a stock cam,some cam numbers are only bragging rights anyway?your detail is your bragging right,even if the overall design don't float that well with me,dont go out of your way for any special camshaft if you have a perfectly usable stock one on hand.

[Noddy78]

if you have a perfectly usable stock one on hand.

Ah... no.

[dave500]

ok,find a replacement,if you can get a stock one good,if its aftermarket don't try and gain power by ordering a hi po one,itll only end in miserable off idle and cruisabilty riding,some hi po ones only suit acceleration loads only and will not cruise.

[maduncle]

My gods - where have I been the last 26 pages?

I just went through a jumbo sized popcorn reading from page one, this is so much fun.

Noddy - I remember your first steampunk build as it was being done, you are very clever at using old stuff and at making new stuff to look old too.

Terry is right, I tried brass velocity stacks too, ran like crap but they looked cool on the F2 until I got the foam filter kit. I ran leather side panniers and had a cream and brass colour scheme - the bike was even called a 'High Tea Racer' as a sort of steampunk cafe racer.

Um - I better fess up here. If you Google 'maduncle steampunk' you will see that I get up to a bit of brass mischief too, although not for a few years now (I grew up  )

So anyway, I have another 44 gallon drum of popcorn oil on order and I am settling in for the mini series.

More drama than Game of Thrones!

[maduncle]

PS - now this one may call steampunk.

http://www.pipeburn.com/home/2014/12/04/ducati-900ss-typhoon-old-empire-motorcycles.html#.VIQ4sSjjZUQ

[Restoration Fan]

PS - now this one may call steampunk.

http://www.pipeburn.com/home/2014/12/04/ducati-900ss-typhoon-old-empire-motorcycles.html#.VIQ4sSjjZUQ

Nice bike and a pretty girl at the end of those threads as well.  But Noddy's gauges and headlight are better, IMO.

Noddy, great job so far.  Keep up the good work.  Really enjoying seeing the fruits of your labor.  And let me add my kudos on those gauges and the headlight.  Absolutely stunning work on those.

Ron