CB360's-from build to blog - 2013, MDS (Mo Dumb Shit)

crazypj

Split personality, I fake being smart
Found some 35mm valves with 5.5mm stems (instead of 7mm)
Lighter than stock but not 100% sure it's going to work as they are also longer than stock by a few mm. May be enough adjustment in the screw to keep geometry correct?
It's a much bigger job than I originally thought, just finding a source of valve keepers and correct valve guide seals has been an ordeal (not paying $1450 each for seals :eek: ) plus, I still haven't found valve spring retainers at a reasonable cost so I may have to make new ones from 4140 steel, not going to mess with Titanium or 7075 alloy
Had to re-design guide tops for the smaller seals but not a major issue as I'm making new ones from (I think) aluminum bronze or maybe silicon bronze or even Manganese bronze , I bought several different types several years ago.
I remember doing a lot of research on different types for valve guides. Aluminium bronze seemed best for high temp applications like exhaust valve guides but only OK for intakes.
Bought some new 5.5mm reamers. ::)
Timberwolf is the guinea-pig, already a month late (sorry TW) ;D

Looks like I have to pull everything off Photobucket and find a real FREE SERVICE , they changed the rules 28th June :mad: :(
Seems I would have to 'upgrade' to the +500 plan to get image linking plus 3rd party hosting.
As I'm only using 26% of 2GB (0.5gb by Photobucket reckoning) no way in the world am I paying $399.99/yr for 502.1 GB storage (even if I had the money I wouldn't do it) :mad:
 

irk miller

You've been mostly-dead all day.
DTT BOTM WINNER
crazypj said:
Looks like I have to pull everything off Photobucket and find a real FREE SERVICE , they changed the rules 28th June :mad: :(
Seems I would have to 'upgrade' to the +500 plan to get image linking plus 3rd party hosting.
As I'm only using 26% of 2GB (0.5gb by Photobucket reckoning) no way in the world am I paying $399.99/yr for 502.1 GB storage (even if I had the money I wouldn't do it) :mad:
Just upload to here. Tim opened up the ability to upload and host images locally a year or two ago.
 

crazypj

Split personality, I fake being smart
irk miller said:
Just upload to here. Tim opened up the ability to upload and host images locally a year or two ago.
I didn't know that, just re-loaded the 305 pics 8)
 

ChopperCharles

New Member
Man, I wish those photobucket pictures all throughout this thread were still working. Really was looking forward to the read-through :)

Charles.
 

crazypj

Split personality, I fake being smart
Yep, I've been in touch with Photobucket, there is a known issue when trying to download albums (basically, you can't, pretty sure it's deliberate blocking?)
I'll have to download almost 1400 pictures, one at a time sort them then try and remember what went where. That is going to take some time, probably what Photobucket is banking on. I've seen complaints where people have 4~5,000 or more pictures.
If your making money from linked pictures they are advertising stuff, $400 is just another business expense, but, if like me they are mainly information for other people, $400 it totally out there, just ain't happening.
 

crazypj

Split personality, I fake being smart
Been having a bit of a rough time but still plugging along. Making a piston holder to machine CB750 (SOHC) for CB500/550 591-605 conversion. As usual, overbuilt but I know from previous piston machining it eventually saves a ton of time plus no chance of distorting pistons. Can also use 'pull piece' to check all piston tops are lsame height. Couple of pics, still needs drilling, tapping and a few bolts plus a 'piston pin' to hold everything together. There will be a drawbar through lathe spindle to allow piston tops to be machined.
 

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focusinprogress

City Limit Moto:Parts-Service-Apparel (716)8038606
crazypj said:
Been having a bit of a rough time but still plugging along. Making a piston holder to machine CB750 (SOHC) for CB500/550 591-605 conversion. As usual, overbuilt but I know from previous piston machining it eventually saves a ton of time plus no chance of distorting pistons. Can also use 'pull piece' to check all piston tops are lsame height. Couple of pics, still needs drilling, tapping and a few bolts plus a 'piston pin' to hold everything together. There will be a drawbar through lathe spindle to allow piston tops to be machined.
I've revised my cb650/550 hybrid engine build because I couldnt find anyone capable of machining forged 836 kit wiseco pistons.......and now you post this......
 

crazypj

Split personality, I fake being smart
It's difficult to find anyone who does motorcycle part machining and modification. Majority of 'engine shop's' can't or won't do anything smaller than 80mm.and multi cylinder. Even less places have any type of piston holders. In my experience, a machine shop may be able to do what you want but you have to be incredibly specific, including clearances and surface finish. They then charge accordingly (usually way over the top as they would rather do stuff they do regularly)
'We' used to give 'awkward' customers with weird old bikes realistic estimates, plus 100% if we thought it would take too long or be 'difficult' to get parts (in a dealership it's much easier to do whatever manufacturer you have)
Anyway, if you decide to do something different, let me know in the new year
Oh, I also radiused the lower edges of the 'pull piece so it will fit into pocket. Because of the less tan stable mount in vice I could only mill one direction and had to rotate part so I was cutting towards vice which is why the round-over is going in opposite directions. I doesn't matter though as function is the important part. The offset is deliberate as gudgeon pin is not on centreline of piston. Piston skirt fits onto lower edge to centralise.
The bars have to be drilled and tapped, I'm going to re-machine the internal 'dome' to match machined piston crown.
A long 'pin' through gudgeon pin hole will have long Allen bolts either end to clamp into 'cap'
 

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crazypj

Split personality, I fake being smart
99% finished piston holder, time to start carving on stuff. I didn't think 15 degree's was correct so got out scrap head to do some measuring.
I'm getting closer to 26 degrees included angle which gives 13 degree chamber angle when I used both hands, in pic, it looks more like 30degrees. I couldn't hold camera and angle finder properly
Anyway, piston mounted and running true(I checked with DTI)
Anglefinder 'in' combustion chamber
 

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surffly

New Member
I'll have to read through the original "gentleman's express" article and see if they mention where they came up with the 15* angle.
 

crazypj

Split personality, I fake being smart
I'm lousy at computer graphics, easier and quicker to just do a rough drawing, then scan and post (couldn't be bothered to get to scanner so took pic.
Top part to represent piston modification, 3mm dimension is missing from top left, the 12 degree angle continues a little high but with only 3mm flat compression may well be higher than with specified 6mm flat and 15 degree angle? I've got a prototype machined, one of the 0.75mm OS pistons I'm going to use in my 550 (eventually?)
Oh, 55mm is the measurement across the chamfer of combustion chamber and not original 550 bore
 

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crazypj

Split personality, I fake being smart
I think I may have a reason for the steeper angle. The original mod was done on a 500f. I can't remember if combustion chamber is same as 550 or is similar to CB750 having no angled 'squish' area?
Here's pic of top, probably going to reduce diameter (or increase flat) to 54mm to make sure there is clearance with combustion chamber. Valve pockets will need machining to at least 550 spec
 

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crazypj

Split personality, I fake being smart
My little sister only told me yesterday, she bought a bike in November. Honda Varadero, but not the 996cc version, a baby V twin 125cc to comply with licencing laws in Britain. Never thought she would get on a bike as she was always a 'horsey' person
Her horse is now officially retired though (22 yr old Welsh Cob, whatever that means? ;D )
 

crazypj

Split personality, I fake being smart
LOL, yep. She moved down west Wales several years ago, more farmland for horsey.
Just been reading some Stephen Hawking quotes, liked these in particular

"We are just an advanced breed of monkeys on a minor planet of a very average star. But we can understand the Universe. That makes us something very special."

"We only have to look at ourselves to see how intelligent life might develop into something we wouldn't want to meet."

He disagreed with Voyager/Carl Sagan 'star map' don't let 'them' know where we are and obviously believed far superior intelligent life is 'out there'
 
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