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Author Topic: 75 CB360 - bad omen "yatagarasu" build  (Read 24097 times)

Offline crazypj

  • Posts: 13155
  • Split personality, I fake being smart
Re: 75 CB360 - bad omen "yatagarasu" build
« Reply #240 on: May 11, 2018, 11:10:24 »
Wish there was a 'joker' emoji  ;D
 I don't remember the numbers but I did post them 'somewjere' Think I worked out to inertia compared to stock so decided a 12,000rpm 'red-line' would be OK particularly as points won't let it rev reliably top much more than 11,500  8)
'you can take my word for it or argue until you find out I'm right'
Best thing I ever overheard
"yep, PJ's my boss, he taught me everything I know, just didn't teach me everything he knows"
Brian Morgan, 1982

CB360's,  http://www.dotheton.com/forum/index.php?topic=11736.0
XS650,  http://www.dotheton.com/forum/index.php?topic=11922.0

Offline MiniatureNinja

  • Posts: 454
Re: 75 CB360 - bad omen "yatagarasu" build
« Reply #241 on: May 11, 2018, 13:58:20 »
I wasn't questioning that it's lighter.  Just making an observation that things weren't weighed under the same conditions between both pistons.
Yea I'm disappointed in myself I thought I was being all scientist with the digital scale. My gf was pissed I was using the kitchen scale for dirty pistons
'75 Honda CB360 - thread

Offline onefromexile

  • Posts: 267
Re: 75 CB360 - bad omen "yatagarasu" build
« Reply #242 on: May 11, 2018, 15:23:29 »
Yea I'm disappointed in myself I thought I was being all scientist with the digital scale. My gf was pissed I was using the kitchen scale for dirty pistons
Thatís not bad I used the Cmm at work to measure and inspect my head job
Port matched within a thou
Overkill
Oh and yeah my gs pistons were about less 1/4 gram off each other but I was able to remove excess casting marks on under side and got em to read exact
Worth it ??
Who knows


Sent from my iPhone using DO THE TON

Offline crazypj

  • Posts: 13155
  • Split personality, I fake being smart
Re: 75 CB360 - bad omen "yatagarasu" build
« Reply #243 on: May 11, 2018, 15:23:40 »
Yea I'm disappointed in myself I thought I was being all scientist with the digital scale. My gf was pissed I was using the kitchen scale for dirty pistons

LOL, got caught. I wait until wife is in work and 'air out' house when I do stuff like that  ;)
'you can take my word for it or argue until you find out I'm right'
Best thing I ever overheard
"yep, PJ's my boss, he taught me everything I know, just didn't teach me everything he knows"
Brian Morgan, 1982

CB360's,  http://www.dotheton.com/forum/index.php?topic=11736.0
XS650,  http://www.dotheton.com/forum/index.php?topic=11922.0

Offline MiniatureNinja

  • Posts: 454
Re: 75 CB360 - bad omen "yatagarasu" build
« Reply #244 on: May 11, 2018, 17:32:03 »
Thatís not bad I used the Cmm at work to measure and inspect my head job
Port matched within a thou
Overkill
Oh and yeah my gs pistons were about less 1/4 gram off each other but I was able to remove excess casting marks on under side and got em to read exact
Worth it ??
Who knows


Sent from my iPhone using DO THE TON
I may use this scale to check that out, they are different in diameter by a couple thousandths so when I gave instructions to machine shop for boring they bored a right and left differently
 One is probably lighter than the other
'75 Honda CB360 - thread

Offline NvgtrWiggles

  • Posts: 172
Re: 75 CB360 - bad omen "yatagarasu" build
« Reply #245 on: May 11, 2018, 18:59:33 »
ran into sort of a problem and have been held up a few days - I seam to have misplaced the shim (thrust washer b) needed for the camshaft end play (part number 90484-369-000)

I am not sure if it slipped in between the cracks in my work bench but it's LOST FOREVER

problem is... everywhere I see that - well the only way to get one is to reuse the one you have.

in other news I got my head back from the shop, oversized 1mm intake and a mildly ported (match port, D shaped exhaust and matched intake boots, small sculpting done to the intake and exhaust around the valve guides and smoothed area at the seats

getting excited to get this thing together

oh, and while I was searching for the thrust washer I keep coming across a "sealing washer" (like this one) and I have no idea what it is where it goes

I have a pile of 360 engines if you need a washer. Yours for cost of shipping.

Offline crazypj

  • Posts: 13155
  • Split personality, I fake being smart
Re: 75 CB360 - bad omen "yatagarasu" build
« Reply #246 on: May 11, 2018, 19:51:12 »
Waste of time measuring top edge of piston to bore. It runs hot and expands to fill the gap.
 About 10mm~15mm from base is where you measure. (depends on type and manufacturer.
I always look for the largest diameter I can find, 90 degrees to pin.
You need to use micrometer, I use inch as I don't have metric with thousandths of mm(tenthousandths of inch vernier micrometers are more commonso much cheaper than metric versions)
Most pistons are made 'surfboard' shaped on lower edge, reduces friction and promotes oil film, but, they can build up an oil wedge at very high rpm and may give a 'smokey' motor as oil rings can't cope. It's part of the reason I like OEM pistons, they were designed to work very well to a specific rpm, plus 3~4 K before oil control is a problem
« Last Edit: May 11, 2018, 19:58:39 by crazypj »
'you can take my word for it or argue until you find out I'm right'
Best thing I ever overheard
"yep, PJ's my boss, he taught me everything I know, just didn't teach me everything he knows"
Brian Morgan, 1982

CB360's,  http://www.dotheton.com/forum/index.php?topic=11736.0
XS650,  http://www.dotheton.com/forum/index.php?topic=11922.0

Offline MiniatureNinja

  • Posts: 454
Re: 75 CB360 - bad omen "yatagarasu" build
« Reply #247 on: May 11, 2018, 20:40:32 »
I have a pile of 360 engines if you need a washer. Yours for cost of shipping.
What do you mean by "pile" ? I'm always up for more parts!
'75 Honda CB360 - thread

Offline MiniatureNinja

  • Posts: 454
Re: 75 CB360 - bad omen "yatagarasu" build
« Reply #248 on: May 11, 2018, 20:42:53 »
Waste of time measuring top edge of piston to bore. It runs hot and expands to fill the gap.
 About 10mm~15mm from base is where you measure. (depends on type and manufacturer.
I always look for the largest diameter I can find, 90 degrees to pin.
You need to use micrometer, I use inch as I don't have metric with thousandths of mm(tenthousandths of inch vernier micrometers are more commonso much cheaper than metric versions)
Most pistons are made 'surfboard' shaped on lower edge, reduces friction and promotes oil film, but, they can build up an oil wedge at very high rpm and may give a 'smokey' motor as oil rings can't cope. It's part of the reason I like OEM pistons, they were designed to work very well to a specific rpm, plus 3~4 K before oil control is a problem
You told me in PM how to measure and I gave those instructions to the machine shop he said that's how he does it anyway so I'm confident in the work done, the valve seats look great, he lapped them in after, 1mm oversize KPMI intakes and I'm doing the porting myself, smoothed the casting lines, d shaped exhaust, smoothed transition and matched intakes to boots
« Last Edit: May 11, 2018, 22:40:51 by MiniatureNinja »
'75 Honda CB360 - thread

Offline crazypj

  • Posts: 13155
  • Split personality, I fake being smart
Re: 75 CB360 - bad omen "yatagarasu" build
« Reply #249 on: May 12, 2018, 14:41:38 »
Should be a little pocket rocket when done  8)
Try not to hurt yourself  ;)
 
« Last Edit: May 12, 2018, 14:43:43 by crazypj »
'you can take my word for it or argue until you find out I'm right'
Best thing I ever overheard
"yep, PJ's my boss, he taught me everything I know, just didn't teach me everything he knows"
Brian Morgan, 1982

CB360's,  http://www.dotheton.com/forum/index.php?topic=11736.0
XS650,  http://www.dotheton.com/forum/index.php?topic=11922.0