Author Topic: RC Engineering 836 Head & Piston Rings  (Read 2499 times)

0 Members and 2 Guests are viewing this topic.

Offline wwsummersjr

  • Full Member
  • *
  • Posts: 17
RC Engineering 836 Head & Piston Rings
« on: January 04, 2020, 11:29:03 PM »
Okay Guys, Way back on the time machine (mid 80's) I was fortunate enough to come across a full blown RC Engineering 836cc SOHC that had ported/polished head w/oversized valves, wild cam, slotted cam sprocket, racing rods, etc, etc, etc... I made the mistake of trusting a friend of mine who owned a M/C shop to go through the head & he basically did a butcher job on the valve seats. Looking to find a professional that has correct stone set & see if head can be saved.
I also heard the 836 piston rings are same as a CB350 4th oversized rings (65mm) can be used. Stock CB350 bore is 64mm & have seen 1st OS as being 64.25mm. Haven't seen 836 rings available (w/o pistons) from Weisco, etc. Anyone got input?

Offline Jerry Rxman Griffin aka MuthaF'er

  • This MuthaF'er is getting to be a
  • Really Old Timer ...
  • *******
  • Posts: 14,902
  • Bought her new 4/75
Re: RC Engineering 836 Head & Piston Rings
« Reply #1 on: January 05, 2020, 12:01:39 AM »
Get in touch with Mike Rieck on here. He's our head guru.

You're good on the 350Twin +4 size as long as you need 2.5, 1.5, 1.5mm rings.
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline gschuld

  • Master
  • *****
  • Posts: 2,346
Re: RC Engineering 836 Head & Piston Rings
« Reply #2 on: January 05, 2020, 09:16:25 AM »
FWIW, RC engineering offered 836 pistons in both cast and forged.  If cast, they will have ART cast into them near the pin as seen from the outside of the piston skirt(ART made the OEM Honda pistons and are high quality FWIW).  Forged would most likely have RC 65H under the piston crown(Arias made pistons).  Lesser chance but possible you have the earlier (pre 1973/4 era) Venolia pistons.   If there is Arias under the piston crown, they are very late RC pistons, early 80s.

It’s helpful to know whether you have cast or forged pistons since the piston/bore clearances would be very different between them.

I would highly recommend Hastings for the rings.  They will have what you need.

George
« Last Edit: January 05, 2020, 09:19:26 AM by gschuld »

Online PeWe

  • Really Old Timer ...
  • *******
  • Posts: 15,531
  • Bike almost back to the 70's 2015
Re: RC Engineering 836 Head & Piston Rings
« Reply #3 on: January 05, 2020, 10:02:42 AM »
I have forged RC 836 pistons from 1983 and earlier cast RC that have  single oil ring.

I used the forged pistons 3 ring oil rings on the old  cast ones which worked fine.
The other rings have same size.

I have Action Fours  cast  836 pistons too. Same ring sizes.

I'm rather sure all these use the CB 350 twin  +1mm rings.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline wwsummersjr

  • Full Member
  • *
  • Posts: 17
Re: RC Engineering 836 Head & Piston Rings
« Reply #4 on: January 05, 2020, 12:45:41 PM »
Info much appreciated fellas! I'll reach out to MRieck about the head.
BTW, this also came with engine...

Offline Stev-o

  • Ain't no
  • Really Old Timer ...
  • *******
  • Posts: 34,238
  • Central Texas
Re: RC Engineering 836 Head & Piston Rings
« Reply #5 on: January 05, 2020, 02:32:22 PM »
Where in Texas are you?  I have a good contact for machine shop work in the Austin area.
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline wwsummersjr

  • Full Member
  • *
  • Posts: 17
Re: RC Engineering 836 Head & Piston Rings
« Reply #6 on: January 05, 2020, 04:11:47 PM »
Dayton, Tx, 20mi East of Houston. I work in Houston/surrounding area. Willing to ship to someone if I have a warm & fuzzy feeling :-)

Offline Stev-o

  • Ain't no
  • Really Old Timer ...
  • *******
  • Posts: 34,238
  • Central Texas
Re: RC Engineering 836 Head & Piston Rings
« Reply #7 on: January 05, 2020, 04:16:07 PM »
Dayton, Tx,

I know where Dayton is, we used to waterski on the San Jacinto River near Crosby.
Nasty river but the booze made it tolerable!
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline MRieck

  • Really Old Timer ...
  • *******
  • Posts: 10,560
  • Big ideas....
Re: RC Engineering 836 Head & Piston Rings
« Reply #8 on: January 06, 2020, 04:37:08 AM »
 Hastings (as George pointed out) or Total Seal for rings. Exactly what happened to the seats? The machine shop I use does not use stones.....they use a Serdi which is pretty much industry standard.
Owner of the "Million Dollar CB"

Offline hondaron

  • Full Member
  • *
  • Posts: 68
Re: RC Engineering 836 Head & Piston Rings
« Reply #9 on: January 06, 2020, 08:22:58 AM »
Stev-o, who do you use for machine shop work in the Austin area ?

Becoming harder and harder to find   :(

Offline Stev-o

  • Ain't no
  • Really Old Timer ...
  • *******
  • Posts: 34,238
  • Central Texas
Re: RC Engineering 836 Head & Piston Rings
« Reply #10 on: January 06, 2020, 03:45:29 PM »
Stev-o, who do you use for machine shop work in the Austin area ?


I'ved used Curtis at Custom Cycle for head work and cylinder boring on my Hondas and Kawasakis.

It's a small shop in Cedar Park, not cheap, but he has always done things right.

https://m.facebook.com/pages/Custom-Cycle-and-Machine/132992610104213
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline wwsummersjr

  • Full Member
  • *
  • Posts: 17
Re: RC Engineering 836 Head & Piston Rings
« Reply #11 on: January 06, 2020, 07:36:32 PM »
Hastings (as George pointed out) or Total Seal for rings. Exactly what happened to the seats? The machine shop I use does not use stones.....they use a Serdi which is pretty much industry standard.
Mike,
It appears the M/C shop I used in the 80's used incorrect stones to cut valve seat angles. The seats probably only needed lapping, but that yahoo did not do a fab-up job to say the least. I was only a novice mechanic at the time, but knew enough to know he screwed the pooch. I became an Air Compressor Technician 41yrs ago & not an M/C brainiac like ya'll. I need to send head to someone that knows WTF they're doing to assess head. 

Offline wwsummersjr

  • Full Member
  • *
  • Posts: 17
Re: RC Engineering 836 Head & Piston Rings
« Reply #12 on: January 06, 2020, 07:42:30 PM »
Stev-o, who do you use for machine shop work in the Austin area ?


I'ved used Curtis at Custom Cycle for head work and cylinder boring on my Hondas and Kawasakis.

It's a small shop in Cedar Park, not cheap, but he has always done things right.

https://m.facebook.com/pages/Custom-Cycle-and-Machine/132992610104213
Stev-o,
I'll give Custom consideration, but that FB link not yielding much info other than a phone #. Link appears corrupt. I'll call him (got a name?) Anyone else know them?

Offline wwsummersjr

  • Full Member
  • *
  • Posts: 17
Re: RC Engineering 836 Head & Piston Rings
« Reply #13 on: January 06, 2020, 07:46:10 PM »
Stev-o, who do you use for machine shop work in the Austin area ?


I'ved used Curtis at Custom Cycle for head work and cylinder boring on my Hondas and Kawasakis.

It's a small shop in Cedar Park, not cheap, but he has always done things right.

https://m.facebook.com/pages/Custom-Cycle-and-Machine/132992610104213
Stev-o,
I'll give Custom consideration, but that FB link not yielding much info other than a phone #. Link appears corrupt. I'll call him (got a name?) Anyone else know them?
NM, I put my glasses on...Curtis :-)