Topic: rc 315 and org timing card

[BPellerine]

kinda neat came all the way from texas.bill

[Medyo Bastos]

is it for sale? put me in line pending price

[BPellerine]

no it is not for sale it took a lot of luck for me to get it.bill

[TurboD]

Isn't the Dynoman DP315 the same grind?

[BPellerine]

don't know for sure but I wanted the orig.bill

[Retro Rocket]

Good timing Bill, I have the 315 timing card right in front of me...   Can you write out those specs Bill, I can barely read them but mine seem to differ to yours, could be because its hard to read..?

My specs RC 315

Intake                                                                               Exhaust

Opens 23 B.T.D.C                                                               Opens 53 Before B.D.C

Closes 53 After B.D.C                                                        Closes 23 After T.D.C

Lift 365                                                                              Lift 365

Running clearance 012                                                      Running clearance 012 cold

Duration 310                                                                     Duration 310

                                                                                                                                                                                                           

[TurboD]

I understand that. I have a RC454 if your interested. 

[Retro Rocket]

Here's a scan of mine Bill...

[Jerry Rxman Griffin aka MuthaF'er]

I gotta get back home and check that against my Yoshimura Daytona sheet. Those numbers look real familiar. More duration?

[Retro Rocket]

I gotta get back home and check that against my Yoshimura Daytona sheet. Those numbers look real familiar. More duration?

I was struggling to read Bills Jerry, but i think you are correct....

[BPellerine]

here is what mine reads rc 315 b meaning billet I guess, yours says 315 no b
intake opens 12 deg btdc
closes 42 deg
lift .358
running clearance .012
duration 234
exhaust opens 42 deg bdc
closes 12 deg after tdc
lift .358
running clearance.012 cold
duration 234
this is an original 315 taken out of an 836 weber carbed engine with branch head built around 1975
hope this helps.bill

[754]

My 315 card is about the size of a pack of smokes.... I dont have the sheet..

[Jerry Rxman Griffin aka MuthaF'er]

From Axl's (RIP) site

Russ Collins Cams

Russ Collins made several cams for the 750 SOHC/4 engine:
                Durat                                                   In o/c
        Valve   ion   Lobe    Over                                      Ex o/c
Cam #   Lift    @.04" center  lap                                       btc/abc
        inches  degr  degr    degr   Description and Application        btc/atc
-------------------------------------------------------------------------------
RC295                                Torque cam
-------------------------------------------------------------------------------
RC295                                Racer cam
-------------------------------------------------------------------------------
RC315   .365    310   104            Hot racer cam, very good for heavy
                                     street and altered race bikes
-------------------------------------------------------------------------------
RC327   .370    270           94     Full competition cam               34/56
                                                                        30/60

And........

Yoshimura Cams

Yoshimura used to make different cams for the 750. Unfortunately, these have been discontinued years ago.
                Durat                                            In o/c   Run-
        Valve   ion   Lobe                                       Ex o/c   ning
Cam     Lift    @.04" center                                     btc/abc  clrnc
        inches  degr  degr    Description and Application        bbc/atc  inches
-------------------------------------------------------------------------------
Daytona .392    256           Must use Yoshimura valve springs   23/53     .004
Race    .360    256                                              53/23     .004
-------------------------------------------------------------------------------
Road &  .378    252                                              20/52     .004
Track   .341    244                                              46/18     .004
-------------------------------------------------------------------------------
Stage 1 .362    253   105                                        21.5/51.5 .006
        .330    244   105                                        47/17     .006
-------------------------------------------------------------------------------
Stage 2 .383    256   105                                        23/53     .006
        .339    256   105                                        53/23     .006
-------------------------------------------------------------------------------
Isle Of .354    264           Must use Yoshimura valve springs   27/57     .004
Man Race.337                                                     56/27     .004
-------------------------------------------------------------------------------
For racing applications, add .002" clearance

[Jerry Rxman Griffin aka MuthaF'er]

Here's a scan of mine Bill...

Those open close numbers don't equal 310 degrees duration? I get 256?? Just like the Yosh Daytona duration

[TurboD]

The open close numbers are at .050, not the true actual open close.

[Retro Rocket]

RC315   .365    310   104            Hot racer cam, very good for heavy
                                     street and altered race bikes

Thats exactly what mine says Jerry. Its definitely a 315, I even have the original receipt for it...
It was bought around 1979- 1980, i'll check the receipts next time i have them out for a date...
Bill, they were all billet cams mate, says it on the installation sheet that is part of the paperwork, looks like the later ones were a little hotter. Mine came out of a methanol run drag bike....

[PeWe]

RC duration based on lift 23/53, 53/23 is 256°/256°  @0.05"lift (1.25mm).  310°  must be total duration.

My old Action Fours SS-1 cam (was said to be for people affraid of hot cams). Data when I timed it last time:
Not that much less: 21/53, 54/22° @ 0.04"lift (1.0mm)   Duration 254°/256°
IN/EX 0.361"lift (9.18mm)  (.360 in spec)

I do not know how much it will differ in duration during the difference in lift 0.01" (0.25mm). I can imagine that the cam is rather agressive here and therefore not much in °  versus lift.

RC315 must therefore be a good cam and streetable when my cam I compare with is very streetable, smooth idle (when carbs are right) and good for touring.
RC315 will be on my list too

RC315 Dyno chart soon?

The cold season is here where I live and an obstacle for my plans. I'm waiting for jets.
After that book Dyno test for my actual cam, Action Fours SS-1 cam. Then change to CX-7, Dyno again and finally my latest cam Megacycle 125-20(25) Dyno for this too. Frame kit make all this fun possible. I plan to publish the results in the forum thread for cams and Dynos.

[BPellerine]

the reason I wanted this cam is bcause it does run on the street with the setup I have ,got mine from greenjeans who had the orig build sheet for the ko engine this is the second engine I have heard of with almost identical components the other being 754s so it does work.funny thing is that the engine did not have an adj sprocket  and was not slotted????bill

[PeWe]

here is what mine reads rc 315 b meaning billet I guess, yours says 315 no b
intake opens 12 deg btdc
closes 42 deg
lift .358
running clearance .012
duration 234
exhaust opens 42 deg bdc
closes 12 deg after tdc
lift .358
running clearance.012 cold
duration 234
this is an original 315 taken out of an 836 weber carbed engine with branch head built around 1975
hope this helps.bill

Really RC315? The data is very mild in both duration and lift.  Data @ 0.05"lift?
RC had a funny sprocket with fixed holes for different advance, right? Possible to turn sprocket the other way too.

[kmb69]

I understand that. I have a RC454 if your interested. 

Sending you a PM on that RC454.

[BPellerine]

rc did produce a 5/0/8 sprocket that you could move to change cam time but my 315 was installed with the stock Honda sprocket ,I have a cyclex adj sprocket for install.bill

[NitroHunter]

It's easy to DIY slot the cam sprocket, very little filing/grinding will be required, that slot doesn't have to open very much! With good cylinder pressure and proper jetting, the 315 was a great hot rod cam and I tore up the streets for a long time running with one. NO problem pulling redline+ in any gear. 

[BPellerine]

that is great to hear nitro as mine bike will be as hot rod as I know how to make it while still driveable.bill