Topic: DP315 vs RC315 cam : excatly the same?

[Jerry Rxman Griffin aka MuthaF'er]

The 125-20 grind shows quite the comparison to the stock lobes below it.

[PeWe]

Yes, the 125-20 has nice lobes!
 
I got the bike running today with 4-4 pipes. DP315 is a very smooth cam perfect for street and probably touring too. Idle Ok too. I have not adjusted the idle perfect yet, 1600-1800 to start with in a fresh rebuild.

No sudden power boost around 6500 - 7500 during my test ride as my other cams. I had to give the piston some in the fresh honed  bores. I did not check the top rpm, only a short visit to 8000 and another 9000 followed by throttle off and a few gear downs to ensure ring grinding in bores.

Cam feels like it want to visit the green area after the red.

The not that high lift and longer duration must be nice to the valve train.  Lift 0.368"  minus 0.10" valve lash.

[BPellerine]

are you still at 836?

[PeWe]

No, 67.5mm pistons 901,75 cc when calculate bore 67.5mm, stroke 63mm.  This size is possible with the "tapered" sleeves, OD 70mm into the case. My case needed to be grinded really much to ensure clearance.

I need one (or 2) more bike(s) for my old 836 and growing pile of parts

[Bill/BentON Racing]

Yes, be careful with .012 " etc,  the gauge doesn't flex much, real easy to have way to much clearance especially going through tappet cap holes. ...ask me how I know! Bill

[PeWe]

Yes, I noticed that it could be too much due to the stiff gauge. I bent the 0.10" (0.25mm) gauge to ensure not bending inside the gap. Much easier to adjust valve lash without valve cover.

One more thing... when timing the DP 315 I came into the valve lash that is relatively much, but cam designed for it. 0.012" on cam card.

I could have tried more lash with another cam, the Megacycle 125-20  that ran very rich around 4500-5500 rpms. 0.10" lash instead of 0.004/005"
Reduce duration and overlap might had changed it to play with the rest as other 2 cams did (AF SS1 and RC295 copy) with even richer jetting.

[754]

 I usually try to just be able to push the feeler in, not seeing how you can end up looser.
Let go if you have to and see if it holds itself or is loose. I like to have slight resistance.
 On the stock settings i hold the guage with three fingers to slightly curve it , then push it in, prefer light drag.
 Some have suggested that a tight fit with correct guage is too tight... I disagree.. if you can lift the valve with a .003 feeler, your feelers are of a material I have not yet encountered.

[PeWe]

I can tighten the adj screw so the feeler gauge will be stucked, more the valve will lift without harming the gauge.
No hurry when I'm not working with bike repair and need money covering my time. Tighten until stucked, then release until it can be moved with the feeling of lightly scraping both sides. I check again when lock nut is almost tightened, once more when nut is tightened. Do all, rotate and check all again.

[BPellerine]

No, 67.5mm pistons 901,75 cc when calculate bore 67.5mm, stroke 63mm.  This size is possible with the "tapered" sleeves, OD 70mm into the case. My case needed to be grinded really much to ensure clearance.

I need one (or 2) more bike(s) for my old 836 and growing pile of parts

so you must have a new piston kit?with higher compression?billp

[PeWe]

No, 67.5mm pistons 901,75 cc when calculate bore 67.5mm, stroke 63mm.  This size is possible with the "tapered" sleeves, OD 70mm into the case. My case needed to be grinded really much to ensure clearance.

I need one (or 2) more bike(s) for my old 836 and growing pile of parts

so you must have a new piston kit?with higher compression?billp

Yes, new for me but used.
Cyl block + Wiseco 67.5mm pistons, std 10.25:1 Used just a little, pistons looked like new. Bores with a fresh light hone. Mike Rieck helped me to get it.

I'm not sure about the resulting CR since the chambers are a little bit opened for old RC 65mm pistons. Head decked some.
I'll check with my compression tester to compare with my old 836 with RC295 cam copy that had around 180-190PSI. DP315 will leak.

The engine runs very well so the compression is good enough today.  MLS head gasket Cometic 0.040" 68mm is in now.
I have a used thinner 0.030" as spare to be used if I need more CR and open the head.

I did not realize that the DP315 cam should behave so good as it does. Smooth constant power from the beginning to top which I have not tried yet. The new crank and rods bearings might need some break in first.
I got a happy low wheelie when twisting the throttle on 2:nd gear. TMR32 carbs react very quick, full throttle in less of a 1/4 turn. Stable hand when driving slowly or take off.

I understand why guys on the forum praise the RC315 (RC315 type 2 as DP315 is if I have got it correct thanks to this forum).

I'm sure that my CX-7, RC295 copy, 125-20 will give more torque, hp with higher lift and less duration. I like the smooth DP315 behavior and it's sound, not that loud.

Engine runs very well with APE lightened, balanced crank and Carillos. Prim hub cush rubbers new, CCC HD prim chains (tighter) as used before, new OEM prim tensioner, all metal cam chain tensioner possible to hear buzzing inside. Head got a little bit more port job when installing 5mm conv kit to adapt to the new guides/valves. 34/28 as I used before but with slimmer stems plus hopefully no more problems with mushrooming F2 Inlet valves. Not even lash caps helped when the adj screw started to dig into the end of the shorter F2 stem.

Again one more reason to not have highest lift. DP315 measured to 0.368 lift -0.10 lash must be good for the long run.
My RC295 copy had 0.398" lift-0.004 lash, AF SS-1: 0.361"-0.004 lash, 125-20: .0377" lift -0.004 lash, CX-7: 0.393" lift-0.004 lash.  All measured in my engine.

I'll see what the Dyno will say about power and A/F ratio. 4-4 will stay, 4-1 might give more power but the sound from the HM300 replicas with no diffusers is very nice, especially when closing the throttle. I like the classic look too.
I wish +95 rwhp, minimum +85rwhp. (836 had +80 with + SS-1, +83 with 125-20)

[BPellerine]

nice to see that you have confirmed what others have said about the 315 on the street,my ha kit has had the valve pockets on the pistons relieved for higher lift but not sure if the flat top would work with the 315.bill

[PeWe]

315 has not much in lift. I measured 0.368". Remove  0.10" in valve lash that will cut the duration some too.

Here piston without base gasket (std fiber gasket). The outer part a little bit over. Almost flush when head tightened and fiber base gasket compressed. I used the thicker Cometic MLS 68mm head gasket.
34mm inlet valves need 1 additional mm in clearance, valve piston. Valve to valve hopefully OK

Edit: The MLS gasket rivets had be fixed. Possible to hammer them flat or drill head and cylinder block. I did both. Use a thicker drill will make it easier to dig holes under the rivets. I used 8mm.

I'll remove the coils completely next time! Or next bike when I do not want to open this one again.

[BPellerine]

nice pewe,my ha pistons set below the head by about the same amount,with almost no dome.you have some power now,what idle are able to get with the 315?bill

[Jerry Rxman Griffin aka MuthaF'er]

What little time my 1000 has run (minutes) the 315 has a nice low speed idle.

[BPellerine]

thanks jerry,bill

[PeWe]

I like the idle around 1400 rpm, 1200rpm might work too. I prefer to ensure the oil pressure in cam bearings.

DP315:
Strong torque curve from the ground up. Comes on low and never quits. Great for heavy street and altered race bikes. A favorite for Street classes. Very tractable with fair idle and quiet operation.

Most of it is correct I like the sound too, not a screamer. I'll see later where the torque will land. RC made a good cam for many years ago   Or was it Isky that designed the 315?

[754]

 I suspect Isky was grinding to Russ Sr specs..

[PeWe]

Had a ride today, idle very stable at 1200 rpm. Even better idle than last year 295 profile.

APE lightened crank and new rubbers in prim hub might have something to do with it too.  Engine runs very smooth and silent.

[PeWe]

DP315 cam installed today.
Lift: In .368" (9.35mm) Ex .367" (9.33mm)
@ 0 lash, .004" lift (1.0mm)
In 34°/65°      Dur: 279°      LC: 105.5°    Overlap:68.5°
Ex 65°/34.5°  Dur: 279.5°   LC: 105.25°   
Numbers tripple checked.  0 lash achived by tighten the valve adj screw until the dial indicator needle moved a little.

Recommended lash is .012" (0.3mm)! Really? Loose 0.3mm lift?
No thanks. I set the In, Ex lash to 0.15mm (~.006")

I'm curious to hear the idle with that late IN close. Open earlier than 34° might not be the way either.
If the cam must have an open 4-1 due to the overlap. I'll start with 4-4 HM300 replica with no diffusers.

I followed the recommendation of 0,3mm valve lash. Cam works really fine with 4-4 exhaust without diffusers. Hm300 replica. Best cam I have used for street. Nice sound too!
Did another timing of the DP315. Sprocket got new Suzuki bolts
@0.3mm (0.118") lash and 1mm (.0394") lift
In 28.5°/56.5°      Dur: 265°      LC: 104°    Overlap:54.5°
Ex 60°/26°  Dur: 266°   LC: 107°

EDIT: The lash in rocker arm/shaft show up and affect the result with lower numbers when using running lash. Numbers at 0 lash is when adjuster screws are tightened until valve start to lift, so the lash in rocker arm/shaft will be reduced.
I have no dyno numbers but cam might work even better with 0.3mm lash.

The idle is very stable around 1000rpms! Increased to 1200-1400 to ensure oil pressure.

[PeWe]

Did a touring test and understand why RC did not mention "touring" in the spec. DP315 has a very nice stable idle, really good street cam. Touring? NO!
I tested touring speed where I held constant 120-130km/h most of the time on a highway. + 30km small streets about 50-60 km/h.
Reserve at only 150km! Refueled at 154,6km. 12,04 liter that ends up with 0.78L/10km!!  (30,16 mpg)
My old Action Fours SS-1 cam should consumed around 0.6L/10km. (39,20 mpg)

I did 50km more when I returned back home and refuled again, 5L!!! Last part a notch higher speed, 140-160km/h a small part up to 180km/h. (23,52 mpg)
With the old SS-1 cam it drank 1L/10km with 2 passengers +  full of luggage and speed constant around 160-180, sometimes more up to 200km/h.

I'm sure it is the overlap that make the otherwise really good cam to a fuelaholic! If gas stations have hooters girls supporting the refuels, no problems!

It woild be fine with a hollow cam with moveable lobes, inside 2 conical bolts, 1 from each side that could be tightened in 2-3 fixed positions moving lobes outwards. Easy to change cam to a tourer, street and maybe more without. Time cam once only.
Or hydraulic controll from a button...

[754]

I don't know why so low..
 My 836 worn out with Webers,  315 can,  stock ports, still got 50 to the US gallon, in fact every tank I used less than my buddies stock 78 750K..   We were running at about 110 kph.

[BPellerine]

maybe the webers?bill

[754]

That is partly true..I told a buddy that I got a Weber manifold for..over ten years ago, that he he got his Webers on one his motors,  they would have paid themselves off already..
 I could be wrong, but something must be pretty rich to burn that much gas..

[scottly]

My experience with an 836 and Webers:
Steady cruising at 55-60 MPH is 60+ MPG, 70-75 is 50+ MPG. Aggressive acceleration uphill or 40 MPH headwinds is about 40 MPG. I've never measured it, but judging by the number of times I added fuel to the tank during dyno testing, I would estimate the equivalent of 20 MPG or less at WFO.      

[PeWe]

I can try a little bit more advanced ignition, today timed at the modified case mark about 3mm after (clockwise)the std mark. I added a mark when checking TDC with a piston stop. Set F mark at std mark willl advance a bit. I need to listen for pinging. My TMR32 carbs have a whistling sound when twisting the throttle so pinging sound is trickier to hear.

Interesting with fuel consumption experiences of an RC/DP315 cam. My cam has 0.3mm valve lash (as spec).

EDIT: Bike runs better after I advanced the ignition, more power at higher rpm. Turned the base plate ~3mm counterclockwise.
Ignition 'F' was aligned with case mark I made after TDC check (piston stop). Mark 3-4mm after std (clockwise)
This means that F @ idle is aligned with std case mark. I have checked TDC with piston stop 3 times.

If true TDC should align with std mark, ignition still to be 3mm advanced, F vs case mark at Idle 1200-1400 rpm?
(I have tightened the springs)

Fuel consumption to be verified again. Difficult to ride constant 4000-5000 rpm on 5:th gear without twisting it some extra!
Let's see if 0.6L/10km is possible with DP315