Topic: Unknown cam - Data seen before?

[PeWe]

The old drag bike I bought only had a 776cc engine and had a RC315 in it, it ran on methanol and ran in the 10's...

Good bottom torque too?
Most of the RC315 cams are nowadays collectible items at display on CB750 horders bookshelves?

Probably the best place for them mate, they're like Megacycle's 125/75, totally useless on the street, only good for flat out drag racing. Cheers, Terry.

Do you roo humpers not twist throttles on the street?  Then again you don't ride F's LOL. Guess I gotta reconsider my 900 with the 125/75 and my 1000 with the 315. Dammit! Now you've ruined my day Terry. back to the garage and the 2 F'n's. And Frank feels it too 

Additional torque with 900 and 1000cc must be a good combination with the high rpm cams

[BPellerine]

the only way to know for sure is to try the 315,I have been told things before that did not appear to be true in practice,your eyes and ears are the truth.bill

[Retro Rocket]

The old drag bike I bought only had a 776cc engine and had a RC315 in it, it ran on methanol and ran in the 10's...

Good bottom torque too?
Most of the RC315 cams are nowadays collectible items at display on CB750 horders bookshelves?

Probably the best place for them mate, they're like Megacycle's 125/75, totally useless on the street, only good for flat out drag racing. Cheers, Terry.

Do you roo humpers not twist throttles on the street?  Then again you don't ride F's LOL. Guess I gotta reconsider my 900 with the 125/75 and my 1000 with the 315. Dammit! Now you've ruined my day Terry. back to the garage and the 2 F'n's. And Frank feels it too 

Additional torque with 900 and 1000cc must be a good combination with the high rpm cams

From everything I've been told,  they are great cams in big bore engines and work very well on the street.... Horses for courses

[Terry in Australia]

Do you roo humpers not twist throttles on the street?  Then again you don't ride F's LOL. Guess I gotta reconsider my 900 with the 125/75 and my 1000 with the 315. Dammit! Now you've ruined my day Terry. back to the garage and the 2 F'n's. And Frank feels it too 

Who are you calling a roo humper, you fugly old drug dealer! I'm glad that Frank's 315 works well in his bike, but the reason I sold Bill(? I can't remember who bought it, but it was someone here) my 315 was it didn't work in my bike at all, no torque below 6 or 7K RPM, but just like the 125/75, it'd then go mental to way past redline.

The "panel of experts" here at the time (when we were auctioning various things to raise money for Bear) told me that the 295 was a much better cam for street use, so I bought one from another member here, but didn't use it, so can't comment. Cams are a bit like carbs, all the "Armchair Racers" here think that bigger is better, so we "over carb" and "over cam" everything and tell everyone that it's working great, but in truth, a milder cam is usually a much better option for the street.

The best cam I ever had in a CB750 was an Andrews "A" grind, in my first K1. I initially bought an "Action Fours" SS-2A, but I was only running (new) stock oversize pistons and I didn't want to get them fly-cut for valve clearance.

The "unknown" cam in my current K1 feels similar to the Andrews cam with lots of low down torque, it was a drop in with no additional timing required, but 2mm more lift than an F2 cam, with a similar profile to a K series cam. Whatever it is, it works very well with my old Mike Reick stage 3 head, and is a joy compared to the Megacycle 125/75.

But of course, that's just my "first hand" opinion. I'll let you "experts" come up with the "truth", ha ha................      

[PeWe]

Terry, this kind of information is very useful in a forum like this. You had 836cc, right?
I guess that an Andrews D should be good for street too.
My latest cam make my bike to run as it did back in the 80's with Action Fours SS-1 cam. The extra lift in the latest cam compensate for the extra of me.. almost + 50% 

These "street" cams must be good for racing too, when the track is full of curves.

Street race work better now. Fun to pass cars very close, full throttle beside the drivers door and chock the sleeping car driver when the sound is wonderful!

[Terry in Australia]

Ha ha, no worries PeWe, yep, mine's an 836, 315's were common in big bore CB750's from the 1970's, but something to keep in mind is that "Street" in US parlance refers to anything that's not a "track", because a "Race Track" in the US is a drag strip. Back in the 1980's when I had my first K1 I had the physique of a superbike rider, but as you've mentioned about yourself, I'm built more for drag racing nowadays, ha ha!

The biggest cams available didn't go in bikes that went around corners like race bikes as you and I know them, they went into bikes that were held at full throttle for 1/4 of a mile in a straight line. That didn't stop guys from putting them into street bikes though, and I bought several CB750 heads from the US with crude porting and old RC315 cams in them, usually with some badly damaged lobes, for some reason?

I sold all my old race parts to the SBR boys in Queensland, and threw in an RC block that had cracks between the cylinders, and several RC cams, including a 295 and a 315. I should check with them and see how their CB750 based drag bike build is going? Cheers, Terry.

[TurboD]

Do you roo humpers not twist throttles on the street?  Then again you don't ride F's LOL. Guess I gotta reconsider my 900 with the 125/75 and my 1000 with the 315. Dammit! Now you've ruined my day Terry. back to the garage and the 2 F'n's. And Frank feels it too 

Who are you calling a roo humper, you fugly old drug dealer! I'm glad that Frank's 315 works well in his bike, but the reason I sold Bill(? I can't remember who bought it, but it was someone here) my 315 was it didn't work in my bike at all, no torque below 6 or 7K RPM, but just like the 125/75, it'd then go mental to way past redline.

The "panel of experts" here at the time (when we were auctioning various things to raise money for Bear) told me that the 295 was a much better cam for street use, so I bought one from another member here, but didn't use it, so can't comment. Cams are a bit like carbs, all the "Armchair Racers" here think that bigger is better, so we "over carb" and "over cam" everything and tell everyone that it's working great, but in truth, a milder cam is usually a much better option for the street.

The best cam I ever had in a CB750 was an Andrews "A" grind, in my first K1. I initially bought an "Action Fours" SS-2A, but I was only running (new) stock oversize pistons and I didn't want to get them fly-cut for valve clearance.

The "unknown" cam in my current K1 feels similar to the Andrews cam with lots of low down torque, it was a drop in with no additional timing required, but 2mm more lift than an F2 cam, with a similar profile to a K series cam. Whatever it is, it works very well with my old Mike Reick stage 3 head, and is a joy compared to the Megacycle 125/75.

But of course, that's just my "first hand" opinion. I'll let you "experts" come up with the "truth", ha ha................      

Terry I completely agree with you. The cylinder head on these old SOHC engines will only flow so much and make so much power, trying to add more camshaft than is actually needed to make maximum power will only kill off bottom end power and throttle response. This holds true with any engine design, unfortunately for us this power ceiling is not very high.

On my last project I spent a lot of time running numbers of current available cams through my Dyno simulating software in an effort to pick out the best cam. Without hurting anyone's feelings, there are a number of cams that are simply not good choices. 

[Terry in Australia]

Thanks mate, I did think about adding a line about folks making up for their small penises with big cams, but I thought that might be a bit too close to home for some of them, so I left it out........ Cheers, Terry.

[754]

I think it has alot to do with carbs....get a set of squirter, and lower rpm power may change dramatically.
I have this nagging feeling that porting for high rpm flow, may alter lowend power... You know the old you don't get something for nothing..  Everything is a tradeoff.
 Got a chance to get my old mystery cam back..it was in a 836 with modded 350. Slugs.. Compression higher than the normal. Cam did nothing till around 6.  No fun putting around town,unless you review the snot out of it.. I think it would behave differently. With the webers.

[PeWe]

How the cam feel like to drive is a very important factor.
Terry, your cam that you like and do not know what it is...
- Is it like an Andrews D that has good IN lift (.385") and "only" 244° duration @.05" lift? 
If duration is like a K cam, regrind? 220/235 @.04"  Base circle must be very thin with +x mm lift.
http://www.satanicmechanic.org/megacyclecam.shtml

[BPellerine]

all I am saying is that like terry if you have tried it and it did/did not work in your engine then you know because you personally tried it.if it does not work for me I have a safety net with a couple of milder cams.I was told I could not kick an ard at full advance on my bike ,that simply is not true,how do I know?I put one on my bike and kicked it over and it started after 3 kicks!still does bill

[Jerry Rxman Griffin aka MuthaF'er]

Playing with the install of my DP315.

Initial results:

The card says it has 285 duration checking at .050". After 3 measurements trying to obtain the 104 lobe center ALL my duration calculations come in at 272.

Hoping to get close to their stated lobe center but thinking that if I do then the intake opening will be a fair amount before their stated numbers. We'll see, but then again I'm not the seasoned cam veteran like my friend Terry   

The fugly drug dealer   

[PeWe]

Playing with the install of my DP315.

Initial results:

The card says it has 285 duration checking at .050". After 3 measurements trying to obtain the 104 lobe center ALL my duration calculations come in at 272.

Hoping to get close to their stated lobe center but thinking that if I do then the intake opening will be a fair amount before their stated numbers. We'll see, but then again I'm not the seasoned cam veteran like my friend Terry   

The fugly drug dealer   

It would be nice with the result you  get.  In/Ex  open°/close°- LC can be calculated and open/close corrected to achive the wanted LC. And max lift.
//Per

[TurboD]

Jerry that 285 would have to be seat to seat, that cam @.050 is 256. A 285 @.050 would be a monster and would be of no use in a SOHC.

[Jerry Rxman Griffin aka MuthaF'er]

Going in an APE 1000 kit 

Dynoman DP315 card:

Int open 23 close 53
Exh open 53 close 23

"above data for checking only" "may vary due to multiple valve jobs" (I picked this head up from a TQ guy a few years back. It has 33.5's plus I had Mike go over it since then) "check at .050" Lift off seat"

lift @ cam  Int 362   Exh 362
duration    Int 285   Exh 285
Lobe ctr     Int 104   Exh 104
Lash          Int .012" Exh .012"

Best so far: ZERO lash per instructions

Int open 32  Close 64  = duration 276 with a lobe center of 106.

Think I'll leave it here. Damn difficult to move that cam 1 degree LOL. Also was told to set it at ZERO lash for degreeing.

I locked her down now. I'm going to play with the lash. The card says .012". I'll try that and .006" to see what numbers I get.

Haven't figured out why the differences in the card numbers vs actual. Seems kinda big to me. Larger opening numbers but smaller duration number?

Mike Rieck will be installing a DP315 in the coming week. HE knows WTF HE'S doing  so we can compare numbers.

OK, just did the other lash settings

.012 : 22/59 @ 107.5
.006 : 24/61 @ 108.5

AND the measured lift is .368

[TurboD]

Jerry. I'll throw my 2 cents in, (we know what's that's worth)

I have run the numbers on the 315 with a 1000cc, I would like to see you at least install it in at zero, my program actually shows it making more power through the entire range from idle (2000) up to 11,000 if you install it 2 degrees advanced (102). Installing it where you have it now (106 2 degrees retarded) shows a power loss through the entire range over installing at 0 104.

[Jerry Rxman Griffin aka MuthaF'er]

We digress from the topic. Sorry. Should we PM?

Great info! THANKS!!  Lets see if I understand.

Whose numbers? My so-far actual  or from the card?

"Install at zero"? Zero lash? (which is what I did initially, just playing with the other lash numbers for experience) or zero degrees from the card @ 104?

"2 degrees advanced (102)"  Lobe center at 102 vs Dynoman's at 104 vs what I have now at 106?

Actual advance over my 106 by 4 degrees?

Can you give me a good indication of what Int opening to shoot for? Would that be 34?

I did one run at 33/58 which gave me 103. Still trying to grasp the entire concept in my un-cam-educated brain. Plus I don't want the 33.5 intakes kissing any pistons either. I plan on measuring clearance by depressing the intakes and exhausts at TDC unless there is a better way other than tearing it apart, claying, tearing apart and putting it back together.

It MAY be sinking in LOL 

 

[Retro Rocket]

Do you roo humpers not twist throttles on the street?  Then again you don't ride F's LOL. Guess I gotta reconsider my 900 with the 125/75 and my 1000 with the 315. Dammit! Now you've ruined my day Terry. back to the garage and the 2 F'n's. And Frank feels it too 

 I'm glad that Frank's 315 works well in his bike, but the reason I sold Bill(? I can't remember who bought it, but it was someone here) my 315 was it didn't work in my bike at all, no torque below 6 or 7K RPM, but just like the 125/75, it'd then go mental to way past redline.
But of course, that's just my "first hand" opinion. I'll let you "experts" come up with the "truth", ha ha................      

For the sake of adding facts for those interested,   what did you do to set those cams up , what were the lobe centers and opening/closing numbers you used when you timed the 125-75 cam.? How much timing dialed in.?  Couldn't that possibly have something to do with why the cam didn't work as well in your application, or as well as it could..?  what carbs were you using ?,  did you have any dyno time or charts to back up your "first hand" experiences ?, What pipe were you using ?  how about some details, that way we can see what the guys that use similar cams and get them to work, have to say or compare..? That type of detailed info would sure make setting these type of cams up easier for others wanting to do the something similar.

Additional torque with 900 and 1000cc must be a good combination with the high rpm cams

Thats exactly what I was alluding too earlier Pewe...

[TurboD]

Sorry to be confusing, I was worried about that after I posted.

I was talking timing and not lash.

I used the intake CL timing on the card as our baseline 104 or "0". When I advance the cam 2 degrees to 102, I am seeing higher numbers over the entire rpm range. Now when I set the cam in at 106 (2 retarded) , I see numbers less than the baseline 104 over the entire rpm range.

In a nutshell. The best numbers I am getting are at a 102 intake CL.
 

[Jerry Rxman Griffin aka MuthaF'er]

Do you roo humpers not twist throttles on the street?  Then again you don't ride F's LOL. Guess I gotta reconsider my 900 with the 125/75 and my 1000 with the 315. Dammit! Now you've ruined my day Terry. back to the garage and the 2 F'n's. And Frank feels it too 

 I'm glad that Frank's 315 works well in his bike, but the reason I sold Bill(? I can't remember who bought it, but it was someone here) my 315 was it didn't work in my bike at all, no torque below 6 or 7K RPM, but just like the 125/75, it'd then go mental to way past redline.
But of course, that's just my "first hand" opinion. I'll let you "experts" come up with the "truth", ha ha................      

For the sake of adding facts for those interested,   what did you do to set those cams up , what were the lobe centers and opening/closing numbers you used when you timed the 125-75 cam.? How much timing dialed in.?  Couldn't that possibly have something to do with why the cam didn't work as well in your application, or as well as it could..?  what carbs were you using ?,  did you have any dyno time or charts to back up your "first hand" experiences ?, What pipe were you using ?  how about some details, that way we can see what the guys that use similar cams and get them to work, have to say or compare..? That type of detailed info would sure make setting these type of cams up easier for others wanting to do the something similar.

Additional torque with 900 and 1000cc must be a good combination with the high rpm cams

Thats exactly what I was alluding too earlier Pewe...

Terry, how much piston to valve clearance did you achieve?

[Terry in Australia]

Terry, how much piston to valve clearance did you achieve?

G'Day Jerry, I was using the RC 836cc (Venolia?) pistons with the 315 cam, I bought the whole top end (cylinders, pistons, ported K0 head and cam) that I bought on eBay, and used the pistons and cam, but with Mike Reick's head. The RC pistons had deep valve pockets, so there were no issues with them "kissing".

Sadly it was too long ago to remember setup specs, (Mike Reick sent me some info, and Hondaman helped too) but all I remember was that it started easy (even with the troublesome 29mm Keihin smoothbores) but had very little power below 7K RPM, that's why I compared it to the Megacycle 125/75 that I replaced it with. I pulled the 315 out after only a few weeks as I was keen to try the Megacycle which had just arrived, once again, the "panel of experts" recommended the 125/65, but I went with the "Bigger is better" theory, but in practise, the milder cam would have been a much better option. If anyone's got a 125/65, I'll be happy to trade my 125/75 for it? Cheers, Terry.

[bear]

I'm very happy with the 125/75.
But advance the timing an extra 5deg, it brings the top of the torque curve down the rev range nicely.
Our application is probably not relevant to this discussion though.

Hey Uncle Tez, l would be happy to buy your cam when and if you pull it out.
Unfortunately I don't have a suitable swap for you though.

Cheers,
Brian

[Terry in Australia]

I'm very happy with the 125/75.
But advance the timing an extra 5deg, it brings the top of the torque curve down the rev range nicely.
Our application is probably not relevant to this discussion though.

Hey Uncle Tez, l would be happy to buy your cam when and if you pull it out.
Unfortunately I don't have a suitable swap for you though.

Cheers,
Brian

G'Day Brian, it's sitting in it's box in my collection of bits, you can have it mate, you can shout me into the Classic next year and buy me lunch, hows that sound? Cheers, Terry.

[PeWe]

I'm very happy with the 125/75.
But advance the timing an extra 5deg, it brings the top of the torque curve down the rev range nicely.
Our application is probably not relevant to this discussion though.

Hey Uncle Tez, l would be happy to buy your cam when and if you pull it out.
Unfortunately I don't have a suitable swap for you though.

Cheers,
Brian

G'Day Brian, it's sitting in it's box in my collection of bits, you can have it mate, you can shout me into the Classic next year and buy me lunch, hows that sound? Cheers, Terry.

Terry, don't give up the 125-75 cam. The 125-75 spec is very close to this cam I found and runs well.
It must be something more the cam need to do the job.
My head has larger inlet valves, 34mm. NOS cast RC836 pistons (old with 1 piece oil ring that I replaced with 3), same model you had before in another thread. (might need wider chambers)

"RC295 copy". @ 0.04" lift:   25/55      55.5/22    lift: 0.393" / 0.363" (9,98mm / 9,22mm)  - Measured in engine

125-75 cam spec  @ 0.04" lift: 26/56  53/24      lift: 0.400" / 0.375"  (10,16mm / 9,525mm) - What numbers in the reality with rocker arm lash reducing the duration?  Or Megacycle might given some extra degrees to the lobes?

[Terry in Australia]

Thanks mate, the head on my engine's one of Mike Reicks very early stage 3 items, it has 2mm larger inlet valves, big smooth ports, modified combustion chambers, heavy duty valve springs, titanium retainers etc. I ran the RC pistons until I decided that they had too much clearance and it was interesting that the cheap eBay pistons are actually a better fit in my bores, I just honed them and installed the new pistons, and I had around .001-.002 clearance with them, as opposed to around .006 with the RC's.

I dropped the new "unknown" cam in, and the difference was like night and day, my engine was smoother from start-up, and the better low down torque was evident when I pulled my first (unintentional) "Power Wheelie" on the bikes maiden voyage. That's good enough for me, if I want to go faster safely, I just ride one of my more modern bikes. Cheers, Terry.