Topic: favorite cam?

[Tintop]

subscribed - been wondering what cam might be best for a big bore (900+) sidecar application.  Thanks for posting those spec's Doctor_D.

[racerx95]

I have an rc327 cam, how streetable is that going to be?

[Don R]

Dynoman has a DP327 which I believe is similar to the RC 327. you can read their specs and application. Max rpm's and big bore. Might be a bit too racey although I bet there are guys here that have used them on the street.

[MRieck]

subscribed - been wondering what cam might be best for a big bore (900+) sidecar application.  Thanks for posting those spec's Doctor_D.

You should PM Bear. I know I sent him a 125-75 and they were using that at one time.

[Sam Green Racing]

So did I.

[lordmoonpie]

From personal experience: when you're looking for a street cam, and a successful racer tells you their cam is very streetable...run.   

JMHO

LOL! Never a truer word spoken in jest....

[Tintop]

subscribed - been wondering what cam might be best for a big bore (900+) sidecar application.  Thanks for posting those spec's Doctor_D.

You should PM Bear. I know I sent him a 125-75 and they were using that at one time.

From the charts that were posted that would be my initial pick Mike.  The 125-X12 looks like it might be interesting as well.

[Bill/BentON Racing]

You'll like it!! Bill....that is if you like to TWIST the throttle!,someone close to you @ 7000rpm,probably behind you by 9-10,000 rpms!!

[johno]

Your nothing but a bunch of horsepower junkies

Re the software simulation, I havent forgotten but will be next weekend for me as I,m on holidays, I thought I had it covered so I could take my beloved forum with me I packed my recently aquired Apple and threw in the CD for simulator and presto went to use it....  the disc only suits microsoft, oh yeh ! I got excited.

Best I can do is, ....I guess the thought for the day might  be  where would you want your peak torque and HP .....and why ?
Cheers and apologies Johno

[kos]

As Jim Dour of Megacycle told me when we were developing our 7 time Daytona F750 winner...your going to like this cam.....I do, best one out there  and you don't need that much compression. Less than 11-1 works great.


F2 Cam #125-35 Get hardweld, stronger, better than any billet cams.


YES< it works in all the engines, not just F2...

[MCRider]

From personal experience: when you're looking for a street cam, and a successful racer tells you their cam is very streetable...run.   

JMHO

LOL! Never a truer word spoken in jest....

yes thank you, and i meant it in the most polite and respectful way.

Don R is the original poster. He's my age 59, and I'm assuming he'll have desires and ride aspects similar to mine. Seeking cam experience.

I've had many big bump long duration cams that feel like Angelina jolie and Jennifer Aniston added together when they come "on the pipe".  I would never use any of them again, as that's just not where my life is.

Don R didn't say what his application was, but assuming its for a street bike, a cam like my wife is MUCH more appealing.  Power lives at 5K to 7.5K, gobs of torque, hoping my puny ass WebCam 41 will deliver. 

But hey, they're only toys. Go for it.       

[Don R]

Thanks MCRider, I did post my intentions further down the thread but you are correct about my goals with this 836. I'm trying to make a mature decision even though my brothers two big cams are in his toolbox in my garage.

 I own a dragster that has a large cam in every respect and I'm painfully aware of the cost of valvetrain parts, especially when they fail. This has been very enlightening and so far a great discussion. Thanks and continue please.

[MCRider]

Thanks MCRider, I did post my intentions further down the thread but you are correct about my goals with this 836. I'm trying to make a mature decision even though my brothers two big cams are in his toolbox in my garage.

 I own a dragster that has a large cam in every respect and I'm painfully aware of the cost of valvetrain parts, especially when they fail. This has been very enlightening and so far a great discussion. Thanks and continue please.

My favorite motor was in the bike in my avatar. Built in 1971/2, that was still early enough that one could definitely identify the origin of the OEM camshafts. It was an 836cc kit, pretty tall domes, with a K0 cam. Torque monster. Spin the tire easily. Great fun.

The big bump cams I've had delivered more peak horsepower but virtually unusable on the street. Always toolin around "below the pipe".

[Doctor_D]

Thanks MCRider, I did post my intentions further down the thread but you are correct about my goals with this 836. I'm trying to make a mature decision even though my brothers two big cams are in his toolbox in my garage.

 I own a dragster that has a large cam in every respect and I'm painfully aware of the cost of valvetrain parts, especially when they fail. This has been very enlightening and so far a great discussion. Thanks and continue please.

My favorite motor was in the bike in my avatar. Built in 1971/2, that was still early enough that one could definitely identify the origin of the OEM camshafts. It was an 836cc kit, pretty tall domes, with a K0 cam. Torque monster. Spin the tire easily. Great fun.

The big bump cams I've had delivered more peak horsepower but virtually unusable on the street. Always toolin around "below the pipe".

While I have a lot of respect for your experience, it's important to understand that modern cams are designed via computer simulation, and even the larger ones are much easier on ones valve-train and are significantly more tractable than they were 20 or 30 years ago.

My 836 with it's 125-75 made more torque from 3,000 rpms than an 836 with a Web 41 we've had on the shop dyno, beat an 850 with a 41a a few hundred rpms north of that, and makes significantly more torque than both from 5k.  Those aren't exactly dizzyingly high rpm's.  I've also lugged it around the neighborhood at 3k, and can twist the throttle at will without the motor protesting.

In any case, it remains that one should pick a cam as part of a "package" of rpm matched components to get the best results.

[MCRider]

Thanks MCRider, I did post my intentions further down the thread but you are correct about my goals with this 836. I'm trying to make a mature decision even though my brothers two big cams are in his toolbox in my garage.

 I own a dragster that has a large cam in every respect and I'm painfully aware of the cost of valvetrain parts, especially when they fail. This has been very enlightening and so far a great discussion. Thanks and continue please.

My favorite motor was in the bike in my avatar. Built in 1971/2, that was still early enough that one could definitely identify the origin of the OEM camshafts. It was an 836cc kit, pretty tall domes, with a K0 cam. Torque monster. Spin the tire easily. Great fun.

The big bump cams I've had delivered more peak horsepower but virtually unusable on the street. Always toolin around "below the pipe".

While I have a lot of respect for your experience, it's important to understand that modern cams are designed via computer simulation, and even the larger ones are much easier on ones valve-train and are significantly more tractable than they were 20 or 30 years ago.

My 836 with it's 125-75 made more torque from 3,000 rpms than an 836 with a Web 41 we've had on the shop dyno, beat an 850 with a 41a a few hundred rpms north of that, and makes significantly more torque than both from 5k.  Those aren't exactly dizzyingly high rpm's.  I've also lugged it around the neighborhood at 3k, and can twist the throttle at will without the motor protesting.

In any case, it remains that one should pick a cam as part of a "package" of rpm matched components to get the best results.

Thanks for that post. And admittedly my first hand experience is a bit dated. 

I will re read this thread looking at the 125-75. Luckily i have a frame rail kit and swapping a cam would be a good winter project. 

[Don R]

Just asking, are some of these lobe profiles new technology or mostly copies of existing grinds? I'm sure it's easier using an existing cam for a master than spending mega$$ developing new tech for a product with limited sales potential.
 Then again, with the new hi tech machines it might be easy to re-work the old tech. or change a ramp angle.
 In any case, I'm grateful some companies support the SOHC bikes and hope to do business with them.

[johno]

Hi Don,
I reckon you nailed it when you said the technology has improved out of site but who pays to use it

Be good if we had a young gun cam grinder on the forum, Ive got more questions than a news reporter on steroids.

Looking at the web these days I would assume the same as you most of the grinds available were from the good old days although Captain Kos indicated he was experimenting with megacycle so one could assume they were enjoying technology. Also the latest action from cycle x would indicate they have had a custom grind made up.  In my experience it is easy to change a few fringe things as long as you dont stray from the master lobe. So lobe centres, overlap, open / close, that kind of stuff.    To suit this hi port thing I,m playing with i,m looking for a lot of extra lift to say .450 to .475  ( or more) and I'm currently talking to the only grinder in OZ who will evan talk about it,  Ivan Tighe ( his son actually)  but I can assure you of two things, it is extremely complicated as the geometry , cam location , rocker ratios all have to be changed, and the cost makes building a CR 750 look cheap.   But I still remember getting spanked by a kwaka 900 the last time I raced about 30 years ago, a man at my age should never give up seeking revenge until the last breath.

Also Don in your old plumbing tade your siblings use all sorts of hi tech stuff, cameras up pipes,  heat sensing pipe locators, go with the flow Don and put a big mean lumpy barstard of a cam in and enjoy the action.          ciao Johno

[754]

 Some of the cams way back like RC had probably some computer design input.. he worked with some of the most up to date grinders of the time..  As Russ Jr mentioned, SR knew some very  capable  people with state of the art equipment...

[bear]

subscribed - been wondering what cam might be best for a big bore (900+) sidecar application.  Thanks for posting those spec's Doctor_D.

You should PM Bear. I know I sent him a 125-75 and they were using that at one time.

From the charts that were posted that would be my initial pick Mike.  The 125-X12 looks like it might be interesting as well.

Brian
We use the 125-75 in our "A" motor. We use this motor for the majority of our racing.
As you know, the limiting factor with sidecars as opposed to bikes is weight.
Getting a chair to accelerate and maintain corner speed is critical.
With only a couple of exceptions the tracks we race on are between 2 and 21/2 km in length, and are reasonably tight.
The 125-75 combined with our motors 68mm stroke produced a very tractable bike that would pull extremely well out of slower corners and had relatively sharp throttle response.
The bike pulled well from 3000rpm, my shift point was around 6000rpm and the rev limiter was set at 8500rpm. The cams high lift / short duration was a perfect fit for this combination and the motor proved to be very competitive and extremely reliable.

Cheers,
Brian 

[Tintop]

Agreed Bear, adding the extra weight, does changes the engine dynamics.  Other than Mosport (high speed), the other tracks have much lower speed corners.  So a cam with strong mid range torque, and good top end would be the choice.  A cam that's all top end won't work well in a sidecar.

I did read in Dave Molyneux's book, that at the TT the sidecars (600cc F2's) are at full throttle 70% of the time , compared to 30% for the solos.  But their working harder with the extra weight, so you still need the torque.

One thing I noticed 2 weeks ago, was how much having the Weber accel pump helped coming out of the corners.  No flat spot from a part throttle roll-on.  


 

 

[754]

 Thats what webers are known for..  I am surprised how much midrange my RC315 had considering it would scream up to 11K or more... easily..

[Greg H]

This is a really interesting read , so o.k guys which cam would you recommend for an all out drag motor , you know , big bore ,big carbs, big valves, in fact big everything .

[johno]

In a perfect world...     the biggest cam......... however you forgot the most important part of the equation, the rider, how good is he ( you)    I always use the cam to suit the rider / driver when ever they let me talk them into it.  Get better results.................data loggers are good, gives the engineer a more reliable feedback, sometimes riders have a bad case of chinese whisper, you know forgetting what they are really doing with the throttle.   Not many riders can get on a pro stock bike and hold it flat till the end, in that case new rider I would be starting on a more controlled cam until the rider come back complaining he wanted more. ( cams are cheap)
This is in reference to the biggest of everything of course.
ciao Johno

[Sam Green Racing]

This is a really interesting read , so o.k guys which cam would you recommend for an all out drag motor , you know , big bore ,big carbs, big valves, in fact big everything .

Aye aye Wigan pie, you slipped in rather quietly
Welcome to the forum, your in the right place to have the time of life.
We have members in here with every combination that you might like to try.
We have street K and autos knocking on the 11s, F and autos in the 10s, 200mph fuelers that run 7s and we even have a member with a single engined turbo nitrous bike that has run well over 200mph, where would you like to start.
Start your own thread Greg, tell us what you have and what your plans are, you'll get all the info that you will need. I'm just a few miles south in Warrington if I can be of any help.

Sam.

[PeWe]

 Well, this can be MY next favorite then?
"Similar to the Mega Cycle 125-75 but with 3 more degrees of duration. We found this cam to work well with 915cc kits and above.
# CX-7 "
Maybe no need of advance it a few degrees to get the fun earlier?