What cams are people having good results with for a dunebike with pipe and carb ?

 

Just wanted to know what your definition of a camshaft for dune quad was?

Here in Wisconsin we have no dunes, but I will give you my definition, just to help get some members talking.

If I lived where I could run up dunes, I would want a motor that reached peak horsepower in the 7000-7500 range. This keeps top rpms to under 8500. Shifting under load at 8K.
Motor life drops has rpms go up. So to drive alot and have some reliability, 8 to 8.5k is high enough.

Cam selection is now based on size of motor to match stated rpm range.

OMR

 

Sorry i should have been clear with my question. I agree what cams are people having good results with on dune and trail motors making lots of torque and peak horsepower below 8000 rpm.

 

hhhhmmmm Let me see.........got some hpr3s for ya LOL [img]i/expressions/face-icon-small-wink.gif[/img]

 

I just wish we had enough sand around here to call a dune.

Sorry, I couldnt help with a decent cam selection.

Im sure some will chim in on this.

 

Short course in cam timing:

For every 10 degrees in increased duration - Peak hp curve goes up 500 rpm
For every .050 extra rise in cam lift - Peak hp curve goes up 500 rpm
For every 10 per cent increase in displacement - Peak hp curve goes down 500 rpm

Size of carb, valves. porting and exhaust all add alittle, but mostly they affect the shape of the curve.

Example: This is on a stock 652cc motor.
Stock cam - .390 lift and 242 degrees duration
A1/A2 cam - .433 lift and 267 degrees duration

Stock peaks at 6300 rpm.
A1 is .043 more lift - 500 rpm
A1 has 25 degrees more duration - 1200 rpm
Total - A1 1700, so peaks around 8000 rpm.
Type of exhaust may slightly raise or lower the point of peak hp a few hundred rpm.

Thus for this example, the A1/A2 cams to fit my original 7500 peak hp, they would work best in a 730 motor.

Hpr3s would work best in a 652cc. Wood 9, Pami Sport cams, and Web 109 all fit this combination, but they have not had as broad a curve as the HPR3s.

OMR

 

Well I am curious where mine will be also next weekend, the ideal was exactly what your looking for OMR under 8800 rpm, hit peak at 7000.
I sent you the cam specs and they are close to the A1/A2 and just as you wrote with the larger displacement to bring down the RPM to about 8500 to match the stock Vortex Rev limiter
The object was not to make these Monster HP numbers everyone writting about but to make a very Broad Increased Usable Torque Band.
I love to be able to ride while in 3rd to 4th gear and just cruise through the bowls and the rolling dunes with the kids.

 

Nice post. I only ask as I have tried different cams mostly looking to build peak HP at around 10,000 rpm before. I have a new project I'm starting and looking to have a very wide torque curve. I was thinking of having a set of A1/A2 ground 4-5 degrees advanced. I just wanted some other peoples experience. This is a 720 that will have 11.5-1 compression. Yes its a steel sleeve with a blown head gasket I picked up cheap. Hopefully I can make that problem go away.