I have a 12:1 102mm JE and I was wondering about the valve reliefs myself. I'm looking for more top end but I still want to be able to dune it. I'm hearing the 280-x14 has not bottom what so ever and that the 280-x4 is a better choice for this application. I drag about 75% of the time and Dune ride the other 25%.

 

The 280x14 is a radical cam and I don't think it's even close to the sparks hi-rev cam but the 280x4 might be. The x14 would not be good for anything but drag racing IMO.

 

In the back of my mind I know Bigger is not always better But sometimes I have a real hard time with that .[img]i/expressions/face-icon-small-tongue.gif[/img][img]i/expressions/face-icon-small-happy.gif[/img]

 

What do you mean by this? That the sparks isn't nearly as big as the 280x14 or vise versa? I thought the sparks hi-rev cam was the same thing as the 280x4, and the difference between the 280x4 and 280x14 was just the duration, but I could be wrong.

 

The duration is the main difference but the valve timming is way different. Between the 4 and the 14.

 

so the 280x4 is the closest to the spaks cam,not the 280x14?I wanted to say that but not sure,lowbow did you think you were talking about the 280x14 or the 280x4..where did you hear about the 280x14 cam and who uses it..

 

I think I read that in a old post. And I belive Zombie is the guy who said all your bottom end would be gone. I was talking about running the 14. I don't know where the sparks cam comes into play but I know the lady @ MegaCycle told me that he is a dealer for them as well as duncan racing. I laughed when she said that I would get a more straight out answer on what to exspect on the rideabilty from duncan.

 

I asked someone before about the high rev cams, but I don't remember what they told me. Would putting in a x14 cam make a 4-stroke perform similar to a 2-stroke. Such as no bottom with loads of top end? Would you have to ride it like a 2-stroke, clutching it etc... Cause I would be willing to make that sacrafice for a really hard pulling mid and topend.

Or do you loose a lot of mid range power too, and it is just more top end at a very high rpm?

 

If you want to know about the MegaCycle Cams. I would call Mark Robertson, he has been using them for alot of years. Since Megacycle first got into business. I'm sure he will answer all of your questions. The 280x14 is entirely too big for any other application other than dumping the clutch at full throttle. Just an option....402 339 1814.
I've been running Megacycle for about 2 years now.

 

The sparks cam is close to or the same as the x4. The x14 is like you said, same lift but a LOT more duration then the x4 and for dumping the clutch drag racing like zombie said and I'm not so sure how good it would work for that. Somebody try one and report back. [img]i/expressions/face-icon-small-happy.gif[/img]