I have been trying to decide which midrange cam to purchase. I have been told to go with the Trinity/Web #461/496 but Trinity gives different information than Web does about the same cam. Trinity gives the cam information for the #696/697 cam but says its the #461/496? Does trinity have it wrong? I have also been looking at the Sparks Racing cam, but there is no information on this cam other than it is $225 vs. $160 for the Trinity/Web. Is this cam worth spending the extra $65? And finally how about FST?

 

noticed the same thing on the trinity site, get the specs directly from www.webcaminc.com. I am running the 696/697 grind webcam, it is great for top end but you definatly will loose some bottom end with this cam, the midrange is probably a better choice for all around riding. dont bother asking sparks they "dont give out info on their cams" which probably means it is also the webcam. the 461/496 also does not require new valve springs

 

Thanks vraptor. I would like to hear from someone about the sparks cam. I am going to put the RD springs in, I want to build something that is going to last. I know that web says you don't need the springs, but its better to be safe. It should reduce some valve trane weight too. Anybody using the sparks or are the sparks guys going to answer? How about Mickey from FST?

 

tried getting the info from sparks directly, if they had a better cam I would consider buying it. I am using the rd springs, they are quite a bit heavier than stock (double spring vs single) make sure the cam you use can handle these heavy duty puppies. I am in the process of building up a second raptor (my brothers), and am talking to Mickey at FST to see if we can use one of his "kits"

 

Not sure which kit you got? RD offers a newer kit that has the lighter Exhaust springs. I am going to try and talk to Sparks today, if they can't tell me why I should spend the extra money for their cam I will probably go with the web. Springs are on there way.

 

Sparks and Dunlap both use the MegaCycle cams (I believe). Those cams were designed for the older 660ccXT Yamaha engine and were not researched/changed for the atv application. Their x3 and x4 cams (both of which I believe are used by the above names) are probably fine but both would require more compression and valve springs. You may even need to cut down the valve guides?? That begs the question --- why install a cam that has lift substantially greater than the valve can flow?? The 660 head with mild porting pretty much stops flowing at .300" lift. In fact, I have seen flow tests show cfm decrease over .300 lift on mild port motors. Going way over that lift (in the case of the x3 and x4 .452/.459" in/ex) is nonsense, creates major valve acceleration issues and is generally too much wear on things.

Now, the Web Cam. The 461/496 is a 242/245 degree duration at .050 with .340/.355 lift. The valve timing events map out to help make low to mid power -- something that most people are looking to achieve. This is the cam used most frequently by Trinity. It is a "drop in" cam, you can run stock springs if you really are on the cheap and, with the lower compression piston, it works fine on pump gas. This combo will get you 60hp with stock carbs and exhaust tip only.

You want to drag race 99% of the time, go with 12:1 compression, a Carillo rod, Fortin gears, a clutch, carbs, swing arm, full pipe, the big 280x4 Mega Cycle cam (if you must -- I would cut the lift back) and expensive race gas (about 73-80bhp and 60 pounds of torque. This is pretty much what Sparks brought down to the festival in Glamis. Your other option is to build the more mild motor and add a N20 system for those occasions when you are feeling a little behind.

 

John/Raptor720,

Please do not talk about what you think I use in my motors. You have made statements about my pistons, cams, valve springs, etc. that aren't true. Yes, Curtis and I build similar motors because we have been doing this for a long time. We have both raced at a professional level (at one time even on Team Honda at the same time) so we have been around the block a few times. Most of our development is at a higher level than the average engine builder. I am glad Curtis was able to come out and show what a professionally built Raptor runs like. It didn't take a high-flowing head to make the HP he made. It's just the fact that he knows how to build a motor and that's why we charge more for cams and other products that we have developed. Basically, the customer gets what he pays for. It's important to talk to each customer to find out exactly what kind of riding he is doing and what will work best for him - that's the bottom line.

 

You are right Mickey, I should not talk about your motors. I have not (and neither has anyone else that I know) seen any of your Raptor or EX machines run (although I am looking for that phantom 720 or 760 bomb that someone claimed you built). There is no "special" magic with the Raptor. Bigger cams, Higher Compression, etc., makes power. Sparks did a good job -- he came to Glamis with race bikes. He has some major building experience from his relationship with Honda. He did the impossible with that 500cc EX -- I am still wondering how you fit that big of a piston in that machine. I know he makes some major fast stuff.