HRC or Sparks Cam?

[416rider]

:devil: I have a sparks racing pipe and I want a cam and piston I would go with the honda HRC kit but its $320. The sparks racing cam is $215 and the 13:8:1 JE piston is $ 210. Which one should I get? also is the new piston worth it?
:devil:

[#1speedbump]

The Sparks cam provides 4hp in the low and mid range and 2hp on top. From what I have been told the Honda cam will only out perform it on the top. Also with the piston by itself I have been told by several builders that you will lose topend

[29FTEX]

Originally posted by #1speedbump
The Sparks cam provides 4hp in the low and mid range and 2hp on top. From what I have been told the Honda cam will only out perform it on the top. Also with the piston by itself I have been told by several builders that you will lose topend

Which engine builders told you that it loses some top end? I have the JE 13.8:1 with HRC cam, and didn't notice any top end loss. There has been someone on here that said there's lost some top end, but I can't tell.

[benwa450r]

You get more than just the cam with HRC kit. You get an exhaust endcap (which you don't need), a t-breather tube ( bigger than stock), a bigger air inlet for airbox, 185 main jet and needle jet. I have HRC kit with Sparks exhaust and air filter, 190 main with no airbox lid. It definitely wakes it up. If you get Sparks cam, you'll need to buy jet kit also. My 2 cents.





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2004 TRX450R, HRC kit, Sparks stainless exhaust, Sparks filter, 190 main, no lid, A/C nerfs, Razr MX on T-9 rims, e-brake block off plate, Renthal low bend, CRF 13 tooth sprocket.

[#1speedbump]

When I stated that you lose topend I was referring to the piston alone without the cam. Several builders have acknowledged this. TC Racing, LRD, Mac Racing,etc just to name a few. Most likely you didnt notice the topend loss because you have the HRC cam.

[r450rr]

i must ask. does anyone have the 12:1 in the je... is it even out yet?


and what does a higher compression actually do,, does it make you have more accelerartion.. more bottom end topend.. what is the pros and cons of me getting the 12:1 compression piston.. (i am also putting the hrc cam in an a yoshi exhaust.. ) so how would the 12:1 help me.. thanks..(oh yea and i was told that i could use regular pump gas on the 12:1 .. is this true?

[29FTEX]

Originally posted by #1speedbump
When I stated that you lose topend I was referring to the piston alone without the cam. Several builders have acknowledged this. TC Racing, LRD, Mac Racing,etc just to name a few. Most likely you didnt notice the topend loss because you have the HRC cam.

That's what I was curious about. Thanks.

[BSTURDIVANT]

Higher compression will boost your combustion chamber charge(air and fuel mixture) bycompressing the molecules tighter together giving a more explosive and efficient burn pushing the piston down with more force- more torque. When this torque is
multiplied by rpm it increases HP. Higher compression helps all thru the rpm, but the torque is very noticeable on the bottom.
Properly designed domes and camshaft profiles with higher compression ratios actually help top end that's why Nascar engines have been run at 16 to 1. Nascar guys make lots of compression with little domes on their pistons to " clog" their combustion chambers. The TRX450 requires a big dome to gain compression, causing less of a gain as the dome size goes up!

[Shawn H]

Someone is selling HRC kits on ebay for $200

[lukester720]

I've ridden hrc equipt 450r's and mine with the sparks cam, and I like the sparks better. I use bottom and mid more than top end, riding trails, tight mx tracks, ect, ect. Tim Farr also runs the agressive sparks cam for mx and the sparks full race cam for tt. Hope this helps!

[robby26wi]

Nascar cant use as much compression as years back...To get compression without a huge dome they actually push the pistons out the bore a bit...