Looking for more top end power????


11 replies to this topic
  • Kuznik

Posted June 04, 2005 - 01:35 PM

#1

Looking for some top end power. what do the yz cams do for the bike will this increase the top end?

What I have is a akro slip-on with a power bomb header and airbox mod and the jd jet kit, I am pretty happy with the jetting after some dyno runs and playing around a little.

I really only want to make mods that will not hamper the longevity, and maintenance of the bike.

Can anyone help out and point me in the right direction. The bike makes 48.8hp but really dies in the top end...

  • Bamster

Posted June 04, 2005 - 04:14 PM

#2

I can't believe you don't have enough top end all ready with the mods you have done.
What year are we talking about?

Where do you ride? Trail ,supermotard?
Do you mean Top end as in Top speed or power in the upper rev's?


I have a 99 WR 400 ,when I YZ timed it, there was a gain in top end power.

  • simon@vic

Posted June 04, 2005 - 04:51 PM

#3

it would help if you told us what the bike was.....................

what ever is it, put in a 2003/4/5 YZ450 exhaust cam. you will never go back!!!!!!!!!

  • Kuznik

Posted June 04, 2005 - 05:30 PM

#4

looking for more power in the upper rev's.

Sorry guys it’s a motard, 04 year, and I run mostly on sport bike tracks, on the street, and some short tracks, anything past ¾ throttle and it seems to lack power, so I shift up and out of that gear sooner than I would like. Tried to fix with jetting on the dyno, no luck.

The bottom and all the way to ¾ throttle position pulls strong! Quickshot made a big difference at bottom end very happy with that mod.

Anyway if I went with a yz cam would this cause me any problems with engine maintenance? Anyone have the part number for this yz exhaust cam?

Most people would not notice the drop in power in the upper rev's playin in the dirt.

  • jonova

Posted June 04, 2005 - 09:05 PM

#5

Go with a set of cams made by Hot Cams. More aggresive grind as well as similar Timing to the YZ.

  • minion

Posted June 04, 2005 - 09:07 PM

#6

Looking for some top end power. what do the yz cams do for the bike will this increase the top end?

What I have is a akro slip-on with a power bomb header and airbox mod and the jd jet kit, I am pretty happy with the jetting after some dyno runs and playing around a little.

I really only want to make mods that will not hamper the longevity, and maintenance of the bike.

Can anyone help out and point me in the right direction. The bike makes 48.8hp but really dies in the top end...


Did you unhook (cut) the grey wire? (Considering its a WR)? If not, that is supposed to be a CDI timing wire that retards the timing at high RPMs. I did that on mine, and I can hit the rev limiter pretty quick if I try.

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  • simon@vic

Posted June 04, 2005 - 10:49 PM

#7

Canadian 2004 bikes don't have a grey wire to cut. so ignore the above.

trust me GET a yz cam. it will not damage or cause any more maintenance then the wr cam. the Yamaha 450 was designed for the yz cam after all. the wr is just a yz they jammed a starter on and choked up allot.

  • beezer

Posted June 05, 2005 - 05:33 AM

#8

I would axe FFR racing what he would reccomend. He runs dirt track with his and I assume a motard engine might be similar.

He posts on this board.

  • Kuznik

Posted June 05, 2005 - 06:26 AM

#9

I'll be looking into getting the yz exhaust cams for sure, I'll do some research on what company.

The Grey wire or the TPS thing, the only thing I have noticed with that is, I have played around with just disconnecting and then connecting the plug, before the powerbomb I couldn't notice a difference in the way the bike ran. With the powerbomb and TPS plugged in it seems to have made the 1/4 to 1/2 power delivery very unsteady at constant throttle position. I know this is a racing carb and does not want any sorta constant throttle so I really do my best to never ride with the throttle at the same position.
Anyway with the TPS disconnected it seems to make it a little better, but when bike is at idle it seems not as smooth, but that really is not a problem just an observation. Any problems with just letting the TPS hang loose other than getting crap inside the connectors.

  • Kuznik

Posted June 05, 2005 - 06:46 AM

#10

On the cams people only change the exhaust cam and not the intake cam? why not both...

  • simon@vic

Posted June 05, 2005 - 07:45 AM

#11

just exhaust

  • Lowedog

Posted June 05, 2005 - 09:40 AM

#12

Have you considered that your pipe may be signing off at the higher revs? Most aftermarket exhaust systems offer nice gains low and mid then sign off on the top. Do some searching on pipes on the YZ forum. There is a guy who posts there that has done some extensive research on pipes with dyno testing. May help you out.

-Lowedog




 
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