It seems my 450 needs more power. Mostly down low to mid. I have a slightly over sized piston, Yosh RS4 Complete, stock every thing else. The bike just seems to be a little flat in the low to mid area. With the Yosh It seems to pull for ever.But I need more power every where. I did have it re-mapped by Eddie. But was with a stock pipe. So what do you guy`s think ?
Thanks

What do you mean by slightly overize piston? Like its not 450ccs anymore?

Unless your riding on a top pro level, I seriously doubt your using all the power on your 450. Or if you weigh 3 or 400lbs then I could see you needing more power.   

Just a little larger piston than stock, no big differance. The motor just seems a little flat at low to mid. Maybe a different cam ? Or maybe another remap for the yosh pipe ?

Thanks

Edited by racerx-936, 03 May 2012 - 01:50 PM.

scotty i need more power.

but captum she can't take much more, i'll see what i can do.

racerx-936, on 03 May 2012 - 01:48 PM, said:

So did you bore it out? Or do you mean like the A and B piston sizes? And I can almost guarantee that it isnt slow, the motor just doesnt have a hit, and that makes you think it is slow

Switch to VP U4.4, and get it remapped for said fuel. Pour in the fuel, instant HP gain. Low to mid is definitely increased, but the HP gains are across the board. I have often been criticized for doing so myself, but I can tell you for certain the difference is noticable. Everyone asks me if I'm pro and if not why am I running race fuel. It is clean, consistent, and the way it livens the motor up is easily noticed. I used it in my 06 and now in my 11. I rode both stock and can tell you with certainty that the HP gains are real. A jump right out of a corner that I did everything I could and would still come up 5-10 ft short with my bike on pump gas, now I clear easily with my bike on race fuel. In fact, I have to moderate the throttle or I will overjump it. Only difference is race fuel and remap as opposed to stock. It is nice to have the instant power on demand to get you over or pull you out of whatever it may be. I am probably going to get ridiculed again, but I don't mind. I am +30B rider that works 2 jobs and doesn't get alot of time to ride so I am a nobody. But I can tell you you won't regret it if your wallet can afford the $80 for 5 gallons. Just my opinion of course.....

adding some fuel in @ the lower TP positions progresivly adds noticable power with your sligth over bore it may want even a bit more than im adding in.

He prolly just wants more low and mid you dont need to call him up n say he dosnt need more power unless hes pro...

Edited by Dasquriel, 03 May 2012 - 07:10 PM.

I think you should get it mapped again for the pipe you are running. think of it similar to carbed bikes and almost always when you change the pipe you had to re-jet, if it was an open loop system with an o2 sensor it probably would not be as big a deal but with closed loop EFI it is a good idea. I gained basically two horses over the entire RPM range with just a re-map after i switched out my silencer.

I really like to keep the rpms down I'd like more power on the bottom as well..  I think a cam would do it.. also the 50mm tb is too big.

Also a 13-1 piston would help

Yes, put a 13 or 13.5 piston in it.  That helps low-end big time and you can run pump gas with the stock cam!  Use a 14.5:1 for race fuel!

Edited by Ed2006CRF450R, 04 May 2012 - 04:44 AM.

I'd like a clarification on what he means by "bigger piston"

Bigger as higher compression, or bigger as from 96mm to something bigger than 96mm?

And more power? More where, more bottom end? More top end with that bike with that pipe and a remap is tough to believe. Ive ridden an 09 with the yosh pipe and a remap (yosh) and it flat hauls ass. It is a little soft on the bottom though.

A higher compression piston should bring that to life though. But if you just wanted more bottom end, a Stage one with the stock piston is an option, but again, looking at remap. But Id try the cam by itself first.

The 50mm throttle body is part of the bottom end power issue. In 2010 they went to a 46 which is a pretty dramatic change.

Thanks for the replys !!!! The piston is a CP 12:80 I believe.A re-map is probably my next route. I have used alot of VP in the past, but it`s just to dang expensive. Keep the ideas coming I appreciate it.
Thanks

Shawn_Mc, on 04 May 2012 - 09:38 AM, said:

Do you know if the 46 work on an 09?  I'm sure the map would need to be different.  I have a tb insert but that just kind of convolutes the intake not optimal imo.  I really like to run my bikes a gear n a half high and I'd like more chug.  I think the 46 would help. She's not ready for a you comp piston yet there's just not enough hours to justify it.

englertracing, on 06 May 2012 - 01:33 AM, said:

That insert basically does the same thing. You just need to remap it. For low end power you need to raise the air velocity at lower RPM and that insert does that for you.

The 09's were a little rich off the bottom anyway, then you added the insert which would raise the velocity, but also reduce the MASS of air flowing in, so you'd need to lean it a little bit on the lower TP settings. Or add some timing in. With it rich, adding some timing would really make it bark off the bottom.

Honestly, I think you should probably call Eddie Sisneros and tell him what youve got. He's probably got a map. A map from a later bike with the smaller TB may work well for you too, but I'd call Eddie.

The velocity would be high untill the insert ends. Then drop off I have the insert in my tool box.  I don't think that approach lends itself to a consistent high intake velocity. It will be low intake boot. High insert. Low after the insert. and then high again as it goes through the throat of the port.  I would only go for a smaller tb and a matching intake boot that matches up nicely with the port.

I don't bite.  I (and many others) run the 50mm TB on my 250s, they work fine on either motor with the proper programming...

Edited by Ed2006CRF450R, 07 May 2012 - 04:25 PM.