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Yfz450R aftermarket throttle body

12K views 13 replies 8 participants last post by  alex450r22 
#1 ·
Hi

I will start a new thread. This subject has been a bit talked about here and there but not all in one. So ...
Share your experience about following throttle body’s:

1. R & D throttle body (Genius throttle body)
2. PEP throttle body
3. RP Race throttle body
4. OEM bored throttle body

With what TB I’ll get most out of stock engine with YZ intake cam+3 big.
 
#3 · (Edited)
You would be better off making sure you have a great exhaust and intake and a dyno tuned Vortex with possibly a custom map......You may want to upgrade your intake cam with an 08 yfz cam or a dirt bike cam depending on where you ride....Like Sheerider said above it won't give you anything without some engine work....


If you don't want to do engine work try upgrading your suspension because that alone will make you drastically faster!

The Black Friday sales will get you 20% off or more so shop around!
 
#4 ·
I have GYTR slip on with OEM head pipe, Vortex,Uni filter with GYTR adapter and YZ08 intake cam. I have very good aftermarket European shocks.
Last weekend I was training on sand-track and it felt kind a weak. Could not get power/speed out of it even I have 13 tooth sprocket in front. 4th gear was really weak.
Can you recommend some add-on or aftermarket part that helps me with this problem. I have kept engine stock as much as possible for reliability reason.
I thought aftermarket throttle body helps here but reading your recommends it is out of the picture unless head porting comes along with it.
 
#7 ·
Piston has about 5 hours. I was thinking to replace piston to 12.5:1 but as much I know this is the higest ratio to ride with pump gas. The question is that with OEM piston the compression ratio was rised by factory to 11.8:1 on model 2014 and on. If i replace the oem piston with high compression piston i get 12.7:1 ratio. Is it ok to ride with pumgas (european oct. 98).
 
#6 ·
Rip that head off and port that thing!
Get cams, valves, take our some metal, and get a better piston in there!
Get a better flowing exhaust and intake and start laying it down!
It's only as unreliable as you make it (or the shop you pay to build it)

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#8 ·
What if you needed to replace your stock throttle body, would you be better off going to an aftermarket with larger bore?

My quad doesn't have a lot of mods- Big three- FMF powerbomb, MSD, FCI intake.

Right now my quad revs to 5000 rpm's at idle and I believe I need a new throttle body. I tried the GT thunder idle adjuster and it doesn't change the RPM's at all.
 
#11 ·
What if you needed to replace your stock throttle body, would you be better off going to an aftermarket with larger bore?



My quad doesn't have a lot of mods- Big three- FMF powerbomb, MSD, FCI intake.



Right now my quad revs to 5000 rpm's at idle and I believe I need a new throttle body. I tried the GT thunder idle adjuster and it doesn't change the RPM's at all.


Your TB is just an air valve. Literally. Unless you dropped it, I can’t see why you would need to change it. 5000 rpm is a lot at idle, and you would have obvious butterfly opening, not fully closing, or whatnot. Find out why.


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#10 ·
Get rid of the air intake. Get a FCI. If you look through it, the yamaha one has 2 90* curves, the FCI is smoother of a bend. I did mods and my FCI came in 3 days later, and I noticed a difference in throttle response and power when the FCI was on. You want to do things in a certain progression from easiest/most reliable then go towards the "clapping it out" spectrum. You may do a few tasteful mods and be happy with the power.
You're on the correct tract with Vortex, and intake cam. The GYTR pipe isn't in the upper tier. I always reccomend yoshi because it has good power, is affordable, and isn't stupid loud, there are other options though. I am not a fan of FMF megabomb or powerbomb. Everyone I ride with always has issues with their jetting/programming, I think the dumb little expansion chamber messes things up IMHO. . Get a different air intake. After that, read Mixxer's Porting Theories Thread. It is a valuable resource. Also read The Straight Dope on High Compression. It's good to understand the reasons we do certain mods, that way you will make better decisions with what direction you want to go.
 
#14 ·
I did put the GT thunder idle adjuster. But I have a vortex now and the my quad wont even try to start due to a tps high voltage. I’m trying to figure that out now. Rp ended up canceling my order for some reason and I can’t order from them since they are away on vacation until next week.
 
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