I am new to YFZ Central. I think this site is great. I have a stock 09 yfz 450r. I am looking at my engine options. I reside near TC Racing engines, and am thinking about having him build my motor. TC is not producing an exhaust for the r model. I do know that a standard yfz 450 exhaust will bolt up, if an aftermarket rear shock is used. Has anyone tried a TC exhaust on the r model? Can a TC muffler be placed on another companys head pipe? I have spoke with supertrapp and found that there is no R or X model exhaust on the drawing board at this time. Is the GYTR (full) exhaust any good? What are the GYTR dyno numbers. I also have questions about the EFI. What is the difference between the EFI controller and an ignition system. Which one would be better? Sorry of the dumb questions, but im new to fuel injection. The $4.00 jet days are over. Has anyone used the GYTR Cams? What were the dyno results? I have also considered waiting a while due to the many unknows of the machine. I am looking for an honest 55-60 horsepower motor. From the information I have been given, Tom has built R model motors in this horsepower range. Any help would be greatly appriciated.

to get 60 hp from the R... YOU need loads of money..
Also Id love to answer your questions, but Im too sleepy, so just go off and read the other posts in the forum, all of those questions have been answered and some more... :)

If you really want to get 58-60 hp, and Tom say's he can do it, then you better talk to him.

Factory Yamaha isn't even getting that kind of hp.............. However, ask Tom what a stock YFZR get's on his dyno.

Then you can intelligently compare his numbers to everyone elses.

As for everything else, this forum has a wonderful search function at the bottom.

I have not not talked to Tom about this. I was advised by a third party that he has made some awsome power from the r model. I have not spoke to Tom about it. What is a reasonable hp# to expect?

You should really become friends with the search function.

I agree, try using the search function.

That said, here's my .02

Don't piecemeal things together. Do it right the first time and buy a complete exhaust for the R, like Motoworks or DASA. Motoworks also offers an EFI controller, so you can dial in the exhaust and other mods, like an air filter, to work together on a unit designed to work with that exhaust.

As for HP numbers, no one is really getting close to 60 on the Yamaha because the five-valve head limits what you can get. ATP did a bang-up job on our project YFZR and massaged a 20 percent horsepower gain out of our quad to get 52 on their dyno.

www.atpracingengines.com

not many ppl have been able to get over 55 out of the R motors. There powerband is set-up too smooth.


I'd start off by getting a 42mm carb for it though. Get rid of the FI that makes the power so smooth and get some hard hitting HP from a carb.

I spoke with Tom today. He gave me some great options. Getting a carb was one of them. When asked about horsepower, Tom stated something that makes alot of sense. He stated that the most horsepower may win a drag race down the road, but high mid range power is much more important in motocross. The mid range horsepower is more important then all out power. I guess I should have spoke with Tom before I made this post. I have had all my questions answered by speaking with Tom. As for horsepower #'s, I guess I should confirm what I was told before I make such assumptions.

60HP is alot to make on a stock bore/stroke motor. Especially the R's. Like i said, for some reason, not many ppl can get good numbers out of them. But it all depepnds on the dyno.

A strong motor in my opinion, would be 52-54HP and sbout 38-42TQ.

bump

I am sorry for their is still people living in the stone age. Anybody that believes that a carburator makes more horse power than EFI is still living there. Good horsepower can be made out of the new 2009, but you will end up spending some money to get it there. We have tested 8 sets of cams, 3 fuel controllers, and everything else that is out there and we are doing it on a new 250 IX EDDY Current Dyno. NMotion pipe from JSR has been tested for the '09' and just like all NMotion pipes before for the YAMAHAS, it is one of the best and we make it with 5 different options according to your sound and engine requirements. Our test bike will be in DIRTWHEELS soon with all the new products, if there are any questions give us a call.

P.S.
If Carbs are still the best for racing why is world super bike, formula 1, and all intelligent forms of racing using EFI?

I was not informed that a carb would get more power. It was explained to me as simplicity. I could easily make changes to the jetting without using a computer. I was advised that EFI would have to be changed for every change to the motor, intake or exhaust. TC can run whatever I prefer and make great power. I fully believe that TC racing produces some of the most reliable motors with awesome power.

I plan to have the motor done before next spring. I will certainly post info when the motor gets done. Total expense will be between $2500.00 - $3000.00. This includes a custom exhaust, porting, piston, cams, EFi mods or carb (my choice) and all labor.

The look on peoples faces, at the races, when you plug your laptop into your quad to adjust the fuel is priceless. LOL

k, from this whole new wave of EFI, what i've gathered is that you can get power out of EFI's, its just harder and takes more money. For a carb, less money and more of a hard hitting, rip your arms off type power. Whereas the EFI is a smooth, softer kind of power.

If you wnat hard hitting, tire shredding power, you get a carb.

Not exactly............ The reason they are getting so much power from the YFZR by putting a carb on it, is because they are also putting the YFZ ignition on it, therefore they are able to match the ignition curve to the motor mods.

Once a decient, programmable ECU come out............ Well you know.

The thing that get's me pissed, is that the new YZ450F comes with a re-programable ECU, and you are able to buy a GYTR gizmo to do it with.

yea, i hear ya. That thing os fricken intense though. I cant wait til i see that motor in a NEW YFZ frame.

They YFZR can actually be made to have more bottom end torque and match the same horse power as 04-08 right now, but you will have to spend money on fuel controller, cams, valves, and porting, we can match all the old motors horse power now with more throttle response then the old bikes had and if you spring for a PC5 with wide band 02 you can map the bike and the bike will auto tune from then on and you can run it on E-85 for about $2.00/gal for more horse power. It is all in the combination, be looking for upcoming DIRT WHEELS article.

I am almost positive that the stock electrical harness and components would stay the same. I am told that if you want to switch to a carb, it is very very easy. The only thing that would change is that a petcock would be needed for the fuel tank.

No way. If you unplug the FI from the ECU, it won't run. It's about a 2k conversion.