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Were i live noise isn't an issue, so took the baffle out of my 150. I thougnt i was letting more air flow through [MORE POWER] A guy told me i was losing power becaise there is no preasure in th engine. Is it true?

no, but i'd do the power up kit too. it made a difference on our 150

You do lower your compression by removing the baffle since there isn't the same amount of back pressure

.sinner wrote:You do lower your compression by removing the baffle since there isn't the same amount of back pressure

Eh...no you don't.

Whoever you talked to was an idiot.

The more volume that you can get in and out of your engine, the more power you will produce and that specific engine becomes more efficient.

Do the power up kit. The engine is starving for fuel now that more air is moving through it!

Thanx alot for the opinions it realy means alot.
im 13 and im decently new to dirtbiking. But i ride everyday-exept snow and our recent 40mph wind.

So does that mean that if I take the baffle out I will get more noise and more power? They dont teach this stuff at MMI, they always tought us that if you take something out you should replace it with something better or put the stock parts back.

The concept is to allow more air/fuel to flow through the engine. Taking a baffle out may not improve anything unless you also increase the airflow into the engine. In other words, a less restrictive exhaust needs a less restrictive intake to be effective, unless the exhaust is so restrictive as to not allow the airflow through that the intake will allow witnout modification.

So. MMI is correct.
Joe

Well said Joe.
And as already mentioned if you have more air flowing in and out, you will need more fuel to go with it.

If you don't readjust your air/fuel mixture you run the risk of the mixture being to lean to a point where engine damage may/will occur.

Honda sells the power up kits to work with these specific mods.
The worlds largest producer of motorcycles is stupid, they know you want more go an that you will pay for it.

Do all mods as per power up kit, install it, have fun.

Either that or stay stock, as long as you having fun.

Where do i get a power up kit for a 2005 CRF150F. They must be pretty hard to find becuz iv looked all over on the internet. HELP!!!!!!!

150_red_rider wrote:Where do i get a power up kit for a 2005 CRF150F. They must be pretty hard to find becuz iv looked all over on the internet. HELP!!!!!!!

For a stock engine -you can try removing the airbox
snorkel. Then purchase and install
the following carb parts from Honda:
For Stock Engines with OEM carb:
• Full Power Needle Kit Part #16012-KPT-921 4th clip
• 42 Pilot Jet Part #99103-KPT-0420
• 108 Main Jet #99113-GHB-1080 (high elevation)
• 110 Main Jet #99113-GHB-1100 (low elevation)

I think that an earlier post confused compression with backpressure,you can run without an exhuast pipe(not recomended)and it wont change the compression of your motor. Depending on how much backpressure is what your exhuast does,basic rule of thumb is more backpressure=low end/less=top end.

Joe hit it on the nailhead,the more you put out the more you need in and vise versa.

SLICK...

There's a little more to it than just moving more air and fuel through a motor. 4 strokes need back pressure to generate low end torque. If you ran your bike wide open all the time, you'd want the pipe wide open with no baffles to create max horsepower at max RPM but the reality is you run your motor in the lower and middle range most of the time. So, a motor needs to be tuned where the maximum performance gives you the most gain. A high performance pipe allows freer breathing but still provides enough back pressure for the engine to have good low end roll on and snap.