Blaster w cbr929 exhaust

[Weelys4days]

Ok so my motor is in the machine shop getting bored, and I just ported the exhaust port and cleaned up the transfer ports. I'm currently on stock exhaust and am about to be rejetting it anyways so I'm making an extra project exhaust from an exhaust pipe off of a cbr 929. I know this may not work but I have the extra parts, tools, and supplies ( and free time at work) to make it happen. What do you guys think? Could this possibly have any benefits

 

[Blaaster]

If you plan to use the stock header and fit the modified cbr 929, you may have to alter the jetting owing to the different breathing characteristics of the silencer.

It would pay to plug chop to confirm!

 

[Weelys4days]

Yes for now I'll be using the stock expansion chamber, and I will surely be rejetting and plug chopping. Almost got it finished today, all that needs done is a little clean up and paint. What do you think?

 

[BlasterFun484]

Wont find much change in performance since all thats made and changed with in the expansion chamber, but sounds, flow, and look will be directed, pretty sweet, i wanna see it mounted now... If i were. You id grab one of these cheap fmf or other used expansion chambers that keep floating around ebay do it all at ounce, than youd realy see and make some difference

 

[Weelys4days]

Thanks for the input, I'd really like to put a nice expansion chamber for it, unfortunately I can't seem to ever find one of those sweet ebay deals, and after buying a slew of new parts, including a new top end, I need to ride it a little more before I can justify spending more money on it. Plus I enjoy tearing my toys down from time to time so I'll get one eventually. I already built a wheelie bar w a roller, and hooked up a rear hand brake and have been loving riding this thing.

 

[MercMenace]

I want to hear what it sounds like. Nice project.

 

[Weelys4days]

Thanks, when my motor gets back from the machine shop, I'll try to post up some more pics and a video of stock vs. Cbr pipe sounds.

 

[rich1]

Ok so my motor is in the machine shop getting bored, and I just ported the exhaust port and cleaned up the transfer ports. I'm currently on stock exhaust and am about to be rejetting it anyways so I'm making an extra project exhaust from an exhaust pipe off of a cbr 929. I know this may not work but I have the extra parts, tools, and supplies ( and free time at work) to make it happen. What do you guys think? Could this possibly have any benefits

Dont waste youre time there is a lot more to it than a piece of pipe and muffler. One is a 2 stroke and the other is a 4 stroke since you don't seem to know the difference forget it !You can damage the motor, having to send it back to the shop a 2nd time.

 

[Weelys4days]

I understand quite a bit about how a 2 stroke engine works as opposed to a 4 stroke engine. I'm no professional but I've been tearing down my own motors and my friends motors for ten years and I'm fairly keen on how things work . I'm always open to gain a bit more knowledge so Please enlighten me on why you think the 4 stroke exhaust would be harmful to my engine.

 

[Blaaster]

Yes for now I'll be using the stock expansion chamber, and I will surely be rejetting and plug chopping. Almost got it finished today, all that needs done is a little clean up and paint. What do you think?

Fitting an aftermarket silencer to a stock header pipe may need a jet change!

Providing the silencer is of the straight through type that provides no back pressure, it would not matter if it was 4 stroke or 2 stroke related.

 

[Larry's Shee]

I like the looks of it

Too little back pressure will hurt performance but not the engine. Too much is worse than lean jetting.

As mentioned, plug chop/ plug read.

 

[Weelys4days]

Yup, I already have my jet kit, and extra plugs and I'm just waiting as patiently as I can for the machine shop to return my motor. It will be bored to .60 over and just got a port and polish too so I'm really exciting to see how much different it rides . Thanks everyone for your Input

 

[Blaaster]

Be wary of the jets that come in in a kit, they seldom confirm to size, and often are not in the usable range.

You best bet would be to order single genuine jets in the range that you may need.

The needle that is supplied in kits is usually useless.

 

[rich1]

I understand quite a bit about how a 2 stroke engine works as opposed to a 4 stroke engine. I'm no professional but I've been tearing down my own motors and my friends motors for ten years and I'm fairly keen on how things work . I'm always open to gain a bit more knowledge so Please enlighten me on why you think the 4 stroke exhaust would be harmful to my engine.

The short of it ....The inlet /exhaust phases are constant on a 4 stroke . The 2 strokes inlet /exhaust phases varies .The 2 strokes use a silencer and are packed , 4 strokes use mufflers that are baffled. Most 4 stroke baffles are too large to work well with a 2 stroke expansion chambers phases. I don't know youre experience since you are new here . As long as you know how to re- jet you should be able to get it to run , how well will be the question. Good luck.

 

[Weelys4days]

So my motor is finally ready !!! I got it all back together today, and while it was apart I noticed it has a hot rods crank, so I was pretty pumped about that! The exhaust mounted up perfectly so I was a happy camper as far as the labor was concerned. I did run into some serious tors box issues(idle screw broke off) when putting the carb all back together but I got it back together and got it to run for the first time in about a month. Exhaust sounds pretty good and seems to hold idle just fine. Tomorrow I begin jetting and the rest of the motor break-in process. This thing sounds like a beast and already feels like it is ready to jump out from between my legs at idle. Throttle response is rediclously faster and I've barely even pumped the throttle just to keep it running while I set the idle. I'll post more tomorrow.

 

[rich1]

Hey ...its the Bomb....Tick ,tick ,tick....

 

[Weelys4days]

Yea yea, this thing is running well, much faster and smoother than before the bore and port job, and when I me and my 105lb friend switch bikes, my blaster will almost keep up w his stock trx 450 and I imagine if the tires had tread, it would be a close race. So I feel like I have this thing pretty well dialed in for the time being. I have a lrd racing expansion chamber on it's way to my house, once it gets here the jetting and plug chopping shall continue.

 

[Larry's Shee]

Hopefully you have leak tested after assembly and re-torqued head and cyl after heat cycles.

 

[Weelys4days]

Yes indeed, I've taken as many precautions as I can and did a lot of research on this specific motor to make sure that it was put together, and broken in properly.

 

[Weelys4days]

Rich1 I have a question for you, and please correct me if the information I've been given is wrong but, I understand that two strokes need the baffles in the exhaust the help create backpressure at a cerain time to help the unburned fuel pass through the transfer ports, I also can see the baffles in my stock exhaust are close to the front of the pipe. So my question is, do you believe it would be beneficial to add a baffle or two in my cbr exhaust in the same part of the pipe where the stock baffles would have been?