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PostPosted: Sun Jun 12, 2016 1:35 pm 

Joined: Sun Jun 05, 2016 12:31 pm
Posts: 3
Hello everyone

In the past few weeks the idea of getting something on two wheels was growing in me, so i did some research and found the best price to performance ratio in form of a used 2011 jc50 cbr in mint condition.
The bike was used by a girl, only driven in the dry and has only 1300km on the clock.

As a former car mechanic, it was clear to me that i'm gonna do all maintenance myself and also modify the bike a bit.

due to really bad weather atm (and also the bikes standing time), i'm not quite willing to drive the bike and decided to first do a complete overhaul on the bike, which includes the following:

- Performance Pack and Springs installation
- Flush the cooling system
- Change all Fluids (Oil, Coolant and break fluid)
- remove all of the stickers on the bike (why on earth did they put the Honda stickers beneath the clear coat? :dry:

Now to my questions:

- Should i also check the Valve Clearance or wait until i hit 4000 km?

- I'm planning on buying a spare second hand stock exhaust and modify it to my liking

File comment: exhaust
ex.jpg [ 30.49 KiB | Viewed 934 times ]

Can i take out the entire middle section and make it straight true to the muffler without power loss? (is this all catalytic converter?)

The goals i want to achieve with this are the following:

- Less weight
- Less heat beneath the engine
- Hopefully slightly better sound

I'm aware of the fact that those little N.A engines need some back pressure and i also don't want to make a obnoxiously loud fart box.

Any thoughts, advices and critics will be very appreciated

Best regards, Don

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PostPosted: Sat Jul 23, 2016 11:25 am 
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Joined: Sun Mar 23, 2014 9:21 pm
Posts: 535
Location: Parksville, BC, Canada
Hi Don;

In no particular order...

You could lash the valves now but I would personally wait until about 4K. What's going to happen is that the wear between the rockers and valve stems will be more/less complete and then it will hold the new settings for longer (because they are broken in).

On the catalytic converter, there is a really common misconception out there that it robs power from the bike. This is not true. The stock exhaust is very hard to beat and generally speaking, unless you have full control over the fuel injection you won't really beat it except in one range, probably at extended WOT with an aftermarket exhaust. The cat is actually in the first wider section of the pipe. It appears you have a resonator chamber and then the actual muffler after that. I personally would not touch the exhaust, if you want to try different exhaust I would recommend replacing it with the inexpensive Yoshimura exhaust that you see on e-bay from Thailand from one seller on there. It's much lighter (about 2.5 lbs total weight) and this will make the majority of the difference. Plus, I like the primary pipe design.

Keep the old exhaust so that you can go back when you get experience with what exhaust really does and does not do.

Honda put the stickers under the clear coat for good reason - so they don't fade or fall off! :laugh: If you're doing an oil change be sure to run a true 100% synthetic oil (JASO rated) or you're just shooting yourself in the foot and loosing HP. You HAVE to run true synthetic on this bike (and probably all bikes).

Best & Thanks!
Marvin Miller
cbr125world Store

...because every day is MotoGP day when you own a CBR 125r...

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