2010 weapon

[woodyracer]

........please catch up with technology mr.gav, its a watercooled, 2 vavle, unicam 125cc single cyclinder, its also fuel injected.

So it is a pretty new motor.

[Str8 Jacket]

........please catch up with technology mr.gav, its a watercooled, 2 vavle, unicam 125cc single cyclinder, its also fuel injected.

So it is a pretty new motor.

Single cam 2 valve?! Old skool as bro! Not new, its cheap!

(Edit)FYI: http://www.suzukicycles.org/GN-series/GN125.shtml
Shoulda bought a loncin!

[woodyracer]

the lay-out may be cheap but the watercooling and FI arnt........

i guess its the "NEW" cb125 single then......lol

[gav]

........please catch up with technology mr.gav, its a watercooled, 2 vavle, unicam 125cc single cyclinder, its also fuel injected.

So it is a pretty new motor.

Its not a unicam motor with 2 valves mr woody, the whole idea of the unicam is one cam running 4 valves!!

[Buckets4Me]

Its not a unicam motor with 2 valves mr woody, the whole idea of the unicam is one cam running 4 valves!!

I thout uni means one and cam means cam and .What was I saying

ye thats right go buy a 150 4 valve head and barrel and CARB
then you might have a chance to keep up with the not so noisy and much older tech gp125's

[woodyracer]

oh yea......just a minor typo there......

[woodyracer]

i dont need that much power......BUCKETS4ME

[Buckets4Me]

yea right
you wish for 22 at the rear wheel

[woodyracer]

who said i dont already have 22 at the rear wheel......hhaahha

[Buckets4Me]

who said i dont already have 22 at the rear wheel......hhaahha

now you are dreaming

[SS90]

Just to play devils advocate (for a change)

I have thought about Woodyracers brave statements regarding noise and had to wonder.

First though woodmeister, as other have pointed out (some in an unkind way) that the concept of a single OHC engine is about as dated as it gets.

Seriously.

It's (marginally) more advanced than a push rod engine (like the old 4 valve Guzzi's from the mid eighties)

IF (and here I am keeping an open mind), the exhaust simply exist a straight header, into a muffler, regardless of the configuration (number of valves, cams etc), Andif you then remove that muffler, well, the noise will be VERY loud.

Something like your old mans Briggs and stratton with the rusted out muffler.

Think of those silly slash cut drag pipes on sportster Harley's.

It would be near enough to half that volume.

Now, here is where there may be an exception.

Your bike, is most likely to have a catalytic converter.

Sometimes (but not always) the CAT is in the muffler.

Occasionally, it is in the header system, located under the engine.

Now, IF that is the case, then, I believe that would be a reason that the exhaust noise is not (according to you) excessive.

By that, I mean, IF the CAT is still in the system (and said CAT is very restrictive), then that could well knock the DB level down considerably.

I have not looked at one of these exhaust systems, but I am trying to "throw you a rope" here Max.

Can you post a picture of your complete exhaust system?

Because if this is not the case, and the header is simply "straight through", then you may well have deafened yourself from the initial start up, and now have impared hearing.....because NO WAY will that pass noise levels on a track.

Fuel injection or otherwise.

As far as performance goes Max, The limiting factor in your engine (other than the small displacement) is the fact that it is single cam.

Is it 4 valve?

I havn't checked.

If so, it makes for a very heavy valve gear, which not only takes horsepower, but, at high RPM (as a result of that weight), it can, after a while suffer reliability problems with the heavy valve gear.

DOHC don't suffer from this, as, in general, the cams operate directly on top of the valve, via a shim and bucket set up, reducing mass, freeing up power, and improving reliabilty.

The Extra cam weight id outweighed (pun intended) by the gains by reducing the mass of the (now gone) rocker arms.

In short, DOHC is much more powerful and reliable.

Check your valve clearances often, in such a set up, they get a hammering.

[SS90]

I got curious Max, and had a look at a picture of your bike.

See this bulge in the middle of the header?

I seriously think that it is a Catalytic converter permanently fitted to your header from factory.

If this is the case (and it would seem) I would do some research and find out if (I suspect it won't) effect your fueling if you went down to your local muffler shop with a sample and got them to bend up a "straight through" header to remove the (it would seem) CAT from the system.

There is every likelyhood some people on here owe you an apology if this is the case Max.

Would pay to test my theory out before you gloat though..............

It would explain why you notice little noise increase when you removed the muffler........

[SS90]

Found an article containing this line

To continue Honda's "green" corporate goals, the CBR125 utilizes electronic fuel injection and a catalytic converter that combine to exceed the stringent Euro 3 emissions standards due in 2008.


on this address

http://www.mcnews.com.au/Testing/Hon...125R/page1.htm

Euro 3 is pretty damned tough...............

[SS90]

Yes you are. You are mind bogglingly stupid. I have trouble with your inability to see clear reason. Of course it is going to be too bloody loud without the muffler, (no matter what size it is). I mean Duh!

But the rules don't apply to you do they? I don't have to have folding pegs, I don't have to have a muffler. My mother says I'm special.

Listen to some of these guys, they have more than half a clue. Dissing respected posters like Mike will earn you no respect. And there is a point. Don't expect people to give you respect. You have to earn it. If people keep telling you you sound like a spoiled brat - Guess what?

Your wise message gets lost in some childish abuse Dave, I expected more from an adult.

Is this the sort of thing your wee boy can expect when his youthful exuberance impedes his ability to clearly define a scenario, I hope not.

Letter bombs to the usual address please.

[Henk]

From the sales blurb on the honda website

Ultra-Low Emissions The CBR125R’s lightweight and compact new fuel injection system also ensures exceptional fuel economy and ultra-low exhaust emissions. Its advanced HECS3 oxygen-sensing clean emissions system features a high-efficiency 300-cell catalyser element installed in-line in the exhaust system to ensure easy compliance with strict EURO-3 exhaust emissions regulations while maintaining top performance.

So there is one in there somewhere. Now you've got me curious as to where it is. SS90 may well be right so guting the can won't give as much extra flow as hoped for and possibly not as much noise as we all assummed. A new header could well be the way to go for more power (and a further weight reduction). Not quite as simple as geting a new pipe bent for something carbureted though since I'm sure there will be a lambda sensor in there somewhere and I'm not sure how critical the positioning on these is. I suspect it will run like complete crap if it is simply left disconnected and that any potential gains will only be realised with dyno time and some tweaking of the relevant maps. The dyno runs may be avoided by doing plug chops etc but the remapping is going to have to happen at some stage. I'm sure that in time FI bikes will out number carburetted in the class and that buckets with USB plugs in a handy location will be nothing unusual but at the moment the number of people who can swap brass with some success outnumber those that can reprogram an engine managment system. Dyno runs are a useful tool for carbed bikes as well and I know mine would probably run better having been tuned that way but it takes away some of the backyard mechanic aspect of the sport and I do enjoy playing in the garage. Maybe one day when I think that a little more power will help. At the moment I just need to hold it on longer and get back on it earlier, and a faster motor is going to make that harder to do not easier so might actually slow down my lap times, would definitely slow down the learing curve at the moment.Fast bikes don't win races, fast riders do, especially in a class where the bikes are reasonably close. You are never going to win races in F4 on cart tracks based solely on power down the straights if you lose it all through the corners.