[duke416ex]

Was just looking through some old posts and came across this one again. Are the original pics working for people? For me they have a watermark and are blurry?

 

[ghott]

Was just looking through some old posts and came across this one again. Are the original pics working for people? For me they have a watermark and are blurry?

Unfortunately - the images were hosted on "photobucket", which, at the time was a free picture hosting site. They have since changed and require payment for hosting images - and I believe that is why the images are blurry with the photobucket watermark over them.

 

[duke416ex]

I was thinking something changed with them b making sure it wasn't just me.

 

[duke416ex]

They may recommend it in the manual but I think they also say a new piston every 20 hours or so. Do your maintenance and keep a check on things and they will last a lot longer than the manual stated, not to say some won't grenade but still they are pretty durable.

 

[Honda 23]

hope the above illustrations and explanations give you some insight into what porting is and how it does what it does....

you can easily pick up 10% hp across the entire rpm band with good port work.... some places it will be more than 10% , but if you have more effiecient ports it helps at every point in the rpm band...

you buy carbs / cams / intakes / pistons and pipes.....

but guess what they all have to breathe through?? lol.... the ports.... make them work and it makes every single mod you have work better/ more efficiently....

my own focus in 35+ years of doing this is for track based racers ... endurance racing engines..... and I am a lifelong offroader , mx, hare scrables, and woods rider myself... with a focus on wide/ early power... with lots of throttle response to control the machine with..... once the band shifts and narrows and moves towards top end only power... I lose interest quickly.... some of the highest output machines I have ever dialed in on my dyno... have been complete unresponsive / sluggish midrange pigs on tracks and woods courses.... it doesn't take long on a track to see if your improvement on paper is a help to you out of tight corners or on a rhythm section.....lol

more torque and wider band will let you gear up and shift less...accelerate more... less clutch feathering... more traction... and less fatigue .... all advantage with no negative for track based competition...

so , info from me is biased to gains everywhere and no trade off bottom to top end.....

hope this is a help to anyone that was wanting to start learning for themselves... lots more to cover...but you gotta start somewhere....

for an excellent overall view into the world of 4 stroke performance you could hardly find anything more worthwhile than the Kevin Cameron book Sportbike Performance Tuning Handbook...

and a good source for more pics and info (no such thing as too much knowledge) is the motoman web pages.....

I will go back and fill in some more info with the pictures as I get some time... but I wanted to start this tutorial forever... glad it's at least started... whew

and if anyone would like to see what the 5 valve world of the YFZ450 port arrangement looks like.... here's a link:

Porting..Theory...Tools..Techniques

thanks so much for the information And pictures on the 04 05 it's helped me immensely and my engine immensely thank you