slight power increase.... please

[radish150]

Hey guy´s... how fast is fast? I mean, my bike runs pretty good really, but I´m not even doing effortless second gear wheelies. I can get one if I crank on the throttle but should I really need to pull up on it in second? My gearing is 14 49, open airbox, pmb insert, wires cut, thats it. I have KILLER suspension, but I need some more ponies.

Once I get my jetting as close as I can, whats the best way to get in increase in power with bolt on stuff? I´m not ready for a big bore or anything, but maybe I could do a performance reed valve, and a pipe and YZ timing? Power now do anything on these? Oh, how bout mild porting job (clean up job)?

thanks,

Mark...

[Matty05]

I really only got a vortex ignition and Procircuit Ti GP exhaust system on my bike to increase power. My jetting is spot on with JD jetting kit. I feel like I need more power too, but it is already about equal if not more power than YZ450F.

The front wheel comes up all the time with no effort sitting down!. Only 5th gear I have to pull on the bars to get it to wheelie. If you are standing up LIKE YOU SHOULD! with correct body positioning, it won't really come up much at all.

Cubes rule on four strokes. A bigbore kit from Athena is only $660 US dollars. Bang for buck, this takes the cake.

http://www.procycle.us/main/bigbore.htm

While you have the lid off the engine, a port job and a set of hotcams would do nicely.

BTW, jetting your bike properly is the best thing you could ever do for starters, there is a lot of power to be had.

[radish150]

Hey now were talking, I could even probably come up with those cams here in peru where I am.

And talking about the sexy bike picture thread? Have I got a pic for you guy´s... haha

thanks,

Mark...

[Dodjy]

should I really need to pull up on it in second?

thanks,

Mark...

If you've got a 450 your bike should come up in second and third, standing, sitting, whatever with no need to pull on the bars. Like Matty said, get the jetting right. If your got the stock 05 / 06 muffler, pull the rear internal baffle out at least or get an aftermarket pipe. I assume you haven't got AIS on your bike.

Just thought of something, what's your altitude. If your up in the clouds you will be way down on power due to the thin air.

[Tilson51]

like he said get the AIS kit on that bike and it should come up

[radish150]

No, sorry it´s a humble 99-400. Ais, honestly I dont know what ais kit is, but ill find out, but I bet it does not apply to my oldie, ill look. I imagine its an automatic ignition sensor???

thanks

mark...

[Matty05]

OK, on the 400, the front wheel should never touch the ground!!!

Those things were scary!!!!!

I would say it may be time for an engine freshen up being a '99.

Hows the fuel in Peru? Why not try a high comp piston?

Don't worry about AIS!

[bluebike1999]

yes... the bike should lift easy in 2nd 3rd and even 4th, no matter where you sit or stand.......

have you done yz timing mod? not sure how much that contributes

[radish150]

Well, this is interesting. I went one step further down on the pilot jet to a 40 and I´m getting some response now to my fuel screw changes. Seems 2 turns is about good, starting is perfect... now I need to choke it a bit when I first start it up, throttle response is super quick. I was at the middle position on the jd red, now I´m one leaner at number 2. When I changed the needle position, I also changed from 165 to 162 main (I was wrong about the 168) and when I goosed it that stumble was gone, but top end felt a bit flatter, so I´m back to the 165, I might try the 168 later when I get back down to sea level. I have better power now, front wheel is lighter, but could be lighter still. So whats with this main jet controversy? Taffy talks about like 150 main jet being enough? What am I missing? Or is he doing something else to utilize that small of a main?

So a question on needle position, how can I tell when its right on? It was rich in the middle range, one step leaner cleaned that up, but what are the chances that I should go one step leaner still? I guess I´m trying to avoid more experimenting, I´m hoping someone can tell me for sure if one click eliminated a rich condition, if one more might be indicated or that would likely be too lean? Do I need to try it or can you guys save me the trouble? Its running really smooth, I´m likein´it.

I have questions about oversized pistons (I dont want to buy a cylinder) on the 400 now, but will post that in a new thread.

Thanks ya´ll,

Mark...

[Matty05]

So whats with this main jet controversy? Taffy talks about like 150 main jet being enough? What am I missing? Or is he doing something else to utilize that small of a main?

He is talking about changing the main air jet as well to something smaller too. On the newer bikes, our main air jet is fixed, so less adjustment we can do. But you on the other hand....... If you have a whole bunch of jets, you can experiment, but I wouldn't really worry too much if you don't.

Sorry mate, you got to do some experimenting! If you lowered needle one clip, lower it again and see if better or worse. Sorry, but this is only way to do it.

I have questions about oversized pistons (I dont want to buy a cylinder) on the 400 now, but will post that in a new thread.

Now, you have a few options with the old 400, you can go out to 420 with a +2mm piston with rebore. Next would be inserted sleave to go bigger.

[radish150]

Good, the +2 sounds reasonable, but I dont think I'm going to get a stock "nicsil" (or whatever it is) replate done here in Lima... is there a more traditional coating technique that might be had here like plain chrome plating? Yea or nay on that? Machine heads lets hear it, shall I chrome plate and +2 or if it's clean in there just do a new P and R? I dont want to loose 3 years of run time for 3 hp.

Oh... who makes the +2... weisco?

I can do the big end of the rod cheap while I'm there, porting too (YIPPIE!), one thing about this place, labor is cheap... even skilled labor, these guys have hussies in their bays, owned by the Pervian mafia no doubt. I once had them completely strip down and rebuild a CR250 motor from top to bottom and the labor cost me 60$... and it ran too

Cheers mates,

Mark...

[Matty05]

The only idea's I would have would be to press in a new bore sleeve.

It might be a lot more convenient to just get a big bore kit with new barrel sent from USA. They seem to cost around $US400 - $500.