Jetting question for new guy on an R

[icanzu]

Hi
I'm from the Zuki side but have a friend (with no computer), who just got a bone stock 05 450R. He also just got a Trinity full exhaust and will be running with no lid in what is shortly to be cold winter weather.

We have no idea which jets are in it stock and also hear that the needle is not adjustable. Is tat true?

Can you tell me what's probably in it and what you recommend we jet to. Can the pilot stay as is and will we need an adjustable needle for just that mod?

Trying to get 3 or 4 jet sizes to start with and need a starting point.

Thnx

PS why does it start clacking and wanting to studder as if its in too high a gear when at 1/8th throttle going real slow...like in 1st?

[wykyd450R]

Stock there's a 118 main, 48 pilot, stock needle 3 clips down and I believe right around 2 turns out on the A/F screw.

As for the noise when lugging it, its normal. It is a engine that's built to be revved, and not tractored.

For the jetting I would think I would start with about a 180-185. For winter/cold, you might have to go up a size or 2, but I'd start about what I said. As for the pilot, you'll need to go up a size, I'd say. If you plan to try and leave the pilot stock, start out with about 3 turns out on the A/F screw. If it still backfires upon deceleration, turn it out 1/4 turn, and try again. Keep doing this until it is right. Not too sure on how many turns out it can be before it don't have enough threads or resistance before falling out. I wouldn't go much past 4 turns out myself. That's why with a size larger pilot, the A/F screw wouldn't have to be backed out so far on the final adjustment.

[icanzu]

Dang! The stock main on a 450 is only a 118? Even with the stock pipe, how can that thing run on so little fuel? So with just the lid off and the full exhaust you need to go up like 6 sizes+? :huh Even my Z400 with the 36mm Mikuni had a bigger main than that stock. :confused:

Is the 05 carb an FCR 39?

Not that I'm questioning you, as such...just hard to believe if ya know what I mean.

So OK we'll get a 175 a 180, and a 185. Those three oughtta cover what we'll need then to get it right?


Thnx

[atv fan 28]

on my 07 with the HRC kit and slip on im up to 170! stock was 120. thats a big difference but it runs like a champ!

[d3ktrix]

He's right that the 118 is the stock main jet. The stock air box snorkel is REALLY restrictive, taking the lid off makes a massive difference.

The stock 05 carb isn't an FCR, its just a reg old round slide keihin.

And yeah those jets are a good starting point. You might also want to grab a 50 pilot, there is a good chance you'll need it.

[wykyd450R]

Originally posted by z thohoe
Dang! The stock main on a 450 is only a 118? Even with the stock pipe, how can that thing run on so little fuel? So with just the lid off and the full exhaust you need to go up like 6 sizes+? :huh Even my Z400 with the 36mm Mikuni had a bigger main than that stock. :confused:

Is the 05 carb an FCR 39?

Not that I'm questioning you, as such...just hard to believe if ya know what I mean.

So OK we'll get a 175 a 180, and a 185. Those three oughtta cover what we'll need then to get it right?


Thnx

Yep, thats the size of the stock main in an 04-05 450r. The 06+ had a lil better carb, which had slightly bigger jetting. The 06+ have the FCR carb. Yep, modding the airbox lid or removing it, really opens it up, and thats the reason for such a raise in jetting. The 118 I know seems super small, even my friend couldnt believe it who owns a 400ex. I told him the size, and he said the same about his being bigger, on a smaller quad lol. I guess its all in the carb size, and design?

Yep, those sizes should get what ya looking for. I would get the larger pilot while I was at it too. ;)

[icanzu]

Yes that's a good idea. May as well have everything at hand. I'm guessing, like with the FCR the tank will have to come out to get to the needle aye?

Any idea what size it is? It is a Keihin of sorts though isn't it?

[d3ktrix]

Yeah u'll have to take the tank off to get to the needle.

The 05 carb is a 42mm Keihin round slide.

http://shared.sploitz.com/05_carb_bore.jpg

[icanzu]

Now to look up what an HRC kit is. Seems like everyone's got one.

Man, after modding my Z for 4 years now it's weird starting to learn a whole new quad from scratch again. Hope my buddy gets himself a computer soon so he can start doing his own homework.:)

Thanks for the help.. I know basics are boring...

[icanzu]

OK it had a 122 main and the needle on the bottom clip with everything stock.

So we just took the lid off and installed a Full Trinity exhaust and a 185 main with the needle on the 3rd clip from bottom and left the stock pilot.

It ran like a bat outta hell pulling well all the way up. Lots of backfiring on decel though. So I went down to a 180 main with the clip on the second from bottom. (do ya count clips from the bottom or the top...I forgot)

So it still puls about the same all the way up but with signif less backfiring.

So am I down to needing a larger pilot? If its got a 48 should I go bigger than 50? If that works to eliminate the backfiring on decal, should I go back up to the 185? It didn't seem to choke up top....

We're at 1300 ft

Thnx

[d3ktrix]

Ya the popping on decel is because the pilot needs to be bumped up to a 50.
Unless u didn't turn the A/F screw out from the stock position.

[icanzu]

Originally posted by d3ktrix
Ya the popping on decel is because the pilot needs to be bumped up to a 50.
Unless u didn't turn the A/F screw out from the stock position.

Aaaaaahh yes....totally forgot about that. Yup gonna try that tomorrow, thanks.

How many turns is stock and where do you think it'll hit right , 2-2.5 turns?

[d3ktrix]

Stock is like 1 or 1.5 turns out, somewhere in there.

Tune it to where it runs and starts the best. If u have to go more then 3 turns out, go up to a 50 pilot.