Thoughts on AIS and Jetting 2005 WR450


14 replies to this topic
  • MorrisWR

Posted June 02, 2005 - 08:55 AM

#1

I've read most of the threads on the AIS on the '05 WR450 so I do have the plug kit ready to remove the AIS. I'm just going to work on the jetting some more before I remove it.

My thoughts are if the AIS is helping burn unburned fuel in the exhaust, maybe I can use that to get my jetting closer to optimal if I can eliminate more unburnt fuel (ie. if it pops less on decel with the AIS by just jetting, than I should get more efficiency and maybe better mileage).

The odd thing is I was always used to more popping from a lean condition so move up the PJ to get rid of it.

I had only slight popping with my stock 450 at about 70 degrees and 3000 feet. I put on the James Dean kit with the blue #3 needle/clip position and the 170 main jet like it listed in the instructions (was thinking of the red but thought it wasn't quite hot enough). The idle mixture screw I left stock at 1.5 (did put in a T handle but left it where stock was).

Now I get huge backfires on decel after the rejet but it seems with the 170 main and the blue JD #3 it should be richer.

My guess is I'm running too rich and excess fuel is coming through the exhaust and the AIS is helping to burn it up causing the bad popping.

Since I've only changed the main and the needle, I'm going to try either dropping to the 168 main or putting in the red needle and see if it pops less.
Hopefully I can get it dialed in on my next ride, then pull the AIS and plug it up. I may temporarily plug the AIS before removal to see how it works.

I was able to ride 50+ miles with the stock setting without hitting reserve so I'll have to do another 50+ to see how far I can go with the new jetting.

Any ideas or comments on the main or needle I'm running? It's starting to get 70+ where I ride so I think leaning it a bit won't hurt.

  • WGP

Posted June 02, 2005 - 11:01 AM

#2

Pull that stupid AIS off and plug it for good :)
Then work on your jetting :D

  • Texas4play

Posted June 02, 2005 - 01:53 PM

#3

The AIS elim kit works for popping. If you are running stock exhaust, unplugged to get the best results buy the PMB exhaust insert from TT. Smooth as butter!

  • MorrisWR

Posted June 02, 2005 - 03:02 PM

#4

I'm running it with the stock baffle removed. What benefit are you getting with the PMB insert over just removing the baffle? Is it mainly for noise? Mine doesn't bother me with the baffle removed.

  • MorrisWR

Posted June 13, 2005 - 11:23 AM

#5

Well, I rejetted and left the AIS on but took a small rubber C clamp to close it off.

It was running too rich before. I went from a 170 to a 168 main jet and changed from the JD blue #3 to JD Red #5 and the popping all but disappeared. The bike ran fine and we did 50 miles. After testing it, I put the clamp on the hose and just took it off after riding.

I think I'll just keep the AIS on since it works. I can test my jetting easily with the clamp off. Limiting the unburnt fuel in the exhaust can be easily checked this way.

  • Texas4play

Posted June 13, 2005 - 02:22 PM

#6

I'm running it with the stock baffle removed. What benefit are you getting with the PMB insert over just removing the baffle? Is it mainly for noise? Mine doesn't bother me with the baffle removed.


All the tech specs are on the pmb website. They show gains and what not but, from a Joe Rider point of view I can tell you it does sound cleaner and feels maybe a little more crisp. I personally give it a
:) but, to each his own ....

  • Lowedog

Posted June 13, 2005 - 04:36 PM

#7

The AIS is simply an air pump. It is pumping fresh air from the intake boot into the exhaust simply to dilute the exhaust gasses. I don't believe that it is burning any unburnt fuel. The popping is caused from the cool air hitting the hot exhaust gasses. Correct me if I'm wrong.

:) Lowedog

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • MorrisWR

Posted June 14, 2005 - 12:35 AM

#8

The AIS is simply an air pump. It is pumping fresh air from the intake boot into the exhaust simply to dilute the exhaust gasses. I don't believe that it is burning any unburnt fuel. The popping is caused from the cool air hitting the hot exhaust gasses. Correct me if I'm wrong.

:) Lowedog


I'm just going by what others have said but if you're just adding air to exhaust gas, wouldn't you still be emitting the gas with no change? If the popping is just cool air hitting hot exhaust gas, why would my changing the main jet to a 168 from a 170 and putting in the red needle (in essence leaning it) cause the popping to go away? And I mean, the thing was almost like a shotgun at times when decelerating and just changing the jetting made it almost disappear.

Not saying you're wrong, I'm just curious as to what's happening with the system.

I can see why people want to remove it though. It is just extra stuff but if I go to sell it, nice to just pull the clamp and have it back to original.

  • Lowedog

Posted June 15, 2005 - 08:35 PM

#9

As far as the jetting change you made, you went from blue #3 to red #5 which is very close and dropping down a size on the main will hardly effect popping on decel. Did you also make a change with the pilot? With the red needle in the 5th position compared to blue in the 3rd position you are actually going to richen the closed throttle setting slightly as the tip of the needle is higher in the emmulsion tube allowing more fuel to pass. It sounds like you blocked off the AIS after rejetting. I would be curious to see what blocking it off with your previous settings would have done.

The AIS (air injection system) is what Yamaha did to get green sticker in CA. By putting clean air into the exhaust it will make the exhaust seem cleaner in a test. Try pulling the tube off that injects air into the exhaust at the pump and plug the hose then start your bike. You will see it is pumping air. By bypassing it it makes jetting far easier as well as getting rid of unwanted weight. GYT-R makes a kit that just plugs the fittings if you are interested in a less permanent removal.

I don't claim to be a sceintist so I can't explain why the popping occurs from the air hitting the exhaust. I think just a reaction of cool air hitting hot gasses. I do know that the leaner the jetting which causes hotter exhaust gasses then the more severe we found the popping to be with the AIS enabled. By dissabling the AIS we found the popping would be far less and would let us get the jetting dialed in.

:) Lowedog

  • MorrisWR

Posted June 15, 2005 - 11:27 PM

#10

As far as the jetting change you made, you went from blue #3 to red #5 which is very close and dropping down a size on the main will hardly effect popping on decel. Did you also make a change with the pilot? With the red needle in the 5th position compared to blue in the 3rd position you are actually going to richen the closed throttle setting slightly as the tip of the needle is higher in the emmulsion tube allowing more fuel to pass. It sounds like you blocked off the AIS after rejetting. I would be curious to see what blocking it off with your previous settings would have done.

The AIS (air injection system) is what Yamaha did to get green sticker in CA. By putting clean air into the exhaust it will make the exhaust seem cleaner in a test. Try pulling the tube off that injects air into the exhaust at the pump and plug the hose then start your bike. You will see it is pumping air. By bypassing it it makes jetting far easier as well as getting rid of unwanted weight. GYT-R makes a kit that just plugs the fittings if you are interested in a less permanent removal.

I don't claim to be a sceintist so I can't explain why the popping occurs from the air hitting the exhaust. I think just a reaction of cool air hitting hot gasses. I do know that the leaner the jetting which causes hotter exhaust gasses then the more severe we found the popping to be with the AIS enabled. By dissabling the AIS we found the popping would be far less and would let us get the jetting dialed in.

:) Lowedog


No, what I did is my 2nd ride after changing from stock jetting was blue #3, with a 170 main jet per JD jet guidelines. That ride it was popping and very loudly (more like a backfire sound). The next week, I rejetted to a red #5, and a 168 main. No other changes. The pilot is still stock. I rode the bike at the same area and same temperature with the AIS in its stock form (ie. not blocked). The popping had disappeared except every once in while a very slight pop. After about 15 miles, I clamped off the AIS on the trail to totally eliminate the popping. The only difference was the main and the needle/clip position.

In the JD kit, it lists at higher altitudes to go from a blue #3 to a red but I don't remember if it was 4 or 5.

The only reason I can think that it quit popping is it is somehow leaner. Stock it was lean and not popping much, then I went richer and popped like a mother. Then I rejetted (at least leaner on the main) and it went back to slight popping.

But, no doubt it's jetted fine now either way. Thanks for the info.

BTW, Lowedog it looks like you're in WA. Where are you located? I might have ridden with you on one of the TT rides but can't remember.

  • Lowedog

Posted June 16, 2005 - 08:47 PM

#11

I'm in Cashmere. I rode at Goose Creek with a bunch of TT'ers 2 summers ago. And then last summer in the Devil's Gulch area.

-Lowedog

  • Indy_WR450

Posted June 17, 2005 - 04:36 AM

#12

Hey MorrisWR;

Why are you not using a 48 pilot! Almost everyone on this forum is using a 48 pilot with the JD kit or stock needle. :)

Try a 165 main with JD red in clip #4 and a 48 pilot with 1.5 turns out on the fuel screw. :)

  • MorrisWR

Posted June 17, 2005 - 08:08 AM

#13

Hey MorrisWR;

Why are you not using a 48 pilot! Almost everyone on this forum is using a 48 pilot with the JD kit or stock needle. :)

Try a 165 main with JD red in clip #4 and a 48 pilot with 1.5 turns out on the fuel screw. :)


I've got the 48 pilot (just came in a few days ago) but hadn't gotten around to putting it in yet. It is running pretty well at about 3000-4000 feet but in the winter I'm sure I'll need it.

I'll try your main and clip later in the summer just to see how it runs but it's pretty good right now.

Thanks.

Lowedog, I guess I didn't ride with you. I've only ridden Manastash (I think it was last year) with a large group of TT'ers.

  • Blaster21996

Posted June 17, 2005 - 06:21 PM

#14

Where does the #48 pilot go?

  • Blaster21996

Posted June 17, 2005 - 08:22 PM

#15

FOUNT IT! http://www.transworl...1018579,00.html
Changed mine to a 48! I'll see how it runs tomorrow!




 
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