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Discussion Starter · #1 ·
OK, guys, don't laugh at me, although this may seems weird.

I installed the D&D slip ons on the 08 Scrambler. It starts easier than with the stock pipes and jets and it runs great . The engine is a lot more responsive - it has really transformed the riding experience since it sounds and runs so much better. Pilot jets are now 45, old ones were 40. 3 turns out on the pilot mixture screw

Here is the strange part: After first starting up, the exhaust from the left cylinder gets warm pretty fast. The exhaust from the right cylinder almost feels chilled since it is cooler and has a lot of moisture which makes it feel cold. Both headers warm up pretty fast, but the gas is cooler on the right. This is both at idle, and more important at about mid-revs. Sorry, no way to measure temps at either location at this time, just holding my hand in the exhaust stream.

After warming up the bike, the exhaust from the right warms up and is dry, but is still noticeably cooler than the left.

I turned the mixture control screw in on the right carb to see if I could warm up the exhaust gas. It warmed up a little at about 1 turn out, but the engine didn't run as sweet at mid throttle. 1 turn out has to be too lean anyway.

My first thought is mixture, since exhaust gas temperature is how you lean an airplane piston engine. The mixture screw doesn't make much difference though.

Any other ideas?

BTW: the slip-ons are sealed well at the joint, the bike only has 800 miles on it...and I can't tell you if I had this condition with the stock setup....
It runs great, but I think the bike may be telling me something. :confused:
 

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The mixture screw only adjusts the mix on idle and the first 1/8 of the throttle. Also I would go back to the 40 pilot at around 1 3/4 - 2 turns out, much more than that and you are going to be far to rich.
 

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I don't know why D&D sends the 45 pilots with their kit. I know they claim they dyno it but, thats to rich -I think their just covering their butts over a little lean condition or their dyno is off. What is going on with your airbox stock, modified or what ?
 

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from what i have seen you can get near the same mix with bigger or smaller pilots by turning the screws in more on the bigger pilots.The only reason to go bigger then the stock 40 pilots is if you have to turn the screws out to far that they may not stay in the carbs.The bigger pilot you go to the more a 1/4 of a turn means to a/f ratio.I think 45 is to big to though
 

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Discussion Starter · #5 ·
The airbox is totally stock. I may try popping the snorkel off to see if there is any change.

I see that most guys who are serious about tuning are going for a dyno run, I think I'll do that too ($25 at Cascade Moto Classics in Beaverton).

It's running so strong that I think I'll mess with it a little more, have a look at the plugs, then go for the dyno. It does suck down the dead dinosaurs like never before - so probably is pretty rich. If I wanted fuel economy, though, I would've bought a Toyota Pius :D

Next step is probably an airbox removal and uni-filters. May try that and see how the 45's are....
 

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The airbox is totally stock. I may try popping the snorkel off to see if there is any change...........

Next step is probably an airbox removal and uni-filters. May try that and see how the 45's are....
It would be a good move to start freeing up the intake, or even removing the airbox all together but regardless, you still wont need those 45's.

As others have suggested, you'd be best going back to the stock 40's.


V.
 

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+1 Agree with Mikeinva and Ventura - the 45's gotta go. In your particular case, with the slip on exhausts but little else in the modication or bolt-on performance area, 40's should be more than fine.

If anything, maybe you should go the opposite way, and look at the mains. Maybe 120's... 125's?

Opening up the exhaust helps on these stock-strangled motors, but doing so without opening up the intake as well usually does not bring forth measurable gains. "Louder" sometimes feels like "faster".

Your fuel economy drop illustrates the very rich running... for no reason, and has no direct reference to "high performance".

Refer to the "Exhaust" sticky, and note than out of 170+ posts, only 2 slightly refer to re-jetting. Exhaust mods are usually the first done to get the bike's "sound" right, which is great, but you need to also open up the intake to book-match the performance mods in order to see any change.

IMHO, "Plug-Reading" went out with the dinosaurs and/or Leaded Gas, unless maybe you install a brand new plug, run a hot ten miles, then check quickly. A/F guages, Dyno runs, or SOTP's feel are likely better.

As Ventura suggests, look at the snorkle removal, then maybe the anti-reversion baffle (restrictor"), and the intake filter upgrade as well. You might then weigh the differences between air box removal, or the dual-filter entry, gutted, Velocity Stacked version, both great approaches to the same end.

Most of all, have fun with the mods, sounds like you're hooked!
 

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If your afraid to run lean, put in 42's, and do mixture screws out 1 to 1 1/2 turns.Then when you remove the air box and get pods you can leave the the 42's in and turn the screws out to 2 1/2 then change your mains
 
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