The power of orange compels you!

[lethe]

I like to go big

bah, brakes just slow ya down

[duccarlos]

Who needs brakes? I just lowside to slow me down!

[Slide Panda]

YOu guys ever see this:
It's for a 2010 530 EXC - the two brothers folks replace the carb jets and pick up 13 HP

" "Why are you installing a smaller jet and needle than the stock size?" Because even though the stock Main Jet is a 180, and we replace it with a 160, the stock needle is very large in diameter, causing the bike to run lean. The needle we installed is much smaller in diameter than stock and even with the smaller 160 Main Jet installed the fuel mixture is corrected and the bike runs perfectly with a free flowing aftermarket exhaust."

This seems backwards, bigger jet causing a lean condition. But the dyno would seem to back the work. Anyone who knows more about carbs care to explain?

[DanTheMan]

This seems backwards, bigger jet causing a lean condition. But the dyno would seem to back the work. Anyone who knows more about carbs care to explain?

Seems from your quote, the bigger needle essentially "clogs" the 180 jet. So their kit is a smaller needle and smaller jet.

[Slide Panda]

Eh? Please expound. I'm only versed in the basics of carbs. This seems to have gone past my basics

[MadDuck]

In this case the jet is a screw with a sized hole through which gasoline passes. The needle is attached to a slide that moves up & down and the needle passes through the hole in the jet. Needles are usually tapered so that as they move up and down with the throttle opening they allow more or less gas.

Even with the larger jet size ( larger hole ) because the needle is fatter it reduces the effective size of the hole in the jet. If the needle were just a tad thinner they they might have had good results with the 180 jet but it sounds like it was too rich. Running the 160 brought them into the good result. Think about this... they most likely also tried a 170 size jet before they settled on the 160.

Follow?

[Slide Panda]

Ok makes sense that it's a relation between the jet and needle. I didn't really get that the two were sperate bits at the end of the day and changing the size relation was what was being worked out here.

So even with a smaller jet, the needle was sufficiently smaller in proportion to allow for more fuel and in better proportions that in they had used a smaller needle on the 180, in this case. - That it?

[Slide Panda]

  I would also recommend the KTM rad guards and the fan kit (especially if you're going to be in stop and go traffic)

Oh it appears to have a fan kit already installed 
- Someone also makes an oil cooler kit as well. Besides lower temps (possible NOT bonus) it does almost double the engine oil capacity.

[TAftonomos]

Thats the cleanest dirtbike I've ever seen 

[Slide Panda]

Now it seems there's a horse race developing. There's an 09 690 SMC in the mix and an 07 525 EXC. The SMC is bone stock and a bit less than the others, but would need to be shipped.

The 525 is $5500 and here's the deets

'So the bike, it is a very low hour 2007 525 with the complete dirt setup and the supermoto setup, I have both fenders, the KTM briefcase and documentation, the KTM SM catchcan, all the fuel vapor setup (this has been removed), I have it all.

Starting at the front of the bike I put the Cycra Pro Bend handguards and shields on, I installed a Scotts setup on the bike to include a new top clamp and post. I have the stock tank and then a IMS tank (have to check on the exact size) that can be used for extended mileage. Only thing about this tank is there is a bolt frozen in the tank, it is one of the bolts used to secure the shroud, not a big deal but it pisses me off. I am not sure how to fix this. I installed a Works Performance skid plate and have the stock one in a box. I installed a Hammerhead shifter, also I bought a Enduro Engineering comfort seat and installed it, of course I have the original seat. I also have a reservation with Recazno (coming up quick) for them to build me one of their seats. I just put new Bridgestone Battlax BT-003 racing street tires on the SM setup, they have less then 150 miles on them, these are super sticky tires that I am loving. Running the 150 on the rear causes the chain to touch the side edge of the rear tire, this is not a big deal once the chain makes it path into the edge just something I wanted to mention. There is a FMF exhaust system on the bike that is wonderful, I also installed the heat shield that you can see in the picture to prevent damage to your gear."

Hrm... The 525 and 530 are same priceand have a lot of similar farkles, but the 525 hasn't seen as much use and has two sets of wheels. But theres's the SMC... gah.

[Monsterlover]

My vote is for the 525/530 with the bias toward the 530.

[kopfjäger]

SMC 690

[MadDuck]

Ok makes sense that it's a relation between the jet and needle. I didn't really get that the two were sperate bits at the end of the day and changing the size relation was what was being worked out here.

So even with a smaller jet, the needle was sufficiently smaller in proportion to allow for more fuel and in better proportions that in they had used a smaller needle on the 180, in this case. - That it?

That's it.

I vote for the 525/530.   The 690 would have better torque but all the goodies on the smaller bike sound too good.

[DRKWNG]

I'd go for the SMC. As stated earlier, the lc4 motor has much friendlier service intervals.

[Slide Panda]

That's it.

I vote for the 525/530.   The 690 would have better torque but all the goodies on the smaller bike sound too good.

Cool. That makes complete sense. I was just listening to the video while doing other work, that combined with my thought that needle and jet were just two words for the same item for some reason left me going 'What the huh?'

Two votes for the EXCs vs one for the SMC. The EXCs timing is a little more flexible, the SMC is on ebay. I'm thinking of bidding on the SMC for a wit ha conservative bid and if it gets beat there's always the EXCs... Though I am liking the notion of getting the 530 and giving Pepe a hard time on those dirt roads he's been exploring.