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Discussion Starter #1
I am thinking of getting the K&N air filter and getting the rejet done. What performance advantage can I expect on the '03?

I have also been looking at the Thunder kits and Hyperchargers. They look great, but I am also wondering if there is any real HP or throttle response advantage over the K&N alone.
 

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I definately felt a lot more performance gain out of the Hypercharger than the K&N. The K&N is great for the money especially compaired to the $300 for the hypercharger. people have been reporting the same performance increase with the thunder kits too.
 

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K&N makes a great filter. When you re-jet, make sure you or your mechanic rides the bike down the road and low and higher speeds. Make sure the throttle response it there from 900 to 6,500rpms.

Sometimes mechanics look in a book, throw in a jet and send it off.

Doing this may gain you 5-8 rear wheel hp.
 

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Discussion Starter #4
Thanks, I will be looking for an upgrade in the spring and will likely match the air intake with a set of pipes.

I don't mind the additional cost of the Hypercharger or Thunder kits in the mix if I thought the extra costs would return greater performance relative to the cost. My friend here builds custom bikes (Harleys). His take is that he does not expect that the expensive kits get enough of a performance return for them to be worth it over a straight K&N. That does not account for the additional good looks of course which may be worth it for some anyway. Personally, I hate the football.
 

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I have an '03 and just put a K&N in the football with a jet kit from motorcyclecarbs.com and have noticed better throttle response and much easier acceleration at highway speeds.
No huge HP difference, just a smoother acceleration and slight increase in top end speed.
For $70 bucks I'm happy with the results.


sandcast69
 

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Discussion Starter #6
Thanks sandcast69.

That's really all I am looking for. When I first tried this bike I was already surprised by the punch it had but I am looking for that throttle response at higher speeds. I did not want to go to a Hypercharger or Thunder if there really was not much more there because I am putting aside some dough for a set of pipes too. I am looking for an option for a custom cover that would go over the "football" inner housing without changing the air inlet size.

I have not decided which pipes yet. I know Lucky hates the idea but I drilled my OEM's to get a feel for the difference in the interim.
 

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crochammer,

You have to re-jet with the K&N and you'll have to re-jet AGAIN when you have the exhaust installed.
It might be a good idea to wait and do the jetting just once instead of twice.
Just a thought.



sandcast69
 

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A. The K&N offers a huge benefit in maintenance. You never have to replace it!

B. Throttle response and acceleration will be noticeably better.
 

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sandcast69 said:
crochammer,

You have to re-jet with the K&N and you'll have to re-jet AGAIN when you have the exhaust installed.
It might be a good idea to wait and do the jetting just once instead of twice.
Just a thought.



sandcast69
Possibly, but not according to the rejet matrix

Aftermarket or stock pipes (baffles or debaffled) & Uni filter or K&N (airbox mounted):
150 or 155 main, 37.5 pilot jet, dyno spring, dyno needle on 3rd notch, mix screw at 2.5 - 3 turns. Adjust idle knob as needed to reach 1100 rpm.
 

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I started out with new pipes on my 03 ( V & H Straights ) and it ran fine. I figured I would skip the rejet ( since it ran good ) and that it was prob. not as necessary as you hear. I then noticed a lot of Blue under the heat shields so decided to rejet.
I installed a K & N at the time of rejet ( if you're gonna do it- that's the time as it changes the jetting ) and afterwards could not believe how much better and especially COOLER it seemed to run!
Altitude makes a difference when jetting also- make a note if you are at higher elevations!
I recommend it if changing pipes or drilling- but not otherwise.
my .02
 

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Discussion Starter #11
Looking at the plugs and based on how it runs it does not appear that drilling the pipes has leaned it out much more than it already was. I will go K&N and likely new pipes at the same time. It makes sense to re-jet at the same time but I am going to try that myself so even if I had to do it twice it puts me more in touch with how the bike runs and how I can fine tune it.

Semi-retired so I have the time and inclination. :scoot:
 

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crochammer said:
...it puts me more in touch with how the bike runs and how I can fine tune it.
Never a bad thing..... Plenty of people around here to help you if you get stuck.
 

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Discussion Starter #13
I got a quick response back from Motorcyclecarbs. They actually show an option for drilled stock pipes + K&N but I have no idea what the difference in the kit is between virgin stock pipes (a new term synonymous with not drilled) and drilled stock. I pose that question to Motorcyclecarbs because it sort of assumes there is merit in re-jetting or doing something if you have drilled pipes and a stock air filter.

I don't see that option in Briman's jetting matrix for a Dynojet kit and I can get one at a good price from Xtreme.
 

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crochammer said:
I got a quick response back from Motorcyclecarbs. They actually show an option for drilled stock pipes + K&N but I have no idea what the difference in the kit is between virgin stock pipes (a new term synonymous with not drilled) and drilled stock. I pose that question to Motorcyclecarbs because it sort of assumes there is merit in re-jetting or doing something if you have drilled pipes and a stock air filter.

I don't see that option in Briman's jetting matrix for a Dynojet kit and I can get one at a good price from Xtreme.
Stock pipes baffled/debaffeled, or drilled are all pretty much the same. The most restrictive point in the stock pipes is before you get to the baffles. I am using 37.5/155, airbox K&N, and stock pipes (virgin)
 

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Discussion Starter #15
Is that the motorcycle carbs jets or the dynojet kit numbers. I seem to remember there is a difference. I suspect the diff. may be only how many shims or where the shim goes between stock or drilled.

For comparison, what are the jets out of the factory?
 

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Discussion Starter #16
OK I got a reply back from Robert at Motorcyclecarbs.com
I asked what the difference is in a kit for drilled versus Not drilled stock pipes and a K&N filter. This is his response:

Kit will come with a 35 pilot and a 152.5 main.
The pilot is a N224.103
The main is a N102.221

Just search those numbers on our site.

Wow now that's what I call vague. Maybe he was going fishing for the weekend and could not be bothered. Now thinking about a Dynojet kit.
 

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Mikuni and Dynojet use different numbers. MCarbs uses Mikuni

You can go with Dyno if you want, it will allow you to tweak with various setups if you think you might want to. Or you can order extra sizes from MCCarbs and do the saame thing.

Have you seen the rejet matrix thread?
http://www.volusiariders.com/viewtopic.php?t=4594
 

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Discussion Starter #18
Thanks but that's a little confusing too because MCCarbs uses different numbers. MCCarbs said 35 pilot and a 152.5 main

The Briman link shows what I think is Dynojet:
"Aftermarket or stock pipes (baffles or debaffled) & Uni filter or K&N (airbox mounted) 150 or 155 main, 37.5 pilot jet, dyno spring, dyno needle on 3rd notch, mix screw at 2.5 - 3 turns. Adjust idle knob as needed to reach 1100 rpm.

Thought I had it but now I have lost it. 150 OR 155 main I mean is there not a big difference. Gives me the twitches now.
 

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Discussion Starter #19
I looked at the Briman post again and the Mikuni to Dynojet conversions don't make sense at all. The Briman link specs. 150 or 155 main & 37.5 pilot. Even if the numbers in the Mikuni/Dynojet conversion charts are switched it does not make sense.

vOlusia. Did you use MCarbs or Dynojet for your 155 and 37.5?
 

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crochammer said:
OK I got a reply back from Robert at Motorcyclecarbs.com
I asked what the difference is in a kit for drilled versus Not drilled stock pipes and a K&N filter. This is his response:

Kit will come with a 35 pilot and a 152.5 main.
The pilot is a N224.103
The main is a N102.221

Just search those numbers on our site.

Wow now that's what I call vague. Maybe he was going fishing for the weekend and could not be bothered. Now thinking about a Dynojet kit.
When I went to MCcarbs, he said I was the first he had heard of having drilled pipes. I had to order a second set because I needed to fine tune it a little bit. That might be the data he is using for drilled pipes. I can't recall exactly what I ended up running for jets.

RR
 
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