HEADS UP!!!

Site upgrade in progress... Core site functions are working, but some non-critical features/functions will be temporarily unavailable while we work to restore them over the next couple of weeks.

Please post any bugs you encounter, but before you do, check to see if it's already listed.

Thanks for your patience while we work to improve the community.

Sign in to follow this  
Followers 0
klmmicro

Rejet and lost top end power -

14 posts in this topic

Quick question -

I rejetted my XRL's carb today and I love what it has done to the bottom end of the curve! It is like a new bike. I puttered around town for a while and it was nice to be able to accelerate smoothly.

The question is regarding when I hit the freeway. Though the bike pulls great at low speeds, it has lost some of the top end pull it had. There was a definate drop in power and response once I hit about 75 by the speedo. Any ideas?

Share this post


Link to post
Share on other sites

I shimmed the needle per the instructions, but did not drill anything. I will probably pull it apart again this weekend and drill it. The jet is a 160 (Dyna) as is the needle and spring. The guys at BD's said it should be about perfect.

It will lift the wheel now...I just need to keep it upright while going down the hills :banghead:

Share this post


Link to post
Share on other sites

I installed the DJ kit a while back in my L, and had the same issue! Given I am at 5000', but the response was similar to yours. Then I got bored one night, and decided to take out the DJ kit and try Daves mods...and bingo, power at highway speeds returned!!

It sucks that we spend so much for the DJ kit (BUT, I got to use the DJ spring and washer for the stock needle), when there is such a cheap mod right under our noses. I guess I wanted to find out for myself, though :banghead:

Good luck!

Share this post


Link to post
Share on other sites

You should drill the slide. As far as top end you should have not lost any thing. Grind the tab on the air fuel mix screw and set at 2.5 turns out and try it again.

Share this post


Link to post
Share on other sites

Removing the smog equipment, the snork and adding a new air filter(uni/k&n) should also help. An aftermarket exhaust is also a solid mod. You should feel a substantial power gain after all is said and done. :banghead: But remember it is just a "L" model, right B-dub! :banghead:

Share this post


Link to post
Share on other sites
Quick question -

I rejetted my XRL's carb today and I love what it has done to the bottom end of the curve! It is like a new bike. I puttered around town for a while and it was nice to be able to accelerate smoothly.

The question is regarding when I hit the freeway. Though the bike pulls great at low speeds, it has lost some of the top end pull it had. There was a definate drop in power and response once I hit about 75 by the speedo. Any ideas?

What else have you done? Air filter, snorkle, exhaust baffle? If you just re-jetted without an air filter that may be your problem.

Share this post


Link to post
Share on other sites

I have the smog removed. The fuel mixture screw is at 2.5 turns. Still running stock exhaust (I like the stealth) and filter. I am going to pick up a Uni this afternoon. The bike is noticably cooler and there is a definate difference down low.

As for not loosing top end, that is what I thought too. It is the part I can't figure out. The drilling would increase throttle response, but not make a difference in the curve I would think. I could be wrong and I am going to do it. I will probably try Dave's mods soon as well.

Share this post


Link to post
Share on other sites

The pilot screw has nothing to do with WOT performance. It's only for fine tuning the idle circuit.

Drilling the slide does not increase top end speed, it only increases the responsiveness of the vacuum piston. Faster movement = better performance and less potential for bogging.

From what you're describing, the motor is probably leaning out. Upsize the main jet to a (Keihin) 158 or 160. Shimming the (stock) needle also helps, if you still have it...

Share this post


Link to post
Share on other sites

I have the stock needle (not in the bike) and I am running a 160 jet in there now. It does feel like it is leaning out on the top end, though the bike is running A LOT cooler, so I sort of wonder.

After reading the page in "Dave's Mods", I think i will try that direction. At least working on this carb is easy!

Share this post


Link to post
Share on other sites

Didn't I read somewhere in another jetting related post that the DynoJet #160 was NOT the same as the Keihin #160? I think it was Dave and he might have suggested that the DJ #165 would be a closer match to the Kehin #160.

Share this post


Link to post
Share on other sites

In that case I will try the 165 out. I figure it cannot hurt anything and it included in the kit.

Share this post


Link to post
Share on other sites

The DJ 160 is smaller than the Keihien 160. I've heard the taper on the DJ needle is not good, the stock one works better. I've had my carb apart a bunch of times just messing around and always come back to "Daves recommendations. Go figure. Get the Uni filter and go from there.

Share this post


Link to post
Share on other sites

Here is what has worked for me. I used the DJ spring, the DJ 160, and I used the washer from DJ to shim the stock needle. Air screw 2 1/4 turns out. Removed the air snorkel. Also using the stock exhaust. It's just about perfect at 2600 ft.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0