Anyone experienced this after shimming?

[toua70]

So I finished shimming my carbs yesterday and went on a 2 hour ride this morning to see how it is. I noticed a lack of power right at 7k rpm to 10k rpm. Anyone experienced this? You can seriously feel the lack of power right when you reach 7k rpm and it slows down (like its struggling) and then once you hit 10k rpm, it runs normal again. Took the freeway home and in 6th gear, im riding around 8k to 9k rpm and again, feels like there's no power. Everything else was done recently too a couple weeks ago (new oil, spark plugs, oil filter, brand new Uni air filter) it ran fine until i did the shimming and i KNOW i did everything right. Any suggestions?

[lgk]

How many shims?

[toua70]

I have a slip on exhaust so I used the recommended two #4 washers on each needle.

[k-os]

Did you adjust your fuel mixture screws as well?

[NinjaBoyEddy]

Try 3 on each needle see how you like that. Tweak the fuel mixer screws too. I know it's a hassle doing it all over again
Have you removed the snorkle? IF you have not remove it and try it like that before you re-shim.

[alex.s]

raising the needles with shims gives more gas in mid range. people equate more gas with more power. the lack of power you are experiencing is too much gas because the needles are too high letting out too much gas too soon making it run rich until it gets more air up top. adding MORE shims, will make it worse.

take the shims out.

people who blindly say to shim without changing anything else don't know what they are talking about.

[Ramen]

I would remove the snorkel before anything else if you haven't done it already. It's the easiest thing to do before attempting further modifications.

[alex.s]

if removing the snorkel adds more air, and he has stock main jets, it may fix his mid range, but then his top end will be lean. and a lean top end is a lot worse than a rich midrange.

[Kevin2109]

Take the snorkel out, you will be fine

[k24_cm7]

Originally Posted by Kevin2109

Take the snorkel out, you will be fine

Try this, it may help.

I originally had a slip on exhaust and it ran okay with a lot of popping when accelerating, and then I decided to pull my snorkel and had the same problem you had.

I added 3 washers per jet(or needle?) and it fixed the problem.

[Kevin2109]

You are running rich, there is no doubt about that. What is causing it to run so rich? Probably not the washers, unless you put some massive washers in there. Double check your work and make sure everything is hooked up correctly

[xSean13]

Yep I had a similar problem and thought removing the snorkel would help, but didn't. Anyways, I took a washer out (only 1 now) and it runs fine.

[Kevin2109]

might be a good read


http://www.ninjette.org/forums/showthread.php?t=74352

[toua70]

Thanks everyone and Kevin for the link. I removed snorkel and now it runs great!

[alex.s]

if you do a plug check you'll notice the plugs start to burn up a nice white color from your system running lean up top now.

[toua70]

Originally Posted by alex.s

if you do a plug check you'll notice the plugs start to burn up a nice white color from your system running lean up top now.

And that's a good thing right?

[Kevin2109]

Originally Posted by toua70

And that's a good thing right?

no

[alex.s]

i drew this graph for someone else but figured it might be useful to the board...

vertical represents how much fuel the carbs let out, horizontal is how much vacuum the engine is sucking (can be thought of as throttle position) the two lines on the left represent stock, and a richer pilot jet, and the two on the right represent stock, and richer main jets. it was drawn to illustrate why you need to change jets when you change exhaust or intake flow but it applies to any shimming really. you can also see the "low-end power loss" people talk about when dealing with pod filters because they dont bother changing their pilot jets.

[x only performance]

Originally Posted by toua70

I have a slip on exhaust so I used the recommended two #4 washers on each needle.

I have a slip-on and i used TWO 3mm washers on each needle. my rig run perfect even with 10k miles on it.

[toua70]

I'm just going to take out one shim each Carb. I'm not liking the way its running though its nice low end. It seems to struggle around 7k rpm. I gunned it earlier and had a burnt smell. I have no clue why

[Gorilla25]

just remember, though our bikes are generally the same, each will be different. some will be fine with 1 shim, others 2 or 3. let us know how it does when you have just one shim on and we'll be glad to further assist you.

[alex.s]

it depends on atmospheric conditions. but im worried that you guys completely missed the point of my drawing. shims are not a good solution to anything.

[NJ Ninjette]

Originally Posted by toua70

I'm just going to take out one shim each Carb. I'm not liking the way its running though its nice low end. It seems to struggle around 7k rpm. I gunned it earlier and had a burnt smell. I have no clue why

I bought my bike in March and it came from the dealer jetted rather nicely, now that it's getting hot out it's getting rich. Just because people say the bikes come jetted very lean doesn't mean they all do and there is no magic formula "add two shims and call it a day".

If you leave the snorkel out, no matter what you do you'll still be lean up top. Listen to alex.s he knows what he's talking about and is actually trying to help you.

[toua70]

Yeah I agree. I took one out from each. If I don't like it ill just set everything back to the way it was. It was a pain. I'm too lazy to ride it now.. just got done like 5 mins ago. Will update tomorrow

[toua70]

Well.. I just got to work and it feels fine now though there was a brief moment where I was smelling gasoline but its probably from when I disconnected the hose last night. So one washer in each seems to be working well.

[sleepless]

Originally Posted by alex.s

it depends on atmospheric conditions. but im worried that you guys completely missed the point of my drawing. shims are not a good solution to anything.

I love you alex.s. Always the solid one-liner solutions, never seems like anyone is listening.

This is how I imagine you: