$0.60 Horsepower...Finally put some washers on the needle

[nascarkeith]

After some motivation from Buddha

Washers are really really easy. About the same work as doing air filter, I'd do it, and if mids are considered not as good, just skip them next time.
You have to get into the bottom - meaning taking the carbs off the bike when you do pilots and mains. Mids wont be any more work then if you even need to.
Who knows, you may be the driving force behind the washer mod. Now giddy-yup ... horse power is horse power.
Cool.
Buddha.

I decided to take advantage of a rainy afternoon and put some washers on the ol' carburetor needles and see if we could gain a little horsepower.  The subject of this experiment is a 2006 GS500f with some appearance mods but an all stock intake and exhaust system.

This is what is needed for this mod:
                                                       Phillips head screwdriver
                                                       Needle Nose Pliers
                                                       #3 washers
                                                       WD-40 or something else to loosen screws
                                                       About an hour of free time
                                                       Poor Man's Rejetting Pictorial  http://www.angelfire.com/mt2/mikesgs500/rejetting/

I noticed that there seemed to be a few differences between my 2006 carbs and the older ones in the pictorial so I took some pics of mine to compare.

First off I didn't have to mess with the rear plastics as in the pictoriali.  Just remove the seat and loosen the two bolts that hold the tank on.


Then lift the tank and turn off the petcock as in the pictorial and disconnect the negative terminal from the battery.
Mark the fuel hoses and disconnect them from the tank.  I didn't drain mine.  I spilled a little gas on the garage floor but it evaporated quickly.
Then take the tank off.  This is how mine looks without the tank.


Once the tank is off remove the screws that hold the top of the carb on as in the pictorial.  This is where a $0.60 job that should have taken me an hour ended up costing about $15 and will end up having to be finished tomorrow.  One of the brass screws stripped.

My wonderful wife had to stop on the way home from work and get me a screw extractor.  I finally got the screw out but will have to get a replacement tomorrow. 

The next steps are were the major difference came in for me.  There was no o-ring on either of my carbs and the needle would not come out of the slide until you removed the white piece of plastic with the small spring that pushes down on it from the top.  This is what the carb looks like with the top off.


This is the slide with the piece of plastic I was talking about having to pull out with some needle nose pliers.



This is what the needle looks like when it comes out stock.


This is how it goes back in.  I am trying two #3 washers on each of mine as a starting point.


I got it all back together and fired it up.  I was able to use the stripped screw put back in with some pliers to hold the top of the carb down good enough for the test cranking.  Here is a short video of the result.  It just sitting on the center stand in the garage so you probably can't tell to much about it especially with the not so great digital camera sound. 


It seems to be running fine to me.  It might idle just a tad higher than before but not by much.  Just revving it on the center stand I can tell there is a lot more throttle response.  Two washers may be too much for a stock setup.  I may go to one after some test riding.

I'll post a review of its effects once I get that stripped screw properly replaced and the rain stops.

[aaronjosephward]

go to ace and get allen head screws to replace the carb screws. those OEM ones suck.
also, you've inspired me to put washers on my needles

[the mole]

60c horsepower huh?
Sounds like an extra 10 hp for only $6.00 would be a sweet deal!

[souljeroflight]

Great post. i also tore my carbs apart tonight and ran into the same thing with the needle. im going with whole lot of new jets tomorrow though from dealer or buddha which ever get here first.......i too didnt have O-rings on top of my baffles and i too stripped out some screws but replaced them with ones from ace.  alll today. i got the yamaha dealer to get the screws out for nothing though. Guy rode a Busa thats why.

[facepants]

It's amazing how big of a difference shimming your needles can make.

[The Buddha]

I have ordered a pack of #3 washers, I am now torn between upgrading mid mains and putting in washers. So my customers get both ...
Good post Nascarkeith.
Cool.
buddha.

[souljeroflight]

Hey Buddha is that an either or option?  Either upgrade mid-manes or shim needle?

[The Buddha]

Yea, however I suspect mids and the washers do the same thing and washers under needle are a bit harder ... especially if you are opening the floats anyway - you have to because you will swap pilots and mains ... However ... ACE hardware has #3 washers, 30c each, may well be faster and cheaper than me sending you now.
Run the 65 mids and try it out. Then get washers, dont do it all at once, you may over do one and under do another ...
Cool.
Buddha.

[souljeroflight]

well because of all the posts ive read (esp. the poor mans rejatting ) i have already put 3 #4 washers on the needles.  I actually had to open up the inside diamater a bit to get them to fit but they are on.  Put everything back together W/ lunchbox just to see........and high RPM's does great but throttleing through 0-3500 RPM's it is very bogged down almost wants to die. AGAIN let me repeat havent put on any new jetts yet. just shimmed needles. im gonna start a new post about ?'s about what jett does what.

[TonyKZ1]

I did the same thing on my 250, only added one washer on each needle though. As they are kinda lean in the midrange, this took care of it, no more hesitation around 6k rpm.
Tony

[The Buddha]

well because of all the posts ive read (esp. the poor mans rejatting ) i have already put 3 #4 washers on the needles.  I actually had to open up the inside diamater a bit to get them to fit but they are on.  Put everything back together W/ lunchbox just to see........and high RPM's does great but throttleing through 0-3500 RPM's it is very bogged down almost wants to die. AGAIN let me repeat havent put on any new jetts yet. just shimmed needles. im gonna start a new post about ?'s about what jett does what.

Today is your day for getting ahead of yourself isn't it ... I was saying #3 ... #4 is too big, does not fit in that last hole.
Anyway, I am making kits for 01+'s, seen enough people get confused already.
Cool.
Buddha.

[souljeroflight]

LMAO yes today is a day for getting ahead of myself Just very anxious.  Hopefully jetts yo mailed will come tomorrow and i can get it buttoned up. You did send 01+ kit?

[The Buddha]

Yea I sent the right kit. Tommorow is a bit optimistic, considering the guy in GA got jets from last friday (yes, 10 days ago) ... today. Oh yea, it went to 5 other further away states before him.    We got mad fay still to deal with. Pouring rain today, and it washed all the paint off my new POS nissan.
Cool.
Buddha.

[souljeroflight]

Buddha you are great! please understand my over anxious, learn the hard way,  ride even in the snow personality.    well my next mod is the rear wheel swap then im gonna quit for a bit with mods. wifey says im spending too much.

[pjm204]

I might have to shim my needles, I bought some #4 washers when I rejetted but never put them in. I seem to have a little popping every so often which may have nothing to do with shimming but I want to see if it helps.

[nascarkeith]

I got things finished up tonight by replacing all the stock carb screws with these


Fay is still giving us some rain here in Alabama so I still haven't got to test it out.  I rode around the block at about 10 mph.  At that speed a quick blip would raise the headlight pretty quickly.  Hopefully it will be dry enough for a ride to work in the morning and a full report. 

[The Buddha]

No you didn't ... float screws on a 01+ are 4mm and 10 long. The rack rail bolts are 5's as are the tops I wanna say ... but rack bolts dont have to be taken off ... ever. The tops I like the lock washer and the flat washer system of stock. I leave those be. Just float bowl bolts I put allen heads.
Cool.
Buddha.

[nascarkeith]

No you didn't ... float screws on a 01+ are 4mm and 10 long. The rack rail bolts are 5's as are the tops I wanna say ... but rack bolts dont have to be taken off ... ever. The tops I like the lock washer and the flat washer system of stock. I leave those be. Just float bowl bolts I put allen heads.
Cool.
Buddha.

Come on Buddha you know what I meant.   :)All the stock top screws like the one I stripped.

I guess this is what I should have said
I got things finished up tonight by replacing the stripped screw and the other 3 on top of the carbs with these.

[nascarkeith]

Here is the report card


A+ Mod

Pros
     Easy
     Cheap
     Much more throttle response
     Little more power
     Engine runs richer and thus cooler

Cons
     Stupid Brass screws strip easily
     Slightly decreased mpg
     Makes you want a new sprocket for even more giddy up

I rode it to and from work today and the improved throttle response and punch are awesome.  I never had to downshift on the interstate to pass and running through the gears on the on ramp was quicker.  It did iddle a little too high but that was easily adjusted this afternoon.  I'm sure this is not as good as a complete rejet but its quick and simple.  As long as you have the time and the tools anyone can do this mod by following the info on this site and the wiki.  As long as a screw doesn't strip its no problem.

After reading the comparison thread on the 15 vs. the 17 tooth front sprocket I will be ordering a 15 tooth soon.  I will also probably drop a K&N filter in and see what happens.  I have never gotten the 58 mpg Suzuki advertises.  I usually average around 48-50 mpg.  I will keep a check on that and see just how much the washers hurt mpg after a few tanks. 

[Skeets]

I really want to do this mod but don't clearly see where I put the washers....