Bike Mods

GAK - The Gonzo Air Kit

By Mark (Gonzo) Jelic, ISRA #13

OK here it is, a full write up on how to install and tune your V-Star/Drag Star 650 to have individual K & N filters. I'm sure this is also going to be possible with the V-Star 1100 and the Royal and Road Stars but someone else will have to write up that.

Essential Parts List
2 x K*N Filters (K&N Part# RU-2760)
2 x #130 Main Jets (Yamaha Part# to come)
1 x Crankcase Breather Filter (J&P Cycles Part# 12-018)

Optional Parts List (for European Drag Stars)
1 x Dynojet Stage 1 Jet Kit
(You'll see why I think it's optional)

1. Oiling the Filters - Before you pull your bike apart, you might as well do this bit first as to do it properly takes time. It takes a good hour for the oil to seep in well and distributes itself evenly over the filters and while this is happeneing, you can be doing the rest of the carb tuning. This is a very important step that K&N report as being the biggest reason people have problems, so take your time doing it.

Each of the K&N filters will come with a small tube of a red coloured oil. This does not mean you need to use a whole tube on each filter! In fact if you use much more than 1/3 of a tube for *BOTH* filters, you will probably have over-oiled and may need to start from scratch! This involves using a special cleaning fluid (do not use fuel) and a whole lot of hassle. Read the instructions that come with the filters and you'll see what I mean.

Cut or pin-prick the oil tube and then slowly dribble a small amount of oil along each pleat in the filter. *YOU DO NOT NEED MUCH!* By the time you get to the end of the filter, much of the oil you put on the first pleat will have soaked *almost* to the bottom of the fold but *don't* get tempted to put some more on just yet. Put that filter aside and go to the second one, and then leave it for another 20 minutes before checking the first filter. If you see any white spots where there is obviously no oil, add a *small drop* and leave it for a few more minutes. Another tip is to look on the inside of the filter and check to see if all the pleats are red. (BTW, you don't oil the crankcase breather filter!)

2. Airbox Removal - While the filters are getting seeped with oil, you will need to remove the airbox that is sitting atop your carbs. This involves removing your seat, then your speedo and then the tank. (Don't forget to turn off your fuel and disconnect the hose before reefing your tank up! ;-) The airbox is secured by two O-Ring type metal bands that go around the top of your carbs. You unscrew them from the left hand side of the bike.

Also connected to the airbox is the air intake tube which can be completely removed (take your time, it's a bitch) as can the plastic bagel (air cleaner cover) on the right hand side of the bike. I have left mine on for the moment as it looks kind of blank without anything there but will be mounting a teardrop cover as a faux air cleaner one day. (Instructions and pics to come ;-)

Last of all the crankcase breather tube is connected at the back of the airbox by a spring clip which will not be required any more. With the airbox now removed and the breather tube in your hands, you might as well put on the crankcase breather filter and secure it with the supplied (hopefully) O-Ring clamp.

3. Fitting the Filters - This is fairly easy with the only thing to look out for is that the filters completely seal around the top of the carbs. Don't overtighten the O-Ring clamps as this could make the fliters slip off the carbs without you knowing. Just tighten till it is hand tight. The picture below shows how all three filters should sit when they are all mounted, viewed from the right-hand side of the bike. Make sure the air filters are all evenly oiled before putting them on as shown by the even pink colour throughout.

4. Fitting the Main Jets - This is done from the left hand side of the bike. There are 4 screws holding the float bowl to each carb. When you undo these, fuel will start pouring out as this is the little reservour of fuel each carb needs to keep in it to run correctly. In short, don't panic.

Once open you will pretty easily see the main jet that delivers the fuel into the main chamber of the carb. On a stock bike, it will have a small square symbol and then "90" imprinted on it. Unscrew this jet with a flat-bladed screwdriver and replace it with your #130 main jets. See the pic below that has the #130 jet installed.

I've also pointed out the float and the adjuster "tang." I have read that with certain problems with this setup, a cause of these problems is to "not have your float levels correct" and to fix this, you need a special Yamaha tool and you adjust the "tang" to set the float levels. However, my thinking is that your bike was running fine before-hand, and changing the main jets does not affect the float levels, so there will never need to be a reason to adjust the float levels unless you play with the floats. So... Don't touch the floats! (grin)

Once the new main jets are in place, replace the float bowls and screw them back to the main carb bodies. I don't have a torque wrench so I don't know how tight, but I just tighten till I can't tighten any more, but before I strip the screw head which is very easy to do with the stock screws. I would recommend replacing those screws with some good quality hex-headed screws if you can find any.

You wont have to look at that side of the carbs again.

5. Adjusting the Needles - OK, this bit is a bit scary as all the parts are realy tiny, easy to loose and/or look like they could break or tear. But don't worry, it's not too bad.

Now you might have noticed I put the set of Dynojet needles as optional extras for European Drag Stars. (This does not apply to USA owners.) Now I'll 'fess up and say I did use a set of these that was supplied in a Cobra Jet Kit. However, the *only* part I am now using out of that kit are the needles and at about US$75, I think that's steep. The other thing is that the stock needles (on European Drag Stars only) have 6 different clip positions on them as well so I have to admit that I really don't know what Dynojet needles actually do that is all that different from stock ones! (If someone can enlighten me, please do.) Now apparently the Dynojet needles are tapered differently and *that's* why you get all this power increase, but frankly I think it's a crock. I'm too lazy to try at the moment, but I'm willing to bet that if I put in my stock needles, I will not know the difference!

USA owners have the option of *trying* to notch your stock needles (they are not adjustable like the European Stars) at the correct position (put the needle in a drill and use a hack saw blade to notch the needle at around the "T" mark) but frankly I think this is too much trouble. Particularly if you need to do a bit of "tweaking" to get the setting right.

OK, to get to the needles, you work on the right-hand side of the bike and take off the bassy coloured covers called the vacuum chamber cover. Get ready to catch the huge spring that jump out at you!

Inside you will find a rubbery diaphram that you need to be careful not to tear (not likely but just be careful) when you remove it from the carb. Inside the tube (official name is "piston valve" although others have refered to it as a "vacuum slide") is the needle. (You can see it sticking out of the black piston valve in the next picture.)

Inside the tube is a plastic screw and when you unscrew this, the needle and a few spacers will come out too. Now I don't know what setting the stock needles will be in (if someone can jump in here, we'd all appreciate it) but chances are that whatever setting it is currently on, you will need to move it two grooves down. With my Dynojet needles, they were on groove #2 (as is shown in the picture) but then I had a set of Cobra drag pipes on and this was the recommended setting. Anyway, I have mine now set to groove number #4 which works well with my drag pipes.

To change groove positions, you will need to slide the black plastic "stopper" down, unclip the circlip and then count down from the top of the needle (the pointy bit being the "bottom" ;-) to whatever position required. Then slide the "stopper" back up against the circlip, put back the metal spacer, the plastic bushing and spring, insert the lot back into the piston valve (align the stopper pin to fit into the hole in the piston valve) and then screw it all back into place. Don't bother using a screwdriver to try to seat the plastic screw since the spring will make that impossible. Just use your finger to start it (be patient, it's a bastard) and use a screwdriver to tighten, but don't go overboard as it's only plastic.

Now this is the bit that gets a bit tiresome because you will need to do the other needle as well and then take the bike for a test ride (put the bike back together again) and then you will probably want to try another setting of the needles (take the bike apart, change needle, and then reassemble bike) and then realise that the original position was better! How do you know if one posisiotn is better than another? Trust me, you will know. If you have owned your bike for anything more than 1000 miles, you know how responsive it already is (let's face it, it's pretty bloody good, even stock!) and when you change any setting to do with the carbs, you will know if it is better or worse! Just in case, at the end of this how-to is a trouble shooter to help anyway.

6. Adjusting Mixture Screws - OK, this bit will be different for the US based owners as the European Drag Stars have a very easy to get to knob on the end of their screws (no laughter, yet please) while you U.S. dudes hide your screws with brass bits. (Cue crude comments ;-)

For the "liberated" Europeans, just turn this screw all the way in (clockwise) and then back out (anticlockwise) for 3 full turns. For the "prudish" Americans, you will first need to remove the brass covers by using a drill to *very carefully* make a hole in this cover and be prepared to pull up short the drill so as not to screw the screw. Use a self-tapping screw to then remove this brass plug. (The Dynojet kit comes with the right size drill and self tapping screw which is good.) Once exposed, do likewise with the mixture screw, turning all the way in and then back out 3 turns. You may need to tinker with this setting a little but this should work fine. See the trouble-shooting section below for more info.

7. Syncing the Carbs - This requires a special tool from Yamaha and quite frankly, I'm going to this only once so I took my bike to my local dealer and got them to sync the carbs for me. The bike will probably run fine without doing this, but you should do it anyway. If the dealer tries to charge you for more than an hour's worth of work, he's ripping you off. Get him to do a test ride and he might want to play with the idle mixture too. At any rate, if you have a good dealer, he will be excited to see you with that kind of a modification on the bike and will want to see what goes into making it work well for his other customers.

Well that should be about it. Apart from the carb syncing, you will probably put your bike back together after step 6 and start her up. Since you completely drained your float bowls, it will take a while for your fuel to get back into the carbs, so a few cranks will be required.

Once started, the bike should be idling nicely without any sputters or stalls. Basically it shouldn't change much from how you had it. Now give the throttle a blip (while still in neutral) and again there should not be any change, a nice smooth roar like it used to. Now stick it into gear and go for a ride. Again, if everything is working well and adjusted properly, you should have a smooth running bike that has a very discernible increase in both power and torque. If not see the next section for trouble-shooting tips.

Trouble Shooting
First of all you need to determine where your problem is which basically involves three different items within the carby.
a) The idle mixture screws
b) The needles
c) The main jets

The diagram below shows where each circuit actually takes part in the RPM range:

So if the bike is not idling well or backfires a lot when you roll off the throttle (and at that stage the bike is actually back in idle mode), then the idle mixture screws need adjusting.

If the the initial acceleration (or pull) when you twist open the throttle is not there, or the engine stumbles, pauses, or possibley even cuts out (dies), then the needles need adjusting.

Finally if the bike does not continue to accelerate all the way to red line (or there is a flat spot in the power band) then the main jets need adjusting.

Now you will notice that with all of these problems all I say is that "..." needs adjusting. That can mean either less or more turns of the mixture screw, an extra groove or less one on the needles, or a larger or smaller jet. The thing is that it would be too large a post to explain all the things that can go wrong. But if you do have any problems you can't figure out, here is a few last minute things you need to keep in mind:

1. Post your questions/problems on the ISRA Forum at http://forums.delphi.com/star_riders/start . We'll try to help you out as best as this medium allows.

2. The bike should always be in some sort of ridable condition and you can always take it to your dealer. To get all the setting right, the dealer should really only take an hour. Besides, you need to take the bike to get the carbs synced anyway so it's not like it's a wasted trip.

3. Lastly, the good things is that nothing is destroyed or irreversible in this procedure so if the shit really hits the fan, then put it all back how you found it.

But seriously, I really doubt you will need *any* of the above "emergency" steps as long as you aren't afraid to tinker a bit. The above settings work fine on most of the 650 V-Stars that have had all sorts of modifications done to them, including the Hypercharger. But don't hesitate to ask any questions on this procedure... that's what we are here for.

And you will LOVE the performance gain!

All hail the ISRA!

© 1999 - Mark Jelic