Different gas tanks?

[TopCatGr58]

Hey Xarik,

No aspersions on your skills or knowledge set! We don't have any idea what folks know or don't until they tell us!

Okay, Db's provided lots of good advice. But I will advice that the size jets he's talking about are probably going to be TOO RICH! More on that in a little bit.

First off, here's a photo from this tech tip on how to put cheap pod filters on AND also make the bike easier to tune in general by the use of Velocity Stack style mounting.
http://www.xs11.com/forum/showthread.php?t=8269

This shows the Prominent Lip on the inside edge of the EMGO style filters...the actual filter element has been removed to visualize the LIP looking directly into the inlet bell of the carb....note how much of the vac. slide port is blocked....it prevents the vac. slide from being able to rise to allow more air in and so it causes an excessively rich condition which gets worse with the higher the rpm's you try to attain.....folks reported that they couldn't even get it above 5K with the restriction!



The tech tips explain about the reasoning of using the velocity stacks.

The 80 and 81's are supposed to have essentially the same carbs....provided you don't have the rare bastardized early 80 series that still have the sharing tunnel between the pilot and main jet towers....which feeds the pilot circuit thru the main jet similar to the older 78-79 carbs....but the 80-81's use smaller mains. The later 80-81 carbs do NOT have a sharing tunnel and the pilot jet feeds directly from the carb bowl and not via the main jet. With the bastardized 80 carbs with the sharing tunnel...the pilot jet tower is supposed to be capped off with rubber plugs so that it feeds only from the main jet tower....otherwise it can be too rich.

The 78-79 carbs used 137.5 mains because they also had to feed the pilots. The 80-81 carbs use ~110-120 mains because the pilots feed from the bowl directly. Despite what the manual said....Yamaha did away with the staggering sized jets fairly early on in production....the cooling/heat difference between the center and outer cylinders was negligible. My 81 Special came with 110's across all 4...Yamaha jetted them leaner due to increasing EPA demands. I put 4-1 pipes on it very early on when I got my bike back in my ignorant youth....thinking that 4-1 pipes would provide more HP! Wrong....they just changed when the HP power band kicks in....moving it up a bit more in the rpm range vs. lower for OEM pipes. The OEM pipes with crossover were tuned for the best ALLAROUND performance.... low/mid/high throttle...but more for low/mid. Anyways....I ran it with those 4-1's for 7 years with OEM Airbox WITHOUT rejetting, and never burned any holes in my pistons...and had great throttle response thru most of the rpm range....redline in 4th....never was able to try it in 5th!

My bike died due to tranny issues, parked for 10 years, rusted, etc., rebuilt it with WISECO little big bore 1179cc kit, etc., and installed Pod filters...then shortly installed the velocity stacks....and it behaves great. I went up to 117'5's on the mains and 45's on the pilots. My compression levels were jacked up a bit with the big bore to around 180 psi...and so I have been using Hi-Test vs. Regular. Everybody says that for the stock bike/engine regular is all is needed, granted the compression of ~10.# to one vs. 9.0 to 1 isn't high octane required...but I didn't want to take any chances with my new $$ pistons...concerned that I might not be able to hear the Pinging of preignition! My plugs look great and have great throttle response..so even though it's a bit more $$, it works for me.

T.C.

[dbeardslee]

From my understanding, it's flooding though. Meaning too big of jets?

Here's a video from the guy who sold it to me showing it running. It doesn't help a ton, but at least you can hear it running. (I know this post started as a tank issue, but if you had this issue before, that'd be awesome to find out what's wrong to save a buck :P)

https://youtu.be/BKhwZV_Tis0

If the pods have lips then they're obstructing the air jets, which probably would make it run rich.

Unfortunately, the pods you just linked are $20 each and will cost me $80! For goodness sake lol

Which is about half what K&N pods would cost you, and that's basically what they are.

[dbeardslee]

Okay, Db's provided lots of good advice. But I will advice that the size jets he's talking about are probably going to be TOO RICH!

TC - I thought you might be along to straighten me out. Kind of why I hedged a little and said to see what was in it first. So are you saying you'd run the stock jets with pods and a 4/1, or would you go fatter as per the jetting recommendations based on what's in the carbs?

[TopCatGr58]

Hey DB,

With both pods and 4-1's I would definitely use the jetting guide to up things a bit...but remember...it says for 2 mods...2 sizes per mod MINUS 1 when you have more than one mod....do the mains go up only 3 sizes. And it would be very helpful to find out what sizes are in there FIRST....and then adjust from there....provided the plugs were okay....but with the PODs restricting air flow the plugs will probably be very sooty/black and will not give a proper good starting point with which to compare. So...others will say to put clean plugs in it....fix the Pods whichever way you want...different no lip pods or velocity stacks....and then do a test run/throttle chop and see what the new plugs look like....along with how the bike responds with WOT...and THEN make adjustments based on findings.

T.C.

[dbeardslee]

Hey DB,

With both pods and 4-1's I would definitely use the jetting guide to up things a bit...but remember...it says for 2 mods...2 sizes per mod MINUS 1 when you have more than one mod....do the mains go up only 3 sizes. And it would be very helpful to find out what sizes are in there FIRST....and then adjust from there....provided the plugs were okay....but with the PODs restricting air flow the plugs will probably be very sooty/black and will not give a proper good starting point with which to compare. So...others will say to put clean plugs in it....fix the Pods whichever way you want...different no lip pods or velocity stacks....and then do a test run/throttle chop and see what the new plugs look like....along with how the bike responds with WOT...and THEN make adjustments based on findings.

T.C.

I did tell him to check what was in it first, but I put up so many posts on this thread this afternoon I couldn't blame anybody for not reading them all. The condition of the plugs didn't occur to me. Yet another reason why you're the Top Cat, and I'm not.

I did notice in the video that he posted that the carbs look like either 80 or 81 carbs from the shiny slide covers. I ran across a set of the bastardized 80's several years ago that didn't have the plugs in the pilot towers, and that REALLY made 'em run rich. I sure hope Xarik's mechanic knows what he's doing.

[Xarik]

Haha well this doesn't seem too bad. That pod fix might be the way I go in order to save a few bucks (or save $70...). That looks like it'd be very simple, but a little ugly, but honestly, at this point, I don't really care as long as it works. For $15 and some struggling, that'll be worth my time.

After the pod fix, it sounds like I just need to figure out what size jets to put in....I only wish that I could get to the bike and do some work on the darn thing because I would save a butt ton of time and money. I'm trying to think of a way to get to the bike and work on it since I'm not willing to spend the huge amount of money....Can I get an opinion on these: http://www.amazon.com/Universal-54Mm.../dp/B008J5323K

if I just bite the bullet, get the nicer pods and go ahead and drive over to the shop and install them, the bike might run well enough the way it is. If not, then I simply talk to the mechanic and explain what I've changed and what you guys would recommend. Also, what plugs should I run? I was border line yelled at for getting the wrong ones for my ninja once (they weren't NGK's lol)

[Xarik]

Or is the issue with the "lip" the area deeper into the rubber ring? Looks like the ones I just linked have a lip in there

[natemoen]

Cheap route would be to just get the original airbox and then a k&n filter in there. Plus, then you avoid all these problems!

Those filters you just linked to are going to have that lip and be no better.

[Xarik]

Cheap route would be to just get the original airbox and then a k&n filter in there. Plus, then you avoid all these problems!

Those filters you just linked to are going to have that lip and be no better.

Looked up the cost of the airbox....that thing is butt ugly and I'd rather stick with spending more money to get the look I want. I forgot that I actually have a good budget for this build, so I think I'll go ahead and purchase the recommended pods from MikesXS.net and put those on.

again, any recommendations for plugs?

I plan on ordering these pods and just driving out to the mechanics and putting these on and tossing the old ones probably (since they are useless to me). I'm also looking at buying some clubman bars from MikesXS.net in order to get the most out of the $12 shipping charge ;P

[dbeardslee]

if I just bite the bullet, get the nicer pods and go ahead and drive over to the shop and install them, the bike might run well enough the way it is. If not, then I simply talk to the mechanic and explain what I've changed and what you guys would recommend. Also, what plugs should I run? I was border line yelled at for getting the wrong ones for my ninja once (they weren't NGK's lol)

Personally I like the NGK Iridiums. Size BPR6EIX. They're a little pricey but they're as close to a foul-proof plug as you're going to find, and they work real well with hotter coils. But the stock NGK BP6ES work fine if the carbs are tuned right with the stock coils. You gap the 'regular' plugs at .028-.032 IIRC, and you don't mess with the gap on Iridiums at all. They come pre-gapped, and you can actually damage them by trying to gap them yourself.

I'd take a look at the pods before I bought anything, just to make sure the lip is present. I'm pretty sure you'll find a lip, but it never hurts to check before you spend the dough.

[dbeardslee]

again, any recommendations for plugs?

In a pinch I've also run Autolite 63 plugs, when I couldn't find the NGK's. They're basically the same as the NGK BP6ES and work fine in these motors. Some plug snobs might not like Autolite, but I never had a problem with them.

[dbeardslee]

Looked up the cost of the airbox....that thing is butt ugly and I'd rather stick with spending more money to get the look I want.

Not to mention the stock box makes removing and installing the carbs a real PITA. Much easier with pods. However, there is one little thing you should be aware of. When you've got a stock air box the carbs are supported both front and back. A lot of folks remove the air box and just let the carbs dangle from the carb hangers, but that's not really what the carb hangers were designed for. The carbs tend to bounce around that way, which can't be good for your carb hangers, and I prefer to run a little brace on mine. That gives them support both front and rear, and gets rid of the bounce. And they're still easier to remove and install than with the stock box.

I went out in the mancave and took a couple pics to show you how you can rig a brace. Not the best pics, but the best I could do without removing the seat and the tank.

Here you can see the brace between carbs 2 and 3. I just used some 1" bar stock from the local hardware store. It's not too stiff (and it doesn't need to be) and it's easy to bend. I cut a little kind of triangular piece to act as a clamp for the front of the brace, drilled it, and used longer screws in the carbs to accomodate it. You don't have to screw it down super tight - just good and snug.



And this shot is with the camera pointed straight up. The hole you see at the top of the pic is where the gas tank bolts down, and the hole below it where the back of the strap is attached is where the top bolt for the old air box used to go.



It takes all of about an hour to make one, and it will keep your carbs from bouncing around, and will help preserve your expensive carb hangers.

[TopCatGr58]

Or is the issue with the "lip" the area deeper into the rubber ring? Looks like the ones I just linked have a lip in there

Hey again,

In the Amazon link, they have the single filter view..it's a bit dark, but when I tilt my screen I can see the details of the innards better, and YES, they are the same as the EMGO if not actually the EMGO....yes, the lip is deep because it has to allow a bit of the section for actually slipping onto/around the mouth/inlet bell of the carb..and when positioned up against the carb, then the lip is right there blocking the airflow...and IF you try to mount it a little bit away from the mouth..then there's not enough to hold onto the carb mouth properly, and they will slip off!

Even with the MikesXS "XS" brand of filters, I would still recommend mounting them with velocity stacks....they help to straighten out the air flow before it gets to the intake inlet bell. With just the filters..the air is coming in sideways and creates a fair amount of turbulence before it makes a 90 degree turn into the carbs. The OEM AIRBOX utilized LONG intake mounts that reach deep inside the airbox to provide the velocity stack affect. For years "we" thought it was just the pods that caused problems...we then found the lip and thought it was the ONLY problem induced complicating tuning....but then when we added the velocity stacks....the Pods worked quite well, and aren't so hard to tune.

We used to think that the generic pilot jets with the wrong # of aeration holes was what caused overly rich tuning problems.
We later found that NON-Mikuni carb parts were the problem....that the generic jets used a different sizing parameter than Mikuni....and were much larger for the same stated jet size....and THAT was what caused the overly rich problems. We later learned that the aeration holes were MOOT, once we sliced the carb bodies in half lengthwise and crosswise, we found that the pilot circuit adds/mixes air into the pilot circuit AFTER the fuel flows thru the pilot jet down in the carb body...and that there was no place for air to get AROUND the pilot jet the way it's screwed into the pilot jet tower...and that's partly why Yamaha made the pilot jets later on with NO aeration holes in the sides...it doesn't matter, just the location and size of the metering hole in the END of the jet! SO...this is why we recommend verifying that you have OEM Mikuni jets and not aftermarket jets!

BTW, the NGK plugs listed above are NON-resistor(BP6ES...the Iridiums ARE RESISTOR)..hopefully you can find them. The ignition system uses Resistor caps so resistor plugs are redundant and can actually cause reduced spark energy, especially with OEM coils...they are only about 15K volts. The ignition control module (TCI) is not sensitive to RF. I actually use non-resistor Champion( The crowd yells BOOO) N9YC, but I also have high power DynaTek 30+ Kvolt coils, non-resistor caps. Here's the Tech Tip of compatible plugs/brands:
http://www.xs11.com/forum/showthread.php?t=2591

T.C.

[dbeardslee]

BTW, the NGK plugs listed above are NON-resistor(BP6ES...the Iridiums ARE RESISTOR)..hopefully you can find them. The ignition system uses Resistor caps so resistor plugs are redundant and can actually cause reduced spark energy, especially with OEM coils...they are only about 15K volts.

Unfortunately NGK doesn't make the Iridiums in non-resistor. I run non-resistor caps with 30k Dyna coils and they work great that way. Probably should have mentioned that.

[Xarik]

Ok, so I can almost guarantee that the filters have the lip, since I can't seem to find a single cone shaped one without the lip on there (and this kid said he bought cheap ebay ones, which is all I can find and they all have lips). So at that point, I mine as well spend a few hours going to the store, to the shop and then putting the air filters on my bike with the Velocity stacks. I'm sure they will laugh at me when they take them off, but at least I will know that they will function properly. This will also save me money, since the cheap air filters will work instead of getting the XS brand or K&N brand.

As for the plugs, I feel like I should have them replaced in order to see what is happening inside of the cylinder (burning plugs or whatever). So will any plug work from that list that you have provided? I may just grab a cheap set to test out and then buy some nicer ones later on down the road (in like 50 miles lol).

As for the jets, I will make absolutely sure that they use Mikuni parts exclusively. I've heard it's a big deal if you start straying and using aftermarket parts as they aren't going to function 100%, so I see the importance of using Mikuni parts.

dbeardslee: That tab looks like a good upgrade to have for my bike, and simple at that. I'm sure I could get a snippers, strip of metal and some screws and have it bracing the carbs in less than an hour if I'm quick .

My biggest hope is that, simply fixing the air intake will allow the bike to run much better. I've had this happen with my Mustang, we had a small air filter on and it kept on getting choked and couldn't get enough air to keep burning the fuel, once we pulled off the filter, it ran fine...we just needed a bigger filter. So this is essentially giving the bike more room for the air to get in the right direction and then it's opening up the whole so it can get where it needs to go as well.

TopCat, if you could shoot me a message with a simple explanation of the velocity stacks, that'd be awesome. I simple need to know what order things are on there. It looks like it's the rubber hose stretched over as far as possible, clamp that, push in the PVC pip as far as it'll go, clamp that on, Rubber repair tape (I'll have to google that one) on the end of the PVC to make a more secure connection, then the filter and then clamp that down? Sounds like I'll just need to cut up some PVC and maybe cut some rubber and then tape....and then assemble.