So ive been a member here for about a year now, but havent posted much so I figured Id change that. I bought an 02 SH last year w/ only 3.5K! I bought it for $3600 and now has 7.3K on 'er. It came with edit: Staintune exhaust with 15/43 gearing on 530 chain.
Last year i got some Ct2's and some ebc brakes to give me a little more security in an insecure world.
This year I followed 8541's Carb mod setup
1 port on Front slide blocked
48jets
needles shimmed .030 front .040 rear.
TPS mod to 492 Ohms
Questions on the shimming, does this affect a certain rpm range or all of it?
Ive noticed I dont have any more lean poping when I chop the throttle now, so I guess it did something different.
1st thing i noticed was that below 3.5K, cruising was alot smoother. As far as the rest, im no pro I think i may have gained a little something more in the mid range, but the top end felt close the same.
What would you recomend to get a more noticeable hp gains up top?

Moving on to the Gearing. The presetup gearing was just a bit to closely geared for me. I felt like I was on a dirt bike shifting every 1/2 second. I also wasnt to wild about 6k hwy speeds.

I didnt realize the front wasnt stock @ 1st so I got a custom 39 rear made. I just found out this was only 1.44% less than stock. I also found out a thin aluminum sprocket doesnt last that long on a SH and neither does a 520chain. So Im going back to a 530chain 15/41 setup to get a little more.

On Ebay I got an front rear sprocket/ chain combo for $85. I thought it was a good deal seeing that the sprockets are made of thick steel and not cheap aluminum. The chain is O ringless so ill see how long that lasts. Heres a few pics of the old and new.

http://i1227.photobucket.com/albums/...uperhawk/8.jpg

http://i1227.photobucket.com/albums/...uperhawk/9.jpg

I didnt have a bike stand so I used my deer skinning hoist... good advice from a local biker







I am very happy with this setup. Stock is good, but this gives me that little bit more of a pull I was looking for, while avoiding the issues of how the bike was prior setup.

Next I installed a speedo healer. Come to find out my bikes speedo was off by 15% with the 15/41 setup. Im suprised it was that high. It was even higher with the 15/43 @ 19% ... And i think thats it for now.

I just recently bought a old pickup so I can haul my bike a few hundred miles to ride the Dragon Tail. Might go to little switzerland, nc to warm up.
Btw how low can you lean these bikes safely? I usually stop when I feel the foot petal start to grind. Can you lean lower safely?

 

There is not much you can do for the top end unless you want to install pistons and cams. A set of the Dr. Honda velocity stacks can help a little but like I said without engine work there really isn't much to be had.

Shimming the needles is for the 3K RPM and above range though it does have some effect on the lower RPMs also.....

As for leaning the bike, well the quick answer would be until it falls over....
Though in actuality the limiting factor is the header dragging in right hand turns. Some fiddling with the ride height can get you a little extra clearance (or less if you pull the forks up in the triples) but as I said the header is the first hard part to touch down.

As for the gearing, I won't touch that one as I'm already in enough trouble around here with the tire slip stuff.... do a search and you will find it is a well covered topic.

 

In high revs (above 7K roughly), you can play in carbs just with the size of main jets. As needles are fully opened, shimming affects nothing there. Other things playing there are air intake - air filter, airbox, stacks; exhaust - pipes, baffles. In your case I would just try main jets one size up, two long stacks and burnie morgan mod on paper filter.
CBR coils mod described here can help too.

In next stage pistons, cams, tuned heads ... as Hawk wrote.

 

Don't want to argue but 2 long stacks will give you less power in the high RPM range and I sit don't agree on modifying the filter at all.

the other thing to look into would be a flo-commander Flo-Commander by Performance Design it can help smooth things out a little bit and also allow you to try the equivalent of one size larger or smaller on the mains just by turning a screw instead of opening the carbs again. If you find the bike would like a little more or less main jet, you can then swap them out.

 

8541Hawk: no argue at all :-) I just have good results with these so its sharing of experiences.

Stacks in theory what I´ve found: two oem long stacks will give you more power in the middle and engine revs slower, and oem short stacks work high rpm and revs faster. Another theory - use long stack for engine with stock internals, and short stacks for tuned engine (cams, pistons ...)
Dr. Honda stacks in lenght are very close to oem long stacks (if they are from CAD file posted here), and far away from short stacks.
So I went with two long stacks and felt noticeable gain in the middle and no change in top revs. For me it is cheaper alternative for Dr. Honda stacks (overseas shipping and tax) I have two short stacks too, but wasn´t convinced to try them as engine runs good now.

When trying Burnie Morgan mod for paper filter and airbox, I felt smoother engine run in low rpms and no negatives.

 

I agree on the alumn sprocket thing. They are only for racing and dont last long there either but are worth it for the lightness.

How far you can lean depends most on tire size and profile and suspension ht and stiffness/ setup. Also on how much if at all you get off the bike. (which helps the bike lean less but tires you out quicker)

Not sure if this pic is legible but its informative.

 

The Dr. Honda stacks are based on the Moriwaki stacks and it is the shape of the bell that is critical and where the power increase comes from.

So there is no real way to compare them to the factory units as they flow better than either the long or short stacks at all rpms.

 

I am able to lean far enough over to grind down my toe sliders when not hanging off, but with stock suspension its pretty scary at that point. Dragging knee is no problem when hanging off. If you are grinding your foot peg I wouldn't try for more lean as the next to hit are the cans. While lean is good, too much lean can be bad. Don't worry about getting over as far as you can, worry about having the most grip and control.

 

Thanks for the responses, links, and the advice of all that have replied. Yes I was referring to the flat spot at around 7.5k+ on my SH. Im may try going up 1 or 2 on the main, but dont want to go crzy spending $. Its just a commuter bike and i dont need perfection. Since ive changed my gearing the spot is almost unnoticeable now except for 5th& 6th gear.

Im not going to add any high flow air filter bc more air requires more fuel and as a DD im looking at a good compromise of fast and good mpg. If I was racing it would be a different story.

Im actually debating on unshimming the needle. Why? Ill explain, on my way back to work from school I had some fun w/ a guy in a bmw that thought he'd try to keep up with me. On my way home i noticed my fuel meter was flashing. I thought ive only gone a 100mls theres no way i need to fill. I pulled over and filled anyway only to put in 3.5 gallons. 27mpg is officially the worst mpg ive gotten on this bike My car actually gets better lol. I did get 36mpg last time i filled w/ normal commuting. So i may just keep it under 6k on steady hwy cruising.

Also as far as cornering goes, thanks smokinjoe for the pics there. Im not a daily grinder, but enjoy taking well known entrance/exit ramp loops on a good lean. Id say my stance is more leaned over and crouched. Ill try sitting upright with a slight lean next time. When Ive ground the pegs i could most certainly knee grind if i hung over a little more like boss man in the pic there Ive never been to a race track but would like to play with it. Does anyone know of a track where a local joe schmoe can ride near charlotte, nc?

 

48mm carbs and a heavy throttle had will give you poor mileage there is nothing that can be done about that..... my record so far is the RLOD (or Red Light Of Death for you new guys) is 70miles

Now for pulling the shims, well you might gain a little mileage your "flat spot" will get worse. To get ride of it you might want to raise them .010 more.

While some people say that the pilots only work until XX RPM then the needles only work to XX RPM and the mains work from XX to XX RPM I have found that not to be true. They all work together and you have to find the balance that your bike wants or likes.

This is why I say my set up is a base line and not the end all of set ups.

It is also why I run 48 pilots and stock mains. The pilots add enough on the top end so I have no need for larger mains.

It is also why there usually are problems when running the 48s with larger mains, the larger mains make the bike too rich on the bottom end.

Of course this is with a basically stock motor.

 

Riding in the City, 70 is where I expect the light to come on. Its the norm. And I am no hamfist.

 

Wow 70mls, impressive, im going to try not to beat that record.
Ive been doing a little reading on how carbs work stating the function of carbs like this below. Supposedly the pilot only affects idle-1/8th. But if you read the 2nd paragraph how does it affect WOT throttle chop also? im going to have to agree with you. Everything is interrelated.

LOW SPEED (PILOT) JET
The low speed (pilot) jet controls fuel flow at 1/8-1/4 throttle. The low speed (pilot) jet is usually not affected by most simple pipe/air filter modifications. However, a slightly lean low speed (pilot) jet can raise havoc in the winter where its fuel is added to the total mixture strength required to start. You may find going one level up will help a winter cold start situation.
Finally your idle mixture is revisited if you have a deceleration backfire situation. When you chop the throttle and use the motor to decelerate, if you get a stream of backfires, try increasing your idle mixture strength 1/4 turn at a time until the backfire goes away. Note: If you reach a point where your idle mixture is 4 turns out (for fuel type screws, NOT air type screws), try going up one size on the slow speed (pilot) jet and reset your idle mixture screw to 1-1/2 turns out and repeat the process.

found this article here carbs 101 - Honda Foreman Forums : Rubicon, Rincon, Rancher and Recon Forum

As for right now I think ill take your advice seeing that youve got an hour or 2 on the SH. I may do some of my own experimenting at a later time when I actually have some.

 

Well if you look at how they work, there is no "cutoff" circuit for the pilots they flow all the time, so yeah they can and do have an effect on the top end. Just like changing the mains as only "supposed" to have an effect in the mid to upper range but they still flow enough on the bottom to have a effect on the pilot circuit.

On of the reasons tuning carbs is often though of as a for of Black Magic.....

 

To go one size up with main jets, you need just one jet, size 180, for 7 USD, for instance here:
KEIHIN MAIN JET 99101-393 #180

 

As Hawk pointed out there are no shut off valves for the pilot circuit so it's always flowing. Though it's a very small amount of fuel as compared to the main jets it is still some none-the-less and will increase fuel very slightly thorughout the slide travel. The needle is down the same passage as the main jets and between the jet needle and needle jet the opening is much smaller than the main so the main jet generaly won't affect fuel delivery until the slide is high enough that the clearance between the needle jet and jet needle are greater than the main at which time the main is the metering orfice for the fuel. That being said some carbs are wierd and an adjustment to the main may actually make a difference through the needle movement.

Generally when you're setting up a carb you start at the low speed or pilot circuit and work your way to the needle then the main jets because each circuit lower will affect the next larger circuit however the larger circuits generally don't affect the lower circuits much if at all.

Also the constant velocity style carbs we have the circuits are less based on throttle position and more on engine RPM and throttle position combined as the slides are not attached in any way to the slide. It's the larger volume of air creating more vaccume under the slide that raises the slide. So if you have a mid RPM stumble at WOT it's not necessarily the main jets that are the culprit being you are at WOT but more likely a needle adjustment that needs to take place.

 

Y just 1 main if I have 2 carbs? I actually bought 2 combo sets of 170-180mains last night. Shoot wish i would have known that a tad bit earlier.

Thank you all so much for the insight as to how carbs actually work. I have a much better understand of it now, than i did just a few days ago.

So I guess ill disclose my 1st soon to be experimental formula. Ill test it out once i get my mains here. My goal is to get close to stock mpg on cruise(38-40) 1/8th-1/4throttle in the stoich afr range and a little more for WOT runs. Im thinkin back to stock 45 slow jet 3 to 3.5 turns out. Remove the needle shims so ive got .010 on the front .020 on the rear. and step up each main+1. From what ive gathered it seems the rear cyl will prolly be a step higher in the main than the front no? What you all think of the idea?

 

Dude, I usually don't get in on this stuff other than to laugh on the sidelines, but are you dense?

Hawks 8451 setup is not what you're planning to do! I don't think there is anyone on here running the mixture screws at 3.5 turns, and if your running a stock filter why on earth would you go up on the mains?

Try the 48 pilots, 175/178 mains, shim the needles, mixture screws at 2 1/2 turns and try it. If that's not better then go your own way. You keep asking questions but don't seem to be able to accept the answers.

 

Stock motor, yes, but ive heard of people needing rejetting for exhaust mods. Not sure if my Saintune exhaust counts for anything. Hawk had stated earlier if you read, that he had problems running bigger mains than stock w/ the 48jet. I currently have his setup and am fairly impressed with it. However im thinking if i drop back my slow jet back to a 45 just to try a bigger main for my flat spot above 7.5K. The 45pilot at 3turns or so maybe enough to provide a good enough fuel supply not to cause lean burn on throttle chop.
Hawk is more than likely right in post#2 stating that not much can be done for the top, but im going to experiment and state the results. If they are worse which is very possible ill go back. I was just stating this to see if anyone has tried this yet.

 

I might have misunderstood what you meant with your question about top end. I took it as a way to get more power, which without engine mods is pretty difficult.

I also suggested going up .010" on the needles to address your flat spot. You also might need to go down .010" with them because without riding or hearing the bike I don't know if you are going rich or lean. Mine pulls just fine through that range.

You can try whatever you would like though I was clear with my views and opinions on running larger mains with the smaller pilots but the best way to learn carbs is to try it and see what happens.

For your other question about the main jet sizes stock is 175 front and 178 rear that is why you were told all you needed was 1 ea. 180 jet to go up one size. Though the only time I have run a 178\180 set up was with a stage 1 engine.

I will also say that ever bike I've tuned has been a little different and the 98-99s are different than the 2000 and later bikes.

This is another reason I suggested a flo-commander, it makes dialing in the set up quick and easy. One of the draw backs of carb tuning is the time it takes to change jets.

I am pretty quick and can have the carbs out, rejetted and reinstalled in around 45 mins on this bike. If you take much longer than that, the atmospheric conditions can change and that can and will make comparisons difficult.

As for the fuel mileage, no matter what you do to the carbs, if you keep the revs above 5K you will not get good mileage. nothing can or will change that.

I tend to ride in the 4-5K range while "commuting" and average in the high 30s. The guys that get in the 40s keep the revs even lower.

Rev the engine higher than 5K and your mileage will drop quickly....

 

That sir is an excellent point. I think ill try this simple shim before re-inventing the wheel so to speak. #4 washers purchased today. Not sure why i didnt jump the gun on this earlier. Must have been lost in my wheel re-inventing

And just to state my experience, +5k doesnt always = bad mpgs. When i had the 15/43 setup i was cruising the hwy @ 6k and my mpgs were typically 38-40 and that was with me beating the dog out of it at every stop light. But thats with the stock carb setting. Im fairly certain it was running lean and out of optimal performance, but i dont think too lean. I never had an overheating issue.

Hopefully sometime this week ill be able to knock it out. Ill post a vid of now and +10 shimmed.

 

For the mileage did you account for the odo error that the gearing caused? If not then your figures will be way off

 

Thats another good point, never thought about that. 38mpg- 19%(7.22 mpg)= 30.78mpg ... So im actually getting better mpgs with your carb mod, well as long as I stay under 5k.

 

Also another thing to try before you tear into the carbs.... try pulling the choke out a touch (well it is actually an enrichener circuit) as see if it pulls better or worse in your "flat" spot.

If it pulls better, you are a touch lean. If it gets worse you are on the rich side.

Just another tuning tool to help decide which way you need to go with your jetting

 

I just tried that and let me tell you I think I gained 5-10hp across the board. When i pulled it out a 1/4 the flat spot went from 7.5k to 8K. Then I pulled it out about 1/2way(2,000rpm idle) and it just about removed the flat spot completely. It was barely noticable from a hair under 9k on.

Just to make sure I wasnt taking a placebo i did a top speed hwy pull. No choke in top gear it went to 8ish and began to slowly climb to the redline.
Then i turned around and ran 1/2 choke and ran all the way to 9k before hitting the climb to redline. Turning on the road after the exit ramp I punched it mid turn with the choke still on and I broke the rear tire loose for a bit mid turn in 2nd! Now my bike really hauls ***

So from what Ive stated do you think .010 is good enough or should I go more?

 

well when the foot peg starts to grind you can lean further because it will pivot up. Also, you can buy rearsets or, for nothing, rotate your pegs 1" to the rear which will raise them about 1.5". Puts the pegs level with the top of the swingarm and gives you a little breathing room relative to lean. Also, shim your rear shock 6+mm and or have Jamie lengthen your shock. You can also put a 190x55 Q2 which will get your *** end up a little higher. Now you've got plenty of clearance.

If you're unsure about lean angle, increase until you feel your rear losing grip and at this point your close to the limit. If you have sticky tires, they will allow a good bit of sliding before your fall off the edge.

Of course, it's difficult to discuss lean in any meaningful way because there are so many variables but clearance you'll have.

 

First what air filter are you running? So what the "choke" test has told you is the bike is still lean. So you might need to go up on the mains but it is hard to tell at this point.

 

As for making geometry changes, well you should Know what the changes actually do before you just start changing things around.

You should understand how the changes affect the rake and trail so you don't get yourself in trouble and also understand your riding style will have the biggest influence on what or if any changes are best for you.

Always make small changes and test before making large changes just because it might work for someone else.

Also make sure you have the sag set properly before changing anything

 

It looks like Ive got a standard OEM filter. Its Honda Red paper. In fact it may be the original. I blew it off last time i was in the carbs. It still looks really clean, no accessive dirt or wear ect.

As far as adjusting anything with ride height, i may try the Q2 190/55 next tire buying time for a little more height and side grip, but i dont see my self doing anything major ATM. Not until im a regular grinder and definately not until ive had my suspension reworked.

 

Well then your bike might be one that wants a larger main jet, so you might want to leave the needles alone right now and go to 178\180 mains and see what happens.

As for making geomerty changes, personally I wouldn't change anything until the forks and shock are set up properly. Raising the rear will just put more weight on your already under sprung front end (if it is still in the stock configuration) Me personally, I like the stock rear tire size also and start with just a spacer on the top shock mount.

This gives you the ability to adjust the size of the spacer and also remove it if you find you don't like it or it doesn't suit your riding style.

 

Ok so I got my multi main Keihin Series 21 jets in today, tear apart my carbs, only to find they are too tall... Ironically it didnt really matter bc i failed to check what the mains were in each carb. I took each apart separately and put it back together before I took the otherone apart so I wouldnt mix up parts when i did hawks carb mod.
Well the last guy didnt do that. Guess what i found on my rear as a main? #175 lol and the front was #178. So i have swapped them to their correct locations. Now this should clear up my problem. Ill report back shortly.

O also got a used SH flywheel on ebay for $48. Figured id join the lightened FW bandwagon. Its from a 99, all fw's are interchangable with all models correct? it said 99-00 fw on the add, but im 99% sure it should have been 97-05 engine compatability.

1 more thing, as far as getting some suspension rework done im 180lbs and going to get some front racetech springs .90kg, would it be worth it to also get the gold valves. Or would staying stock valves and putting in thicker fork oil suffice?