Did you check the air mixture screw? Getting the carbs out is easy if you use a strap to lift the front of the tank. If its backfiring, it's not right. I'd put the oem jets back in and shim the needles.

What's a healthy supply of soot? doesn't sound to healthy to me. Pull the plugs and see how they look.

It's your bike so naturally it's up to you.

 

brownish exhaust is what mine looks like.
Shim: just a little washer(mic'd to .040).
I have a homemade oiled foam filter so i don't know how that would compare with a K&N, but I would guess similar flow rates. Esp since I cut the flap off the housing allowing greater flow too. Many on here say that K&N adversely affects running?

what for exhausts do you have?

I don't like to tear **** apart just for the hell of it either, however when i do get in there, I want to check everything out with a fine tooth comb, mostly so i can do it once only. Air mix, needles, diaphragms, jets, etc., anything and everything, kinda like a baseline for future reference.

 

You mean the float bowl vent lines

 

haha. I thought all those little black rubber hoses under that big black box were vacuum lines. thanks for the correction.

 

air screws stock position likely. get em out of there, slot em and set them to 2.25 turns out as a base line setting.

shim .040in

these settings you're reading in the manual you can stick where the sun don't shine when you desmog , change exhaust system and who knows what else . Now you're in the lab experimenting unless someone else here rides those altitudos(spanish-haha). Then you can use those settings as a more realistic baseline and go from there.

lean form the factory is always a good assumption.

 

Well on the VTRs I've messed with, the bike is lean on the bottom & mid-range and the top end is fine.

That is why I tell folks to start with just shimming the needles .040" and installing a #48 pilot jet (and for the record, this set up made the most power on Dan Kyles dyno when he did back to back runs with this set up, then a FactoryPro kit and then a DynoJet kit. Things might have changed as this was done in early '98 and FactoryPro and\or DynoJet may have made changes to there kit after these runs were done)

I am very close to sea level but it is a good starting point and all you need to buy is a set of pilot jets instead of an entire jet kit.

 

i never changed pilot jets, but I will order some #48s for sure. **** I was just in there to set the valves, but I didn't remove the carbs. No biggy, I'm gettin good at it, esp since I don't have to remove the tank =, makes it easy.

I'm riding at 2000ft to 3000ft.

 

do some searching to see if you can find jetting/carb adjustments for 5000ft, and you can PM some forum members from denver.

 

I believe the OEM slow jets are #45s.

It's up to you, but I wouldn't be dealing with the air screw for the first time w/o removing the carbs. Get em out, slot them or whatever you decide, then set them to 2.25 turns out. Find out what jets you have, change your pilots to #48s, shim needles & put it back together. Then if you want to fine tune, run engine and adjust with tool.

Don't hesitate to take the carbs out because with not having to remove the tank and the repetition of pulling them a couple times, it's pretty easy. Just takes a little patience and perseverance.

 

The stock pilot jet size is #45 and it is listed on page 5-2 of your service manual.

 

That is weird that you have a #48 OEM and the air mix settings don't seem right for that Pilot jet and relative to bigger jet in rear and lower air setting.

I have a 98 also, and the honda manual says slow jet#45, front main #175, rear main #178.

And what i read somewhere is that to tell if you need a larger pilot, you back out the air screw till rpm drop, then screw it in a hair to restore rpm. Now if you back out air screw and rpm doesn't drop, you need a larger pilot jet.

Do your have a Honda manual, was your bike ca only model, european model or other, because #45 is standard set up AFAIK.

We need someone more knowledgeable than me to weigh in here cause i'm out of my realm of expertise, and that doesn't take much.haha

 

The correct way to determine what size pilot jet to use is based on the setting of the fuel screw (it is not an "air" screw as it meters fuel not air)

If the bike runs best with thew screw set at 1 turn out or less, then you need to go down 1 size of pilot and try to adjust it again.

If it runs best with the screw turned out 3 or more turns, you need to go up 1 size.

 

oh, then the air mixture screw is determining how much fuel is metered to how much air is passing through?

So in R80gsman case, things are totally screwed up in that he has large pilots @#48, which means that his air mix settings should be less instead of more(closer to 2 than 3 turns out). what are yours set at?

On cars where the air screw was accessible, I just back it off till rpm drop and then go back a hair and it was good.

 

Oh some carbs the screw meters air and on others it meters fuel. On a SH it meters fuel, that is why you turn it out to richen the mixture.

I can't tell you exactly what mine are set at. It is somewhere between
2 1\2 to 3 turns out with the rear turned out around 1\4 turn more than the front. So I think I'm at 21\2 in front and 2 3\4 on the rear but while fine tuning I just messed with them a bit till it was right but didn't seat them to find out exactly where they ended up at.

The proper way to set them on a bike is to turn the screw in until you get a 50rpm drop, turn it back out until you get the 50 rpm back and then open it another 1\2 turn.

 

Both on how to setup the fuel screw and how to determine the size jet your bike should work best with... Both procedures are like 8541Hawk described, and both should give a decent baseline to work from...

The simple fact that most VTR owners will end up with 48's and between 2.25 to 2.75 turns on the screw is another matter... I still say it's a smart idea to do that on each bike, just to confirm...

And if you ask me what setup my bike has exactly my answer is along the same line as 8541Hawk's... Thumb and finger, so-so... Fine tuning isn't something I can put down in numbers, it's something I do "by ear"...

 

it would be probably be much easier, less confusing, and make more sense if we had a SH baseline set-up for all of us who get in there for the first time. The numbers are already there, but you'd have to dig around extensively and then gather some kind of numerical consensus to figure it all out.

for instance, baseline for a superhawk desmogged with aftermarket exhaust or bafflectomey might include:

TPS 500 +- 10
pilot/slow jets #48
needles shimmed to .040in
pre-set air mix screws 2.25turns out(then adjust with bike idling accord to manual)

could resolve a lot of questions maybe...haha

 

I have a similar set-up, OEM jets and Pilot, .040 shim.... however air mix @ 2.25 and no popping. Maybe you got air mix out too far out and if you're going to do the proportioning thing for front /rear, you might want to make it more accurate:like 2.50F 2.60R in lieu of 2.75, or better yet 2.25F and 2.30R. Evidently you aren't going to set the air mix while idling, so try my settings and see if that helps. Did you sync again after adjusting air mix?

 

Ok now I'm damn confused by reading this......

First the screws control fuel (this is at least the third time I've stated this in this thread) so turning them in will lean it out and cause it to "pop" even more.

As for the 1\4 turn difference, that is what I use for a base line until it is fine tuned.

Setting the mixture at idle is the way it is supposed to be done, so I really don't get what you are saying there.

 

Sounds like you are on the right track and opening the pilots up a bit more should cure the popping but then you are at the 3 turn setting, so yes the #48 would be a good idea.

 

nath... Sorry, but sometimes you are just a little bit stubborn... But we still like ya...

The screws are for metering fuel... They have nothing to do with air... The closest they get is air/fuel mix... And like it has been said, they are leaner turned in...

As long as you keep thinking of them as airscrews you are going to get into trouble sorting this out in relation to each other...

The difference between cylinders are also individual, no fixed amount... The only constant is that the rear is set richer...

 

haha. I'm a bad boy and stupid too.

yeah I got the part, that they control fuel, but i didn't get the name change to pilot screws. They are not air mixture(where did i learn this? I believe it's been referenced by others before me.), they are pilot screws, ya hear me PILOT SCREWS!

Now my rationale for turning them in is that it also has been referenced herein(I believe I got it from Hawkrider). Anyway, the reason I suggested it was because 2.25 works well for me with #45 pilot jets, so if it works good for me, and his is popping, you see what i'm saying. Anyway, I am going to try #48s and set w engine running as soon as I figure out how to make a tool that works on my now slotted PILOT SCREWS(you like that don't you), and then pre and post sync the carbs.

Relative to the ratio of 173 is to 175 as 2.50 is to X, X would not be 2.75, but closer to 2.60. Now i realize that this is just a starting point for live setting, but for those of us who can't set while idling because of no tool or too lazy or stupid, you may as well put it closer to the same setting front and rear or just a hair more on the rear.

The strange part of it is in terms of my set up is that I have cut the flap and installed a foam filter which likely flows as much or more air than a K&N, yet it pops not and runs strong through the rpm range.

Anyway thanks for being so patient. PILOT SCREWS, no air no air no air no air. See I got it now.

 

This would work with your slotted Pilot Screws......lol

http://www.motionpro.com/motorcycle/partno/08-0119/

 

A little bit stubborn. Just a little bit. thanks for the gentle appraisal. I'm one stubborn *****..........no doubt! and that's one of my best attributes. haha

 

but i have air screws. Thanks anyway though. haha

 

that's it, I've had it with you. Every time i try to help you, I get my *** reamed. haha

cheerio old chap!

 

if you want to little more info:
http://www.superhawk996.net/

then click on vtr1000, modificat, jetting.

and then click onto the Factory link

 

Well this set up will work but once again the information I am passing along came directly from Dan Kyle. If you don't know who he is, well here is a quick blurb from his site: http://www.kyleusa.com/Home_Page.php

Founded November 10, 1997 by Dan Kyle, a master mechanic, who has built a reputation for blazingly fast and utterly reliable engines that have won 5 AMA National Roadracing Championships. Dan was crew chief and engine builder for the highly successful Erion Racing and Two Brothers Racing teams. He has prepared engines for riders Rich Oliver, Fred Merkel, Larry Pegram, Michael Barnes, Andrew Stroud, John Kocinski, and other champions. Dan has twice been awarded the AMA Tuner Of The Year.


So I'll just touch on a couple of quick points. If you want to believe the advice, fine. If you think it's wrong and want to go your own way, that is just fine also.

First, removing the restriction from the header. It is not a good idea. On back to back dyno runs the engine made less power with it removed.

Installing a jet kit. There really is no need. The factory needles are very good, they just need to be shimmed up a bit and make as much, if not more power, with a better curve than either the FactoryPro or DynoJet kits. The only needles the work any better are the HRC units but they are pretty much impossible to find anymore. The kit also has a couple of other tricks in it but hell I can't get you guys to believe this simple set up so why should I beat my head against the wall by trying to defend the other things that HRC did (and yes I run an HRC kit in my bike).

These setting are for a stock motor and if you make major modifications things will change but for the average member you can get as good if not better performance by installing $10 worth of pilot jets and a couple of washers instead of over $100 for a jet kit.

 

nath, You're not stupid, but you may be suffering from a bout of "oldtimers". That can happen at our age.

The correct term in automotives is "idle air/fuel mixture screws", since they are used to adjust the idle air/fuel mixture. But since the last car with a carburetor (Hyundai Excel) was built in 1989, most auto techs today wouldn't even know that.

 

Believe it! The 48 pilots and the needle shim works great! I took Mikes advice on that 6 months ago. I went 2.5 out on the pilot screws, after trying 2.75, but that may vary with each bike and your altitude. Also, keep those carbs clean.

 

Is that compliment, consolation, or a combination thereof? If you keep the cup full, you can't learn anything because you already know it all. If you keep the cup half empty, there is always room for growth through learning. In my case, maybe the cup is leaking. If that's the case, it's just a matter of how fast and how long to ground zero. haha