Dead Spot Help!!
 

Hey everyone im new to the forum i just picked up a 99 Superhawk, i love it but im having a odd problem. if im rolling in around 5k rpms and WOT it bogs out while accelerating and usually straightens out around 7k rpms. if im crusing or accelerating 1/2 , 3./4 throttle seems there is no problems. I Can bounce it off the rev limiter in Neutral no problems no hesitation. it seems only when its under a load.

it has DD Slip on pipes
brand new factory air filter ( emgo generic one)
Dynojet Stage one kit install by a professional shop last week
brand new spark plugs
fresh oil change
all new brakes, clutch fluids.

i thought this would fix the problem it has not.

please help me!!!

did the shop dyno tune the jet kit or just install it, sounds like a tuning issue

the shop i go to does not have a dyno, he installed it according to the paperwork.

my bike did this before i had the jet kit installed , thats the reason i ordered the jet kit was too fix the problem. the bike feels 100% better with it installed, it just has the hesitation at that rpm only on wot- its extremely weird and aggravating. i keep reading on the throttle position sensor and the petcock but i dont know if it connects with my issue im having.

have the carbs been cleaned? might have some residual junk in them that you only suck up into the jets at Wide Open Throttle.


If in doubt - clean them again.

check out the carb setup thread... setting up a jet kit and tuning carbs from what a peice of paper tells you is barely a baseline. every bike is different even of the same make and model...(when it comes to carbs) this is a tuning issue and can be worked out.

Andy I do support clean carbs and clean bikes... well atleast clean carbs...

haha just realized your like an hour away from me, if that.

what I'm trying to say is your going to pull your carbs half a dozen to a dozen times before your happy with how it runs accross the RPM band but even then theres probably room for improvement.

Wish I could be more help but I know dynojet does things a little different and all I know is factory/factory pro

Thanks for the support
 

the shop i got to completely cleaned and and reassembled everything. he said he set them to 2.5 back , one of my needle holders has a tab broken off- the previous owner broke it when trying to put a jet kit in by himself i assume. taking apart these carbs are way out of my skill level. He told me the carbs were disgusting and he went threw them with a fine comb, and i believe him ive been goin to him for like 8 years and hes done jet kits on a few of my bikes. like i said the bikes run great, its moves quick , sounds mean. but if i wide open throttle her it seams only in second gear and third if im almost at a stand still. so im like putting a load on the bike , like rolling at 50 MPH then giving it WOT. its between 5-7. it like studders and wakes up real fast usually around 6.5-7k. ive read so many posts yesterday on this site trying to look up information. my petcock doesnt leak but im wondering if its a fuel delivery issue. ive seen the honda rebuild kits on ebay for about 40 dollars look like it has the two metal pieces assembled with the o rings on it and comes with the one spring. once again thanks for all the help im a newb here, and yah scottie im not far from you. i just got off a 2013 gsxr1000 and got this hawk because i wanted something differnt and i love it just this small issue gotta figure out. :confused:

my mechanic says that this could be just because is carb, that im asking alot of the bike opening it WOT from a standstill. im assuming this quirk could be fixed, i sure hope so.i think im going to attempt to get to my petcock valve see if i can take it apart make sure everything is good, i guess it doesnt hurt to check first.

I know you have faith in your guy but it sounds like he hasn't set up many twins.

They are different than an I4 and add to that the DJ kit and I am surprised you only have one flat spot.

To say it is because the bike has carbs is just silly.
The bike didn't have the issue you describe when stock (if it did all the reviews would have mentioned it) but does have the issue with the jet kit.

So you tell me, is the problem the carbs or how they are set up.

Also don't think you are going to see any massive gains, no matter what you do. You can make it run a bit smoother and pull cleaner but you will only see a couple hp no matter what you do.

As a quick tip, tune for ride-ability not peak HP or you will have nothing but problems.

i bought the bike used from a private sale and it always had this "flat "spot. we did the jet kit because it seemed like the logical problem, at least thats what we thought. the bike runs much better , only between the 5-7k range like i said only on WOT. it studders briefly than goes. she has only 12,000 miles and its a 1999

Read this click here. It's a tuning guide for our carbs. You might even be able to teach a thing or two to your shop guy. Or, have him read that guide.

Try the Blip Test:

1. Start by warming the bike up to normal operating temperature.
2. Blip the throttle up several thousand RPM's or up to redline if you so desire.

As it comes back down to idle one of three things will happen and these are the three results:

1. Upon return to idle it hangs. Where ever it hangs in the RPM's it is running lean. Even a slight hang just before returning to idle means it is running lean at idle.(Must return directly to idle without popping,lag, or hanging).

2. Upon return to idle it goes slightly past and below idle then returns back up to idle speed momentarily. This is a rich run condition.

3. It returns directly to idle w/o any lag, hesitation, or going below idle you have a perfect a/f mixture and run condition.

Keep scrolling down on that link I posted. There is A LOT of information there. There is even links (with pictures) on how to remove your carbs and work on them yourself, if you so desire.

i will look into that, i just pulled my tank and took apart and reassembled the petcock no problems there the diaphragm looks good everything functions great. my TPS i just ohmed it without taking the carbs out it is at 783 ohms. could this be the problem?

when i had the bike together i didnt notice anything on like the blip test. im going to try to set the tps, to 500 then reassemble back then i will try the blip test.

The main issue is the extra lift hole and the short springs that DJ uses.

They don't work very well on these bikes.

Some have said they have got it to work but without a dyno chart who knows how they were actually working.

Not to be a buzz kill but adjusting the TPS will not have any effect on your issue.

Now you say the bike has always had a flat spot.

This is not normal, so now you have the double issue of still trouble shooting the first issue while also trying to dial in a jet kit (and the jet kit you chose has proven to be the hardest one to get to work over the years)

So IMHO you have a slide speed issue.

Hope you get it figured out.....

I just reassembled bike and got her running check this video i just made it.

also i seen your comment and i tried messing with the tps but im not going to get into that right now as its not going to fix my problems and is a pain in the balls.

here is the link. in neutral it seems fine.

quick backstory on my jet kit.
my mechanic said the bike previously had the dynojet kit in it, he removed all old and put the new stuff in. we didnt know it had a jet kit prior untill it was all apart. he said the mixture screws were all messed up not even close to what they need to be. if im not mistaken it had the 180 in front and 185 in back- whatever the paperwork says to use with factory filter and a slip on exhaust system. i have all of the rest of the parts in the kit, all the other jets etc.

in the video is seems to run great but backfires quick when i rev it to 5k fast
also it seems if looking at bike from the rear the left hand side muffler gets hotter than the right, the exhaust from the right seems much colder than the left. im asssuming this is because the right muffler comes from the front cylinder.

https://youtu.be/r-UkmHKtIfI

once again thanks everyone.

If you get down on your knees and look at the way the exhaust is designed, you will see why the left muffler will always get warmer than the right while the bike is idling. I has nothing to do with the tune of each cylinder.

I'm a newb when it comes to these bikes, figured I'd throw that in their wasn't sure thanks I thought they was individual pipes.woops...

So it's not the tps, or petcock. My dynojet settings are 180 in front 185 in rear, and both needles clipped at #4 position. That's what my mechanic wrote on the paper. I called another local bike shop said it was 85 dollars to do a couple runs on the dynojet and 100 bucks an hour to tune it. Damn....:eek:

You dont need a dyno to get rid of the flat spot, you need a dyno to get it absolutely perfect throughout the entire rpm band but you can get it damn close on your own... like hawk said earlier it sounds like you have a slide speed issue and are probably running a little rich with those main jets... the way dynojet does things is drilling an extra "bleed" hole in the slides. Theres already two from factory... you want one hole in the front two in the rear... adjust needle shims according to his carb setup thread. Put the factory springs back in... see how it goes and adjust main jets to suit... your screws are close to where they need to be already

Hey, don't worry about it man. We have all been there.

I have to disagree with Scottie, remove the DJ slide springs and replace with stock. Epoxy the second slide hole on both carbs. Your main jets are just fine for your exhaust.

You have to ask yourself if $185/hr to tune your engine is worth it. Messing with the carbs vs. your time.

Being a young guy with zero knowledge, I would DEFINITELY hit that up.

I don't have factory springs unfortunately. That shouldn't be too hard to do right? What if I epoxy the holes and try with the dj springs

:brownnoser:I thought i said that... maybe i worded it wrong... as for the main jets, I dont know how DJ jet sizes run but like i said, once he has the slide holes filled and factory springs back in to adjust main jets to suit(if necessary)...

You told him to:
I told him to have just one hole on each carb slide. :p

Is he running velocity stacks? I thought the consensus when running the factory different length velocity stacks was to have 1 hole in one and 2 in the other...

Ok so I need plug the new holes made from the dynojet kit. I do not have any of the factory carburetor parts so I'm hoping if I close the two holes and leave the dynojet slide springs in I will be ok. If not I have to buy a factory set of slide springs. I appreciate all the help o Def don't want to go pay some guy 300-400 dollars to tune this thing that would be a waste. I just need it running good to enjoy it, and I love it now can't wait till she all set

Actually, I believe you are right. Oops. Didn't mean to post the wrong information.

I have a spare set of carbs and doubt I will ever need the stock springs from them. They can be yours if you like. Drop me a PM.

Lol... Hawk you crack me up. I actually laughed out loud just now...

Scottie I'm using factory stacks both slides have 2 holes factory I believe I just looked. I'm hoping I can plug these holes with out pulling the airbox I never got that far and really don't feel comfortable doing so.

Your gonna need to pull the air box and pull the carbs... youll know why the first time you try and seat the diaghram seal with the cover and spring ;)

Is it worth a shot trying to plug hole and try it with the dynojet slide springs because I do not have factory springs.

Crux just said he'd hook you up... deal with the flat spot til you get the springs and also recommend #48 pilot jets... please read "carb setup" thread... i know it will be overwhelming at first but you will be happy you did