Superbroke

The symptoms are: Its most certainly running rich judging by the smoke coming from the exaust at higher rpms. it likes to buck, and kinda stutter at steady throttle throughout the rpm range. at extremely high rpms it also likes to choke and stutter. most of the symptoms are affected by engine temperature, the hotter it gets the crappier it seems to run, when its bone cold it rides pretty close to par, save the occasional sputter. it stalls somewhat rarely when coming to a stoplight. It seems mostly unaffected during deceleration and during acceleration it seems ok, except a stutter here and there during modest acceleration. It also likes to run with a dead cylinder when i first fire it up in the morning but the other cylinder catches up within a few seconds. The bike idles pretty clean but likes to pop just a tiny bit in predictable intervals. when letting out the clutch during take off it sputters and just dosent like to really take off until the clutch is withdrawn and im actually moving. The bike despises running below 2.5 grand at steady throttle, it feels very choppy. One important detail is that i have is that there is no TPS on the bike currently as it is completely broken, and in dire need of replacement(if u can find me one i would be your best friend forever). Surely all these frustrating problems cant all be related to the absence of a tps right? or wrong?? Lemme know what you think. im a crappy auto mechanic, so i can probably execute most any task on a bike. Please help me my bike is running so shitty im getting 22.5 miles to the gallon.

Bluesuperhawk83

pull the carbs and clean them.

7moore7

Sounds to me like you would want to look into it being a choke (enrichment) issue- I would inspect your choke lines and make sure that they are not partially stuck open at any part- either at the "y" where they split or where they enter into the carbs.

msethhunter

Replace the TPS, clean/synch the crabs, new plugs, etc. How long has the gas been in the bike? What color is the smoke?

Superbroke

Its my daily driver so the gas is as fresh as can be. The smoke is black.

8541Hawk

What size main jets does it have in it? Did someone try to install a jet kit of some kind?

msethhunter

Pull the carbs off, clean them up, and report back with what jets are in them. Sounds to me like they just need a good cleaning/adjustment.

If you want them clean as a whistle, get some MEK, take ALL the rubber out of them and soak them in the MEK for a few hours. Blow them out with some compressed air and a can of carb cleaner, and re-install them after you figure out what jets need to be in them. DON'T take them off of the rack. Leave them as an assembly if you can.

PUSHrod

Overly rich and the ecu has no idea what to do with the ignition because it has no idea what you are doing with the throttle.

Never hurts to have clean jets and circuits in the carbs, but I'm betting the low speed circuit is at least partially obstructed. Is it happier with partial choke? Big clue there.

lazn

Also is the airbox stock and are you running an aftermarket air filter?

8541Hawk

I just love tinkering with carburetors! Yeah, I know ->

I also like to tune for 'rideability' rather than horsepower. Roll on / off in turns is what's most important. If you wanted more HP you would have bought a different bike, right?


Here's what I would recommend.


0- go buy three or more cans of carb cleaner from kragen / OSH / etc.

1- tank off, airbox off, carbs off. Take them off as a unit, you can keep all the linkage and bracketry in place. Clean 'em off. Go on, use a whole can!

2- remove from each carb the float bowl, jets, needle jet holder (also known as the emulsion tube), float and needle, fuel adjustment screw, diaphragm cap and slide and blow it through thoroughly with carb cleaner and if you have it with compressed air. Now do it again because you missed a bit! Before you remove the fuel screw turn it in until it gently seats while counting the turns. Should be about 1 3/4 turns from stock. When you back them out to clean in behind them there will be a spring, washer and o-ring. If you're lucky they come out on the fuel screw, if not use a probe or a straightened out paper clip to fish them out. Also do one carb at a time or keep the parts separated as there are a few bits that are different between the front and rear carb

3- replace the float needles. They need to be replaced every 2-3 years IMHO.

4- set the fuel screws per the jet kit instructions

5- reassemble, ideally with a fresh air filter.

6- reassemble the tank, etc.

7- sync the carbs with vacuum gauges, manometer or twinmax.

8- warm up the bike, set the idle speed to about 1,000 rpm, fine tune the fuel screws to get the smoothest and fastest idle.

9- re-set the idle speed

10- go ride

AK Ronin

I had almost the same exact symptoms just by running a K&N airfilter on my bike with aftermarket exhausts and a stage 3 jet kit. If the carbs are good, might wanna look into getting a new air filter or see if anyone has modded the air box, of course after you get your TPS thing figured out.

Superbroke

Thank you all so much, i think ill pull the carbs tomorrow afternoon and get back to u guys at nite. everything on myy bike seems to be stock on the air and fuel delivery side, it has two bros slip ons, can backpressure effect drivability dramaticly? the bikes pretty rode out at 47k so it wouldnt surprise me if routine maintenance is all it needs. Also can anybody give me a lead on a used tps? the best ive found is 65 plus s n h.

7moore7

You may be able to pick one up from someone parting out their bike...

https://www.superhawkforum.com/forum...art-out-25199/

Or just buy the set of carbs that this guy is selling... 100 shipped gets you a lot of backup parts...

Superbroke

Carbs are clean. jets are 182k(front) and 185k(rear) after some diagnostics ive found that the rear carb is the problem as i put my hand over the front carb and it died but i did the same with the rear and it continues to run, mostly unaffected by the fact that my hand should be smothering the poor bike to death. Im very frusterated and i cant bear to ride my bike as it is now any longer!!

7moore7

Could be an improperly seated diaphragm or even a torn one. Sometimes it happens when you re-assemble the carbs. Push up on both of the carb slides; they should slide back at the same rate.

If not, the fast one isn't seated properly, and you just gotta take the round black cap off and make sure to get it in there right.

Superbroke

ok so i broke down and bought another set of carbs and new set of problems along with it. immediatly upon putting the new carbs on the bike ran alot smoother and most of the misfiring ceased. now the problem is that it seems too lean. the bike wont accept any sharp throttle increase unless i pull out the choke or partially block off the airbox. there also seems to be a great deal more popping out of the air box(ususally during steady throttle) and backfiring. the backfiring i can deal with but the airbox backfires are messing it up and causing misfire. the bike only runs and drives well without choke when i partially block off the air box opening, and it seems alot better when i do this except it still coughs out the airbox, and the top end is nowhere to be found. if i dont block off the airbox it runs like dirt when not in motion buts seems pretty sweet just driving along(plenty of top end and low end) except for the airbox farts. im really not sure where to start with this problem. perhaps my pilot jets are too lean? please help, im dying to have this problem fixed so i can ethier ride the pig or sell it for what i paid, and get something fuel injected(EFI is so much more forgiving!!).

Thanks -Nick

killer5280

You have never really addressed your problems. You have just traded one set of problems for another.

lazn

https://www.superhawkforum.com/forum...-set-up-24769/

geekonamotorcycle

clean and set your carbs man. It really is very very simple.

8541Hawk

Did you take the new carbs apart and clean them or just throw them on?

It sounds like you just installed them. In which case, the pilot jets sound like they are clogged and maybe some of the internal passages also.

So first step would be to pull the carbs and clean them (who knows how long they were sitting and if the fuel was drained before the sat that long)

You can use the carb set up thread, if you want, while you are in there.
Or you can put it all to stock (though I would just replace the pilot jets no matter what as they just are too cheap to waste a bunch of time trying to clean them out) and have a base line to start your own tuning from.

As for the TPS, yes you want to get that replaced. Not running it will not cause the problems you are describing but it does make the bike feel a little flat, which just adds to the issues you are having.