Can't get it running right!
 

I bought this Superhawk after it wasn't started for 3 years. I brought it home cleaned the carbs, replaced the fuel, replaced the spark plugs and installed a new battery. It fired right up. But, when I ride it, it pulls to about 4500 rpm and then runs like crap to redline. If I accelerate slowly it is better, but not right. Also it backfires a lot during deceleration and between gear changes. I went back and did the carb set up like suggested here and it idles perfectly smooth now, but still has the other problems. The bike is stock with a slip on muffler and I have worked on bikes for decades, but I can't figure this out. Help!

Have you looked to see if the airfilter needs replacing / cleaning if aftermarket.

Check for air leaks in exhaust/header system and carb intake.

is the timing right? (can easily be set 180 out, esp after head rebuild if CCTs have failed)

Are the vacuum hoses correctly fitted, not kinked and intact.

Perhaps the vacuum line to the petcock is sucking on the wrong nipple.

Everything you guys mentioned I have checked except the timing. If it was 180 degrees off I wouldn't think it would even run. The air filter is clean and oem. It only has 10k miles, so I would think it couldn't be something major. It realley fells like a needle problem, but the bike is pretty much stock and I've never had a slip-on cause a bike to run this poorly.

www.vtr1000.org • View topic - Timing 180 degree's out

If you're convinced the carbs are responsible, and eliminated the usual suspects, then take a gander at these threads:

https://www.superhawkforum.com/forum...leaning-27529/

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

Are the diaphragms seated properly in the carbs?

If they are I would then check the filter screen in the tank and the petcock to make sure the diaphragm is not damaged and that it is in the full "open" position

Diaphram is good and I sucked on the petcock vacuum line and gas poured out. I am going to check the timing even though this motor has never been apart. Maybe one of the CCTs is bad.

What about the carb diaphragms? It sounds like you know how to check if they are seated properly but did you check to see if one of them possibly has a pin hole in it?

Of course the other obvious question, that still has to be asked, did you sync the carbs?

Ask me how I know of this situation :rolleyes:

If it was a CCT gone wrong you'd know about! Add that on the list of items to replace pronto with manual CCTs along with R/R (if you have an early unfinned one)

Are you sure the carbs are back on securely and the seals aren't hardened/perished, causing leaks?

For my 2 cents, did you make note of which needles came out of which carb and did you put them back in the same? They are different sizes front to back.

Check for blockage in the float bowl vents, and make sure the slide vents are not obstructed where they plug into the airbox.

You have twice mentioned the slip-on. This bike has dual mufflers. Has someone done a poor job at converting the exhaust to single?

I hack-jobbed mine into a single when the clamp on one side broke, and with some tuning it still hauls ass (and the bike is lighter than before).

PVLIR! Yes...be sure the petcock vac line is on the sideways nipple, not on the bottom nipple of the petcock :cool: It happens all too often.

Wanted to add about the Emulsion tubes and mains to check they were in the correct carbs as well. I dunno how far apart the carbs when the OP cleaned them, but it's something else to consider looking into if it wasn't already mentioned.

Everything in the carbs is correct. I checked the numbers on the needles and made sure the emulsion tubes were in the right place. The carb boots are good too. I do have a single exhaust, but I have hand made plenty of custom undertail exhaust with no problems. Also the idiot I bought it from was running with no mufflers at all and he had no complaints about it.

Have you pulled the plugs and checked them?

If you say everything in the carbs and fuel system is fine then the only other thing is the ignition system, which would mean bad plugs or an issue with the coils or plug wires.

Are the wires push firmly in the boots? You possibly could pull the wires out of the boots to see if there is corrosion at the end of the wire also.

I changed the plugs. I was starting to wonder if it wasn't a coil problem too.

The plug wires just push into the boot, so I would first make sure one didn't get partially pulled out when you reinstalled them