Hello all,
so here is where I am at with a recently purchased 1998 superhawk, 30k miles. When purchased, the bike was running good, even took it on a 800 mile trip to colorado. Anyway, just recently the bike ran out of gas (low fuel light was out) so I ended up having to run it dry to get it to a gas station, during which the last little portion i pulled the choke to give it one last sip of fuel. Once re-fueled the bike began to run rough.

symptoms: bike will start up and idle fine. once it is warmed up and throttle is applied it has a "lag" or "bog" from the time the throttle is pulled to when the engine actually revs up. when engine is revved up to about 3-4k rpms it usually begins to ping pretty bad. The RPMs do not "hang" when coming down.

during riding, taking off from a stand still is sometimes pretty rough, like it is lacking power. once moving at low speeds 5-15mph it seems to bog and kind of jerks back and forth until you give it a good handful of throttle. On highway speeds during acceleration it seems perfectly fine, UNTIL you steady the throttle in one position, if left in the same throttle position for about a minute or so, the rpms will begin to drop and the bike begins to bog down once again and will have a substantial loss of power. Although if you give it a quick burst of gas the rpms will pick up and once again it will run ok for a minute.
On deceleration it will occasionally have a backfire, but not always.

on a couple occasions when the bike was left to idle for an extended period of time, 15min or so the bike dropped rpms down to about 400-500, barely running and when attempting to throttle up it just died.

WHAT HAS BEEN DONE...

I've removed the carbs and thoroughly cleaned them, PER honda service manual, carb seems to be in stock condition, no mods and original jets. everything checked out, no damaged parts.

Ive also checked all fuel lines and fuel filter in the tank for obstructions, replaced spark plugs, *old spark plugs indicated a rich running condition*, done oil change, air filter. I've also even tried running some sea foam through it and so far no luck. starts up every time, but when i get going it just isnt right, and as of recently I have suspicion that the clutch is about to go out on it also. I would like to get the engine up to par before tossing anymore money at it. I've never had any problems like this on previous hawks.

THANKS IN ADVANCE FOR YOUR HELP AND INPUT!!!!!

 

hmmm.....sounds like the TPS may need to be adjusted. are you sure it was pinging? that would be pretty hard on your motor and may ruin it if you werent careful

 

What is the chances that you sucked some smegma in off the bottom of the tank when you ran it low, and then biffed on the reassembly and have a slide diaphragm out of place or something similar?

 

due to the fact that there is no fuel pump i would think the petcock would always suck up "crud" since its at the lowest point in the tank. so i wouldnt think that it just now sucked some nasty crap up.

 

PVLIR

 

Fact smact, I would be checking the diaphragm's if he took the top of the carb apart. I have seen it go wrong, and the only thing he did was run it out of gas...AND the he worked on the carbs. Me thinks human error whenever I can.

 

lol ya i hear you. im willing to bet the lean condition broke something tho.

 

Just a thought. The Super Hawk doesn't have a choke, it has a fuel enrichment circuit. I had an issue with mine when the "choke" cable became separated at the point where it splits to run a line to each carb. I had the carbs off and apart 4 or 5 times and couldn't find the problem because it wasn't in the carbs. I didn't actually see what had happenned, but apparently, the line kind of snaps apart and then even though you think the fuel enrichment has been turned off, it hasn't and you're running too rich once the motor warms up.

My mechanic found the problem and I haven't had an issue since.

 

ahh, yes the point at which the cable "y's" into two can seperate and leave you on half pull. you MUST make sure to check this as you put it back in. any choke will cause major problems.

 

weird. glad it got fixed tho.

 

I was going to suggest the same thing.. Look at the cheap & easy first.

My guess, you never got the "choke" back off.

 

By the symptoms I would start with the pilot jets. I does sound like they are clogged.

The passages are very small and can be difficult to clean.

Yes there could be some reassembly problems also. So your best bet would be to pull the carbs again. The first test would be to lift each slide with your finger and let it go. Does it just drop closed? Does one close at a faster rate than the other? If so you have a diaphragm issue.

If both move at a controlled and equal rate then the problem is jet related. Of course this is all reliant on having the carbs mounted correctly. You can also check the choke cables at this time.

The other bit to check would be the emulsion tubes. This is the part that the main jet screws into. They also have some very small holes in them. Just be careful as they are different from front to rear.