bostonhawk

I bought my 1998 SH about a month ago. It was somewhat neglected, but I have been slowly reviving it. It is a 1998 with original exhaust and 31k miles. Since I bought it I noticed the following. When I pull out the choke in the morning and start it the rpm are higher, somewhere around 1500-2000 for say 10 seconds and then they slowly drop and idle low, just below 1000. The bike also stalled this morning because of too low rpm. When the bike warms up the idle is probably about 300rpm higher. I have played around with idle speed and now have it idle high, like 1300-1400rpm to compensate. There is also a smell of gas. I thought that maybe it is running rich. I put a new air filter. When the bike is warmed up it runs well. I am wondering if it is something about the choke mechanism/cable that is giving me this problem. Do I need to clean the carbs or is by virtue of smooth running while warm I can assume the carbs are OK? I am not very mechanically inclined and any input would be appreciated.

kardiac996

If you have a full stock setup you are probably running more lean then rich at least technically you should be.

I usually go through all motions when purchasing a used bike especially one that is neglected. Start with service items, Proper oil change, Air filter, Carb clean, brake service/clean, check valves for clearance and adjust if necessary, also battery and amperage, spark plugs.

Spark plugs and battery tend to be never touched and i found swapping these to be a great help in overall health of my bike. When I pulled the diaphragms off my carbs all the old foam from the airbox had broken down and lived in these locations. I would have never guessed that they were just jumping around in there so the latter just makes sense.

Once you complete most of the above you can start gauging actual issues. But since the bike is rather solid and easy to maintain I think the neglect is causing your symptoms.

hope this helps.

bostonhawk

Thanks for the quick feedback. I did change the oil (put synthetic Mobil 1 and used a Puralator filter) and put EBC HH brake pads since prior to that the bike was just dangerous and could not stop properly. When I changed the air filter I did notice some disintegration of the foam on the top of the airbox. I guess my next step would be to look at the carbs and change spark plugs. Since I have 3 other bikes, I didn't want to spend too much time on this, but looks like I will need to.

kardiac996

The previous owner with mine had an airbox full of acorns...

at the end of the day you never know where the bike has been haha

Good luck hopefully it just needs a good carb clean and your back to zipping around.

HRCA#1

BostonHawk please take some time and read 8541Hawks carb setup guide in Knowledge Base it will provide most of the info you'll need, also check your TPS and adjust to 500ohms or less.

bostonhawk

Thanks! I just noticed that about 30min ago. A lot of useful info and the pics are useful as well. It maybe too much for me to tackle...we shall see.

7moore7

The thread is long, seems somewhat complicated, but that's only because he really covers everything from actions to reasons for them. I would guess that you're running lean on the low end as well, which putting in #48 pilots will solve. It would not be a bad idea at all to go through and clean your carbs if it's been sitting. It will also give you an idea of what is already in there.

So if you've got an open day off, get some carb cleaner and a couple of screw drivers. Buy some #48 pilot jets, some epoxy and some washers and sit down and get to know your bike a bit.

HRCA#1

The hardest part is pulling the carbs also be sure to dowload the sevice manual.

bostonhawk

Thanks. I have downloaded the service manual already. With two little children, not sure when I'll get the time to do some bigger jobs :-(

saige

your idle from factory is between 1100 to 1400 rpms,mine is set at 1300.
it is possible the plastic nuts that hold in the needles to the carbs for your choke is broken.this will cause the wire to slop around and not stay on its desired setting.hence rpms go down.
you can adjust the choke *** a little tighter to help keep it in place,but that doesnt always work.once you get the carbs off,you can see if they are broken or not,than will be able to see which way you need to go about it.

syncing the carbs will help a lot too.it is important that is done,along with the air mixture screw.2 1/2 turns on rear,2 1/4 on the front is the starting point.

but overall,take carbs out and clean them before you make new adjustments,when cleaning,make sure everything goes exactly where it belongs.some parts look the same,but dont belong in certain places.clean one carb at a time.

while having the carbs out,it is best to put in manual ccts and take out the pair system.
it really seems like a lot,but it all can be done in one day if you take your time doing it.

here is the manuals and how to's
https://www.superhawkforum.com/forum...-manual-11365/
https://www.superhawkforum.com/forum...-removal-9875/
https://www.superhawkforum.com/forum...pe-ccts-11275/
https://www.superhawkforum.com/forum...-set-up-24769/
https://www.superhawkforum.com/forum...n-sensor-9876/
https://www.superhawkforum.com/forum...why-how-25117/

here some extras.
https://www.superhawkforum.com/forum...erencing-7884/
https://www.superhawkforum.com/forum...cap-mod-23004/

bostonhawk

Thanks for the useful insight and links - much appreciated! Maybe, I will tackle this on day when the weather is bad or when winter comes. As for the idle, I find that after 30 minutes of riding it idles higher than after 10 minutes. I am assuming that 1300rpm is after 30 minutes of riding when the bike is fully warmed up. I should start by playing with the choke cable as well.

7moore7

Just get the little ones to help... couple bottles of carb cleaner with a red spray tip that work awfully similar to squirt guns and a monotonous project with no direct reward for them... what could go wrong?

Jack Flash

Boston, when you takle the carbs, the screws that hold the float bowl, are almost everytime, siezed in the carb body. Use a good screw driver with the right philipps shape, long handle if poissible.

Once you have them off, if you manage not to stripe the heads, use an anti-sieze before reinstalling them. This will allow you to remove them in the future without any problems.
If you stripe the heads, two sollutions, get new ones at honda, or even better, I swapped them with allen head screws.

Good luck with your new project