I have a '99 Superhawk w/ 38k mi and as the title says, it seems to bog down between 6 and 7k rpms. There is plenty of power above and below but every time I'm in that range I lose power.

Is this a carb sync issue?

I just bought it so I haven't figured everything out yet(also it's in storage for the winter) but I'm also feeling a 'miss', like the engine stops for a millisecond, usually at lower rpms. It is completely random and I don't believe it happens when it's fully warmed up.

p.s. the cct change sticky thread(https://www.superhawkforum.com/forum...pe-ccts-11275/) seems to be missing its original pictures, but the 'strip down' thread(https://www.superhawkforum.com/forum...restorm-26597/) I think has basically the same thing.

 

Since the bike is in storage, a good carb cleaning is in order. And since you have just bought the bike, change plugs while your at it.
Do you have the bikes history, meaning, what did the PO tell you about it ?
Was it daily driven or stored for long periods of time ?


Once your inside the carbs, check what's in it main jet wise, and, idle jets. Order new ones if they are fairly dirty. They are not that expensive, and easy to get. Once done, sync carbs again and test ride if problem is still there. From what you mention, it may be a lean syptom caused be dirty internals. Also, use the search engine. There are more than one person on this forum who have encountered this problem.


If you follow the steps Calitoz explains in the Knowledge Base, you will be fine. No need for pics. The hardest one to change is the front. Kind of a PITA since you have to work your way around the forks.

 

Also: do you have the PAIR system still installed? What kind of air filter/exhaust does the bike have?

It would be good to know whether the carbs have been touched, especially the mixture screws.

Also, if you do a search you will find my post on modifying the oem ccts, converting them to manual. Done with simple garage tools, for less than $15.

James

 

Sorry I just skimmed technical pages to see if there was anything like my issue, search would have been better.

Had hoped to avoid the carb clean since I just did it on my Nighthawk but at least it only has 2... Plugs are easy enough as well so I'll do that.

The previous owner had in storage for a month or 2 before I bought it and had taken it to DC and back from MI before it was stored. He rechecked the valve clearances at about 25k mi and synced that carbs sometime in the 10k mi before I bought it. He did leave some hoses in connecting to the carbs so he could sync them easier and after reading I'm guessing it could also be that those have rotted and are leaking air into/out of the system.

I have not been in the system to check if the PAIR system is still installed and haven't checked the airbox/filter.

It just has the standard exhaust.

So my list should be:

Spark plugs, Airbox/filter, PAIR removal, carb clean, and CCT's to hopefully get her running all well and safe?

Thank you

 

Yes, also check those vacuum lines like you mentioned. They need to be plugged when not syncing the carbs.

James

 

So at the VERY LEAST you should
1st) march out to your garage and drain the fuel tank. Preferably til totally empty (shake it upsidedown after syphon. Its not that hard but if you dont do this you are doomed to crap in your carbs til you do it.

2nd) You should drain the float bowls as thats where all the gunk is sitting and contaminating your bike.

It is not a carb sync issue. These carbs are are not super hard to clean but thats the next step.

Add some techtron fuel system cleaner or some good quality fuel cleaner. First one to remove water then one to clean carbs. Fill the tank with premium gas (non ethanol if you can find it)

 

check the timing
being 180 degrees out can give the same symptoms

 

Would you elaborate on this please.

 

xeris if you just ignore it, maybe it will die quietly.

 

I hope you're just talking about the cam chains, but maybe ignition timing? I will be replacing the tensioners and definitely checking the timing.

 

Hondahawk, all things being equal you will see no difference by changing the ccts. In fact, you should NOT do it until you have solved the feuling issue you have now.

The chance of some wacky cam chain issue causing this is less than winning the lottery. Start with the basic things then work your way up.

Yes you could have bad pistons, warped crank or conrods but any evaluation of that is way down the line from clean you tank then your carbs.

CCTs only let the cam chain continue doing exactly what it should. It is not a fix for poor powerband performance. It just doesn't work that way.

 

smokinjoe, yea I was not going to change the tensioners to fix this issue, just as a preventative measure. At 38k miles, from what I've heard, I'm lucky they haven't slipped and destroyed my engine? And my Haynes manual says they should be changed at 50k mi anyway.

The other reason is I'll basically be at the tensioners when I pull the carbs so i figured might as well do it?

 

hi hondahawk
over here on the vtr1000 form there was a member that had his timing set 180 degrees out after he changed the ccts he rode the bike for a year or so before asking why the bike bogged down at 7k he was told to check the timing and it was found to be out by 180
apparently some Honda garages can get it wrong to

like others have said give the carbs a good clean first and when your at it remove any dirt or water which may be it the tank
dirt and water was the reason my bike would not start after i had just bought it
a carb clean sorted it out
hope this helps