Vacuum hose adventures

[Will]

My bike has been giving me headaches since I put a quarter turn throttle on it. The quarter turn throttle came with a cable which didn't last, and eventually made the bike nearly unrideable. Nothing like more than 100 hp, minimal weight, and an unpredictably abrupt throttle which slams open and then is hard to shut again.

So, I put the stock throttle assembly back on. Swapping out the throttle cable is a royal PITA, as those of you who have done it know. You have to remove the tank and airbox, then remove the throttle bodies. There is a boot which is hard to get at to remove. And then there are all the vacuum hoses. If you ever take it apart, make sure you put them back in the right place...

So, I got it all back together, and found it very difficult to start. Since I didn't have a whole lot of time to mess with it, I didn't ride it much, and it mostly sat, neglected. I felt bad, but with it's behavior, it was going to kill itself and me, too. It wouldn't hold a steady RPM no matter what, and it surged like a tsunami in a bottle at just about every steady throttle opening.

Finally, this past weekend, I got some time and a place to work inside to pull it all apart again. Sure enough, I found a vacuum hose disconnected. I can see how it got disconnected during reassembly, since it was close to some other hoses and wires which probably caught it and pulled it off. It almost came off again this time, but I was looking, caught the problem, and put it back together before reassembling everything. I hate pulling the tank, since wrestling with the quick disconnect isn't my idea of a good time, so I really wanted it back together as it should be.

With a freshly charged battery, the bike fired right up without a problem. It took a while to warm up, and I'm sure the fuel in it isn't the best now, but it runs just fine. Now it's back to the fun stuff, like figuring out what map I really want to have loaded.

Nothing like mechanical adventures to keep you humble.

[shaunthesoundguy]

I wonder if that is the problem I have been having.

I was installing the APE cam chain tensioner to get rid of that vibration and I let the chain lose tension and it slipped a tooth. So I had to dig in there to reset to reset the cams and chain, and while I had her apart I decided to balance the throttle bodies, remove and plug the secondary air injection, and remove and plug intake flapper. Ever since then I have had a check engine light and an odd surge of power around 2500-3000RPM, and a terrible stutter around 5500RPM that if I try and hold the throttle there or decelerate down through that range the bike does this awful surging. Havi

Thought it was maybe EXBV related so greased that up, but didn't make a difference.
Still have a CEL, and have since moved so dont have access to my friends tuneboy anymore to know what is causing the light. But that isn't really my concern, I just want to get rid of this power surge because it is making the ride less fun, having to avoid 5500RPMs makes riding around town a disaster ... only seems to be noticable around that RPMs...

I guess I should dive back under the tank and take a look and see if I've knocked off a vacuum line, but that wouldn't cause a CEL would it? So it must be something else...?
I'm stumped.

EDIT:
Also, I'm anything but mechanically inclined, this is the first vehicle of any kind I have worked on myself. Had the aid of the manual and a friend here and there to get that much done. I really enjoy doing it myself, and can't afford a dealership to look. But I'm worried that maybe I crossed something up or who knows.. The bike seems fine if I keep her wound up and avoid riding below 6000, but as a commuter bike that is next to impossible.

[TripleThreat]

Will, Glad you got it sorted... Please don't neglect her... She begs to be ridden and ridden hard...

STSG... Yes, a loose vacuum line will cause a CEL. Sounds very likely that your problem is vacuum related... Give it a look!

[shaunthesoundguy]

Thanks for the quick reply TripleThreat.
Didn't realize that the computer would know if a vacuum line was connected or not, I guess it makes sense though.
Will have a look and see, hopefully it is obvious and one of the ones under the tank and I don't have to pull up the whole air box.

[TripleThreat]

Check the line that runs to part # 23 - Vacuum Solenoid.



Or parts 9 (that mounts on the back left corner of the airbox), 13 (3 way fitting) & 7



Jeff

[Whisky_Richard]

Originally Posted by shaunthesoundguy

Still have a CEL, and have since moved so dont have access to my friends tuneboy anymore to know what is causing the light.

The bike is OBDII, so any scanner will work. You will need the manual to decipher the codes tho. The OBDII scanners can clear the code too. I used one to see the exup valve throwing codes...