Honda CBR600 with stuck throttle when turning right
by, 6th March 2011 at 11:58 (1677 Views)
I regularly attend NASS, and one of the things I have been poor at is slow full lock turns. Recently it felt like I have been getting worse, not better.
At a recent session I noticed I can do left full lock turns much better than I can do right full lock turns. Which got me wondering if it might not just be me.
So for an experiment, while the bike was stationery, I tried holding the throttle open a little bit against the bar end, so that I was confident that the throttle would not move. And as I approach right full lock the throttle started increasing. Aha I thought. When I did let go of the throttle I also noticed that it did not "snap" closed. It was stuck open.
I have Oxford grips fitted, and one of the others present said it might be possible that the grips are rubbing against the throttle body and getting stuck open.
So I waited for the weekend to come around so I had some time to play. First I tried squirting in a little bit of silicone between the grip and the throttle body, in the hope that it would make it slip better.
Well, after a couple of minutes the Oxford grip started rotating freely around the throttle. So I guess something in the silicone spray disolves the super glue used to hold on the Oxford grip. No matter. I re-tested my issue, and it was exactly the same, so now I knew it was nothing to do with the Oxford grip.
Next I examined the throttle cables. There were two of them. There were no kinks, obstructions, and the cable exteriors looked fine. I did discover though that when the throttle was stuck if I wiggled the throttle cables the throttle released.
Then I did a bit of a search on You Tube, and found a video explaining how to lubricate the throttle cables, and how to adjust them.
I was a bit scared about adjusting the cables, but lubricating them sound ok, so I went down to Cycletreads and bought some lubricant for the throttle cables. I must say, it looks a lot like CRC or WD40 ...
Anyway, I took the throttle assembly apart and squirted in the lubricant, and played with the throttle. I did this until I could just start to see the lubricant come out of the bottom of the cables (on the right hand side of the fuel tank). Alas, it seemed no better.
The YouTube video said the throttle cable nearest the front of the bike was responsible for making the throttle "snap" back again. I tried wiggling just this throttle cable when the throttle was stuck, and the throttle released, confirming it was indeed this cable.
I got the bike's user manual out, and tried adjusting the throttle cable where the cable attaches to the bar throttle assembly. Alas their didn't seem to be enough adjustment to make a difference. So I came to the conclusion I needed to adjust the other end of the throttle cable. The other end of the cable is on the lower right hand side of the fuel tank.
I read the user manual, and discovered you can remove the front two bolts from the fuel tank, and it lifts up like the bonnet of a car. You then put a wedge in (that comes in the tool kit) and it stays up. From there I had easy access to the cable. I loosed the nut that holds the adjustment in place, and started turning the adjustment one way (figured I would try one way and then the other). Luckily the issues started resolving itself almost straight away to my relief.
I then checked the throttle could open all the way and snap closed at left full lock, centre and right full lock. Then did up the locking nut again, and rechecked. I was feeling very happy!
I put the bike back together, and went down to Cycletreads again to get some grip glue. I then came back and cleaned up the silicone I had applied to lubricate the grip originally, applied a liberal does around the throttle and grip, stuck it back together again, and left it for the night to dry.
Gave the throttle a test once dry, and everything is working great. I think I have had this problem for a while, but it has been gradually and slowly getting worse so I didn't notice it "just happen". The throttle seems very responsive now. If feels like the throttle is instantly closing when I let go of the grip now.