Throttle stop screw knob is completely frozen

Decided to do a PAIR valve delete and synchronize the starter valves on my 08 VFR800A. Removed PAIR equipment and added block-off plates with RTV sealant, it seemed to seal nicely. I also yanked out the flapper valve equipment while I was at it -- hoses, the valve and the vacuum canister, and plugged the hole at cylinder 2 with a vacuum cap. Ready for the synch, I started it up and observed that the idle was very low, maybe 1000 once warm (on dash tach) -- of course still stripped down to the throttle bodies. I tried adjusting the throttle stop screw knob on the right near the clutch cover, but that thing is completely seized up, can't turn it in either direction. I was able to trace the cable to the wax unit (?) under the throttle body, it seemed to be routed fine, no snags. I can see threads on the top side of the wax unit (?), indicating I believe that there is at least some room to turn the adjuster counterclockwise (which would lower RPMs), can't tell if it's maxed out clockwise though. If I twist the adjuster, the entire cable will just wrap around several times without budging the threads on the other end. I've tried doing this while engine is warm (by manually holding throttle to 1500 until warm) and cold, no luck.

Can anyone help? My first problem is getting that throttle stop screw knob unstuck, then I need to figure out how to get that idle to spec. If the adjuster is maxed out, then maybe I have a vacuum leak or I pulled something I shouldn't have? I yanked a lot of stuff between the vacuum port on cylinder 2 and the flapper valve. Other than that, I have vacuum lines going from each cylinder plugged into my Morgan Carbtune, I can't see where else I could be missing anything.

It ran fine before all this with maybe ~1400 idle on tach, what caused me to dive into all this was that the throttle was super snatchy at low throttle. No FI codes before this, now I'm just getting the map sensor and air temp sensor codes because they're unplugged to do the starter valve sync. Thanks.

 

Mine was stuck too when I bought it, but a bit of WD-40 cleared it up. You need to hold the plastic part still, while turning the phillips head screw inside it clockwise. It's real sensitive, so you'll barely need to turn it at all.

 

Tried PB blaster and WD-40 more than once through the wax assembly and the throttle stop screw knob. If I grip the black plastic knob still, I have only about a mm play in the screw back and forth, I've tried strong-arming that thing to death both directions and it feels locked solid. I also tried my old method of twisting the entire knob and screw assembly as one (Which seems to be how others in various forums suggested it?), that still just coils the cable around and doesn't do anything.

I'm completely stuck here and almost out of ideas. I think I might remove the throttle assembly and get a closer look at the wax unit. It looks like I can replace the wax unit and adjuster for $80, I may just have to do that -- very frustrating though.

 

For anyone who might read this in the future, I finally got it out, almost a month later. All of my efforts to get the adjuster knob to work were useless (I do not believe that the previous poster was correct in asserting that the screw moved independently from the knob, they seem to work together). Just a little background info: The adjuster assembly is a knob on a long cable that ends with a threaded rod with a narrower tip. The tip of the rod pushes against a plate, which in turn cracks open little air holes (starter valves) for each cylinder which bypass the throttle butterflies, permitting idle. So the end of the adjuster unit is not attached to anything, it just applies pressure.

After much effort and research, I eventually ordered a new adjuster from the Honda dealer and worked my way down in. I drained the gas tank and set it aside, took the fairings off, popped the throttle body off, removed everything except the fuel hoses and the evap canister lines (CA model) and finally was able to flip the throttle body over. From here I could get a large pair of pliers over the base of the adjuster and force it loose. Now, it took a GOOD amount of force directly with the pliers to get that bugger to turn, there was no way in hell the adjuster was ever going to cut it. The assembly just slides right out once you've completely unthreaded it. With the old unit out, I see the cable inside the black rubber sheath has been severely damaged from my strongarming it, and now has a permanent coil in it.

So, on to the rest of the job. But what a bugger just to get the adjuster working again, sheesh. I hope this unfortunate information helps someone else one day.

 

Hi Jixig


A couple of things

Firstly a big :thumbsup: for coming back with an update on this. Sadly many forums have threads which end inconclusively, simply because once the issue raised in the original post is fixed they forget to provide an update explaining precisely how the issue was solved.

Second it looks like you missed out on an official welcome to the forum - so WELCOME to the MadHouse :welcome:

When you get time please swing by the "introductions" section of the forum and say Hi to the rest of the folks on here, and maybe post up a photo or two of your vfr (its easy - click the "insert image" icon and follow the prompts to select and upload images from your computer).

You may also want to update your forum profile (Forum Actions/Edit Profile) to include the specs of your VFR and a rough location (city/state is fine). That way the information will appear automatically alongside all your posts, and if you need help with a problem you may find another forum member lives nearby and is willing to drop by and offer help/advice - especially if you have a well stocked beer fridge!

Meantime hope the rebuild goes well and your VFR is back on the road soon.

Take care ATGATT




SkiMad












and welcome to the forum