A little VFR Maintenance

My 2007 anniversary bike is running strong, but I've been chasing some random hard starting issues on the silver 2008 bike. Sometimes it didn't want to start cold, sometimes hot. But because it starts fine hot sometimes, I am not worried about a valve adjustment. In fact, I plan to never do a valve adjustment on it.

I pulled every connector I could get to and inspected them. Wires were good, nothing burned, connectors were clean inside. I gave them a shot of DeOxit and reassembled. I did a starter valve synch as well. Replaced the old hoses with some silicone while I was in there, but I'm not pulling the assembly to get to the boots until I have to. Yes, I did eventually get to those last couple of vacuum lines and replaced them. I should have taken another pic afterwards but I didn't. I got a good sync on the starter valves and buttoned it up. I did a few short test rides with cold and hot starts and found that it started ok, but cold high idle was non-existent. In fact, It started at about 900 to 1000 rpm and warmed up to 1200.

I read up on the wax unit and everywhere I looked, people said not to adjust the factory set adjustment nut. Then why is it adjustable? Lol. With the VFR.D crash, I didn't have the luxury of checking the wealth of info there. I couldn't really make things worse than a non-working wax unit, so I went out on a cool 68 degree rainy early morning and tore back into it. The linkage was free, but the wax unit plunger was floppy loose. It should be tight and pulling the starter valves when cold. I started the bike and adjusted it to about 1500 rpm. I let it warm up and it settled back down to 1200 rpm where it was supposed to be. I shut it off, threw a fan over the top of it to help cool everything off quicker, and worked on other stuff for a couple hours. I came back and gave it another start, popping right up to 1500 rpm and warming up to a nice 1200 rpm idle. I figure I may have to adjust it again this winter when the engine is cold soaked down around 40 degrees where the wax will be shrunk up a little more. The thing may end up running too fast at startup.

The battery that I put on a couple months ago does seem weak, so I think the combination of the battery, not really noticeable but weak contacts on connectors, and out of synch starter valves have all contributed to the issue. I've ridden it on a dozen or so short rides of less than an hour and it has started good every time, but the voltage does drop more on startup than with the other bike. I may switch batteries on them to see how fast the thing spins up with the other battery.

Yes, I have brown recluses, so ignore the whispy little webs in the pics.

 

Sounds like a good diagnosis on the wax unit. When cold, it should be pulling all the starter valves open against their return springs, so no slack beween the nut on the shaft and the linkage. I had a different fault, where a couple of the SVs had actually seized in the part-open position, and when I cleaned those I lost the adjustment of the reference SV and had to go a few rounds of adjustment before I got it all settled down again, the happy point where the cold idle was a decent speed and the idle speed dropped before it reached operating temperaure. I get a cold idle of about 1800-2000rpm when cold, and aimed to get the SVs to drop back onto the idle adjuster screw when the temperature was 45-50C.

 

What did you have to do to clean the SV's and free them up? I sprayed a little penetrating oil on the linkage, but nothing into the valves themselves.

 

Penetrating oil and a little "percussive maintenance" got them free. I assumed they got stuck on old dry fuel residue or something. When your engine is hot (and the wax unit has stretched out) you should be able to grab the linkage and move it against the SV springs, easy to see if they're all moving or if there is some binding somewhere.

 

Good to know. I worked mine when the wax unit was hot and everything moved freely. I assume each valve was returning all the way down because it settled into the same idle speed every time.