Now that Bill has passed, who takes up the mantle of local tech guru

[thewoodman]

I have two issues it seems.

1) On a 4 day trip around mid-Florida this past weekend, I had an interesting throttle issue crop up. Some background history might help with diagnosis. For the past few months, my ear has detected a slight exhaust note change: as if one cylinder was not firing correctly; maybe a bad plug, or a bad spark plug wire. Subtle with no noticeable performance decline. New wires are on order and a compression check found nothing concerning. Though I don't recall the exact result, there was no more than 5 psi difference. 180-185 I think I remember.

So, this past weekend, on a slow gear change, the engine actually revved higher between gears and wouldn't slow back down from there. It now idles at about 1,200 RPM which is 400 RPM higher than set. It has a strange exhaust note at idle and almost a backfire pop on deceleration. With grump not with us any longer, I'm asking for opinions and directions on how to narrow down the diagnosis. Any thoughts out there?

Also:

2) I need a new exhaust system since I found a hole in the front left header pipe and unless I can patch it, it's time for new pipes for the old girl. At 24 years old and with
115k miles. I guess it's time. So, if anyone out there knows of a decent set of relatively unmolested stock pipes, please keep me posted.

[John Schmidt]

Look for vacuum leaks, especially if the bike hasn't been desmogged.

And...if you are running the thin-walled aftermarket exhaust then a vacuum leak can also atribute to hot running and possibly be part of the cause of the hole you refer to in the post.

[Skinhead]

Look for vacuum leaks, especially if the bike hasn't been desmogged.

I agree with John.  A vacuum leak will increase your idle, especially if the bike was running rich to begin with.

[Thunderbolt]

Agree with the experts that have commented previously.  Tighten all the bands/clamps, three on each cylinder.  Change the intake O-rings.  There are some short vacuum lines on the carbs that if I remember right have something to do with the cut valves, they are only about an inch or so long that don't always get changed when the other vacuum lines get changed and if you remove one you will see that if you squeeze it cracks will appear.  If you still have the oem petcock the vacuum line should be changed that operates it also. 

[thewoodman]

You all have confirmed my meatball diagnosis; being a vacuum leak related issue. Bill and I desmogged it a few years ago so, hopefully that eliminates a few places to look. I was about to replace the timing belts and install new plug wires in a few weeks anyway, so, while the tank is off, I might as well replace all the o-rings and the rubber connectors between the carbs and intake runners. They are all original. Looking for vacuum leaks isn't my most favorite thing to do; kinda like chasing an electrical short that comes and goes.

Exhaust is original, double wall and has seen it's better days. Found close to new in NJ. Time to replace them too.

That's the problem of living in Florida; No downtime from riding to take machines off-line for needed maintenance. Probably should have a second Valk if I had the space to park. Thanks to you all.

thewoodman

[John Schmidt]

Not sure why you're pulling the tank, replacing belts doesn't require it and as for replacing plug wires, not necessary. We have many members with a lot more miles on their bikes and still running the original wires. Same applies to the rubber connectors, they don't wear out. Re. the o-rings, I assume you're talking about those where the carb runners attach to the cylinder head. That can be done without removing anything, just loosen the six bolts on one side then go to the other side and remove the six on that side. You can now lift the carb bank and R&R the o-rings on one side. Replace those bolts and screw them down most of the way, leave them slightly loose and repeat the R&R of the o-rings on the other side. You have to loosen(not remove) the bolts on the side not being worked on to allow you to lift the carb bank on the other side. Also check the caps on the back of the carb runners, they cover the vacuum ports and will get hard as a rock and crack.

I'm a firm believer in "if it isn't broken, don't fix it."  Some folks will "fix" stuff until it is broken!

[BCoy]

I would verify that all the desmog plugs are still securely in place, I had one vibrate out less than a year after mine was desmogged. Just my two cents.
Ride safe,
Bill

[thewoodman]

The reason that I put it out there is for the group thought. Everyone knows something and/or raises a point. the reason that the tank is coming off is that since I have the bike in a refresh mode, the air cleaner needs change and to clean what got cruddy since the last time I've been under there. thanks all for your input.

WM

[agrady1995]

I haven't been on this forum long but I own 2 Valkyries and am a maintenance technician by trade. If anyone in the Florida state wants to hire me out to come and do work for them, let me know. I have never owned a car, but I can show up with all the tools and parts needed. I just wrapped up a job in Zephyrhills doing a complete carb cleaning, replacing all rubber parts, syncing ( I own a digisync and a 30L ultrasonic cleaner)...


Contact me if anyone is interested!