Finally got to ride it...

Mickey85

XS400 Enthusiast
Messages
71
Reaction score
1
Points
8
Location
Valparaiso, IN
And it sounds like a very angry wasp...

This is a long one...

I only took it down the road and back, but I got it to 4th gear and about 40 mph.

Now, for the problems... The clutch is very on/off. I adjusted it at the chain cover, tightened the screw until it reaists, then back off 1/2 turn, and it still is very on/off. Could it just need broken in after sitting for 30 years?

Also, after going down the block and back, it doesn't want to run off choke, and on choke revs high. I checked for leaks, and didn't find any. The idle screws are set at 2.5 turns as the main jets are rich enough to start without the choke. I did notice before riding it that the right air cleaner boot was wet. Usually this would indicate a sticky float...I've been fighting these Damn floats literally for 9 months. When you flip the carbs, they're loose enough to bounce. I checked the hang and they're within spec.

Continuing on...the handlebars are crooked. They're new bars. I tried loosening the forks and twisting to get them straight, but I don't think that worked.

Finally, I synched the carbs after checking the valve clearance. Of I'm doing the valves right (pretty sure I am) they're right. I got a dual vacuum gauge from mikesxs. I found I had to synch over 4000rpm bc at idle the needles were bouncing halfway around the gauge. Is this normal? What could it indicate?
 
Lots of your running issues are from a vacuum leak. You can balance your carbs at 4K rpms because there is so much flow at those speeds that it naturally balances. Spray some starter fluid around your barbs until you locate your leak. Fix it so it balances at idle and the rest will likely come into line.

Jim :cool:
 
Shot the whole thing with carb cleaner, no throttle response. Now the right cylinder isn't running, it'll occasionally pop. Sigh...
 
Now I fired it up and it ran fine. Backed the pilotscrews out another turn. Shot both carbs, boots, and the entirety of the air cleaner assembly with starting fluid, no throttle response. Decided to take it on a ride, about 6 miles of town driving, stop and go, sub 45 mph. Damn thing is scary! I'm used to a buell that rides like a new car drives...this thing is a 300k mile farm truck in comparison. Anyway, it ran great, good throttle frsponse, started right up, etc. Now though, it seems to be rich. After it warms up it'll idle about 500 rpm, and when I got home it died. It'll start right up with a crank f the throttle, but died again. Wtf.

At this point, I may just ride it around and see if just normal use doesn't bring it around a bit.
 
Make a manometer to sync the carbs. Much more accurate and only costs a few bucks to make. You should sync at idle.
 
I did. It worked for shit. Next time I"ll build one with PVC lengths to even out the pulses.

Regardless, I popped the tops off the carbs and wound them up to shorten them an inch or so - seemed to help the issue of the super low idle.

Further, I think I got the clutch adjusted a bit better...I put on the original handlebars (with a whole lot of sweep), which straightened out the cables more. Readjusted the cables, and I think I got the clutch readjusted. It seems better...the handlebars suck though - not very comfy to me. Maybe the next paycheck I'll shorten the cables and go back to straighter bars.
 
This is like Christmas...after sitting all night at 45ish degrees, it started and puttered without choking, and had great throttle response on half choke.

07ab226.jpg
 
Scratch that...the springs didn't help with the low idle. I adjusted the valves. Weird thing was, using the marks on the alternator, the right side was loose enough to jiggle the rockers around, while the left side was tight. Go figure. So I specced the right side to the right tolerance and left the left side alone. Is it bad if the valves are tighter than spec?
 
Back
Top