legendary yamaha
IG:ne_caferacer_club
I noticed that the choke went off, so it’s not running only in choke, but it shouts down anyway
-
Enjoy XS650.com? Consider making a donation to help support the site.
XS650.com receives a small share of sales from some links on this page, but direct donations have a much greater impact on keeping this site going.
need help with my '77 xs650 Not idling and blinkers stay solid
- Thread starter legendary yamaha
- Start date
your tickover or idle sounds a little too slow . try adjusting it to the recommendation ...around 1200rpm You can always lower it slightly later once you have added the correct jets and synced the carbs correctly and set the air/fuel mixture to around 14.7 :1 .
are you sure that you have fitted the metal shroud underneath the adjustable clamp band ?
legendary yamaha
IG:ne_caferacer_club
Yes, 100% can get other close up pictures tonight.
I suspect you would benefit from some new clamps. After 40 odd years of being clamped up the metal will have stretched and there is probably insufficient gap left for adjustment.
if you cannot obtain a replacement and you cannot tweak the clamp you can as a temporary measure wind some thin tin as a shim around the stub beneath the clamp band and on top of the shroud to give you a little more adjustment on the clamp . It will need a little fiddling until you get the right amount of shim length and thickness. I'm sure I am not the only person to have used a pair of tin snips and a baked bean can to create a shim before now lol
looks like you have some back firing out of the exhaust. There are several possible causes , typically it could be excess fuel from a rich mixture igniting in the exhaust , or possibly an exhaust valve is incorrectly adjusted and is not fully seating or the seat or valve face is damaged .. It could possibly be an air leak on the exhaust manifold
legendary yamaha
IG:ne_caferacer_club
Aren’t those tapered aftermarket mufflers supposed to back fire, also I have noticed the leak on the end of mufflers beacuse It was start smoking after a good warm up.
Cool video 
Agree the idle sounds just a tad slow for a bike still being tuned in.
it does idle, a good sign
Agree the idle sounds just a tad slow for a bike still being tuned in.
it does idle, a good sign
you've been watching too many movies lol
In a word no....I thought I saw a periodic flame come out of your silencer .
It could mean too much fuel from an overly rich mixture ie running idle with the choke on .It could also mean a leaky exhaust valve . ie too tight setting or sticking maybe .
Your too loose clamp could be the wrong one. It might be the clamp intended for the rear of the carb where the airbox is attached. That one would be bigger. You could compare the two clamps you have side by side and see if that loose right one is actually physically bigger than the other one (larger diameter).
I see you have points. You may just need to dial the timing in better and more exactly. These bikes like their timing set dead nuts. Or just a few degrees retarded is good too. Many of us run them that way.
I see you have points. You may just need to dial the timing in better and more exactly. These bikes like their timing set dead nuts. Or just a few degrees retarded is good too. Many of us run them that way.
Last edited:
Its really important to make only one change at a time and keep a note of the result of that change. Mark adjustment screws with some tipex or tape etc so that you can go back to an earlier setting if you need to . Whatever you do don't start messing with the electrics or ignition components before sorting the carbs and visa versa .
Did you bench sync the carbs when setting the initial idle screw setting before fitting the carbs ? if so
I would get your idle speed set correctly first then roughly set your idle mixture screws .
Make sure that both the choke valves are fully seated when the choke is turned off or you'll never get the idle right.
5Twins makes a good point about the clamp .He has forgotten more about these bikes than I am ever likely to know . It can get confusing with 2 people offering advice so I'll leave you in 5Twins capable hands good luck I'll be following your progress
Did you bench sync the carbs when setting the initial idle screw setting before fitting the carbs ? if so
I would get your idle speed set correctly first then roughly set your idle mixture screws .
Make sure that both the choke valves are fully seated when the choke is turned off or you'll never get the idle right.
5Twins makes a good point about the clamp .He has forgotten more about these bikes than I am ever likely to know . It can get confusing with 2 people offering advice so I'll leave you in 5Twins capable hands good luck I'll be following your progress
Last edited:
legendary yamaha
IG:ne_caferacer_club
The one clamp is physically bigger and wider, as for the timing I have no idea where to start and How to do it, I haven’t tuched the ignition.
It seems to spitting fuel out the exhaust . Sounds and looks to be running rich,
legendary yamaha
IG:ne_caferacer_club
What should I adjust if running rich?
Confirm your needle/seats are properly shutting off the fuel flow ? check float level using the clear tube “sight glass” style check ?
Last edited:
Confirm your idle needle valve is turned the proper number of turns.
Varies by the year model bike
76-77 1.5 turns +/- .5
78-79 2.25 turns
Varies by the year model bike
76-77 1.5 turns +/- .5
78-79 2.25 turns
It's running on 1 cylinder, the right cylinder.
The left cylinder is dead, backfiring.
Get the left cylinder running, and the idle will skyrocket.
Need a running closeup vid of the points plate...
The left cylinder is dead, backfiring.
Get the left cylinder running, and the idle will skyrocket.
Need a running closeup vid of the points plate...
just goes to show how easy it is to overlook the obvious I guess I assumed wrongly that the ignition spark had been verified for both cylinders. It almost sounds like one cylinder is firing periodically and igniting all the unburnt fuel that has collected in the silencer hence the big flame out the silencer now and again and the strange HT ticking noise
legendary yamaha
IG:ne_caferacer_club
Well thanks for the good news, I have no clue how to test or get the cilinder running.
