gooch
XS650 Enthusiast
The entire wiring harness is new. The barbs on the carb are blocked with some home made looking caps but I know they're tight because I can see the vacuum making them 'breath' in and out.
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Bog of Idle when choked won't run without choke
- Thread starter gooch
- Start date
gooch
XS650 Enthusiast
what would something stupid like, switching the plug wires do?
Toast
Addict
I don't think it would have run at all if the plug wires were switched...but it wouldn't hurt to ensure you have spark at each plug.
I'll toss this out for discussion instead of a solution...but would bad timing have this effect?
I'll toss this out for discussion instead of a solution...but would bad timing have this effect?
ANLAF
XS650 Guru
Just one more thing on the carbs:
Check out my thread: CARBURETTOR ID and BUTTERFLY VALVE SYNCHRONISATION and the video-clips I put on YouTube at -
- the problem
- the solution (thanks to 5twins).
If the carbs have been thoroughly cleaned it may be that the adjustor screw was moved. In effect you will have two carbs running differently no matter what you do at the mix screw.
It's worth checking simply to eliminate that possibility of the cause of your problem.
Anlaf
Check out my thread: CARBURETTOR ID and BUTTERFLY VALVE SYNCHRONISATION and the video-clips I put on YouTube at -
If the carbs have been thoroughly cleaned it may be that the adjustor screw was moved. In effect you will have two carbs running differently no matter what you do at the mix screw.
It's worth checking simply to eliminate that possibility of the cause of your problem.
Anlaf
gooch
XS650 Enthusiast
I did a bench syncing and it was off but i see little to no change. If I pull the choke and screw the idle screw all the way out it wants to run decent with a highish idle.
Cleaned the pilot circuits once again.
Cleaned the pilot circuits once again.
gooch
XS650 Enthusiast
I just want to make clear this, choke on this bike is push down and choke off is up right?
That's the usual set-up, yes. Pushing down the lever lifts the choke plungers and turns the chokes "on". Lifting the lever back up lets the plungers go back into the carb body and shuts the chokes "off". You can watch the choke plungers while operating the lever to see just what they're doing.
gooch
XS650 Enthusiast
Ok, that's what I thought.
ANLAF
XS650 Guru
Just going back to the beginning to try and get the symptoms correct - when trying to idle does it suddenly speed up and then back down?
And when you turn the throttle does it fade and pop?
Anlaf
And when you turn the throttle does it fade and pop?
Anlaf
gooch
XS650 Enthusiast
Finally figured it out. Luckily the dude that was welding my tail light on knew a hillbilly that worked for beer and he helped me out a ton.
we bored the 30 pilots out to .040 with a drill bit and it fired right up perfect, then test drove and bored the 140 main out to .063. I guess it was just really starving for fuel and I hadn't compensated enough for the pipes and filters. Rode the damn thing home with the new tail light.
Thanks for all the help guys.
we bored the 30 pilots out to .040 with a drill bit and it fired right up perfect, then test drove and bored the 140 main out to .063. I guess it was just really starving for fuel and I hadn't compensated enough for the pipes and filters. Rode the damn thing home with the new tail light.
Thanks for all the help guys.
Watch your plugs and fuel mileage for a while.
gooch
XS650 Enthusiast
whats a ball park fuel economy on these bikes?
ANLAF
XS650 Guru
Don't know about the fuel economy, but I'm with gggGary, and while you are testing out larger jets you may be running rich or even very rich. Don't be caught out in the middle of nowhere with fouled plugs. Take a plug wrench with you until you are sure you have the mix right.
Anlaf
Anlaf
Last edited:
well I see mid to upper 40's over several mostly stock bikes. Light cruising can get it into the fifties but that isn't me very often.
Yes, many report about 50, I only see that on a mostly highway tank. All around town, slower running will get me low 40s. If you can't even get that and are seeing mid to high 30s, I'd say you're a bit rich on the jetting. Oh, be sure to tell the next guy you drilled those jets. He'll be wondering what's wrong when his mileage sucks and the jets appear to be stock. Personally, I frown upon doing that. It's a hillbilly or farmer's fix for sure.
At the VERY least take the numbers off the modified jets.
Its seems the majority of lads on the site, throw out the air box and the stock exhaust, and put on pods and open exhausts. This of course means larger jets, and more fuel being consummed. I assume they are tuning for more power and not fuel economy.
Being a contrarian, I like to use the stock airbox, stock air filters and stock exhaust. That makes it very simple to tune, and results in a smooth running engine, that gives excellent fuel economy. On long trips (2000 kms) , I average 55.8 mpg or 23.76 kms/litre. If I'm just doing short trips around town, its more like 52 mpg.
gooch
XS650 Enthusiast
saved me a ton of cash and time not having to step up jets 2 at a time until I got it right. If this all works out I would have ended up with a drawer full of un-wanted jets and the bike running exactly the same.
But yes, If I sell the bike I'll let the new owner know what's going on, that's why I made note of what sizes we drilled them to.
ANLAF
XS650 Guru
I am running 135 main jets, 27.5 pilots and one up on the needle position (from 3 to #2) and is running well.
Try raising needle position - while you are there check whether you have put the plastic disc on top of the needle jet when you put them back together - easy mistake to make.
Anlaf
Try raising needle position - while you are there check whether you have put the plastic disc on top of the needle jet when you put them back together - easy mistake to make.
Anlaf
theimbalance
XS650 Member
Gooch, great to hear you got it figured out, it gives me some hope right now. Any updates on how the bike runs today? I am having a very similar problem with my 78, and I went up 1 on the pilot and 2 up then back down to 1 up on the mains (UNI pod filters and some aftermarket straight mufflers)...and it will not idle with the choke off. This was after cam chain adjust, valve adjust, and ignition check.
Just wondering if you've been fouling plugs or riding just fine since upping your pilot jets...thanks!! Or for anyone else reading this, did you really have have to up your jets that much? While I realize every bike is different, it seems a bit extreme compared to most people's setup.
Just wondering if you've been fouling plugs or riding just fine since upping your pilot jets...thanks!! Or for anyone else reading this, did you really have have to up your jets that much? While I realize every bike is different, it seems a bit extreme compared to most people's setup.
