I rebuilt my carbies and installed a pamco ignition with a 3ohm dynatek coil, I hooked everything up and filled the carbies wit fuel, It took me 30 plus kicks to get it to start but it idles really high then dies then takes another 10 kicks to do start again and it just keeps going on and on like that til I eneded up dying in the floor. I can also smell fuel, I hav only the headers so the exhaust is really short
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Bike idling high then dying
- Thread starter Chop089
- Start date
My chainsaw does that when it's running out of gas.
Sounds like you may have a fuel starvation problem. When enuff fuel finally makes it into the engine, the engine starts, then quickly uses up what little fuel exists and starves...
Sounds like you may have a fuel starvation problem. When enuff fuel finally makes it into the engine, the engine starts, then quickly uses up what little fuel exists and starves...
I am Carbon
shade tree mechanic
I agree with twomany
With all the changes you've made, it could be one of many things, or a combination of several things. You said you rebuilt the "carbies" but if you're not very knowledgeable about carbs, they could be in a worse state than before. Even with a Pamco, you still need to accurately set the timing with a timing light. Has that been done? Are you still using the mechanical advance and if so, is it clean and lubed so it retracts (retards the timing) properly? Like I said, it could be any of these things. If the advance is stuck on full, it will be hard to start and race if it does. If the timing is off, it can be very hard to start. The gas smell could simply be from the multiple kicks and not starting. You're shooting more and more fuel into the engine and it isn't burning it because it isn't running.
It only runs really high for about 3 secs before dying again so I can't do the timing. When I rebuilt the carbies all I did was clean all the dirt and shit out and replace all the brass pieces. I checked the mechanical advance and it seems to be in good order
What model carbs?
What Float level are you setting them at?
Was the bike running fine before you did this?
Adjust the idle screw so that the bike will idle high, get it running, then adjust the idle screw down and go from there. Do you have sufficient fuel supply?
What Float level are you setting them at?
Was the bike running fine before you did this?
Adjust the idle screw so that the bike will idle high, get it running, then adjust the idle screw down and go from there. Do you have sufficient fuel supply?
its a 1976 xs650c so it has the BS38 carbies
the floats are set to 27mm as per the manual
the bike hasn't been started in over 8 years, thats why i rebuilt the carbies
i think I'm gonna make the carbies run bit richer and see what that dose tonite, ill do what you said and screw the idle screw all the way out too
the floats are set to 27mm as per the manual
the bike hasn't been started in over 8 years, thats why i rebuilt the carbies
i think I'm gonna make the carbies run bit richer and see what that dose tonite, ill do what you said and screw the idle screw all the way out too
27mm isn't the right spec for '76 BS38 carb floats. It's 2mm too lean. That might explain things. Reset them to the proper 25mm and maybe that will provide enough fuel for the bike to run more than a few seconds.
I am Carbon
shade tree mechanic
Yes what 5twins said 27 is for BS-34s
CV Carbs - one of the best how-to manuals ive found for the original carbs
This manual has been prepared by Grizld1 (aka Dick Russell, Yamaha 650 Society
Tech Advisor) and 5twins.
http://www.amckayltd.com/carbguide.pdf
CV Carbs - one of the best how-to manuals ive found for the original carbs
This manual has been prepared by Grizld1 (aka Dick Russell, Yamaha 650 Society
Tech Advisor) and 5twins.
http://www.amckayltd.com/carbguide.pdf
When you replaced the brass parts, did they have the same markings as the ones you took out? often the brass parts that come in rebuild kits are not the right ones for the XS650. About the only brass parts from a kit that work is the float valve. The Float bowl gasket is about the only thing very usable from a kit. Better to use the carb guide to tear down, clean and inspect your carbs then replace any worn parts buy buying just the parts you need.
another thing, just filling the bowls might start the engine but as the fuel gets used it leans out. The float valve is a metering device, it keeps the proper level of fuel in the bowl. This prevents an overly lean or rich fixture.
With out a good supply of fuel the carbs lean out. I have a fuel tank of an old riding lawn mower. It holds a few quarts of fuel. Plenty for testing. It has a 1/4 inch outlet, from this to a fuel shut of valve, from the valve comes a couple feet of 1/4 fuel line to the carbs. I have tees if the carbs have two fuel inlets.
I mount the tank on top of the frame if the tank is off or on the handle bars.
Leo
another thing, just filling the bowls might start the engine but as the fuel gets used it leans out. The float valve is a metering device, it keeps the proper level of fuel in the bowl. This prevents an overly lean or rich fixture.
With out a good supply of fuel the carbs lean out. I have a fuel tank of an old riding lawn mower. It holds a few quarts of fuel. Plenty for testing. It has a 1/4 inch outlet, from this to a fuel shut of valve, from the valve comes a couple feet of 1/4 fuel line to the carbs. I have tees if the carbs have two fuel inlets.
I mount the tank on top of the frame if the tank is off or on the handle bars.
Leo
I'm pretty sure they were the same :/, i got it running now with the choke on but wen i try to turn the choke off it dies, i adjusted the floats to 25mm and thats what got it starting after 2 kicks, the last time i tried to start it just before smoke came out of the carbies 
. i have a funnel with 2 meters of fuel line running to the carries but it uses all that up in 10 secs, i also changed the jet needle to the richest it would go
. i have a funnel with 2 meters of fuel line running to the carries but it uses all that up in 10 secs, i also changed the jet needle to the richest it would go
I am Carbon linked the carb guide, read it, print it out, read it. Once you read it several times follow the steps to tear down, clean, inspect your carbs. Replace only the parts your inspection indicates need replacing.
The carb guide also has a section on "Tuning for Mods"
Just moving the needle up won't really solve anything till you get the rest adjusted as well.
Leo
The carb guide also has a section on "Tuning for Mods"
Just moving the needle up won't really solve anything till you get the rest adjusted as well.
Leo
There's more to the pilot jets used in these than just the numbers. There were two different types used and what type is needed depends on the year of the carb set. And just because your bike is a '76, that doesn't mean the carb set is. They are easily and often swapped. The first thing you should do is positively I.D. the year of the carb set you're working with. Then you can proceed to verifying whether the installed jetting is correct for it.
Your carbs are not BS34s, they're BS38s. Yes, they appear to be a '76-'77 set. The 45 pilot is wrong. Also, the vents on the inner sides of the bodies shouldn't be interconnected, they should just vent individually to atmosphere.
The jets that came in your rebuild kits are wrong. The whole kit may be wrong if you bought BS34 kits.
The jets that came in your rebuild kits are wrong. The whole kit may be wrong if you bought BS34 kits.
Ok thanx I just ordered a new rebuilt kit from geoffsxs ( http://www.geoffsxs.com.au/OpenCart/index.php?route=product/product&path=4_36&product_id=773
I hav fixed the vents now so they are venting to atmosphere, what that have called issues too?
I hav fixed the vents now so they are venting to atmosphere, what that have called issues too?
