2004 Rmz 250 hard to start

Amarwood

Amarwood

Got a Rmz 2004, tidy bike had near enough an engine rebuild. Just one problem when its hot and ive been riding around its hard to start. starts great from cold first or second kick. Got told to try a cooler burning spark plug but that doesn't seem to of sorted it. Looked up on the internet seen things about could be the valves. Seems to have less compression when its hot. has the decompression lever weather that is not working I'm not sure. It bump starts fine just kicking it off is a problem.

if any one has any soloutions id be gratefull as it want it right, annoying when you have to either find a hill or wait for it to cool before trying to kick it off.
 
SRAD97750

SRAD97750

Moderator
Staff member
Amarwood:
Got a Rmz 2004, tidy bike had near enough an engine rebuild. Just one problem when its hot and ive been riding around its hard to start. starts great from cold first or second kick. Got told to try a cooler burning spark plug but that doesn't seem to of sorted it. Looked up on the internet seen things about could be the valves. Seems to have less compression when its hot. has the decompression lever weather that is not working I'm not sure. It bump starts fine just kicking it off is a problem.

if any one has any soloutions id be gratefull as it want it right, annoying when you have to either find a hill or wait for it to cool before trying to kick it off.
Click to expand...
Time to check the valve clearance. Seems as they get tighter, they won't start hot.
Record all your findings each time you do a valve clearance check. Like most things, the numbers tell a story over time.-BIG DAN:thumb:
 
Amarwood

Amarwood

SRAD97750:
Time to check the valve clearance. Seems as they get tighter, they won't start hot.
Record all your findings each time you do a valve clearance check. Like most things, the numbers tell a story over time.-BIG DAN:thumb:
Click to expand...


Is this a simple thing to do or is it more of a technical thing. Any steps to help me along ?
 
Amarwood

Amarwood

SRAD97750:
Time to check the valve clearance. Seems as they get tighter, they won't start hot.
Record all your findings each time you do a valve clearance check. Like most things, the numbers tell a story over time.-BIG DAN:thumb:
Click to expand...
Bike has had brand new valves in do just got in contact from where It got from
 
SRAD97750

SRAD97750

Moderator
Staff member
Amarwood:
Is this a simple thing to do or is it more of a technical thing. Any steps to help me along ?
Click to expand...
This video is for a 2007. I am not sure if the specs are the same, but the process will be the same.
ONLY ADJUST SHIMS IF THE MEASUREMENT IS OUT OF SPEC.
http://www.allthingsmoto.com/forums/f-13/how-check-adjust-valves-47609/
Amarwood:
Bike has had brand new valves in do just got in contact from where It got from
Click to expand...
Yes, there was a clearance when they were installed. That clearance has most likely changed. I recommend checking them every 20-25 hours of trail riding. -BIG DAN:thumb:
 
O

ossagp

Easy cold start and hard hot start says too rich to me. your spark plug heat range wont have anything to do with that, no matter what a Jr parts changer tells you.
 
jackson409

jackson409

Clean carb and when you think you have it clean...clean it twice more. I had an 08 RMZ do the same thing. i adjusted the valves but did me no good. After I cleaned the carb for the second time it fixed my hard starting issue. I still got rid of it. The valves were at there last shims before needing replacement.
 
Mihylo33

Mihylo33

ossagp:
Easy cold start and hard hot start says too rich to me. your spark plug heat range wont have anything to do with that, no matter what a Jr parts changer tells you.
Click to expand...


Ditto.

No start cold and an easy start while warm is usually a valve adjustment issue. Easy cold start and a hard start warm will be the carb.
 
O

ossagp

That variety of carburetor is pretty advanced compared to what used to come on motorcycles. It is also a good reason or part of the reason that the bikes they come on work so good. If it is running well other than the starting I would hold off on a full disassembly until you have a manual showing every part, and a full rebuild kit. On the other hand the most likely culprit will simply be setting the float. That will require little effort than removing the float bowl and setting the tab on the floats themsleves. I dont have the specs on the suzuki, which should be the same as the kawasaki of the same year since those used the same motor.

The need for cleaning is usually exemplified by circuits being plugged up and not enough fuel being able to pass. In this case, you are getting too much fuel. The float level starts rising as soon as you start riding in a float controlled carburetor. The carbureted bikes you used to see winning races on tv's and read about the nationally competitive pro's riding had the float set before each event or at least checked. 12 years later, yours probably last was set at the factory that made it.
 
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Mihylo33

Mihylo33

Amarwood:
What's best way to clean carb so not going to upset it ?
Click to expand...


You will need a manual and some carb cleaner.
You'll need the manual to set the floats and for the disassemble and reassemble.
You'll need the manual regardless of what you do.
Without a manual you will find yourself in Barney before you know it. Trust me.
 
Amarwood

Amarwood

ossagp:
That variety of carburetor is pretty advanced compared to what used to come on motorcycles. It is also a good reason or part of the reason that the bikes they come on work so good. If it is running well other than the starting I would hold off on a full disassembly until you have a manual showing every part, and a full rebuild kit. On the other hand the most likely culprit will simply be setting the float. That will require little effort than removing the float bowl and setting the tab on the floats themsleves. I dont have the specs on the suzuki, which should be the same as the kawasaki of the same year since those used the same motor.

The need for cleaning is usually exemplified by circuits being plugged up and not enough fuel being able to pass. In this case, you are getting too much fuel. The float level starts rising as soon as you start riding in a float controlled carburetor. The carbureted bikes you used to see winning races on tv's and read about the nationally competitive pro's riding had the float set before each event or at least checked. 12 years later, yours probably last was set at the factory that made it.
Click to expand...


Thanks for that detailed reply. Il start with the carb then see if that helps. Thanks
 
O

ossagp

A lot of times it isn't limited to one thing, but you gave a pretty classic example of one that is too rich. I dont know if yours is equipped with a hot start button, if it is, see if that is functional as well. it is really just a contorlled leak to let in more air when hot. holding the throttle wide open when kicking may help too, but sometimes that activates the pump circuit to the point it can make things worse. you can try leaning things out by resetting the fuel screw to a leaner position once started, but the float should be routine maintenance anyway, and a good way to set the field level again so to speak before you try some bandaids
 
Amarwood

Amarwood

ossagp:
A lot of times it isn't limited to one thing, but you gave a pretty classic example of one that is too rich. I dont know if yours is equipped with a hot start button, if it is, see if that is functional as well. it is really just a contorlled leak to let in more air when hot. holding the throttle wide open when kicking may help too, but sometimes that activates the pump circuit to the point it can make things worse. you can try leaning things out by resetting the fuel screw to a leaner position once started, but the float should be routine maintenance anyway, and a good way to set the field level again so to speak before you try some bandaids
Click to expand...

Yeah bike has got the hot start lever is there a way to check if that is functioning correctly. I can see what you mean by holding the throttle open out, end up flooding it probably. But yeah il have a play about now I know I've gathered some information
 
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