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  #1  
Old 02-06-2013, 11:46 AM
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Usflag got a yamaha 450f 2005 Will not Kick only Bump .. Help?

i bought a yamaha 450f 2005 model that kicked over when i bought it. It was running kinda crappy though.

So i changed the oil, oil filter... topped on the radiator.

It would kick over and run but after riding it for a few minutes it would not kick over at all ! only bump start.

I got stuck out in the desert with it and was pissed so after that i took her home and opened her up.


1. Valve check... the last person to do a valve adjustment over tightened the cam shaft cap and it mushroomed the edges along the valve lifter buckets. Those were not fun to re shim...

but i adjusted/reshimmed the valve in spec.. put her back to gether...

2. took off the back shock to get the to carbutator and cleaned that! put it back together...

bike wont kick...


3. i changed the spark plug to a brand new one.

sounds like it wants to kick almost but it wont.

so i bumped it and tried to set the idle correctly ...

but it will not kick over! it only bumps.. it runs pretty good when it bumps but any suggestions guys? I have no money for a mechanic at dirtbike shops...

i do everything my self with research and my experience
im only 18... and this is my second yamaha .. upgraded from a 250 to a 450 and now im having serious issues.

what do you guys think???


Top end?

bottom end?

valves?

/wirings? stator? idk if my bike has a stator i thought thats for elec start

Im stumped... id aprecciate any help fellas
Thanks
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  #2  
Old 02-06-2013, 12:01 PM
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stators are common to all the modern ones that make power for the ignition. a bleed down test or a compression test may tell you if that is the problem making starting difficult. I would want one or the other to have for future wear reference anyway.

I think the biggest problem you have is carburetor maintenance though. I have owned lots of bikes that were really worn out, but would still start.

cleaning the jets and setting the float is cheap as in free, but not totally easy on that one. you will need a manual. i think if you do that you will find starting a lot easier though.
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Old 02-06-2013, 12:30 PM
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I would like to add to a very good list of things that Oss has given you...
1. Double check the pilot jet as it may still be clogged. Use a welders tip cleaner to get it clean.
2. Check the coil mounts for rust and corrosion.
3. Do an OHms test of the coil.
4. Double check the valve clearances.
5. Double check the cam timing.
6. Check the ohms readings on the stator.

The service manual for this bike is a must have!

Paw Paw
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Old 02-06-2013, 01:57 PM
RiV RiV is offline
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Like noted by Paw Paw, recheck your valve clearance & timing.
If your valves are tight again then it needs valves/valve job, if
the timing is off (depending on retarded or advanced) the engine
can run like it has low compression. It can especially be bad on the
exhaust since the timing effects the operation of the decompressor
which would definately make it hard to kick start......or if someone
put a WR450 exhaust cam it-same result if not timed for that cam.
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Old 02-24-2013, 04:00 AM
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Usflag UPDATE

So i re-checked the valves.. theyre in spec.
I changed the spark plug and ignition coil.
I took the carb apart and cleaned the jets and everything.

the bike wont kick though. I bump started it on my street and it fired right up.. ran pretty good but dies easily... so in that case it didnt run that well. however it always starts when i bump start it ..

but kicking it ... impossible. you could give it 1000 kicks and it would never turn over.

compression feels normal...

sometimes the exhaust pops when i kick it over but its more of a crack noise.



any suggestions? i just wanna be able to kick start my bike

Thanks
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Old 03-03-2013, 10:24 PM
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Sorry man you got screwed no Lol not f#@&in funny

---------- Post added at 09:24 PM ---------- Previous post was at 09:23 PM ----------

This should happen to know one
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Old 03-04-2013, 07:41 PM
RiV RiV is offline
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You may want to check that you have a true top dead center by
using a small diameter rod or screwdriver to visually verify that the
piston is at the TDC when the flywheel marks say so. One thing that
I have seen make similar Yamaha models hard to start is if the slide
has a crack in it, you can look on a parts diagram to see how its made
to know where to look, they usually don't idle well when their cracked
tho. The choke circuit needs to be clean as well, but just whacking the
throttle wfo a few times kind of eliminates that possibility via accel
pump. (thats the smaller portion of slide that cracks) GL
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Old 03-04-2013, 08:27 PM
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#1 double check that you're actually timed correctly and are not a tooth off. that will make all the difference in starting. The bike will still run, and depending on the bike may actually run stronger when the timing is off.
#2 check to make sure you're timing chain isn't stretched by checking your timing marks on the head, this will cause the same thing as #1 and make for real hard starts.
#3, double check your valve clearances are in spec, and Ideally at the loosest spec so they can wear in, rather than having to reshim all the time.
#4 if none of this works, do a leak down and compression test to see that the motor is in proper running order.

In general, a weak spark is a weak spark, so its doubtful it is your stator. it would either run, or not. Not push and not kick start. I had a kx250F before that would wear valves in every second ride, and be a bear to start. Then my timing chain stretched, all valves were in spec, and it wouldn't kick start but would push start and run strong every time. I think that's most likely your problem.
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