2010 YZ450F 157 Hours now hard to start after rebuild


11 replies to this topic
  • freerider_australia

Posted June 08, 2012 - 12:39 AM

#1

Just to let people know that i have done 157 hours on orignal piston and is still in good condition and i have never had to adjust valves
i only had to do a rebuild beacause i had a clunking noise when pushing bike in neuteral it ending up being third gear was chiped on dog where it pushes on to 5th gear
after rebuild new gears new stock piston rings it is nearly imposiblle to get it started by kicking(maybe 20-30kicks) i can get it started by rolling down a small hill and bump starting
i get no software error codes and when i get it started it goes like a brand new bike i have done a hour on it and still no better may i need more hours ?

thanks david

  • GEOF

Posted June 08, 2012 - 04:37 AM

#2

Double check your work...especially in the carb area. All hoses connected, all lines routed, good spark. I would replace the plug with a new one,,,an absolute must for me.
Air filter clean and re-oiled. Check the HT lead and coil are all connected tight. Was every thing a success in the cam dept when you assembled? Is the fuel flow okay..has a bit of crap sneaked into the carb when it was being rebuilt. Were you working from an after market manual or an manual for that matter i.e can you check all the specs.
Certainly try a new plug first off.

  • KJ790

Posted June 08, 2012 - 06:19 AM

#3

I would double check your cam timing and valve clearances to be sure.

  • grayracer513

Posted June 08, 2012 - 08:42 AM

#4

has a bit of crap sneaked into the carb when it was being rebuilt?


Something makes me doubt that's the problem. :cry:

  • GEOF

Posted June 08, 2012 - 12:34 PM

#5

Something makes me doubt that's the problem. :cry:


I don't know much about this model.....just trying to offer some areas to check. I am guessing by what you have said above that this is an EFI model? :cry:

  • grayracer513

Posted June 08, 2012 - 02:35 PM

#6

I don't know much about this model.....just trying to offer some areas to check. I am guessing by what you have said above that this is an EFI model? :cry:

Yes sir. :cry:

Dirt could still be involved, but they way EFI works, dirt that would make it hard to start would normally cause the bike to run very poorly. The OP might want to check the flywheel for being properly keyed, check the voltage to the fuel pump while cranking, things along those lines. A mis-keyed flywheel wouldn't show up as a fault code, either.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • GEOF

Posted June 08, 2012 - 02:43 PM

#7

Yes sir. :cry:

Dirt could still be involved, but they way EFI works, dirt that would make it hard to start would normally cause the bike to run very poorly. The OP might want to check the flywheel for being properly keyed, check the voltage to the fuel pump while cranking, things along those lines. A mis-keyed flywheel wouldn't show up as a fault code, either.


Cheer thanks. This will be interesting to follow. Always keen to learn new things as this is a whole new ball game for me....The EFI.

  • Tech707

Posted June 08, 2012 - 02:43 PM

#8

I would double check your cam timing and valve clearances to be sure.

I'd start here first

  • fireball722

Posted June 08, 2012 - 04:43 PM

#9

mine does the same thing , and I have not found why , once the bike have start once in the day it will start in 1 crank start every time but cold ..... I was suspecting coil but not sure and my key is in there at the flywheel , maybe not enough charge (electricity ) but how to find it ?

  • freerider_australia

Posted June 11, 2012 - 01:48 AM

#10

Just to let people know that i have done 157 hours on orignal piston and is still in good condition and i have never had to adjust valves
i only had to do a rebuild beacause i had a clunking noise when pushing bike in neuteral it ending up being third gear was chiped on dog where it pushes on to 5th gear
after rebuild new gears new stock piston rings it is nearly imposiblle to get it started by kicking(maybe 20-30kicks) i can get it started by rolling down a small hill and bump starting
i get no software error codes and when i get it started it goes like a brand new bike i have done a hour on it and still no better may i need more hours ?

thanks david

the bike run really well when i get it started i have been bump starting by rolling down a hill normaly starts no problems doing that way i suspect that i am not getting enough speed when i kick it and the efi is not working properly

  • BBrown626

Posted June 11, 2012 - 03:41 PM

#11

Your timing is probably off by one tooth.

  • freerider_australia

Posted June 13, 2012 - 04:41 AM

#12

Your timing is probably off by one tooth.

your right both intake and exhaust where out by 1 tooth i do top end rebuilds but this time i paid someone to do the gearbox repair and topend rebuild i am superised it was out as the guy is very good mechanic
it now starts easley now
thank to all that helped





Related Content

 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.