YZ250 - hard starter - Page 2

turtlemann14 · 02-21-2008, 04:35 PM

opens the valves i belive

tigmaster · 02-21-2008, 04:37 PM

It makes a lean air/fuel situation causing a 4 stroke to start when hot. 2 strokes usually have no trouble starting when hot so a hot start lever is not necessary.

turtlemann14 · 02-21-2008, 04:43 PM

but it open the exhaust vales to let air in right?

haha one of my friends always used to use it when the motor was cold, kinda defeats the use of the choke ay?

would this help a flooded bike?

tigmaster · 02-21-2008, 04:48 PM

Well, that is a different unit. I can't think of the name at the moment but that is a usually centrifugal device that holds one or both of the exhaust valves open just a slight bit so that you can actually kick over your high compression 4 stroke. On Yamaha's they have a lever that does that and requires a specific routine to get it right. On the centrifugal ones, once the engine is running the lever flips out so the valves can close.

kkmp · 02-21-2008, 07:59 PM

Thanks for all your replies. Here's some answers to your questions:

There's no hotstart lever. Yes, I've used the choke and tried it in all positions. Brand new plug with the rebuild. Pulled it again and it looks good. I've mixed the gas at the ratio suggested in the owners manual (can't remember what the ratio is because I haven't ridden it since last fall). The old piston looked suprisingly good with no major scratches or flat spots. Nikasil plated so no honing was done. Yea, I could have babied it a bit more during the break in but... Coolent is topped. Slight bog - and I mean slight. So it sounds like a thorough carb cleaning might help out? I'm not a master mechanic - this is the first time I've ever done a top end and had to follow the instrucitons in the manual to do so. Keeping that in mind, are you suggesting just using carb cleaner inside and out or is there more to it?

Thanks.

wr250f95 · 02-21-2008, 08:18 PM

does the starter, when you push it how does the compression feel?

gscx · 02-21-2008, 08:20 PM

well if there is a bog it could just be because a 2 stroke will do that because they dont have much torque, but i still dont understand why it is so hard to start though

tigmaster · 02-21-2008, 08:23 PM

I would check the carb possibly. However, I would check electrical specs first. Check the resistance of the stator.

wr250f95 · 02-21-2008, 08:23 PM

I would start with compression

tigmaster · 02-21-2008, 08:25 PM

I would question compression as well, but he did say new rebuild and you can't really mess that up with a Nikasil bore. Did you reuse the head gasket?

02-21-2008, 04:35 PM	#11 (permalink)
turtlemann14 Pro Mototips Member Join Date: Oct 2007 Location: West Virginia Posts: 3,422	opens the valves i belive __________________ If it does not move at first, get a bigger hammer!! Myspace Kawasaki z1 900 1973 rake extended, big bore block 1127cc, carbs, straight pipe exhaust, coils, and new paint job Kawasaki klx250 1979 custom fiberglass silencer+ Honda xr200r 1985 stock = Dakaw Dk250 2008

02-21-2008, 04:37 PM	#12 (permalink)
tigmaster Administrator Join Date: Aug 2006 Location: Missouri, United States Posts: 7,072	It makes a lean air/fuel situation causing a 4 stroke to start when hot. 2 strokes usually have no trouble starting when hot so a hot start lever is not necessary. __________________ --'03 CRF450r-- --FMF Pipe, Pro-Tech Revavle-- --Vortex Basket With Tusk Disks And HP Springs-- --Pro Taper Triple Clamps And Bars-- --Devol Full SP With Moose HGs-- --Renthal 13/50 With R1 Chain-- --Now It Is The End, Probably...-- --'06 CBR F4I-- --Bone Stock-- Check Our Latest How-To Here

02-21-2008, 04:43 PM	#13 (permalink)
turtlemann14 Pro Mototips Member Join Date: Oct 2007 Location: West Virginia Posts: 3,422	but it open the exhaust vales to let air in right? haha one of my friends always used to use it when the motor was cold, kinda defeats the use of the choke ay? would this help a flooded bike? __________________ If it does not move at first, get a bigger hammer!! Myspace Kawasaki z1 900 1973 rake extended, big bore block 1127cc, carbs, straight pipe exhaust, coils, and new paint job Kawasaki klx250 1979 custom fiberglass silencer+ Honda xr200r 1985 stock = Dakaw Dk250 2008

02-21-2008, 04:48 PM	#14 (permalink)
tigmaster Administrator Join Date: Aug 2006 Location: Missouri, United States Posts: 7,072	Well, that is a different unit. I can't think of the name at the moment but that is a usually centrifugal device that holds one or both of the exhaust valves open just a slight bit so that you can actually kick over your high compression 4 stroke. On Yamaha's they have a lever that does that and requires a specific routine to get it right. On the centrifugal ones, once the engine is running the lever flips out so the valves can close. __________________ --'03 CRF450r-- --FMF Pipe, Pro-Tech Revavle-- --Vortex Basket With Tusk Disks And HP Springs-- --Pro Taper Triple Clamps And Bars-- --Devol Full SP With Moose HGs-- --Renthal 13/50 With R1 Chain-- --Now It Is The End, Probably...-- --'06 CBR F4I-- --Bone Stock-- Check Our Latest How-To Here

02-21-2008, 08:18 PM	#16 (permalink)
wr250f95 Super Moderator Join Date: May 2007 Location: New Mexico Posts: 6,952	does the starter, when you push it how does the compression feel? __________________ "LIFE'S JOURNEY IS NOT TO ARRIVE AT THE GRAVE SAFELY IN A WELL PRESERVED BODY, BUT RATHER TO SKID IN SIDEWAYS, TOTALLY WORN OUT, SHOUTING'...HOLY S**T... WHAT A RIDE!" this, is why I ride.

02-21-2008, 07:59 PM	#15 (permalink)
kkmp C Rider Join Date: Feb 2008 Posts: 2	Thanks for all your replies. Here's some answers to your questions: There's no hotstart lever. Yes, I've used the choke and tried it in all positions. Brand new plug with the rebuild. Pulled it again and it looks good. I've mixed the gas at the ratio suggested in the owners manual (can't remember what the ratio is because I haven't ridden it since last fall). The old piston looked suprisingly good with no major scratches or flat spots. Nikasil plated so no honing was done. Yea, I could have babied it a bit more during the break in but... Coolent is topped. Slight bog - and I mean slight. So it sounds like a thorough carb cleaning might help out? I'm not a master mechanic - this is the first time I've ever done a top end and had to follow the instrucitons in the manual to do so. Keeping that in mind, are you suggesting just using carb cleaner inside and out or is there more to it? Thanks.

02-21-2008, 08:20 PM	#17 (permalink)
gscx Pro Mototips Member Join Date: Aug 2007 Location: bridgeville DE Posts: 1,947	well if there is a bog it could just be because a 2 stroke will do that because they dont have much torque, but i still dont understand why it is so hard to start though __________________ 2004 YZ-125 - PC exhaust, Blue applied triple tree, blue turner OV bars, ASV levers, Sunline sprocket and gold chain, FC springs, white plastic . DONT MESS WITH ME, I HAVE A HAMMER AND WILL USE IT!!!!!

02-21-2008, 08:23 PM	#18 (permalink)
tigmaster Administrator Join Date: Aug 2006 Location: Missouri, United States Posts: 7,072	I would check the carb possibly. However, I would check electrical specs first. Check the resistance of the stator. __________________ --'03 CRF450r-- --FMF Pipe, Pro-Tech Revavle-- --Vortex Basket With Tusk Disks And HP Springs-- --Pro Taper Triple Clamps And Bars-- --Devol Full SP With Moose HGs-- --Renthal 13/50 With R1 Chain-- --Now It Is The End, Probably...-- --'06 CBR F4I-- --Bone Stock-- Check Our Latest How-To Here

02-21-2008, 08:23 PM	#19 (permalink)
wr250f95 Super Moderator Join Date: May 2007 Location: New Mexico Posts: 6,952	I would start with compression __________________ "LIFE'S JOURNEY IS NOT TO ARRIVE AT THE GRAVE SAFELY IN A WELL PRESERVED BODY, BUT RATHER TO SKID IN SIDEWAYS, TOTALLY WORN OUT, SHOUTING'...HOLY S**T... WHAT A RIDE!" this, is why I ride.

02-21-2008, 08:25 PM	#20 (permalink)
tigmaster Administrator Join Date: Aug 2006 Location: Missouri, United States Posts: 7,072	I would question compression as well, but he did say new rebuild and you can't really mess that up with a Nikasil bore. Did you reuse the head gasket? __________________ --'03 CRF450r-- --FMF Pipe, Pro-Tech Revavle-- --Vortex Basket With Tusk Disks And HP Springs-- --Pro Taper Triple Clamps And Bars-- --Devol Full SP With Moose HGs-- --Renthal 13/50 With R1 Chain-- --Now It Is The End, Probably...-- --'06 CBR F4I-- --Bone Stock-- Check Our Latest How-To Here

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