KLX250/351SF valve clearances

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  #1  
Old 02-18-2018, 08:49 PM
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Default KLX250/351SF valve clearances

First off, ever since I did the upgrade the bike has not run right. Here are the pictures of the inside of the engine when I first pulled the cover. Note: I bought the bike new (0 miles) and no one had touched the engine as far as I know.

Now, the manual and the original thread about valve clearances shows a different configuration for how the cams are set. Has my bike been wrong from the factory?

Also, my valves are so tight now with the 351 that there is no clearance at all. Do I dare order shims that are half the thickness?
 
Attached Thumbnails KLX250/351SF valve clearances-20150529_213616.jpg   KLX250/351SF valve clearances-20150529_214552.jpg  
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Old 02-18-2018, 08:55 PM
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Page 5-20 of the factory manual shows that at the "T" mark, the lobes should be out, looks like my cams are off 180 degrees. Seriously?

Would this affect valve clearances? I also had 2 valves replaced by the shop last summer when I was trying to get the bike running, they reassembled the bike just like my pictures, which is not what the manual shows. They said 2 of the valves were bad, I only have 5K on the engine, almost all of that is on the original head. I haven't gotten 15 miles on the new head because it won't stay running for more than 5 minutes.
 
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Old 02-18-2018, 10:19 PM
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You are off 180 degrees, rotate the crank one full turn to the T mark to get to TDC compression stroke. It is not a big deal, you are on TDC exhaust stroke. The cams will look just like this, with the lobes will be sticking out at about an 11 o'clock (approximate direction) on the intake and about 1 o'clock (approximate direction) on the exhaust. Notice the notches in each cam are 180 degrees opposite the ones in your picture. After rotating the crank one full rotation to T again, check your valves there and get whatever shims necessary to get clearance at that point.







Here is a link to the posts where this image came from. https://www.kawasakiforums.com/forum...problem-33685/

Key thing, the KLX and some other singles fire every 360 degree rotation of the crank, the spark on the exhaust stroke is what is called a wasted spark since it does nothing. It simply means as long as the piston is at TDC the cams installed properly will have it at TDC compression.
 
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Old 02-19-2018, 01:23 AM
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Alright, thanks. Now I'm trying to figure out what size shims to get. I'm subtracting the upper limit of the clearances from the existing shim sizes to get the new sizes, going to order a range of 2.65-2.8 for both sides. I'm figuring if the lobes are touching, if I subtract the lower limit it may not be enough, so I'm shooting for something in the middle to the upper limit to be safe. I'm calculating 2.7 for the exhaust and 2.8 for the intake. I'm going to order 2.7, 2.75 and 2.8, maybe even 2.65, ebay has sets of 5 for 5.36 a set, so $21 for all the sizes I may need.

Correct me if I'm wrong, please.
 
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Old 02-19-2018, 01:45 AM
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This makes it easy

http://www.maultechatv.com/techguides/Valve%20Clearance%20Calculator/
 
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Old 02-19-2018, 02:14 AM
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Originally Posted by ranger01
Alright, thanks. Now I'm trying to figure out what size shims to get. I'm subtracting the upper limit of the clearances from the existing shim sizes to get the new sizes, going to order a range of 2.65-2.8 for both sides. I'm figuring if the lobes are touching, if I subtract the lower limit it may not be enough, so I'm shooting for something in the middle to the upper limit to be safe. I'm calculating 2.7 for the exhaust and 2.8 for the intake. I'm going to order 2.7, 2.75 and 2.8, maybe even 2.65, ebay has sets of 5 for 5.36 a set, so $21 for all the sizes I may need.
Correct me if I'm wrong, please.
Are you basing the needed shim sizes based on actual clearance with the crank properly lined up? It's unusual for the exhaust valves to need much in the way of shimming.

Ride on
Brewster
 
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Old 02-19-2018, 03:36 AM
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All 4 valves had 0 clearance with the stock shims in. I removed all the shims and measured the clearance. 0.559mm gauge was the largest I could fit with no shims.
 
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Old 02-19-2018, 11:44 AM
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Make sure you KNOW the caps seat flat on top of the valve. For some reason in the back of my mind I'm thinking the shims sit in a little recess atop the valve. If so, that would make the shim requirement that much larger.
 
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Old 02-19-2018, 12:11 PM
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You'd better get someone who knows what they are doing to help you. All the valves should not have zero clearance.
 
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Old 02-19-2018, 12:52 PM
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Originally Posted by ranger01
Page 5-20 of the factory manual shows that at the "T" mark, the lobes should be out, looks like my cams are off 180 degrees. Seriously?

Would this affect valve clearances? I also had 2 valves replaced by the shop last summer when I was trying to get the bike running, they reassembled the bike just like my pictures, which is not what the manual shows. They said 2 of the valves were bad, I only have 5K on the engine, almost all of that is on the original head. I haven't gotten 15 miles on the new head because it won't stay running for more than 5 minutes.
I would be showing them the picture and getting your money back/the work done right ...
 


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