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post #1 of 15 (permalink) Old 01-02-2011, 07:37 PM Thread Starter
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Help on a strange issue

'04 RC was running fine and parked it for about 2 weeks while I was out of town. Started it up and it did not want to idle right with the choke out. Talked to a few folks checked the pressure regulator out and it checked fine per the shop manual.
Pulled the plugs they both looked fine so I ran a compression check. Rear was 150 and the front was 90. Checked the book it said to check the valve clearances. Front cylinder intake were a loose .006 while the exhaust was a tight .012 on one exhaust valve and then .010 on the other.
Is this enough to cause the compression to be low on the front cylinder?
There was no blow by in the crankcase along with it not using oil so I do not think I have a broken ring issue.
Any help would be greatly appreciated
Thanks
Don
316-993-4640

2004 RC51 with multipul mods
1985 VF1000R SOLD 😭
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post #2 of 15 (permalink) Old 01-02-2011, 08:05 PM
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Now that you have done the valves hows it run, what is the compression?
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post #3 of 15 (permalink) Old 01-02-2011, 08:14 PM Thread Starter
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Originally Posted by cbrbear View Post
Now that you have done the valves hows it run, what is the compression?
I have not adjusted them yet that was the reading when I pulled the valve covers off.

I will have to wait so I can get some shims to adjust the valves. Dealer does not open until Tuesday. GRRRRRRRRRRRRRRRR

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post #4 of 15 (permalink) Old 01-02-2011, 08:34 PM
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gotcha...well let me know what you find!
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post #5 of 15 (permalink) Old 01-02-2011, 10:52 PM
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If you're gong to check/adjust valve clearances, always start with the front cylinder first.
Once done with the front, the rear cylinder is only 270 deg rotation away.
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post #6 of 15 (permalink) Old 01-03-2011, 06:55 PM Thread Starter
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Ok checked the clearance again and was getting the bike ready since the bike dealers are not open on Monday here. Looking at the cams and noticed there is two gears. One is off alignment just a little and appears to be spring loaded. What is this for and is it needed??? I am thinking it might be used to keep pressure on the idlers. Am I right????
Call me dumb but never seen this before even on my VF1000R but it noisy when riding but sounds GREAT.

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post #7 of 15 (permalink) Old 01-04-2011, 02:05 PM
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Those are split gears.
They are used on straight cut gears to eliminate gear backlash and noise.

When installing the cams, just try and make sure the alignment marks are close to the head surface edge.
When you tighten down the cam bearing caps, the marks should then perfectly align.
If the alignment marks are not not aligned, and the crankshaft was not rotated, then remove the cam bearing caps and reposition.

If everything is right, the alignment marks should then point to the flat edge of the head surface as in the service manual. Then torque the caps to spec.

It's difficult to check alignment on the front cylinder with the radiator in the way.
The rear cylinder check is a breeze with the fuel tank off.

Last edited by SubSailor; 03-13-2011 at 07:41 PM.
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post #8 of 15 (permalink) Old 01-04-2011, 06:41 PM Thread Starter
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I found that out on the front so off came the rads. I am waiting for them to over night a shim Grrrr. I am hoping this will solve my low compression. Everyone is saying it will. I just for the life of me can not figure out why it happened all of a sudden. I guess that is a question that will never be explained LOL.

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post #9 of 15 (permalink) Old 01-05-2011, 01:27 PM
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If there is clearence on all the valves, then they should be all sealing, sounds like something else.If you have a shim which is on the tight side of spec, you can just sand the shim with wet & dry sandpaper to get the right thickness.

Last edited by mondo; 01-05-2011 at 01:34 PM.
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post #10 of 15 (permalink) Old 02-16-2011, 10:15 PM Thread Starter
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Finally got it back and running properly. Had some issues going back together either I did not get the cam mark properly or something but could not get her to run right after adjusting the valves. Took it back down and reassembled everything and seems like she is running great. Gotta wait for the snow and ice to disapear so I can shake it down. Compression came up and to within 10% of the back cylinder.

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