CBR 1000F "Hurricane" 1987-1996 CBR 1000F

Valve clearance woes

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  #1  
Old 08-21-2006, 06:31 PM
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Default Valve clearance woes

Hi guys,
I'm new on here.
I've had my 95' for four months and clocked up 10,000 trouble free miles.
I decided to check the valve clearances 'just in case' as I could find no record of them having been checked recently by the previous owner. I should state at this point that I had no problems with performance or valve noise up to this point. Bike has 43,000 miles.

The inlets all seemed OK (a little slack if anything but I left them). The exhausts however all measured too tight. I couldn't get a 7 thou feeler guage in at all. Anyway, I adjusted them all a little looser so a 7 thou would go in but not an 8 thou. This task was complicated by having to lash two short allen keys together with tape in order to get one long enough

I bolted it all back together and voila...... it sounds like a tractor. Actually that's a slight exaggeration more like a sewing machine.

Any ideas what I did wrong? I followed the procedure in the Honda manual for establishing TDC. I have to confess I didn't recheck all the valves after rotating the engine as I was pushed for time. Perhaps once they'd settled they all were too loose??

I've got some extra long allen keys on order and I'm determined to have another go before I admit defeat and give it to someone who knows what they're doing.

Any ideas for round two?

David
 
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Old 08-21-2006, 07:26 PM
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Default RE: Valve clearance woes

Welcome to a great forum.

First off, I am in the states. Here, poeple are less tolerable to engine noise. We set valves tighter than other countries.
Second, intake has cool air/fuel mixture passing over the valves cooling them while the exhaust valves have hot spent gass passing over them.

The exhause valves have a looser gap so the they stay in contact with the seat longer for cooling.

With that said, my book says,

Rotate the crank CCW to align "T" mark with index mark (index mark is just left of the mark with "SWID")

The EX and IN marks on the cam sprockets should be flush with the head away from each other at this point.

Check #1 and #3 IN for 0.010+or-0.02mm(0.004" +or- 0.001)

Rotate crank 180 and align mark to "T"

Check #2 & #4 EX for 0.180+or-0.02mm(0.007 +or- 0.001")

Rotate crank 180
The EX and IN on the cam sprockets should be flush with the head twards each other at this point.

Check #2 & #4 IN (.004")

Rotate crank 180

Check #1 & #3 EX (.007")

Edit: Im an idiot ( I can't type)
 
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Old 08-21-2006, 07:41 PM
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Default RE: Valve clearance woes

I believe you were 180degrees off -- that certainly would cause everything to rattle. I did the same thing the first time I adjusted the valves on my first bike. Bike sounded o.k. before and clackity-clickity afterwards. Just start over and make sure you have all the right marks lined up and it'll be fine.

Just don't run the bike until you get it sorted out. Loose bits clanking about are not a good idea.
 
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Old 08-22-2006, 01:51 PM
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Default RE: Valve clearance woes


ORIGINAL: UKDavid

Hi guys,
I'm new on here.
I've had my 95' for four months and clocked up 10,000 trouble free miles.
I decided to check the valve clearances 'just in case' as I could find no record of them having been checked recently by the previous owner. I should state at this point that I had no problems with performance or valve noise up to this point. Bike has 43,000 miles.

The inlets all seemed OK (a little slack if anything but I left them). The exhausts however all measured too tight. I couldn't get a 7 thou feeler guage in at all. Anyway, I adjusted them all a little looser so a 7 thou would go in but not an 8 thou. This task was complicated by having to lash two short allen keys together with tape in order to get one long enough

I bolted it all back together and voila...... it sounds like a tractor. Actually that's a slight exaggeration more like a sewing machine.

Any ideas what I did wrong? I followed the procedure in the Honda manual for establishing TDC. I have to confess I didn't recheck all the valves after rotating the engine as I was pushed for time. Perhaps once they'd settled they all were too loose??

I've got some extra long allen keys on order and I'm determined to have another go before I admit defeat and give it to someone who knows what they're doing.

Any ideas for round two?

David


David,

Why are you setting your valve clearances to .007" ????? If the manual calls for 4 and you're setting them to 7... well that's almost double the clearance and I would think that would make a bunch of valve noise.....


Mike

 
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Old 08-22-2006, 02:29 PM
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Default RE: Valve clearance woes

Thanks guys,

In response to andrewmr, the clearance for the exhausts is 7 thou not 4 (as you say, nearly double).
I'm sure I followed the right procedure to ensure I wasn't 180 degrees out but it's certainly a possibility.
I'll let you know what happens at the weekend.

David
 
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Old 08-22-2006, 07:00 PM
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Default RE: Valve clearance woes


ORIGINAL: UKDavid

Thanks guys,

In response to andrewmr, the clearance for the exhausts is 7 thou not 4 (as you say, nearly double).
I'm sure I followed the right procedure to ensure I wasn't 180 degrees out but it's certainly a possibility.
I'll let you know what happens at the weekend.

David
I use the old method and turn the engine for each valve setting so that the top of the specific cam lobe points opposite the valve pusher. By that they will all be adjusted on exactly the same position of the base circle.
 
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Old 08-23-2006, 01:27 AM
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Default RE: Valve clearance woes

This is really off the wall, but you didn't by any chance set them to .07 mm instead of .007 inches did you? If you did, don't feel bad. I am sured that you wouldn't be the first.
 
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Old 08-23-2006, 03:48 PM
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Default RE: Valve clearance woes

DRam: I'm pretty sure I didn't mix up thousandths and mm. But it wouldn't be the first time I did something like that so thanks for the suggestion.

R1000: I like the idea of looking at each valve (or pair of valves) individually. Following the Honda method, the lobe of the cam was not pointing directly away from the valve and I was a bit concerned the valve might not be 100% closed.

If I understand you correctly, if I just rotate the engine so the cam lobes for a particular pair of inlets or pair of exhausts are pointing straight up (directly away from the valves), I must be measuring the clearance when the valve is closed and therefore at the correct point. Is my understanding of your method correct?

Just took delivery of my nice new extra long allen keys. Don't you love having an excuse to buy a new tool?

David
 
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Old 08-23-2006, 04:08 PM
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Default RE: Valve clearance woes


ORIGINAL: UKDavid

DRam: I'm pretty sure I didn't mix up thousandths and mm. But it wouldn't be the first time I did something like that so thanks for the suggestion.

R1000: I like the idea of looking at each valve (or pair of valves) individually. Following the Honda method, the lobe of the cam was not pointing directly away from the valve and I was a bit concerned the valve might not be 100% closed.

If I understand you correctly, if I just rotate the engine so the cam lobes for a particular pair of inlets or pair of exhausts are pointing straight up (directly away from the valves), I must be measuring the clearance when the valve is closed and therefore at the correct point. Is my understanding of your method correct?

Just took delivery of my nice new extra long allen keys. Don't you love having an excuse to buy a new tool?

David
Your understanding is 100% correct. If you don't already have a small torque wrench for locking the adjuster nuts, you will have another excuse also. I always (one time on this particular bike) use a torque wrench for this since a broken engine cost much more.
 
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Old 08-25-2006, 03:28 PM
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Default RE: Valve clearance woes

I'll chip in here as I too will soon be checking my valve clearances. Does anybody use the special locknut wrench suggested in the manual? If so, how are you applying the correct torque to the locknuts? Is the special tool being used first to tighten the locknut securely while holding the adjuster, and then switching to the torque wrench? If the special locknut wrench is not being used, what other methods are people adopting?

Also, do people renew the cylinder head gasket as a matter of course or simply stay with the same one (my bike is a 99, so I doubt the gasket will have perished)...

Thanks
 


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