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Location:
Perth, Western Australia
Registered:
June 2003
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 18r-g tech help. New timing chain causing unhealthy noise!!
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Sat, 03 April 2004 15:02
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Hey, i just put the new timing chain on my 18r-gu. All went well, all original marks lined up correctly. I only replaced the top chain for the moment. I now am faceed with a tapping noise under the rocker cover (similar to a valve on 18r-c) and when you go past 2000 rpm its really loud and unhealthy sounding.
Also, even after replacing the chain, the rattling is not as bad, but is still there when you giv it high revs and drop it back to idle quickly. Its got me beat. I figure maybe i should check the valve clearances and ect? Im unsure on the specs for the 18r-gu (18r-geu head yamaha) so any help would be wicked...
Thanks
Steve
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Location:
Rocky Mountains, Canada
Registered:
May 2002
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Re: 18r-g tech help. New timing chain causing unhealthy noise!!
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Sat, 03 April 2004 16:12
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How did the chain guides look?
Did you replace those too?
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Location:
Brisbane
Registered:
October 2002
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Re: 18r-g tech help. New timing chain causing unhealthy noise!!
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Sat, 03 April 2004 23:07
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r u sure the chain is tensioned
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Location:
Rocklea qld
Registered:
February 2003
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Re: 18r-g tech help. New timing chain causing unhealthy noise!!
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Sat, 03 April 2004 23:10
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Are you its not hitting the tappet cover. Check that for any scratches on it. I know thats what mine was doing.
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Location:
Perth, Western Australia
Registered:
June 2003
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Re: 18r-g tech help. New timing chain causing unhealthy noise!!
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Sun, 04 April 2004 01:15
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Well the tensioner is supposed to have 0.5-1mm movment if u stick a screwdriver up the end. I set it to that and tried tightening it as well. what would be hitting the tappet cover?
the chain guides looked good i didnt think they would need replacing
Steve
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Location:
Rocklea qld
Registered:
February 2003
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Re: 18r-g tech help. New timing chain causing unhealthy noise!!
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Sun, 04 April 2004 09:48
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the timing chain could be hitting the cover
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Location:
Perth, Western Australia
Registered:
June 2003
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Re: 18r-g tech help. New timing chain causing unhealthy noise!!
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Sun, 04 April 2004 12:25
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I traced the rattle that i thought was the timing chain. OMG it was so queer. I was looking around and noticed the alternator rattling around, and both bolts that hold it to the block were missing...And im like WTF?!?!?!
Now all im left with is the tapping.
I belive it is valve clearance but have NO idea how to change the valve clearance in this engine. Someone please give me a rundown on how to change the valve clearance on an 18r-gu
Thanks
Steve
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Location:
Perth
Registered:
May 2003
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Re: 18r-g tech help. New timing chain causing unhealthy noise!!
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Sun, 04 April 2004 14:27
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Setting the valve clearances is a time consuming job.
1. Measure current clearances ensuring that the cylinder you are measuring is currently at the top of the compression stroke. This is done by starting with the engine on number one compression (grooves on each cam facing vertical). Check number one clearances. Turn engine 180 deg clockwise (anti clockwise while facing engine from front of car) and check number three clearances. Turn engine a further 180 deg and check number four clearances. Turn engine another 180 deg and check number two clearances.
2. Now you should have recorded all the current valve clearances on a piece of paper. If they aren't in spec then do the following:
3. Remove both cams, first turn engine back to number one compression (another 180 deg) so the cams are easy to realign later. You can get the cams out with the gears on by backing off the tensioner, removing all the cam retaining caps and removing the front inner cam cap retaining bolts (use two nuts locked together on the stud to remove the stud).
4. Remove buckets but be sure to keep them in the order they came off. Just as they wear into a certain position.
5. Remove shims, these may be stuck under the buckets, KEEP SHIMS IN ORDER!!! EG. Place them on a piece of paper and number the positions.
6. Measure shims using a micrometer.
7. Calculate difference between thickness of shim and valve clearance to work out the new required shim thickness for each valve. Eg, original clearance = 6 thou, shim 80 thou, required clearance 10 thou therefore need a 76 thou shim.
8. Either have shims machined by a machine shop or get new shims. I have heard that if you go to motorbike places they can help. Particularly ones that do Yamahas.
9. Replace new shims in tops of valve retainers IN THE CORRECT ORDER.
10. Replace buckets being careful not to knock shims out of place, cams etc etc.
11. Once cams fitted, double check cam timing, re-check new valve clearances.
Either that or you remove the head, take it to a head shop and they grind the tops of the valves to get the correct clearances - this is expensive though.
PS Expect a large email.
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Location:
Canberra
Registered:
December 2002
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Re: 18r-g tech help. New timing chain causing unhealthy noise!!
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Mon, 05 April 2004 02:49
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Are you still after this steve because i will scan it out of the book for you.
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Location:
Rocklea qld
Registered:
February 2003
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Re: 18r-g tech help. New timing chain causing unhealthy noise!!
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Mon, 05 April 2004 08:04
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have fun
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