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Post by McF on Dec 28, 2008 19:24:34 GMT 1
Initiated on previous site by TelfordNTV
Have just checked and adjusted valve clearances for first time since I've had bike (probably for some time). Bike has 48000 miles and i've got no idea of service history. It has run fine in the 6 months I've had it but thought after daily use I'd treat it to a full service. Have adjusted valve clearances to setting advised in haynes manual but on both exhaust valves have had to screw adjusters nearly all way out to get even close to 0.2mm so that. I fear that with a bit more wear on the adjuster screws the rocker arms will be hitting directly on top of valve. The valve clearances are now on tight side, whereas before there was no clearance at all. The adjuster screw was tight on top of valve. The bike now runs fine as it did before) but doesn't sound any less "tappety". Is there any other way to adjust them or is it a top end rebuild?
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Post by McF on Dec 28, 2008 19:35:23 GMT 1
This sounds strange
I would be very surprised that you got this amount of wear ever, but especially not after only 48k miles.
The only relevant parts that can wear here are the adjuster bolts, the rocker face, the cam or the end of the valve.
Any wear that creeps in will require the adjuster bolt to be screwed in and increase the distance between the rocker arm and the valve. From what you have described it's not wear that you have taken up.
You will not thank me for suggesting, but if I were you - the first thing I would do is take everything to bits again (I assume it's all reassembled) and recheck the clearances - the idiot question is did you have the engine at TDC for each cylinder individually when adjusting?
I haven't started work yet, but my spare engine is on the floor in the garage. I will pop the rocker covers off and measure the clearances and count the exposed threads for you and repost.
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Post by telfordntv on Dec 28, 2008 20:42:34 GMT 1
No offence taken for asking. I followed haynes manual - so set the TDC for the rear cylinder then the TDC for the front using the 2 the marks on flywheel. I'll wait for your post then whip the covers off and have another look. Is the way described the best way. It's how I,ve done it cars before - never worked on bikes much in the past.
Cheers
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Post by telfordntv on Dec 29, 2008 16:56:03 GMT 1
Re-set them today and found problem. Front exhaust rocker arm has play. So this is what is making tappety sound, not valve clearance. Am unsure wheteher to drop endgine out and rebuild top end or break bike as I don't have alot of money to spend on it. Will put ad on parts for sale and see what interest before I make a decision.
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Post by McF on Dec 29, 2008 18:22:31 GMT 1
Re-set them today and found problem. Front exhaust rocker arm has play. Hi Telford, haven't taken my rocker covers off yet, was thinking of doing it tonight, I've been busy making best use of daylight while we had it. Any idea which part(s) are worn? I may have a spare top end (I bought most of a spare engine in bits ages ago). It still sounds an odd amount of wear with relatively few miles on.
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Post by telfordntv on Dec 29, 2008 21:29:07 GMT 1
Been thinking about it this afternoon and cannot see why wear should be so bad so thought I'd give it one last go. Threw haynes manual away and ignored timing marks on flywheel. Just turned engine over until rockers topped out and set gap to what felt right. Result - runs perfect. Cheers for advice. I'll run it for a few days and just make sure it's ok. If not I may well be in touch for a spare top end !! Once again thanks for advice.
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Post by Buzzin (^_^) on Dec 29, 2008 23:31:05 GMT 1
Well, technically it's not impossible of course that a previous owner set the timing different (as in rotated the flywheel without the chains being on....but I would imagine that would f4 up the rest too... But hey! if it works, it works!
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Post by McF on Dec 30, 2008 10:15:58 GMT 1
Threw haynes manual away and ignored timing marks on flywheel. Just turned engine over until rockers topped out and set gap to what felt right. Well done you for perseverance - assuming you reassembled each time, that's a lot of irritating work to do. I took some time out last night and got my engine on the work bench and my camera set up. This engine was running beautifully until I sold my last NTV, except it was boiling over (suspected head gaskets gone). I replaced the original engine (mild first gear problems) before selling the bike. I checked the clearances and all was well, I've taken some photos - click on the thumbnails for a larger photo Front Cylinder, viewed from left side Front cylinder Exhaust viewed from right side Front cylinder exhaust viewed from left side, with feeler gauge (0.20mm) I hope it now sounds as though your bike is running well and sounds sweet
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Post by telfordntv on Dec 31, 2008 15:37:23 GMT 1
I wouldn't say she runs "sweet" but certainly she runs quieter than before and the top end is certainly not as clean as one in your photos. Rear Cylinder is fine and runs really quiet. Front one - hereafter known as "the awkward B*****d to get at" was the problem. Gaps on exhaust are nearer 0.15 than 0.2. If I set it 0.2 it was still noisy. If I set gap at 0.1mm she sounded really quiet but thought that might be a bit too tight and risk damage. Gaps on inlet are spot on 0.15. I think cam chain on front cylinder will need replacing at some point so I think I'll look out for a top end once christmas is paid for.
I can't think that previous owner set up cams wrong as she has always run well and gives 200+miles before reserve to a tank. Reading the old forum this seems OK. She just sounded tappety at higher revs.
Regarding peserverance - the language did get very heated in the garage a few times - there's even an ad posted to break bike at one of my lower moments. I'm sure I'll laugh about it a few weeks though.
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Post by McF on Dec 31, 2008 16:14:21 GMT 1
Don't worry Telford, many of us have already been there - me especially! My dog Zach (who lives in the garage when I'm there - follows me like a sheep but then he looks like one!) no longer blushes when he hears the naughty words. We have two Wheaten Terriers (approx Spaniel size). Zach velcroes himself to me when I'm home and never lets me far from his sight. He's the smaller of the two, on the left where they're sat, in the front / airborne in the other As always, click on the thumbnails for a larger image Situation you're describing still sounds odd, but as it's the M-Fecking front one, even I'm not going to suggest you take another look at it. The only reason my looks so clean is because it's not in the frame!
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Post by sickpup on Jan 1, 2009 17:53:05 GMT 1
Situation you have sounds like the valves are receding into the head. Tends to happen more often on the rear cylinder as it runs hotter being behind the front cylinder and the header wrapped around it.
Could be a cooling problem, could be a lubrication problem. If it was me I'd check the clearances again in 500 miles and see if anything has changed.
Valves don't need to be checked with the piston at TDC just where the cam isn't on the valve.
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Post by telfordntv on Jan 2, 2009 12:53:50 GMT 1
Cheers Sickpup. Although the thought of stripping it down again doesn't thrill me I know that the cam chain will need doing at some point this year. Ideally would like to look for a spare engine to rebuild at leisure and do a swap. Will have to pay for xmas first and keep a look out here on boards. Happy 2009
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Post by wellsplattered on Feb 16, 2009 21:46:38 GMT 1
im confused!
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Post by McF on Feb 17, 2009 0:20:25 GMT 1
Any reason why? I have posted under "tappet clearances" with info for clearances
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pozo
Ahh! Just passed their bike test
Tech Consultant and Graphic Designer
Posts: 43
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Post by pozo on Feb 13, 2012 13:40:55 GMT 1
Hello all, When I found out that I couldn't fit my spark plug tool through the 'service hole' in the valve cover I decided to take the valve cover off at the rear cylinder. While I had that, I thought I'd check the clearances as well. Unfortunately there was no way that I could get the flywheel-nut cover off to rotate the engine :S First off it seems to be a weird non-metric size (my 10mm hex didn't fit in quite right), but it did catch on. I put quite a lot more than 15N of force on there (the Haynes recommended value for re-installing it) and it still would not budge. Just to be sure: the cover has regular thread so we twist it off anti-clockwise right? There was no mention of it being 'clockwise-thread' but I hope I haven't accidentally over tightened it now... It was pretty cold out, near to freezing temperatures, so maybe that didn't help? For clarity it's this one: Picture borrowed from www.elsham.pwp.blueyonder.co.uk/deauville/tappets/index.html
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