Thumper Club Forum
Technical => Bike Problems/Questions => Topic started by: themoudie on August 06, 2009, 09:56:53 PM
-
I am seeking sensible thoughts, before I disembowel the*********************************!
Went out tonight, having finally finished with Herrman the MuZ Tour, with the intent to sort Sally out for the road.
New chain and sprockets, new fork oil/dust seals/gaiters (initial reason for being off the road), change of oil afore laying up and a squirt of oil down the bore. Emptied the carb and some of that additive in the tank to keep it sweet.
Turned the motor over 4 times on the kickstart nice and slow, just to make sure it all turns with no knocks, clunks or bangs. Went to turn it over gentle again and the piston came up on compression stroke and stopped afore TDC with a 'dunk'!!!!!!!!!! >:( >:( >:(
Have taken the spark plug out with same results when trying to turn the crank over.
Rocked the motor back of compression by engaging second and easing it back. No problem, no nasty scraping, but again refused to come over TDC with a 'dunk'!!!!!!!!!! >:( >:( >:( Tried turning over with the kickstart after taking out of gear and again crank turns until afore TDC, when there was another 'dunk'.
Bike was laid up after running with no problems and spun over 4 times after 6 month layup, so why the sudden 'dunk'??? ??? ??? ??? ???
Seized ring in a land, exhaust valve come down and now stuck down with carbon/'gum'?
At present the carcass will be wheeled into a dark corner, afore having the motor removed, prior to a full strip down, from the top down.
Sensible thoughts please. ::) :'( ::) Bill.
-
Is the engine full of petrol???????
-
The only thing can think of, is that there was something sitting in the inlet port, when you turned it over it dropped through the valve and now sits on top of the piston, stopping it turning over. Similiar thing happened to a mate but he had stripped the carbs off beforehand, from your description it doesnt sound like thats happened to you. Have mice been nesting in the airbox ?
-
Is the engine full of petrol???????
Aye Richard,
Definitely not hydraulicing, took the plug out after the 'dunk' and it's clean as a whistle. No liquid, no smell. Thank you for the suggestion and I wish you well for this weekend.
My regards, Bill.
-
Turned the motor over 4 times on the kickstart nice and slow, just to make sure it all turns with no knocks, clunks or bangs. Went to turn it over gentle again and the piston came up on compression stroke and stopped afore TDC
Bill, I would suggest a stuck down valve, not at full opening, but at a point low enough to just catch the piston. Could be just a lump of carbon from the exhaust valve or port, freed by your oil application or just knocked free resting on the valve seat and preventing full closure. Could be carbon build up on the inlet that has oxidised and sticks the valve in the guide but I would expect this to happen more on the port side of the valve so preventing opening not closing, the clunk and resistance would then be cam action on the valve stem via rocker/s shim or whatever.
Furry John
-
Aye John,
My thoughts, after contemplation!
Thank you, Steve and Richard for your thoughts. If I get time this weekend, there maybe a rocker cover coming off, or if I'm really lucky the head. Will report back and maybe try to leave piccies somewhere.
Hope the SALE goes well later on today! Bill.
-
hello bill,
sounds interesting.... :-\
Valve lifter acting comical? The one on my old 620 went a bit haywire on the dyno, bending the valve but all else was ok. It ran nice afterwards with just a new valve (and the compressor removed)
Something *in* the combustion chamber?
I'll put my money on a sticking valve...
(?!! snapped camchain?!! Surely not!)
Or something in the bottom of the motor (rather than the top) stopping the chain turning??
keep us posted. You'll maybe be needing you alternator puller sent back up, eh?!
a
-
Valve lifter acting comical? The one on my old 620 went a bit haywire on the dyno, bending the valve but all else was ok.
My money is on this. Worked for the first few kicks and then stayed in the open position
-
you can remove the cambox cover with the engine in the frame...
a
-
Aye to you All,
Busy at work and selling Dad's railway stuff, so Sally is on intermitant attention span! ;)
Last night pulled the rocker cover off, after again gently turning the motor with the 19mm socket on the generator end of the crank. Still the clonk, and we are definitely on the 'blow' part of the cycle! ;) Inlets don't move, whilst the exhausts depress evenly and return evenly. Left hand tappet slacker than the right and slacker than recommended, but not ala castanets! Comprende? Ci. :)
With cover off, all valves equal with their partner in height above the cover mating surfaces, nothing slack or lower than t'other. No change to the 'clonk' syndrome. ::)
Next manouvre is nothing to do with Mr Hymlic! Disconnect tensioner and remove the head, me thinks. The wee emoticoms may change at this point! :o
Goodnight and thank you for your valued comment. Bill.
-
does it lock up when you turn it backwards, at say, around about 350 deg? or can you go backwards nearly 2 cycles, 700 deg? if it's only one cycle its going to be in the top cavity or summat the crank/flywheel is meeting....if it's 2 cycles it will probably be the timing chain side of things, but presumably you can see the timing chain and cam wheel with the rocker cover off...does it all look ok?.... just a few musings
SteveL
-
Aye to you All,
Update! ;) Could have been worse. Lifted head today and flaky deposits of carbon on top of piston crown at the front. Loose and moist! ::) [002! :-*] More adhering to squish on head. Must have fallen off with initial disturbance and then stuck to the piston crown. Hey presto 'Dunk' and only 350 degrees rotation of the crank.
New head gasket required, and a check out of the bore, piston gaps, guides and valve clearances. Cam appears fine with little wear and the bore looks OK, but will get a 'looksee'. Gasket for chain tensioner, can it be bought singley? Will cut one out of gasket paper, rather than buy a whole set. Head gasket will be a 'Genuine' part or else a copper job. Any opinions? Quite a bit of carbon which would explain smell of burning oil on overun, without smoke or haze. Also build up on exhaust side of head and exhaust valves of white concretion deposit from burnt fuel impurities/additives. Will clean off afore rebuilding. Piccies to follow.
My thanks to you all for the 'thoughts', info and guidance, Bill.
-
Big Man!
Great news! Clearly he had just spat the dummy, as you are lavishing too much on Herman!!
Gasket for chain tensioner, can it be bought singley? Will cut one out of gasket paper, rather than buy a whole set.
Dunno... try Fowlers. Very quick postage, but Yam parts are never cheap!! google em to get a phone number. I think they will sell singly, but they will prefer a part no. Can supply number from the files if you wish, (but will reauire a wee bit "looking out". Let me know....
Head gasket will be a 'Genuine' part or else a copper job. Any opinions?
I think John Goode had a copper one up for grabs?? If not, go genuine. I think (SteveL will confirm I'm sure) that a 97mm piston will be ok with a std gasket?? Tho be careful of part no's, the head configuration changed a bit over the years... (or was this just XT??). Am too tired. Must be gettin old! Zzzzzz...
see you,
a
-
Aye Andy,
Well Sally being Sally, what else might you expect?
I'm trying Flikr to share some images as promised, but the Yahoo password etc is so up it's own*** that I'm not sure if the link will work ??? Anyway, below is the link.
Carbon stops piston ::) (http://www.flickr.com/photos/themoudie/)
Thanks to you all, Bill.
-
Clearly you need to run it harder!!
More concerted turning of the loud handle is necessary!
cheers
a
-
Clearly you need to run it harder!!
More concerted turning of the loud handle is necessary!
cheers
a
Aye Andy,
Plenty of 'Bombholes' up here, but no 'Revett's' and I doubt if I have the nuts! :-[
Maybe have to shorten the gearing, or trade in for something softer! Then I can erect the screen, don the deer stalker, stuff the meerschum in the gob and chuff around a 5 mile circuit and that would be sad! :'(
Look after yursel' and I'll sound a tootle next time I'm over the Kilpatricks or the Dukes ringpiece!
My regards, Bill.
-
Clearly you need to run it harder!!
More concerted turning of the loud handle is necessary!
cheers
a
Aye Andy,
Plenty of 'Bombholes' up here, but no 'Revett's' and I doubt if I have the nuts! :-[
Maybe have to shorten the gearing, or trade in for something softer! Then I can erect the screen, don the deer stalker, stuff the meerschum in the gob and chuff around a 5 mile circuit and that would be sad! :'(
Look after yursel' and I'll sound a tootle next time I'm over the Kilpatricks or the Dukes ringpiece!
My regards, Bill.
Like one of these you mean Bill? ;D
(http://www.hi-star.co.uk/Helmets/deerstalker%20b%20090608%20tmb.jpg)
(http://www.hi-star.co.uk/Helmets/deerstalker%20d%20090608%20tmb.jpg)
Everoak Deerstalker I believe ;)
Ideal for mooching round the work sites with the meerschaum laying a smokescreen ;D
-
Aye Smudge,
A fine piece of cranial protection, in the best traditions of a 'sporting gentleman' from air they pairts! ;)
Thank you for clarification of the intention! 8)
My regards, Bill.
-
Further update to the saga. :)
Dismantled valves today and found that all 4 valve seals which are normally 'difficult' :-X to remove from the top of the valve guide had been behaving like YoYO's! ??? None were attached to their respective guide and were free on the valve stems.
Have mic'd up the springs, valves etc and think that new valve seals, exhaust gaskets, cylinder head gasket and cam chain tensioner gasket are all that are required! :-X Now removing thick deposits of 'gloopy' soft carbon over the baked on stuff, see link to inlet valves!
Inlet valves (http://www.flickr.com/photos/themoudie/sets/72157622121325560)
Has anybody else had this problem, of detached seals? I can only think that the inner spring may have fouled the outer metal body and 'pinged' them off! ??? There is enough inuendo scope in there to keep the Stalwart happy for days! ;D
My regards, Bill.
-
Bill,
Presumably the gloop is due to oil getting down the stems.
I know that the V6 form motors have valve stem seals which are like the carnival horses and go up and down with the valve. But never noticed this on a SRX motor! In fact, they are always tight when I find em (got to screwdriver them off...)
Were they pattern stem seals?? I have previously tried a number of different ones. Some were too small, some too shallow, I was told that Vmax ones may be the way to go, in the end I used Genuine Yam ones for that application.
-
Aye Andy,
Yep, the gloop is definitely the oil going down the stems.
My experience with the SRX motor up until now, is the same as yours. Seals on tighter than a.....! ;D
The seals weren't 'pattern' jobs, genuine ones from Yamaha. What makes me wonder about the inner spring pinging them off, was the thin rings of rubber left under the lip at the top of the valve guide, where they are supposed to be held! ???
John's head gaskets have arrived and I am about to order the other seals and gaskets required from either Linsdell's or Fowlers. Not tossed the coin yet!
Watching the MGP? Link MGP (http://www.manxgrandprix.org/)
Go safe, Bill.
-
The seals weren't 'pattern' jobs, genuine ones from Yamaha.
Lier,Lier, yur pants r on fire! :-[
My apologies Andy and others whom may have read the above. Found the receipt today (sad) pattern jobs from Weemoto at £1-80 something a shot! Genuine ones from Fowlers, now on order at £5-60 something a shot! ::)
Just a little something for the weekend Sir? I think I might prefer the sealing potential of the genuine articles rather than the 'pattern' parts after this incedent. Time will tell and it may be 'You gets what you pay for!' etc etc etc yawn! ???
A chastened numpty!
-
A-ha!
Too Scottish Bill!! Head-job for a few quids worth of parts.
(agreed tho, price of Yam seals is daft) >:(
a
-
Someone told me today that a mate of his had spent £6,000 recently on a head job for his Manx Norton.
eek! :o
GC
-
Was going to make some comment about a head job for a Manx Norton and then remembered that this is a family friendly site.
R