Sally's woes! Locked up SRX600.

[themoudie]

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.

[OMEGAMAN]

 Is the engine full of petrol?

[Steve H]

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 ?

[themoudie]

 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.

[Furry John]

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

[themoudie]

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.

[andy230]

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

[Steve H]

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

[andy230]

you can remove the cambox cover with the engine in the frame... 

a

[themoudie]

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!

Goodnight and thank you for your valued comment. Bill.

[Steve Lake]

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

[themoudie]

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.

[andy230]

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

[themoudie]

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

Thanks to you all, Bill.

[andy230]

Clearly you need to run it harder!!

More concerted turning of the loud handle is necessary!

cheers

a