Very Sick NC30 - Major heart surgery underway

[NGneer]

Following a really pleasent week touring around Ireland with my old man and some of his mates on the bikes (plus a quick jaunt to Preston and back from Leeds) i was finally on my way home after a round trip of about 2250Km. Bike is runing well and having nailed it along the M180 turned of for the last 20 miles or so to my place down the A15.

Suddenly a bit of a lack of power. Felt just like i was running out of petrol but i knew i had only recently filled up so couldn't be that. A car going the other way flashed me a second or so later and instictivly i looked behind me to see if it was me he was flashing or somthing else and saw the plumes of smoke i was generating..."Oh F**K!" thought i and pulled straight into the laybay i was just passing. Bike would still start and run (if not fully happy) but made lots of whitish smoke - so i figured the head gasket had gone.

Got recovered the last 20 miles home and set about pulling the engine through to see what i could find. There is a lot of bits in the top end of these things isn't there..

Someone please tell me the hole in the rear right piston is some gucci HRC weight saving mod i don't know about. If not i am guessing this may be the problem



I had started of working with the engine in the frame (hoping to just replace a bust head gasket) but realised this is going to be a full engine strip so out it came...



I guess it would probobly be easier/cheaper to just get a replacement engine, but a week ago i would have said this one ran like a dream, so you never know what you are getting. Hence i have decided to have a go a doing a full engine overhaul on this one, depending on what i find when i split the crank cases.

Wish me luck...i am going in

[CMSMJ1]

Got any pics of the valvetrain mate? Did you melt that hole running lean or did you smack it with the end of a valve?

Bit of a pain in the bumhole for you....

You coming to Cadwell on the 12th by the way? hmmm? hmmm??

[w00dzy]

Unlucky buddy.. good luck on the rebuild.. atleast you have an inside room to do it all in

CMSMJ1 - you mention running lean could have caused the damage..

Just wondering.. what damage could occur if an engine is run rich?

Cheers

[NGneer]

Just realised that this could turn into a bit of an epic and as such this thread is really in the wrong place . Please would a passing MOD be kind enough to move it to the V4 Workshop section, Ta Muchly

[NGneer]

OK - onward. Busy working through the list of things you have to remove before you can actually split the crank cases and i have got to removing the clutch and hit a problem. I have unstaked the clutch nut flange from the input shaft and locked up the cluch using the primary drive gear and a rag (as per Mr Haynes fine book). My problem is that i still cannot get the clutch nut off! With some serious effort (using the correct Honda clutch nut peg socket) it turns and whils the clutch / primary drive are jammed solid it appears the input shaft is turning with the clutch nut????

Any bright ideas very welcome.

Hope i can remember where all this goes back and don't end up with too many piececs left over


Oh and Mark/W00dzy - not running lean i am just putting it down to its intersteller milage and being pinned wide open for quite a long way - me bad

[CRM]

shit, thats not great. is that the bike you came to cosford on ? thats bad luck mate, cheaper option might be to buy an engine, paul riley might have a couple for sale..

[Jon]

A melted hole like that is generaly from preignition from a hot spot in the chamber rather than detonation running too lean.

Check your spark plug and valves in that cylinder to see if one of them has been getting overly hot for some reason, exhaust valve not seating fully or spark plug with shattered insulator ect.

Detonation will normally shatter things from a shock wave effect rather than a nicely melted hole.

My 2 cents worth anyway.

regards
jon

[vfrman]

You might have to use an impact on that clutch. If it is turning the shaft, your clutch plates are slipping.

[theoutsider]

Weld the hole,job done.Just kidding.
Good luck with the rebuild bud.

[royster81]

good luck Ian, you and i are in the same boat but if you decide to call it a day on that motor give me a shout or if your looking some parts give me a shout as i think i might have too many bits from mine ...