NC30 engine problems

[gammakeith]

Hopefully you can see that the lug has broken where it was previously welded. Managed to get the exhaust studs out the new head and the dowels out of the old one is usable condition. Just need to pull and check the valves/seals now.

Keith

[manicguitarist]

You are missing the opening [ on some of the img tags

[gammakeith]

You are missing the opening [ on some of the img tags

Thanks you, kind sir! All sorted now.

Keith

[manicguitarist]

Thank you! The bike looks lovely.

Keep us updated....

[richyrd5]

hhmm,so it was you who outbid me on that ebay head!!! .i was just going to get it as a spare to go with my rear and rvf cams but seeing your predicament i will bid no more and hope you get it for the £30 its at now.good luck .also 16 valves on a ducati!!!,surely you mean 8?unles of course you have a desmosedici??

Yes, managed to win it in the end. Not sure if it was good value but have not got the time to wait around. Your restraint on the bidding is much appreciated, kind sir :-) I'm just hoping it is not warped.

As others have said, the twin cam V2 Ducatis have 8 valves but 16 shims to play with. The closer shims are a right bugger to change.

Keith

Your welcome chap. glad you won it after!!.i won the set of nc30 cams that i needed..won for £1..!.+£8.90 for postage.so £10 all in for 5 cams and carriers.bargain!!. good luck with the rebuild..nice bike btw.

[Neosophist]

yeah thats been smashed up at some point.

While its all apart check the waterpump impeller blades are good, ive seen a few disintigrate after being run on normal water.

give the radiators a good blasting out too get all / any crap out of them.

[gammakeith]

Well that's the new head rebuilt ready to go back though now sporting an inlet valve from the original head as one in the "new" head was slightly bent. It was enough for the valve to bind in the guide quite badly and would certainly have caused running problems. However, that valve seat was not at all burnt and valve guide was fine so I'm left scratching my head at that one. The original head had a badly mangled valve guide seal and another very slightly bent valve. The valves are quite skinny so perhaps they are getting bent by clumsy attempts to remove/replace the collets? I was a bit naughty and didn't fit new valve guide seals. Even the exhaust seals on both heads were still soft and nice and tight on the valve stems so not a big risk to take. The seats were all good and a few twirls of fine grinding paste was enough to clean them up.

Better look at the radiator/water pump etc next and start to tidy up some of the manky looking wiring

Keith

[manicguitarist]

I love this kinda stuff!!m Thank you.

[Neosophist]

Well that's the new head rebuilt ready to go back though now sporting an inlet valve from the original head as one in the "new" head was slightly bent. It was enough for the valve to bind in the guide quite badly and would certainly have caused running problems. However, that valve seat was not at all burnt and valve guide was fine so I'm left scratching my head at that one. The original head had a badly mangled valve guide seal and another very slightly bent valve. The valves are quite skinny so perhaps they are getting bent by clumsy attempts to remove/replace the collets? I was a bit naughty and didn't fit new valve guide seals. Even the exhaust seals on both heads were still soft and nice and tight on the valve stems so not a big risk to take. The seats were all good and a few twirls of fine grinding paste was enough to clean them up.

Better look at the radiator/water pump etc next and start to tidy up some of the manky looking wiring

Keith

I've taken valves out of zxrs especially that have been really bent but engins ran perfectly (blown headgaskets aside.)

Perhaps a bit of hydraulic lockign from fuel could bend the valves a little

[gammakeith]

I feel like I am making some progress now The front head is on and re-shimmed. Just need to shim up the (undisturbed) rear head now and I can put the carbs etc back. Had a slight hiccup when I managed to ping a shim into the engine! Still it was relatively easy to drop the sump to recover. In the end it was easier and safer to remove/replace the shims with cam carriers completely off.



With the sump off it meant I could check the oil pump to see if the oil has been kept clean. Fortunately, the pump was in great condition so the bottom end is also likely fine. The oil had some antifreeze in from the blown head gasket so certainly needs a change. The water pump vanes are fine so likely not run on straight distilled water.

I pulled the clutch as the basket was notably "wobbly" and the mangled nut showed it had been off before. I was quite surprised to find a plain bush on the basket rather than needle rollers though the bush and shaft were (just) within spec. Plates and sprag etc were all fine so its all going back with new nut. Its a shame that Honda don't list a replacement bush for the basket. I'm guessing a wobbly clutch basket is a characteristic of this bike?

Taking the clutch cover off was interesting. The paintwork was very poor and turning it over revealed the reason! Obviously yet more evidence for a crash though the repair is good and the cover undistorted so it will be going back after a new paint job.





The carbs are also rebuilt and ready to go back. They were spotless inside though the screws were all mangled, the float bowls were on the wrong carbs and the main jets were mixed up! It seems that our fairly ham-fisted amateur? mechanic was trying to find the reason for the bike running poorly. All sorted now with shiny new Allen screws. The same? mechanic also extended the breather for the coolant header tank as I presume it was blowing out antifreeze over the rear wheel due to the blown head gasket.

Should be able to make more progress over the Christmas break!

Keith