Changing an NC30 gearbox?

[skinnydog0_0]

The original engine is already apart on my bench, as i threw a valve, and f**ked one cylinder . This is now the doner engine.


Pic of the damaged cylinder


This is ready to be transplanted into the NC30 engine

[Malc]

One thing to bear in mind also if you plan to split the cases without removing the heads - one or two of the crankcase bolts are a ball-ache to undo, and pretty near impossible to get a torque wrench on when putting it all back together again with the heads in place.

Don't worry at all about turning the engine upside-down, nothing really will get loose and fall out - be careful though when actually splitting the halves that you don't dislodge the main shells and get them mixed up, other than you should be fine.

All that said - you got to take so much off the engine to actually split the halves, you're as well doing a complete pull-down anyway!

[skinnydog0_0]

One thing to bear in mind also if you plan to split the cases without removing the heads - one or two of the crankcase bolts are a ball-ache to undo, and pretty near impossible to get a torque wrench on when putting it all back together again with the heads in place.

Don't worry at all about turning the engine upside-down, nothing really will get loose and fall out - be careful though when actually splitting the halves that you don't dislodge the main shells and get them mixed up, other than you should be fine.

All that said - you got to take so much off the engine to actually split the halves, you're as well doing a complete pull-down anyway!

Thanks Malc,
Yes very good point about the crank case bolts, and for the cost of a couple of head gaskets i think it would be worth while to get them off. Also might make getting the rest of the engine out a little easier with the heads off, as there is less weight to shift about.
I had better get on to David silver for some more bits.

[skinnydog0_0]

So i have finally finished. here is an update on how things went.

First off remove,
Fairings,
Tank,
Air filter,
Carbs,
Rads,
Exhaust,

then,

Drain engine oil
Disconnect oil cooler.



Then i remove the front wheel, but replace the spindle.
I use the car jack unde the spindle to support the front and remove the front paddock stand and leave the front spindlesupported on the car jack (sorry no pic of that as i had greasy hands and i dont like to leave it supported like that for any longer than i have too.
Gently lower the front car jack till the front forks are resting on 2 blocks of wood.



Then undo all the engine mounting bolts making a note of the castle lock nut positions with a marker pen, remove bolts and store in a safe place.
Disconnect all the electrics not forgetting the neutral switch
Then with the help of the wife i lift the frame off the engine,



If i lift the frame off the engine on my own i remove the rear cylinder head and exhaust manifold, it just makes it much much easier.
As i had the lift the engine on my own, i decided to remove the cams, and head to lighten it a little.







Next to remove the clutch, primary drive gear, starter clutch and oil pump chain and sprocket.
One thing i would sure do differently is get the clutch off with the engine in the frame. undoing the clutch nut was an absolute F,ing nightmare my lad learnt some new words that evening, most begining with B or F or C



Then to remove the alternator. I made myself a tool to hold the rotor, and use a metal pole on teh socket to get enough power into it.
This is one job that i find easier with the engine on the bench, as the rotor holder can push against the bench and it makes it easier to apply pressure on the socket





Then to remove the sump, oil pump and filter. This is a UK spec NC30 engine so has a different pump and supply pipe layout.







Then time to split the crank cases. Undo the bolts as per heinz manual, and make up marker boards for the bolts,

Lower bolts,



Top case bolts,



And gently seperate the cases,



You can probably see that the front head is still in place, no need to take it off for removing the gearbox.

Then time to swap out the old NC30 gears for the NC35 ones

NC35 ones to go in,



Then time to remove the selector drum and gearchange mechanism.
I fount that because i was replacing the whole lot, there was no need to completely take ity apart.
I just unscrewed the 2No. bolts holding the retaining plate and slid the whole assembly out in one piece.



Sorry i didn't get a pic of the assembly as a whole as i wanted to get it into the engine as soon as poss, incase i forgot/lost something.

One thing that was interesting, was the outer gearchange casing on the 35 has a needle bearing where the 30 doesn't.
this is the 35 one,



and this is the old 30 one (without the bearing)



Now it's just a case of going in reverse and putting it all back together.

[Neosophist]

UK NC30 engine uses the same oil pump et al as the NC24. Same part numbers.

[skinnydog0_0]

I was a bit keen to get the bike back together so i didn't take many pics of it going back

I put the alternator back in with the engine on the bench for the same reason as i did for removing it. I left the clutch though untill i had the engine back in teh frame.



Made life much easier for tightening the clutch nut. Word of caution, i thought i had everything back right in the clutch housing, but one of the plain plates had caught on the teeth of the one way clutch and hadn't seated properly, i did the clutch nut to the right torque, but it was way down thw shaft, and no way to get the nut staked. so took it all apart and re-assembled again, making sure that everthing was as it should be.

Everything else went as it should, and was basicly just the reverse of taking it out and apart.
The only thing i did differently was that i left the rear head off till i had the engine in the frame. This was due to me being on my own and not wanting to do my back in
Once the rear head was back on, i set the rear cams as per the heinz manual, and bobs your uncle

I have a push button gearchange set up on the bike, and this was causing me some issues with the unit hitting the exhaust or being mounted so far out from the engine that the fairing would drag on the floor, see the white scuffs on the red bulge



I have had a different mount made by a friend, it is not perfect but it was cheap and it does the job





It replaces the engine mount spacers on the left side of the engine and mounts the actuator just off the exhaust but closer into the sump.





I have taken the bike for a good run, about 100+ miles, and teh gears are silky smooth, no hesitation, and finds neutral quite easily . it was a bit of a job, but it was well worth it.

Just a quick thanks, to all the people that have posted similar topics on things as the info was invaluable



Now i have the fairing back on and teh bike running,

[skinnydog0_0]

UK NC30 engine uses the same oil pump et al as the NC24. Same part numbers.

Thanks Neo, very useful to know Do you know if the oil cooler is the same too, as in the pipe shape and spacings from the rads and forks?