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Re: Bikemonkey's NC30

Posted: Thu Jun 28, 2018 11:30 pm
by CMSMJ1
Great work dude. if and when I can get the time adn space to do the same, I'll be following you. I suspect the gear selector on mine is fucked.

Handy that you've been doing it all adn taking nice pics. I will be wanting to clean pistons, lap valves, deburr the ports and generally sort it out. not going to happen soon though

Re: Bikemonkey's NC30

Posted: Tue Jul 10, 2018 9:51 pm
by bikemonkey
Progress!

Last week I prepped the engine for rebuild, removing all the old gasket and cleaning the mating faces. That was boring and time consuming, I didn't take any pictures surprisingly.

Today my new (used) gearbox turned up, and after swapping over a bearing and a couple of thrust washers it was ready to go into the engine.

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But first I changed the selector forks for the ones I had lying around as they were in near new condition apart from a slight bit of surface rust. Installed the selector drum and gave it all a healthy coat of oil.

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Then I put the gearbox into the engine, coating it with a good amount of oil, especially the bearings. New output shaft seal and clutch rod seal fitted. Input shaft bearing plate torqued and gears set to neutral to test freedom of movement.

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After that I applied a good coating of oil on all the crankshaft bearings and any area that had had it wiped off. Before applying the gasket sealant (threebond) I cleaned all the mating faces with brake cleaner to ensure a good seal. You really don't need a lot of this stuff, so smeared it thinly with my finger removing any excess. And I still think I put too much on!

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Getting the lower crankcase on was a pain solely due to the selector forks not playing ball, but I got there. 10x 12mm bolts fitted first and incrementally torqued to spec. Then 7x 10mm bolts fitted and incrementally torqued. After those I got the upper bolts in and torqued, which was a massive faff with the two bolts I had to leave fitted, but I got to them eventually.

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As you can see above one bolt is missing (bottom left). This bugger snapped on me before the torque wrench clicked. Luckily when I removed it it came out whole. PHEW! :oops:

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I'm guessing either some oil was in the female thread and threw the torque figure out, or the bolt was simply past it's best and let go.

Either way I have ordered a new one and can still get on with the rest of the rebuild this week :peace:

Re: Bikemonkey's NC30

Posted: Wed Jul 11, 2018 1:06 pm
by NGneer
Glad you managed to find a gearbox Oli - rebuild is looking good :-)

Re: Bikemonkey's NC30

Posted: Thu Jul 12, 2018 12:06 pm
by bikemonkey
So last night I got loads more done on the engine, better alternative to the football in my opinion!

Started off with re-assembling this lot, coating everything in oil as I went.

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The sprung loaded assembly above has a plate that goes under/over it which was a pain to get on without things pinging everywhere, as such I forgot to take any more photos of that bit.

The case went back on with a new gasket and a new shaft seal :peace:

Oil pump was next, along with the pipe and relief valve.

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I used a thick piece of acrylic to jam the oil pump chain to be able to torque the sprocket bolt.

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Water pump got bolted on with a new seal.

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I left the clutch pack all together so it just slid back on nicely. Need to torque the nut up once I've fitted the engine, I'm not happy doing it on the bench without a proper engine stand or clutch holding tool.

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Primary drive gear, spacer and washer went into place with a little lining up with the clutch.

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Starter motor, starter gear and starter clutch all placed in. Got to torque the starter clutch bolt later too.

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I wondered how I'd know which pick-up went where, but there made so you literally can't mix them up!

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I put the clutch case on after that, without a gasket, just to keep everything in place when it gets lifted into the frame.

Generator was a doddle, just need to remember to torque that up too. Again case put on with no gasket.

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I fitted the sump cover properly with a new gasket as I won't be needing to go in there again.

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And fitted a new oil filter just to seal everything up.

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Just waiting on a new bolt to replace the snapped one. Whilst I'm waiting for that I'll clean up the frame and the bits on the engine I missed.

I'd do the valve clearances but I don't want to turn the engine without everything torqued up properly, so I'll just do them once it's in the frame. Not like I'll have much in the way anyway!

Once it's in I'll still have the wiring loom to finish before I can get it started anyway!

Re: Bikemonkey's NC30

Posted: Thu Jul 12, 2018 11:21 pm
by jim157
You're doing a great job there mate.

Re: Bikemonkey's NC30

Posted: Sun Jul 22, 2018 9:50 pm
by bikemonkey
A while since my last update, I got a bit sidetracked I'm afraid!

Since last time I have cleaned up the frame

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And fitted the rear exhaust manifold.

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Also this final piece of the puzzle showed up and got torqued in, without breaking this time!

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Then this evening after being let down twice, I decided to fit the engine on my own. (I do not recommend doing it on your own!)

It was a massive faff involving a big jack, two ratchet straps, blocks of wood, strength, swearing and because of the heat plenty of sweating!

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This is why I don't recommend fitting an engine on your own..... :oops:

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I also bent the gear selector shaft.... Another thing to mess about replacing!

Without dropping the engine again the only way to free the chain was to remove the swingarm. Much quicker and easier :whistle:

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After that slight detour I torqued up the front sprocket, clutch nut and starter clutch nut.

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And fitted the rest of the clutch gubbins back in.

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Next was to torque the alternator rotor down. Now I had a massive moron moment here too (I blame the heat....). The thing wouldn't torque down despite me locking up the rear wheel with the engine in gear. It was also making a horrible noise when I tried to torque it up.
So off came the rotor, cleaned up the end of the crankshaft and taper on the rotor and put back on. Same thing.
Then the lightbulb moment came, swiftly followed by the acknowledgement of muppetry. The clutch had been slipping!
These little bikes don't put out 85NM of torque, so of course the clutch couldn't handle it! What an idiot I am.

Stuffing some thick rag inbetween the primary gear and clutch gear solved the issue and a lovely click came from the torque wrench. Phew.

Finally back on with the engine cases, new gasket for each and all bolts torqued to spec. (I really like the Teng 5-25NM torque wrench I bought for the rebuild).

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So I'll be on the hunt for a new gear selector shaft I guess! And I reckon tomorrow will be time to try sort the wiring loom!

Re: Bikemonkey's NC30

Posted: Mon Jul 23, 2018 9:47 am
by CMSMJ1
living the dream :)

Re: Bikemonkey's NC30

Posted: Mon Jul 23, 2018 10:28 am
by CB1pod70
It'll all be worth it after the first few laps on track... ;)

Re: Bikemonkey's NC30

Posted: Tue Jul 24, 2018 9:00 pm
by bikemonkey
Last night I got the wiring loom into place and had a massive faff about as I realised I had mixed up the 6 pin connector I have for my clocks and the 6 pin connector for the CDI. :oops:

No pictures as wiring is boring IMO.

Then tonight I went over what I had done and attempted to tidy everything up.
I found something strange though. The 6 pin wires coming out of the CDI have NC35 colours, yet the bike is still running on NC30 pickups....

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NC35 wiring diagram.

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The orange and blue wire seems to be redundant as the speed limiter so I tied it up at the side as I think it may need to be ran to ground. I already have a de-restrictor box in place.

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After I tidied it up a bit with a bit of tape, I connected everything up and put the battery in the test it out.
Lights on and starter motor works. A good start but I'll have to wait and see if it runs properly before I wrap it all back up.

A much needed return to all things nuts and bolts needed after that. Out come the thermostat housing to be re-fitted.
The seal was absolutely minging, probably only sealed by corrosion....

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Out it came for the new one, seal groove and engine face cleaned up too.

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And mounted back on the engine.

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I realised that I said I'd do the valve clearances whilst the bike was so stripped, so I got started with that.

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Managed just the rear head tonight before I got too bored and tired, but I already have 3 clearances to sort out!

Shim swapping probably isn't going to be an option either, bummer.

Re: Bikemonkey's NC30

Posted: Wed Jul 25, 2018 9:37 pm
by bikemonkey
Back to the valve clearances and it seems I need 7 valve shims....

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After that bore and added expense I swapped the gear selector shaft over as the new one arrived. The one on the left has a bend on the splines. I could have heated it and bent it back but I really don't want anymore gearbox problems. Plus the 750 could do with a less corroded one and the part is exactly the same, so I'll fit it to that once I've bent it back.

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Speaking of heating and bending, it was necessary on the crash bung tie-bar. R&G charge ridiculous prices for individual spares....

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Not perfect, but fits a lot better than it did.

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I've had these fresh powdercoated brackets sat in a tin of new spares for a few years now and thought whilst I'd got the old ones off I may as well swap them over.

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Also fitted the exhaust tonight, which took a bit of fiddling as it seems that the rear header went on at a slightly different angle to what it was before.

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Tomorrow I'll probably fit the coil packs, fill the engine with oil, fit the cooling system and carbs and fire it up to check the wiring loom.

Then it'll get the top rad removed again ready to swap shims out, front wheel fitted properly, chain tension set and loom removed the be wrapped :peace: