NC24 ENGINE REBUILD

[pagan1001]

Hello again guys!, I am just about to start rebuilding a second engine for my much loved NC24 and am just wondering if anyone has done this already???.

I am just needing to know the best place for parts and if it is worth while sending the heads away to have the valves reseated and getting a port and polish!????. Or is the cost not worth the difference that it will make??.
Also do I need a stand that lifts the bike off the ground like an ABBA swingarm stand??? for removing the engine or is there a way to remove it without one???. I keep reading about honda special tools for removing the engine but is this just for the newer models? and can I remove my with standard tools?? oh mine is 1986.
Hope some of you have been here and can maybe help save some money as I know parts are VERY, VERY expensive.
Incase some of you are wondering WHY the hell would you do this if my bike is running fine........ well she is but there is something internally wrong or needing serviced as I have had a lot of things go wrong with her. I now have a good second engine so would be as well stripping it and giving it a full check and replace anything that is of spec. So when I swap the engines I know everything is 100%.

I will keep you all updated as I go as I am sure there will be a lot of problems as well as things I need to find out.

[Neosophist]

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Incase some of you are wondering WHY the hell would you do this if my bike is running fine........ well she is but there is something internally wrong or needing serviced as I have had a lot of things go wrong with her.

-snip-

Not to sound funny but if you don't have an idea what's wrong why are you going to tear apart a running motor to fix 'something' that may not be the cause of the problem.

What exactly is wrong with the bike / engine? I can tell you how likely it is to be interally related.

but with regards to your question.

You don't need any special tools to get the engine out nor do you need an abba stand.

Block of wood under the side-stand to keep the bike level, remove pretty much everything, jack under the engine.. drop it down and lift the bike up over the engine.

Not only can parts be really expensive, some parts are not available, some parts reqiure proper tools to remove / assemble and if you don't know what your doing you can make things a lot worse.

This shouldn't put you off as with propre care and time and tools it's not beyond the skill of a home mechanic. (apart from serious jobs such as reboring etc) but if you don't know excatly why your stripping it how do you know it's going to make things better?

[pagan1001]

Well if you remember my last or first posts when I got this bike I got it cheap but the oil light was on ......................... but did go off and temp high very high so stripped the bottom and oil pump strainer was blocked so dont know how long its been run like that but by the look of the gasket and state of the bolts I would say a long time!!!!!. So there could be or would be over heating and possible oil starvation so bearings may be on way out as there is noise all the time plus my cam snapped in half but that is still a mystery!!! plus a lot more that was wrong like the radiator gauge and the thermostat switch was buckled!!!. LOADS!!!!

I have built my own car so do know my way around just the first time with a bike! I do have most tools for the job ahead.

But your bound to know what I mean when I say you know when something is just wrong????

With the cam shaft snapping I really want to get this engine out and give it a full once over to see if there is something underlaying

Sorry I have written this quick so everything is not listed so please dont take it word for word just wanted to give you the general idea of the problems.

But to be honest I am looking forward to doing this so its not like I am doing it but hesitant about it I am looking forward to inspecting everything and replacing parts that I need to I love this kind of thing......... then at the end of the day the engine I fit should be practically new. cheers

[pagan1001]

Sorry you might not have understood I have a second engine now that runs so doing a swap then stripping the one that is in my bike now. Then going through it component by component. If its fine great!!!!!!!!!!! but I can assure you there will be something that has failed or is going to fail very soon!!!

And I have checked out parts and prices so do know the cost to expect if things are bad but it will be worth every penny.

[Neosophist]

. If its fine great!!!!!!!!!!! but I can assure you there will be something that has failed or is going to fail very soon!!.

What makes you think something is going to fail very soon?

A friend in Japan has an 85,000km NC24 engine that still has perfect compression and runs without fault.

My own has 58,000km on it now and has no problems at all.

[pagan1001]

Three friends have the same type of bike as me two with a lot more miles and one with less but all bikes run better sound and ride very smoothly. They ALL have none of the engine noise that I have. YES you are right I really do need a compression gauge but going on comparison there is a HUGH difference in the overall running of my machine.
I mean sometimes I try to start her she jams up so have to rock the bike back and forth before she turns over. Also the rev counter will flicker from 1300 rpm to above 2000 then down to 900 never staying on the right engine speed and believe me everything has been checked to try and sort this. Also even when she is warmed up she will cut out when changing into 1st or 2nd gear. Plus there is a little oil on the spark plugs when they are removed...... not a lot by any means but it is there. These are just some of the things that are worrying me as well as the previous problems which were quite severe.

I mean if your camshaft snapped what would be your course of action??????????

I love this bike and plus am dying to find out if there is anything else wrong and the best way to do this is to strip the engine and check it all. Then like I said before once it goes back in I know the engine is fully serviced back to factory specs.

The person who had this bike before obviously did not take the best of care of her...... shame on you!!!!!.

Pity you did not live close by cause I am sure if you took the bike for a ride or just even heard it you would be yeah something is wrong!!!

[Neosophist]

Three friends have the same type of bike as me two with a lot more miles and one with less but all bikes run better sound and ride very smoothly. They ALL have none of the engine noise that I have. YES you are right I really do need a compression gauge but going on comparison there is a HUGH difference in the overall running of my machine.

I mean sometimes I try to start her she jams up so have to rock the bike back and forth before she turns over.

Remove the clutch side cover, you'll see the starter motor sproket and the drive sproket it connects too.

You either have bad teeth on one of these or the starter motor itself is worn, possibly bushes.

Also the rev counter will flicker from 1300 rpm to above 2000 then down to 900 never staying on the right engine speed and believe me everything has been checked to try and sort this..

You mean the idle isn't right or the rev-counter is moving without the revs changing?

Obviously everything hasn't been done else it would be running properly.

If the idle is actually jumping about that much you more than likely have an airleak around one of the carb rubbers. Sometimes these can be impossible to see unless you change the rubbers or know exactly where to look.

If the counters moving on its own it's an electrical problem

Also even when she is warmed up she will cut out when changing into 1st or 2nd gear. Plus there is a little oil on the spark plugs when they are removed...... not a lot by any means but it is there. ..

Cutting out when changing down gears is a classic sign of the bike running overly rich. fouled plugs would support this.

These are just some of the things that are worrying me as well as the previous problems which were quite severe.

I mean if your camshaft snapped what would be your course of action??????????..

I don't really understand what you mean here... is this just a random scenario or something your worried about happening?

Becuase stripping and rebuilding a running engine isn't going to prevent a camshaft from snapping, unless you know theres a specific problem that is likely to cause the camshaft to fail. (you can change the camshafts just by removing the rockerboxes btw...)

Most of the broken camshafts i've seen on here are from incorrect installation. One should only break in the engine due to oil starvation, which you'd need to be wheeling for ages, block the sump up or put sugar or something similar in your oil.

I love this bike and plus am dying to find out if there is anything else wrong and the best way to do this is to strip the engine and check it all. Then like I said before once it goes back in I know the engine is fully serviced back to factory specs.

The person who had this bike before obviously did not take the best of care of her...... shame on you!!!!!.

Pity you did not live close by cause I am sure if you took the bike for a ride or just even heard it you would be yeah something is wrong!!!

If the engine is noisy check and set the valve clearances, they are the main cause of noise, and something that can also affect the running of your engine.

Stripping and rebuilding your engine isn't going to change the way it runs.

It's like saying i'm going to perform open heart surgery to correct your eyesight.

The only thing that was of slight concern would be the oily plugs, but combined with everything else you've said it is most likely running rich and fouling the plugs, the other internal problem would be worn bores which would scrap the engine as you can't get oversize pistons and rings.

The Jamming start can be fixed at worse case by removing the clutch cover.

The running problems you need the carbs properly looking at and probably new rubbers to seal them onto the engine, jetting correctly set and float heights are quite critical.

Compression test the bike first. If indeed you do have worn out bores scrap the block.
Remove all fluids
Check / Set Valve Clearances
Strip, set and rebuild carbs
Install new carb rubbers
Remove clutch cover and inspect starter motor and sproket teeth, replace where necessary.
Check water-pump and thermostat as well as coolant flow around bike.
Install new fluids
Check altenator / reg-rec output.
Balance carbs

But yeah, go ahead and strip the engine if you want 'peace of mind'. Your problem(s) are elsewhere though

[CMSMJ1]

Great post Neo.

[pagan1001]

Not meaning to be a dick but I have checked everything you have mentioned.
I have fitted new carb rubbers and checked the clutch side of the engine and all is well also have given the carbs a full service. Honestly Neo I have been through everything apart from inside the engine.
I have fully rebuild both heads and had them checked out.
You may be right about some electrical problem but have been going through that as quickly as I can.,

Its the fact that when I bought the bike it was oil starved with the pump gauze being blocked that is the main reason I want to get inside the engine as I dont know how long it was like that.
I mean pretty much everything you wrote I have either replaced or checked which as you say either there is an electrical fault I have not come across yet or it can only be internal. I| am buying a compression tester today so this will verify if there is some problem.
I cant give you any more answers as I have already done everything you have said and I cant really check anything else. But thanks for the post xxx

[pagan1001]

Sorry missed this question? Yes the rev counter is jumping about but the engine speed is also changing by that amount also.