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Nsr250 Mc21se Rothnans


paul8899
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Being as the coke test is taking a while I decided to try and finish the fork bottoms off

So after 4 hours rubbing them down they now look like this

20161002_172501_zpsrnu24a99.jpg

20161002_172523_zps5enlrwu8.jpg

20161002_172554_zpshontrrbf.jpg

They just need another going over to get them how I want and the should be ready.

When I got ever so slightly bored of rubbing all the marks out of these hateful things I took the carbs and reeds off to see how the crank looks.

It looks like a crank so that's one potential problem out of the way. While I had access to the crankcases I filled up the top cylinder with petrol and it leaked into the other case so at least I know what's wrong.

When I took the reed blocks off I found a couple of bits of nylon in there and they looked a bit like this

20161002_152016_zpse45uhhxx.jpg

Are these standard fitment ?

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3 hours ago, paul8899 said:

Being as the coke test is taking a while I decided to try and finish the fork bottoms off

So after 4 hours rubbing them down they now look like this

20161002_172501_zpsrnu24a99.jpg

20161002_172523_zps5enlrwu8.jpg

20161002_172554_zpshontrrbf.jpg

They just need another going over to get them how I want and the should be ready.

When I got ever so slightly bored of rubbing all the marks out of these hateful things I took the carbs and reeds off to see how the crank looks.

It looks like a crank so that's one potential problem out of the way. While I had access to the crankcases I filled up the top cylinder with petrol and it leaked into the other case so at least I know what's wrong.

When I took the reed blocks off I found a couple of bits of nylon in there and they looked a bit like this

20161002_152016_zpse45uhhxx.jpg

Are these standard fitment ?

Those forks came out excellent! Could you please make a small tutorial on how to do this?

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I dont know how paul done his, but a good way i found to get that ' factory ' honda look was to finish them off with a course scotch pad, plenty of wd40 and do em in a circular movement, not up and down.

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I managed to get the fork leg straightened out today :)  

To do this I made some nylon blocks up which had half the diameter of the fork leg machined in and then I whacked the high spot of the bend until it was straight.

The reason I made nylon blocks instead of using v blocks was so that the fork had a big bearing area which will minimise any chance of deforming the fork when it's under pressure, plus the v blocks have sharp edges which could mark the leg when it's being un bent.

20161003_173914_zpsyzuexkdo.jpg

Once I'd got them looking pretty flat by rolling them on a surface plate I checked the ends by turning the legs in the nylon blocks and checking the run out with a dti.

They aren't running exactly true but I think .004 will be good enough

 

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20 hours ago, Dexter21 said:

Those forks came out excellent! Could you please make a small tutorial on how to do this?

Here's how I did the fork bottoms.

First off I filed the big marks out using a swiss file, you have to make sure that they are filed at 90 degrees to the fork leg because if you angle the lines then when you come to rub them down the filing marks will be harder to hide.

Once I'd got rid of the dents and marks I locally rubbed down the areas that had the most damage with some 60 grit emery, again making sure that the direction was the same

20161003_175116_zps6ehpggzd.jpg

Then I wrapped some emery around the fork leg

20161003_175041_zpsr7ootrtv.jpg

When I was doing this I was careful to get the lines straight as it's easy to get them angled when moving along the leg

Then I finished them off with red scotchbrite

20161003_175137_zpsbmszmguj.jpg

Again keeping the direction the same. When I used the scotchbrite I did the leg in sections because if you do it all in one go it's easy to get swirl marks on the leg which dulls the emery marks down.

The important bit on doing these is to keep the direction the same or you'll lose the brushed effect and you might as well get them bead blasted and save yourself a few hours

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26 minutes ago, lesviffer 750 said:

I dont know how paul done his, but a good way i found to get that ' factory ' honda look was to finish them off with a course scotch pad, plenty of wd40 and do em in a circular movement, not up and down.

I did try them doing this but the swirly marks did my head in so I got them all straight ( mostly )

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3 hours ago, paul8899 said:

Here's how I did the fork bottoms.

First off I filed the big marks out using a swiss file, you have to make sure that they are filed at 90 degrees to the fork leg because if you angle the lines then when you come to rub them down the filing marks will be harder to hide.

Once I'd got rid of the dents and marks I locally rubbed down the areas that had the most damage with some 60 grit emery, again making sure that the direction was the same

 

Then I wrapped some emery around the fork leg

 

When I was doing this I was careful to get the lines straight as it's easy to get them angled when moving along the leg

Then I finished them off with red scotchbrite

 

Again keeping the direction the same. When I used the scotchbrite I did the leg in sections because if you do it all in one go it's easy to get swirl marks on the leg which dulls the emery marks down.

The important bit on doing these is to keep the direction the same or you'll lose the brushed effect and you might as well get them bead blasted and save yourself a few hours

Thank you very much for taking the time, I will try that too.

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Well, I managed to get the front wheel in and luckily enough it now nice and straight

20161008_165539_zpse2fkrqxv.jpg

20161008_165739_zpstbygx2w8.jpg

Now I've got to re-paint the disc centres, the top yoke and clean the calipers.

Once that's done I suppose I'll have to tackle the engine

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Being as the sun was out I thought I'd get a better picture of how the forks turned out

20161009_110133_zpsxbtqemmf.jpg

I'm quite happy with how they came out :)

I also started to clean the discs up, this is how they came out from being dunked in coke for a week

20161009_120558_zpspwbfodxu.jpg

The coke took most of the ingrained dirt off and they only needed a quick wipe down to get the rest off.

I found the masking tape today which gave me an idea, so after about an hour the discs looked a bit like this

20161009_191407_zpshuh3rrww.jpg

I'm going to lacquer them in the week then they can be fitted.

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2 minutes ago, jim157 said:

Do you mean solar gold (like used on the mk3 capris) ?  Moondust seems to bring up an actual silver colour. 

I think the original disc colour was silver so I used the paint I had left over from when I did the discs on my 3ma.

I might paint them gold but I'm not sure if they should be silver or gold, some of the pictures show silver , some are gold.

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On 09/10/2016 at 10:01 PM, jim157 said:

Ah right sorry, the silver looks like a pale gold when viewed on my phone.

Just looked again on my tablet and they're clearly silver.

The crappy lighting in my shed doesn't help either ;)

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Thanks, it's looking a lot better than it did :)

There's only a few little jobs left to do on the bike before I have to try and fix the engine.

I've ordered the centre bearing from my local bearing supplier and all going well I'll have it in my grubby little mitts at the weekend, then I'll see how difficult it is to rebuild a crank !

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7 minutes ago, Dexter21 said:

A press, some common sense and time would get you most of the way there. The condition of the big end surfaces will dictate if it is salvageable though.

I've got access to a press and some time so I'm most of the way there ;)

I've had a look up the reed block hole and the big ends look ok so it's looking hopeful that it's not scrap.

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17 minutes ago, Dexter21 said:

It always does, the prettier you get it looking the faster it sucks up your money.

It's not so much the getting pretty that's the expensive bit, it's the getting running bit I'm not looking forward to.

So far I've spent about £70 ( and called in a couple of favours ) to get it looking like it does.

It needs a new chain / sprockets , brake pads and lines and I think thats it chassis wise.

If I'm lucky the big ends will be ok and all the bottom end will need is the centre bearing changed which should cost about £150 ( bearing,seals and gaskets ) , if it needs a new crank then it's just over £600, if it needs a replate and new pistons as well it's about £1100.

One good thing is that if it needs everything doing to it then I'll have an almost new engine so it "should" run perfectly, the bad thing is that I'll probably have to sell the rg125fun project I've taken forever to get halfway through

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Ahh herein lies the trap. Now £600 + £1100 seems too much. Give it some more TLC and many shed hours and for some reason  £1700 seems not so much. Anyways NSRs are lovely and it will reward you when it's done.

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1 minute ago, paul8899 said:

The £1100 was for everything, if it was a £1700 engine rebuild I'd be selling it !

I'm hoping that it's going to be as good as it looks :thumbsup:

Astonishingly £1700 would not suffice for an engine rebuild if you were doing this before 2015. consider yourself lucky and yes it is as good as it looks! :D

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