Gn250 Clean up for rebuild

stablepeach · Derestricted Danger Joined: 04 Aug 2020 Karma :

Hi everyone, this is my first post and apologies it's likely to be a long one...

TL:DR I've acquired a GN250 in poor shape, is it salvageable?

Background:

It's been 10 years now since I last had a bike, I was quite comfortable tinkering and doing maintenance on it (XJ600N) nothing significant but I did things like replace/repair the exhaust, dismantle and repair starter motor, replace chain, remove wheels etc. All pretty simple stuff I suppose.

I've been struggling with the urge to get a new bike for a long time, mainly due to money constraints and family... I'm now in a position where I'm looking for something to do in my spare time (hobbies seemed to dissappear with babies) and I have a little bit of spare money so that I can afford to gradually buy bits etc.

As such I've come to acquire very cheaply (and I imagine with very good reason) an old GN250.

My intent is to strip it down, clean it up and put it back together again. For two specific reasons - 1 - I'd like to clean it up, remove all the rust and crap and make it look a bit more presentable. but more importantly 2... I've always wanted to do this. I couldn't do this when I relied on the bike as a commuting vehicle and never had the time or money at any other point. I want to get under the bike and understand how it's all put together and put it back again.

I am well aware of my limitations and also that there is a reasonable chance I will fail. I guess that's why I've specifically not invested too much money up front. I'm keen where possible to clean up and reuse the original part.

So I've done the easy bit... I've stripped it down to the different components and started to try and clean them all up... the frame seems to be in reasonable condition - there's surface rust but this cleans up pretty nicely with a wire brush on an angle grinder. The spokes are rusty but again, seem to come up good without too much work and the rims appear in pretty good stead.

The forks look fine apart from rusty nuts on the bottom, I'm not sure at the moment I intend to do anything, maybe just a bit of paint for the look of it.

The swingarm was pretty pitted and has a few small holes (see pictures) I imagine this needs fixing before painting - I've heard of metal epoxy would this be suitable for this type of hole or would I need to get something welded over the top?

The exhausts are really badly eaten into where they met the engine (more pics)... Sand paper and angle grinder have made a difference but given this is into the metal I'm worried that I'll just thin the metal and weaken the exhausts - are these save-able? Am I on the right path or do these need chucking and replacing?

The tank looks to be in ok condition, two small dents I intend to fill and then paint over.

The Engine is a sorry affair, the plating appears to be flaking off, it also looks like someone in the past may have painted it which has also started to peel off. I'm intending to go at this with a brass brush/dremmel tool to see if I can at least clean this down to see what I'm dealing with. I had hoped to leave this bare metal but now I'm not sure if the finish is going to be horrendous.

I drained the oil out as I wasn't sure what state it was in... I'm assuming it would be advisable to refill it even with the engine sitting unconnected?

I guess it's also worth noting that when I got the bike the engine would turn over - so it seems ok in that respects...

My final question for today - Painting vs powder coating...

Originally my intent was to prime and paint this mysefl, however I've been recommended powder coating. When I then read up on a few places I see that many will do the removal of paint and rust and the rust treatment as part of the service. I'm assuming this comes at a cost but suspect they will do an infinitely better job of it than I would - so I just wondered if anyone had done this and whether this would be a better way of achieving the desired result. This is the type of thing I've seen... https://windridge.co.uk/index.php/non-architectural/motorbikes/prepare-frame

I'm sure some will think I'm an idiot and I probably am way in over my head - but that's kind of the point... I want to learn and try things out that I couldn't on a bike I relied on.

Any help and advice is gratefully received and I'm sure that this won't be the last post on this topic...

Thanks a million,

Matt
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StablePeach

Nobby the Bastard · Harley Gaydar Joined: 16 Aug 2013 Karma :

1) your exhausts look serviceable
2) I couldn't be arsed to read your wall of text to find out why you posted a picture of the casings. Succinct is helpfull.
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
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stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

Powder coat is great, they usually media blast it and prep but make sure it's someone used to doing motorbike frames so the mask/plug the bits you do not want coating.

Be aware that media blasting is also great for finding rusted-out parts so don't have a go at them if it comes back looking like a colander.

Pics of swingarm aren't showing for me but if it's rusted to the point it has holes in, I'd suspect it is scrap or would need attention from a good welder with an awareness of structural soundness.

Give the engine a good clean down with paraffin and a stiff paintbrush to get all that crap off it, then hot soapy water, then cold water. Then make a decision.

Others may think different but I personally wouldn't do anything cosmetic until I was happy I had a running motorcycle. I'd want to hear the thing running, even if it's a total lash-up or at least be confident it is going to run. Imagine powder coating the frame, painting the motor, welding the swingarm then finding the crank's fucked?

If it's being styored somewhere reasonably dry, I wouldn't worry too much about the oil but it'll do no harm to bung some in there.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

Oh yeah.

PLEASE don't go near the frame with a fucking angle grinder.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

Bhud · World Chat Champion Joined: 11 Oct 2018 Karma :

Did you want to show a photo of your swingarm? It didn't come out. Just another photo of your exhaust (which seems fine).

jeffyjeff · World Chat Champion Joined: 02 May 2020 Karma :

Welcome stablepeach,
I'd like to commend you for challenging your comfort zone and attempting repairs you never tried before, bravo. I agree with stinkwheel that it best to hear it run first before committing to further expense. Don't know if I agree that powder coating is best for you in your case, though. Sounds like you could easily spend more than you paid for the bike to have the frame and swingarm powder coated; powder coating is expensive and you can achieve excellent results with a rattle can and some elbow grease. Regarding the swingarm, if it is rusted to the point of holes in it, you are better off finding a used part from a dismantler. Good luck to you and keep us posted on your progress.
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History shows again and again how nature points out the folly of men - BOC

A100man · World Chat Champion Joined: 19 Aug 2013 Karma :

It was cheap I reckon as they are a deeply undesirable bike, but these days practically every dog has its day and there seems to be a following to convert GN250s into 'street scramblers' . That said I'm not sure the semi-cruiser style model we had with a tear-drop tank and slightly stepped seat is the same at the one used for those (youtube) projects...
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Now: A100, GT250A, XJ598, FZ750

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600

pepperami · Super Spammer Joined: 17 Jan 2010 Karma :

As soon as I read brat/scrambler in your post , I lost all interest. Sleeping

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I am the sum total of my own existence, what went before makes me who I am now!

stablepeach · Derestricted Danger Joined: 04 Aug 2020 Karma :

Thanks everyone for the replies... sorry the post was so long I wasn't sure how much of the context was actually useful.

I've edited the post to remove the reference to Brad/Scrambler as really my intent right now is to try and see if what I've got can be made back into something bike shaped and run. I've no intent to remove anything anytime soon.

I've tried again to attach an image of the swingarm for reference.

A few have commented the exhausts seem fine - I have taken this to mean that given a good cleaning/scrubbing they'll be ok? Is there anything specific I can do to make them look as good as they can (polishing the metaphorical turd?)...

Thanks for taking the time to help, this is going to be a long process me thinks...
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StablePeach

A100man · World Chat Champion Joined: 19 Aug 2013 Karma :

Hmm underside on brake side by the looks - likely to be the worst area.

I'd loook for a new (replacement) one if possible but you could still try and get that one welded professionally - with all corroded part cut out. I probably wouldn't trust my 'pigeon shit' on a safety critical part for example.
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Now: A100, GT250A, XJ598, FZ750

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600

pepperami · Super Spammer Joined: 17 Jan 2010 Karma :

Take the bike for what it is.
It’s an older Suzuki GN250.

Get it up and running and mechanically sound, then worry about making it pretty.
I for one am more impressed by a fit & healthy bike that looks a bit tatty than by a sh*t bike that’s all shiny and no go.
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I am the sum total of my own existence, what went before makes me who I am now!

KiwiBob · Borekit Bruiser Joined: 25 Jul 2020 Karma :

jeffyjeff · World Chat Champion Joined: 02 May 2020 Karma :

The exhaust headers look sound. Why don't you consider wrapping them? https://br.pinterest.com/pin/739786676270144973/

BTW your scrambler idea is cool to me. Turning some old POS into a roadworthy motorcycle is a worthwhile endeavor. Have you heard of the "Dirtbag Challenge?" It is a bike build competition in San Francisco for homebuilt custom motorcycles. Check this out for some inspiration. https://www.youtube.com/watch?v=m6GB-s1ib5g
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History shows again and again how nature points out the folly of men - BOC

A100man · World Chat Champion Joined: 19 Aug 2013 Karma :

jeffyjeff · World Chat Champion Joined: 02 May 2020 Karma :

After reading the brat bikes post in "general bike chat", I see your point. Seems that in SF they are resurrecting bikes from the scrap heap and returning them to the road (though I won't go so far as to say roadworthy). But in the UK, people are taking roadworthy machines and relegating them to the scrap heap, or very near it. Sad. No wonder the term "brat bike" makes so many of you fighting mad.

BTW, don't piss all over the 'murican just because of where I'm from. I'm well aware that we have become the laughing stock of the world. Rolling Eyes

no need to rub it in. Hopefully better days ahead.

At least we can all agree about Steve McQueen, right? Cool

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History shows again and again how nature points out the folly of men - BOC

A100man · World Chat Champion Joined: 19 Aug 2013 Karma :

jeffyjeff · World Chat Champion Joined: 02 May 2020 Karma :

Cool. Happy to be here and hope to contribute.
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History shows again and again how nature points out the folly of men - BOC

stablepeach · Derestricted Danger Joined: 04 Aug 2020 Karma :

Thanks again... the advice here has been really useful!...

The dirtbag event looks mental, the best quote has to be the last.

What I've got isn't ever going to be possible to return to exactly how it started as it was in a pretty poor shape when I got it... but I think getting it back to close to seems like a sensible goal for now.
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StablePeach

jeffyjeff · World Chat Champion Joined: 02 May 2020 Karma :

pepperami · Super Spammer Joined: 17 Jan 2010 Karma :

Robby · Dirty Old Man Joined: 16 May 2002 Karma :

The swingarm rust is concerning.

They tend to rust from the inside out - so all the bit around the rust holes is likely to be extremely thin. To fix it properly, you need to cut out all of the rusty and very thin metal and replace with new metal.

Luckily, it's a simple swingarm so not difficult to weld in fresh metal. Get some plate for the flat bit, and appropriately sized round tube for the round bits. Cut out repair pieces with a dremel. If you can the repair section exactly the same size/shape as the bit you cut out, you should be fine brazing it at home. Easier to pick up than welding, and far cheaper tools - just a mapp gas torch and some flux-coated brazing rods.

The tricky bit of the whole process is removing the old metal and cutting repair patches of the right size.

KiwiBob · Borekit Bruiser Joined: 25 Jul 2020 Karma :

stablepeach · Derestricted Danger Joined: 04 Aug 2020 Karma :

So I'm struggling to find a replacement swingarm, ebay has some but the shipping from Australia is a bit, well, pricey.

I've heard that GS and GN bikes are very similar and that the parts are interchangeable, a quick look and the parts do look pretty close.

Does anyone know if this is the case? Thanks.

I've started cleaning up the flaking crap from the engine that appears to be an earlier paint job gone bad...

I've not had as much time to spend on this recently as I'd like, but I'm still going, albeit slowly.

Thanks again for the advice and help.
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StablePeach

A100man · World Chat Champion Joined: 19 Aug 2013 Karma :

stablepeach · Derestricted Danger Joined: 04 Aug 2020 Karma :

Hi, I've had someone offer me a used swingarm which has been media blasted and powder coated, however it has rust holes in it as well.... picture attached... so I'm assuming the advice would be to decline and try to find a cleaner one?

Was a bit surprised that they seem to think this would be fine as the structural welds are ok in which case the one I already have looks in better state tbh.
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StablePeach