I may have a cunning plan, opinions please?

[Tristan.]

I've been wanting to try this non tarmac lark for a while now, after squirming and fishtailing my way down a few cornish mud-covered backlanes I loved the rush, but didnt like the chance of binning my nice bike.

Anyway, in my garage is an NSR125, the plan was to fix it up, sell it and get a 2t 125/4t 250 or therabouts basic off roader, then I had a bit of a brainwave.

Given the NSRs dryweight of 130 odd, why not sort it out for off roading?
Far as I can see it, for the very basic kind of scratching about I'd be doing, there are four things I'd need to sort out:

Tyres - front is 100/80-17 rear is 130/70-17, am I right in thinking off roady type ones tend to be bigger diameters than these? Would I struggle to find some for those dimensions, and what sort of price would I be looking at, they'd need to be legal, but other than that I have the CB for road stuff, so they can be as impractical as they come.

Low down grunt - the NSR will have pretty tall gearing I would imagine, a big rear sprocket might help matters a bit, other than that, just something to live with.

Toss on the ground-ability - since the bikes just been sat in the garage for ages I've pretty much forgotten it in monetary terms, so I couldnt care less if it gets thrown about, risers and renthals with guards would probably go on, but the fragile bits are so small and enclosed by the huge frame that I dont have to worry about them, one thing that looks vulnerable is the exhaust, any suggestions?

Suspention - This one has me stumped a little, would underfilling the forks be an acceptable shortcut, or would I have to sort springs too, or perhaps a whole new front end, the rear shock I can see no easy way round, other than machining linkages for a more suitable shock. I think suspention will have to wait till I have it working and tested.

ta

[mr.tattoo]

bits would snap and fall off so quickly mate, plus the bottom would get ripped off first hint on a rut or bumps
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[Gazdaman]

Agreed, the work required wouldn't be worth it.

You'd need to raise it up ALOT. So new forks and rear shock.
You could get nobblies in those sizes though, not particularly easily though.

So new forks, new bars to raise it all up, new rear shock, new tyres.

And after spending all that money you'd still look like a nob on a sportsbike with nobblies. And it'd be very poor at the job.

Depending on the state of the NSR, sell it and get a cheap offroader, or do it up, sell it and buy a slightly better offroader.

A KLR250 can be about £500 depending on condition.

Gaz

[G]

Nice idea, but afraid I wouldn't recommend it.

I've got a CRM125, which is essentially an NSR engine in a trail chassis.
I've been able to 'keep up' with more sensible off roaders fine on green laning, but I've been putting a lot more work in that those on the proper off-road bikes.
The problem isn't the gearing - as standard the CRM gearing isn't far off the NSR gearing, but the low down power. Riding on a very wet motocross (but no jumps) style track I was having serious issues getting going - the bike either just bogged down because of the lack of low down power, or span up because it had too much power in too low a gear, or I was having to use the clutch to get going at all, again dropping too much power to the rear wheel for the conditions.
While I'd say a lack of low down power shouldn't ever be a problem on the road if you know how to use the clutch, it is a problem off-road.

For trail and enduro, tyre sizes tend to be 21" front and 18" rear. You can definitely find off-road 17" rear tyres that would fit your bike. 17" fronts might be used in some kiddy sizes, but probably on a lot narrower rim.
Your cast wheels are likely to get generally damaged by rocks, where a spoked wheel wouldn't or would at least be easier to fix.

Suspension travel isn't essential, but is very useful off road. You don't have much.

Ground clearance is more useful and would need a general lift, which not only would require new forks, but might mean a new swingarm design (this is something I've wondered when considering converting a Triumph 675 to an 'adventure' style bike).

You could possibly make a bash plate to protect useful engine bits.
Exhaust system on 2 stroke trail bikes tend to stick out too. Yours would be a bit low at the back, but that's only a problem for deep water.

So there's lots of good reasons why not to do it. I'd spend the time sorting it out to sell or swap for a trail bike if I was you, suspect you'd appreciate that a lot more in the long run.

Despite two of my trail bike's being out of action (hopefully the CRM will be working soon) - I should still have at least one spare trail bike, so if you want to blag a go sometime, feel free.

[Tristan.]

Cheers for the information, I've been up to the garage to take a look at the bike since I wrote the OP, for the first time since easter, and I'd forgotten just how exposed the exhaust is, back to plan A I guess. My original thoughts where that one of the big attractions of having a more focussed off roader just used for playing in the mud, is that it doesnt matter if it gets dropped and knocked about, so if it wasn't for the exhaust I might of been tempted to play about on it as it is. Saying that an xr250 went past earlier, and I did think "want it" so hopefully I can get a new toy within a few months.

Thanks a lot for the offer G, though your in Reading right? Bit of a trek and I dont know what hours I'm working for the next few weeks

[m0l0t0v]

[G]

Yep, in Reading, but rarely do off-roading in Reading, though recently it's mostly been going the other way.