Derbi GPR 50 (1999?) 'Cracked Piston' Buy Or Not?

[wentalong]

Hey all,

After my first thread the other day and loving the amazing help and info I got back from others I wanted to say thanks, and what an shining first impression to the forum you've all made!

Anywayyy, I've been looking for a bike the past few days and I've found someone with a 1999 (I think) Debi GPR 50 with an 80cc kit on it, the person wants 300 for it (haven't negotiated yet) due to him claiming the piston has been cracked? How does this normally happen? are there side affects of this? Like cracked block or shaft etc... Also can I guarantee this won't happen again?

What do you all think on this buy? Is it worth it? And worth the risk of something else being wrong? He claimed everything else worked so he can show me the electrics working at leastt,

Thanks for all the help and suggestions in advance!

Curtis

[Noxious89123]

If the piston is cracked I would have thought there could be damage to the bore too. I'm certainly no expert though!
____________________
'06 Honda CBR125RW-6 ~ '00 Honda CBR600F-Y ~ '07 Honda CBR600RR-7 ~ Bikeless
'53 Ford Ka 1.3 ~ '03 Vauxhall Astra SRi 1.8 ~ '52 Vauxhall Astra SRi 2.2 ~ '53 Vauxhall Astra GSi

[wentalong]

Yeahh thats what im thinking, However even if the Cylinder is ruined a kits only 130 from adrenalin pitstop

https://www.adrenalin-pedstop.co.uk/p/Polini_80cc_cylinder_kit_for_Derbi_Senda_Gilera_RCR-1771.aspx

as for fitting from my garage im not sure but i shouldnt imagine it being too much,

[P.addy]

At £300, factor in a rebuild @ £350.

Nearly 700 to get it OTR illegally.

Or Just buy a working 50

[wentalong]

yeahh but its 300 without negotiation, im preety sure i could have it at atleast 250 and maybe 150 if i can persuade him the engine is useless thus so is the bike and these bikes tend to sell for 700 at decent condition so ideally i can make money out of it if i wish,

[DrDonnyBrago]

If you have to ask if it is a shit idea, it is a shit idea.


What I mean by that is, if you were capable of fixing it up cheaply and selling it on, you wouldn't need to ask on here.

[wentalong]

well i suppose you have a point, but i was curious as to what normally causes pistons to crack (i know there are a number of variables)

Also im looking for everyone's opinion on the matter, as we will all have different views on it, the way i see it i could get £700 worth of bike for £400 providing i get the bike for £200 and new 80cc piston kit &fitting for £200 or more,

so if i was to fix it and use it, still shit idea? if so, how comes?

Thanks,

[Ingah]

[MyCarVsYourHe...]

The fact that the kid put on an 80cc kit means he's messed with this bike, and you have no idea how much he's messed with. He was able to diagnose that the piston was cracked, but hasn't bothered to fix it, this may mean he thinks/knows it will be a recurrent problem. Like the guy above said, he either doesn't want to spend to much on the bike (more then it's worth) or he doesn't fully know what he's gotten himself into, possibly causing damage to other parts of the engine in the process. I'm assuming you're 16? because why else would you buy a geared 50/80cc, if I'm right then I recommend riding a scooter until your 17, then you can get on a reliable 4t 125 that will do the same speed for a fairer price, and then do a bike test.

If this guy offered me this bike for £200, I may be tempted to take it as a project because I may be able to squeeze a profit out of it, only because I live near a great breakers yard, but I wouldn't hold high hopes for it.

[wentalong]

Thanks for all the replies guys

Yeah i'm 16, and i understand what everyones said, and i suppose i may have to go down the scooter root then however im going to be cheeky and throw an offer in for 150, see what he says and go from there because if he takes it i'd probably get that for breaking it.

Also are there any scooters you'd immediately recommend for a 16 year old? I've only got about £600 maybe £700 to spend and was thinking of having a ped that leaves lots of room for small improvements/add-on's like stereo system etc...?

Thanks

[P.addy]

[MyCarVsYourHe...]

Your only going to have it until you reach 17, my advice is to keep it stock, no modding or tuning because that will actually kill it's resale value, no one in their right mind wants to buy a 50cc scooter that's been f*cked with. Peugeot speedfights and Gilera runners tend to hold their value, and they fall in that price range for a good conditioned speedy expect to pay up to £500, and up to £700 for a healthy runner. Or get on Ebay and try to find a Gilera DNA, they fetch about £550 for average condition. Better riding style then the traditional scooter seating position. Try to stay clear of geared 50cc bikes.

[wentalong]

lol fair enough i was just going through a moment of madness where i saw someone slap a turbo on his ped :') this is what i saw

https://www.youtube.com/watch?v=Bn272R2wIJQ

beautiful in its own way

But i know what everyones saying but the one thing i really want to do is make it sound less like a hairdryer so i was hopeing if there was an exhaust i could find that'll reduce the sound i wouldnt mind buying it, as for piston kids and everything else i suppose it wont be worth my time or money as im only using it till november

[MyCarVsYourHe...]

Sorry but standard 50cc 2T are always going to sound like hair dryers, Any performance exhaust will make it go NEEEEEEEEEE instead of zzzzzzzzz. As long as you keep the stock exhaust the sound shouldn't be a problem.

[Pete.]

As above, about the cheapest major component to replace in an engine is the piston. He could sell it on easily if he just bought the cheapest crappiest piston rather than as a non-runner. I've seen some biblical animalisation of engines at the hands of clueless youths, there's surely something nasty hidden in that engine - my advice is get it very cheap and budget for a replacement engine or let it go.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[wentalong]

Hmm yeahh your very right mate, ii judt asked and he said the lowest was 300 so I'll get back to him in a few weeks if I don't already have a ped and hopefully he'll realise no one wants it and he'll let me have it cheap, and I may be young but I know to steer clear of those chinese parts! only top quality for my ped

Also, how comes everyone recommends I stay away from geared 50's?

[MyCarVsYourHe...]

To much maintenance for the same speed as a reliable 4T 125.

[P.addy]

[Robby]

To go against the grain a bit here, I would buy it.

It is likely that it has had an 80cc kit fitted, but the rest of the fuelling system hasn't been adapted to cope with it, leading to a cracked piston.

I would fit a normal 50cc barrell and piston, and make sure that the carb is set to factory settings, or the recommended settings to go with whatever exhaust has been fitted.

No matter what else has been butchered, you'll have the whole thing stripped down so you can see. It would also be worth taking off all of the bodywork to get a look at the frame and wiring, in case anything there needs attention while you have it apart.

This way you would turn 17 with a bike you can sell, some good experience of riding a geared bike, and some knowledge of how to fix things. All very useful skills that will save you thousands over the next few years.

Whatever bike you buy at that sort of price, it will need some work during the next year. Don't be scared to ask for help during a major thing like a rebuild, someone on here will probably be local and happy to pop around and give you some pointers. Follow the Haynes manual, don't scrimp on anything during a rebuild, and make sure that gasket faces are spotlessly clean. This can take a while.

If I could have had a bike like that on the road for under £600 when I was 16, I would have been a happy boy.