Apria 125

[sydduckett]

they were watercooled strokers 21bhp and 12 bhp very good motor if it was me id go for a 250 crosser engine there small cheap and rip ur arms off as for blowing up the reason for that was kids not looking after them that's all very good motors and in a scooter frame u would be a fekin good rider to max it

When all my mates had fizzles I had to be different and went for a fantic, boy did I push that a long way.... I do like the sound of them though. have to agree with you re maxing it out. mate has a Rossa and he's never been able to open her up in the top two gears...

Does Frank Sanderson sell the frame section parts on there own or do you have to get the whole loop as well?

Ta

[tonydevon]

as mentioned already its an aprilia RS125, another possible donor of similar power and size is the cagiva mito

both 125cc eletric start, powervalve etc, realistic 25-28 bhp and 11-12ftlb at rear wheel

gearings simple to work out

take the roll out of the stock tyre, then the roll out of your chosen new rear tyre, and reduce final drive ratio by the same %

rear sprockets are easy and cheap to sort, just get a blank and machine etc to suit your bore and hole PCD etc, or your cheap like me then you simply buy the right size ie 520 and 30T for example, then make the adaptor from sprocket to wheel to suit the sprocket

all the RS125 are 2 strokes, full power is very easy to achive just a small mod to the CDI, but 99.9% of them are done already, what kid would ride a 12bhp when they can more than double that for a few quid LOL

rejet accordingly, this would be the norm anyway as I doubt you use the original airbox,

the cagiva mito at worst is knock restrictor cone out of exhaust or cut off the extra chamber and plate it over, again this is done on 99.9% of them already, rejet and tweak the airbox, if your using it

they go in stock loop with ease, no widening required.

they are no more fragile than anything else, look after them with good oil and jetting correctly, they fine, much like a lammy, except a whole new top end is about £200, they have decent electrics, and in terms of value are pretty much unbeatable

I paid £150 delivered for an engine with cdi, carb, powervalve servo, then got very lucky and got the exhaust for about £26 delivered. was a risk but worth taking as thats all I could afford

safest route would be to scour the ads for a crashed one that still starts and runs, remove all the good bits, flog whats left and at least you know you got a good running motor from the start

[sydduckett]

as mentioned already its an aprilia RS125, another possible donor of similar power and size is the cagiva mito

both 125cc eletric start, powervalve etc, realistic 25-28 bhp and 11-12ftlb at rear wheel

gearings simple to work out

take the roll out of the stock tyre, then the roll out of your chosen new rear tyre, and reduce final drive ratio by the same %

rear sprockets are easy and cheap to sort, just get a blank and machine etc to suit your bore and hole PCD etc, or your cheap like me then you simply buy the right size ie 520 and 30T for example, then make the adaptor from sprocket to wheel to suit the sprocket

all the RS125 are 2 strokes, full power is very easy to achive just a small mod to the CDI, but 99.9% of them are done already, what kid would ride a 12bhp when they can more than double that for a few quid LOL

rejet accordingly, this would be the norm anyway as I doubt you use the original airbox,

the cagiva mito at worst is knock restrictor cone out of exhaust or cut off the extra chamber and plate it over, again this is done on 99.9% of them already, rejet and tweak the airbox, if your using it

they go in stock loop with ease, no widening required.

they are no more fragile than anything else, look after them with good oil and jetting correctly, they fine, much like a lammy, except a whole new top end is about £200, they have decent electrics, and in terms of value are pretty much unbeatable

I paid £150 delivered for an engine with cdi, carb, powervalve servo, then got very lucky and got the exhaust for about £26 delivered. was a risk but worth taking as thats all I could afford

safest route would be to scour the ads for a crashed one that still starts and runs, remove all the good bits, flog whats left and at least you know you got a good running motor from the start

Cheers for that Tony, I think I'm going to give it a go. when you say fits in a stock loop I'm presuming that the tube still finishes just inside the bridge piece area then the new frame and mounts take over?

Ta

[tonydevon]

you going ahead with this, be great to see another bike engined build

I know mines the mito, not the RS125 but my biggest concern was the cooling, I can very happily tell you that it very rarely goes over 60 degrees

saw it rise to 80 degrees but thats only after it was sat on the dyno for a few hours, indoors, warm day and not the biggest fan in the world blowing at it.

the lower power vs say a ypvs is deffo worth the trade off in my opinion, cheaper to buy and rebuild, no apparant cooling issues with rad under floor, and come sale time its learner legal

[sydduckett]

I'm pretty sure I'm going to go down this Route. I have a ratty series two Indian with Spanish and Italian parts that I intend to use as the donor. I want to keep the tatty look so I will stick the rad on the front of the leggies for max air flow. At a later date I'll probably give it pared down street racer look with decent paint but to be honest I'm in no rush as I like riding the rat......

Sef

[sydduckett]

you mentioned using the exhaust it came with, did this take much modding to get it fit the lambretta shape.

Ta

[Yanker]

The geared version is the rs 125 ...the auto is a sr 125 same as a gilera runner or italjet dragster engine ..both completely different the series 4/5 is auto the series 6 is the rs125 geared bike engine

Except the 2T Gilera and Italjet are LC, whilst the SR is not....???? Scooter engines that is.

[tonydevon]

Exhaust depends how you build it. But as its such an important part and expensive to have remade, I built around mine with exhaust fitted to the motor. Just made more sense. I modified the stinger. Same length and bore for obvious reasons but different shape to put silencer where it needed to be. Also shortened the silencer as they are rather long and look silly on a lammy

the expansion chambers for mito and RS125 are both pretty fat, I found that the easiest way to route and fit them was as close to the centreline of the scooter as possible, angled enough to clear the rear wheel when fully forward, this way although your ground clearance is pretty minimal, you retain full lean with no problems, mine leans left and right until the rear runners touch down, and as of yet no real problems with exhaust, it grounded very lightly going in and out of the dyno place as it is a big step with just a very short ramp, ie just built up with some concrete, mines at stock ride height, thats how I wanted it, it had to look like a nearly stock GP as it went past. obviously jacking it up like a lot are, will help with both clearance and increase lean angle

Ratty s2 is my next build. Probably rgv250 motor.

[sydduckett]

Going to start getting things together. first thing is donor engine and pipe. like you I will try and mod the exhaust it comes with. I will be picking your brains a bit if that's okay...

Sef

[tonydevon]

yeah cool, more than happy, Im no expert but my ol banger seems to work LOL

the trick with building things like this is to use what you can and what skills you have, work around things rather than having to make things or spend money to sort it later. planning is a huge part of it, before I even cut the first bit of steel, I knew exactly how I was going to make that scooter, obviously final details are sorted on the fly, but this way theres no nasty surprises, they tend to either cost money or time

it all depends on budget of course, if you got the money to have custom made expansion to fit it etc, then fairplay and go for it

for me the big buzz is making things for as little money as possible, the greatest feeling at the end to be able to say, "I made that" and mean it, rather than just listing a shopping list of people and suppliers etc.