View Full Version : Apilia AF1 50 1986 Rebuild

10-09-2013, 06:33 AM
Hi, my name is Stuart and I'm a new forum member from the UK.

I joined because I have purchased an 86 Af1 50 project in bits and would like to share the pics and progress as these bikes are getting quite rare.

I used to own an AF1 125 Europa but now mainly ride off-road bikes (KTM 250exc). I am trying to decide if I can actually obtain parts for the Aprilia AF1 as it is in need on an engine rebuild, suspension rebuild, panels ect.

If anyone has any info at all on this model please post below as it would be much appreciated.


10-09-2013, 03:46 PM
Hi Stuart!
Nice Af1! Am I right in thinking they're RV engine'd? Patrick has an Af1 or two If I remember correctly.
Is that a Series 2 escort RS turbo in the background? Is it yours?

Getting parts for the engines could prove difficult, have you thought about an AM6 swap?

10-09-2013, 04:34 PM
Vsmotoparts have a 2 top ends (none stock tho) don't have any cranks tho have 1 clutch 3 carbs and no exhausts it will be very hard to get fairings and as hard to get stock engine parts most prob

10-10-2013, 09:28 AM
Thanks for the replies guys. I only paid 100 quid for the bike last week.

Yes it is the rv engine and Patrick has helped by supplying me engine diagrams.

If it's possible to run an am6 I will just because of part availablity, are the mounting patterns the same?

My main concern is obtaining the one missing panel, without it the rebuild can never be finished.

And yes, the Escort is mine although it's not an s2, its an xr3i running a 2 litre zetec.

10-10-2013, 10:58 AM
I wouldnt deal with VSmotorparts, especaily not with these bikes.

Did you download the files yet?

AM6 engine doesnt drop straight in, and if you get it to fit than you need to look for a rare RS50 1998 AM6 sprocket, wich is narrower and has an offset compaired to the 1999 RS50 AM6 so it can be lined up with the rear sprocket.

10-10-2013, 03:37 PM
I would really consider an Am6 swap. Get a nice mild 70cc cylinder kit on it with a 21mm carburettor and it will be a blast to ride.

10-10-2013, 05:00 PM
RV4 engine is also pretty fast mate, verry little resistance/drag.

Problem is the cranks, verry hard to find an "race" crank, i had a custom made one as mine was used for racing but i blew the big-end bearing and its probably done a lot of damadge.

Only 1 stock engine left here wich i need if i want to rebuild mine, still not sure about that.

Like i said, mines a Mono seat version, think the side fairings are difrent on that also.

50cc.nl does have various parts for the AF1-50 (RV4)

10-11-2013, 01:14 AM
Thanks for the posts guys, I will consider both engine options but this weekend I will look at both engines I have and see what I've got to work with.

I'll post pics on here as I think I've potentially got an rv4 and am6.

Patrick, I have downloaded the files and they are great, actually got something to work with now.

10-11-2013, 07:34 PM
OK, i pull them offline than wen i get back home.

Use www.photobucket.com to upload your pictures to and than use the IMG links to post them here (just copy and paste the link directly here)

10-13-2013, 02:31 PM
I had a bit of time spare to start looking at the engine today. Turns out I have 2 rv4 engines however both have faults with the left hand gear casing. I have two barrels and heads. One looks to be the standard minarelli, the other a polini 70cc kit. The polini kit is knackered though, the piston and head is ruined, looks like something has been above the piston. The cylinder skirt is also cracked. My plan is to strip the bottom ends and try to make one good engine.

I will also link the pictures via photobucket.


10-13-2013, 02:33 PM

10-13-2013, 02:58 PM

Pictures via photobucket

10-13-2013, 04:03 PM
Aluminium Polini it is verry good on these engine if you want to replace it, i had modified my clutch to avoid it slipping, but dont recall exactly how anymore, been years since i messed with a RV4 engine...

faults with the left hand gear casing? any pics of whats the fault?

10-13-2013, 04:31 PM
The starter motor bracket i broken and there is a chip in the gen cover. I think I can get it welded and cleaned up, I will take a pic when I get a chance. The big end bearing on one of the bottom ends has gone but the other feels good.

I'm tempted to fit a polini kit if the price is right.

Can you obtain ignition keys via aprilia?

10-13-2013, 06:06 PM
You can get these keys at any good locksmith mate, but you need atleast one original key, otherwise you have to buy a w hole lockkit wich isnt to expensive imitation for these bikes.

10-14-2013, 04:34 PM
I haven't got a key for it maybe I'll try the local aprilia dealer.

When my gear puller arrives I'll rebuild the bottom end if I can get hold of a gasket set.

10-15-2013, 08:37 AM
If you can not find new parts that you need for it let me know, i might be able to find someone who has.

10-15-2013, 03:01 PM
Thanks, first I will need a gasket kit for the engine, I saw one on ebay for a 1986 af1 sintesi 50, might go for that.

Also that rear panel on the right.

10-15-2013, 04:02 PM
That gasket kit is for your bike than.

10-15-2013, 04:04 PM
Ahh thats good, it says a full gasket set

10-20-2013, 01:21 PM
Not much progress on the rebuild I'm afraid.

Started splitting the engines but encountered all of nasty surprises. Rounded off bolts, welded on sprockets, cracks ect.

I need to purchase a dremmel cutting tool and try again.

10-20-2013, 02:09 PM
Not much progress on the rebuild I'm afraid.

Started splitting the engines but encountered all of nasty surprises. Rounded off bolts, welded on sprockets, cracks ect.

I need to purchase a dremmel cutting tool and try again.

Sounds like its been bodged at some point in its life :( Like all learner legal bikes.

10-20-2013, 03:02 PM
Yep definitely some botchery, luckily I have a second engine in slightly better condition.

11-03-2013, 04:21 AM
Sorry for not posting in a while but I have been waiting for parts, can anyone tell me the flywheel puller thread size for the rv4 engine?

11-03-2013, 10:55 PM
Same as for the RS50, 19x1

Remember to give a shout if you can not find parts you need.

11-04-2013, 07:06 AM
Thanks very much I will order one.

On the 1 of the 2 engines the flywheel has been removed but I'm still having problems splitting the crankcases.

Is there a good method that you have found?

11-05-2013, 04:23 AM
Long time since i worked on one, think theres a few points that stick out where you can push the halfs apart, but best way remains using a specail tool that bolts into one crancase half and pushes the crankshaft out so it pushes the other crankase half off with it.
You can try hitting the crank and output shaft gently with a plastic hammer to help the crank halfs to come apart.

11-05-2013, 03:08 PM
Thanks for the info, I will try again this weekend.

My flywheel puller turned up today.

11-05-2013, 11:20 PM
Dont forget to mark of the position of the stator ground plate on the crankcase or you never get it back the way it should be (not sure if its fitted the same way as the one on the AM6 though)

11-06-2013, 07:43 AM
I have marked the outside of the flywheel, will that be sufficient or do I also need to mark the stator.

I'm sure it will be clear once I remove the flywheel.

11-07-2013, 04:35 AM
Dont need to mark the flywheel, and theres no point in marking that as it can only go on one way because of a woodruff key.

But the Stator plate can be rotated on the screws that it bolts onto the engine with, so before you take that off make sure you mark it exactly so you can fit it back with in 0.5mm of the way it was installed, otherwise you might have a reall hard time getting it back in the right position.
If the ignition timing is off and you have to install the flywheel, use a timing light, note how much its off, take the flywheel off, rotate the stator plate, fit the flywheel, check with timing light, etc. untill its timed right again.
So just marking the stator plate will save you all that trouble.

11-10-2013, 12:45 PM
Thanks for the info, now that I have split the engines I understand what you mean. I have marked the stator plate so hopefully won't have to mess around with ignition timing.
I noticed a few bits when I was stripping the gearbox/ bottom end.
1)The gear selecter was seized on one engine.
2) Big end bearings had seized so will need replacing.

I'm hoping I can still get hold of the gear slecter shaft seal as it needs replacing.


11-10-2013, 12:55 PM
I have also got some welding work to complete on the outer casing where the starter motor sits.236328236329236330

11-11-2013, 04:08 AM
the plastic gear is from the RPM counter, its supost to drive a worm/corkscrew shaped gear that sits there in the opening on top of it, hope uot removed that your self or got a spare in the other engine.

write down everything your missing or thats broken, i have a look than in the end what ive got for spares on these bikes, got e few crates of stuff but its a lot of work to go trough them so anything thats missing in the end you couldnt get of ebay in the uk, i have a look for than.

11-11-2013, 07:40 AM
Yep the plastic gear was already knackered and stuck on the shaft, so I decided to cut it off as I have a spare.

The next stage will be for me to purchase new bearings / seals, then weld any damaged areas of the casings.

I will then sand blast, repaint and install the new components.

Don't suppose you have got a spare RH side panel have you?

11-12-2013, 11:59 AM
I dont have spair fairings, and like i said, mines a mono seat.
I would have to look also what state the fairings are in, i crashed it hard wen my gearbox blew up causing the rear wheel to lock up completly at 80mph+
I rather not sell the fairings because im not sure what i want to do with mine.

11-12-2013, 04:04 PM
yes thats fair enough, fairings are rare so I don't blame you for wanting to keep it.

Wow 80 mph is fast for a 50cc, what capacity you running?

11-12-2013, 05:34 PM
yes thats fair enough, fairings are rare so I don't blame you for wanting to keep it.

Wow 80 mph is fast for a 50cc, what capacity you running?

80mph is easily possible with a well ported cylinder kit, 21-26mm carb, race pipe and ignition timing changes. I don't know what kits are available for the RV4 engine...

This thread really makes me want to purchase an old single swing arm RS50 or an AF1 50 but I need funds for a car!!

Can you buy big end bearings for these cranks and do you have the press tool to swap the bearings? Can you not get new crankshafts for these?

11-13-2013, 06:14 AM
I ment 50mph (80kmh)... needle bearing in the gearbox blew and the shaft punched a hole in the engine casing at that point (probably the result of it being run on Nitromethanol feul)
Also had 70cc setup wich did over 80mph easly, but that setup ate angine, only lasted a few hours at most and than i needed an other one, usualy the same needle bearing blew, but last time i ran the 70cc setup it snapped the woodruff key (probably didnt tighten the flywheel up enough) and it trew blue flames out of the exhaust from it misfiring and wrecked the big end of my custom made crank shaft.

You can get big ends with conrods for these cranks, just like for the AM6 engines.

11-24-2013, 11:40 AM
Right I have been making slow progress but have finally removed the crank (gear puller took ages to arrive).

The big end bearing is knackered and there is some wear to the crank where the main bearings have seized.

New crank, or split and replace the big end what is the best route?

Also I have not had chance to measure the main bearing dimensions, but if anyone knows the sizes it would be helpful (same with the crank seals)


11-24-2013, 01:09 PM
My advice would be to get a new crank.

11-24-2013, 02:53 PM
Do you think its beyond repair?

I wondered whether I could split the crank and replace the rod bearing

11-24-2013, 03:32 PM
Do you think its beyond repair?

I wondered whether I could split the crank and replace the rod bearing

Im sure you could fit a new big end, but I would prefer the reinsurance of knowing the crank is new. Is the little end eye perfect?

11-24-2013, 04:03 PM
Yes the little end of the rod looks ok.

I might get a quote to split the crank at my local engineering firm. They've done plenty so will work out the most economic route

11-24-2013, 04:47 PM
Yes the little end of the rod looks ok.

I might get a quote to split the crank at my local engineering firm. They've done plenty so will work out the most economic route

I dont know how much a new crankshaft costs for the RV engine, however, if its under 150 I'd fit a new crank. Not worth messing about.

11-25-2013, 03:34 PM
I got a quote today for 35 quid to strip and rebuild the crank if I supply the rod assembly.

They will also inspect the crank first. Might give it a go.

11-26-2013, 04:16 PM
Sure thing, it's called SEP, in kegworth, derbyshire.

I've used them for rebores in the past, really helpful.

12-03-2013, 04:43 PM
Any progress?

12-08-2013, 08:55 PM
Yeah any update on this?

If your after info on the af1 models use Google translate and have a look at this: http://www.125stradali.com

I'm keeping an eye on this I've got an '89 af1 replica I'm sorting at the moment for my Mrs' lad. Funnily enough I'm in Northampton too!

Have a look here if you want a peek at my thread...


12-11-2013, 07:38 PM
better just ask me :p: but really for you guys only this bit is intressting (i didnt read it my self to see if the info is actualy correct): http://www.125stradali.com/01/19/af1-50-19861989/

He still didnt reply hey? im wondering if hese still looking for the fairings, if so i might have a look in the crates if i can find the side fairing and take a pic of them to see if they would fit because mine has a mono seat and they might be slightly difrent.
Not rebuilding my 1986, to much missing, not sure about the 1989 one also, all the fairings are knackered, and one spoke on the rear wheel is badly damadged, but with good wheels it could be made into a nice naked bike by mixing some of the bikes parts up and doing some chopping.

12-15-2013, 10:36 AM
Hey guys, sorry for not updating in a long time.

I haven't been able to make any progress due to financial commitments elsewhere. I still need to sort out my bottom end bearings, gaskets ect.

I have been able to start preparing someengine casing's using my mates sand blasting kit.

Patrick, I've been looking for the fairings for my bike continuosly and having no luck.

Amk2vr6 I will have a look through your thread as well. I'm near Market Harborough so not far.

12-15-2013, 10:39 AM

12-15-2013, 10:40 AM
The casing looks much better when taken back to the bare aluminium, but I will still spray black so that it looks orginal.

12-15-2013, 11:32 AM
I have a look and see what i can do with the fairings, dont even know if there in one piece, but guess anything is better than nothing, hope it doesnt cost a furtune to ship from here to the uk.

12-15-2013, 01:12 PM
Thanks, if you do have a fairing I will look into postage.
So is your bike written off from crashing it. It's a shame you can't rebuild it?

12-15-2013, 02:29 PM
Think I might have found the panel i need, do you think it is correct?

12-18-2013, 04:23 PM
I have finally managed to purchase the missing panel

12-22-2013, 02:17 PM
Does anyone know if I could use rs50 forks with and mudguard on my bike?

For example, are the fork diameters the same?

12-22-2013, 02:18 PM
Does anyone know if I could use rs50 forks with and mudguard on my bike?

For example, are the fork diameters the same?

The pre 99 model RS50 forks might fit, cheap enough to try anyway.

12-23-2013, 07:10 AM
Thanks, I will try and spec up a set.

I need to look at other aspects like brake caliper mount, wheel spindle diameter ect

12-23-2013, 12:27 PM
Forks are way difrent mate... way thiner, caliper mount is way off also, front fender suports are also much higher because the RS50 uses bigger wheels.

And the fairing in the picture is not the same as mine, its almost the same but as i suspected the mono seat side fairings are difrent, they come back up a little bit in the rear to join the mono tail.

Im not rebuilding my bike because its been used for racing and its missing parts because of that.

I highly recomend keeping the bike as close to Original as posible or it will lose almost al of its value.

If you need any parts let me know and i have a look what i got laying around, though im not gonna do anything up to the new year.

Hope you enjoy the holidays, Merry Christmas

01-03-2014, 03:44 PM
I think I might need to refurbish my forks then.

Still waiting for my panel to turn up, I ended up buying through paypal so really hope I don't get ripped off.

Yes I think keeping close to original will be best

01-04-2014, 08:09 AM
Think my forks are in perfect condition, dont think they been shortened, but not sure, think they just lowered the bike on the forks and they only made them stiffer.

01-07-2014, 04:10 PM
The chrome on my forks is pitted, not sure the seals will last long or even work but I could try fitting new ones

Did I mention I also snapped the fender on it the other day. Doh!

I'm finally sending the crank away tomorrow to be separated

02-18-2014, 07:16 AM
Right I relaise progress has been very slow.

But I have just received my crank and rod assy back from the engineering shop.

Just crank seals and bearing to go and I will be able to rebuild the bottom end.

02-20-2014, 02:23 PM
Progress is very slow man! Have you sorted a decent top end kit?

03-30-2014, 02:23 PM
Very slow indeed, the project is on hold as I've just bought a house. But I will restart soon.

04-02-2014, 03:53 AM
Optionaly if you can get one you can trow in a gear selector roller of a RV4 off road style bike or Red rose wich will reverse the shifting patern, it than goes 1st up from neutral, and 2nd, 3rd, 4th down.
I done that on mine.

06-25-2014, 04:39 PM
Finally getting started again, built up the bottom end to test the gears all engaged and to make sure I had not lost any parts. I noted I need to sort end float on the gear shafts, I've also purchased new main bearings and seals 255941255941

06-26-2014, 06:16 AM
Might been worth taking the whole engine apart, taking all the old paint of and respraying it with heat proof black paint mate...

06-26-2014, 03:18 PM
Yes I think it needs tidying up, I was actually debating hand painting the bottom end and spraying the cases

06-26-2014, 03:18 PM
New gaskets, bearings and rod assembly

06-26-2014, 06:18 PM
Did you make that central gasket your self? or did you buy it?

06-27-2014, 11:54 AM
Should it have a gasket between the halves?

06-27-2014, 12:48 PM
Yes needs a gasket, I bought a gasket set online, bottom and top end. Got a seal kit from Holland. Got to make a decision on the top end now

06-29-2014, 03:37 PM
Yes needs a gasket, I bought a gasket set online, bottom and top end. Got a seal kit from Holland. Got to make a decision on the top end now

I only ask as the AM6 engines don't use gaskets between the two halves.

06-30-2014, 01:35 PM
That's interesting, how does it seal around the bottom of the crank? Metal on metal is normally a bit risky, or do you use sealant?
Anyone tried a 90cc top end kit?

06-30-2014, 02:56 PM
AM6 uses sealand to join the 2 crankcase halfs.

90cc AM6 or 90cc RV4???

07-01-2014, 03:11 PM
90cc rv4 kit cheap on eBay, quality is debatable.
My oil seal kit turned up today, output shaft, crank seals eft
Can't post the pic for some reason

07-04-2014, 03:09 PM
Assembled the clutch and surrounding drive train and the water pump and oil pump today.
I'm starting the frame on Sunday, I'll post pics

07-06-2014, 02:48 PM
A couple of pics of the 90% complete gearbox assy.
Just need to assemble the stator and flywheel

07-13-2014, 02:43 PM
Can anyone tell me how long an rs50 shock is?

07-17-2014, 02:58 PM

07-17-2014, 02:59 PM
Frame all stripped and now at the powder coaters with a load of other bits (swing arm ect)

09-02-2014, 01:37 PM
New rear shock assembled onto the frame and polini 70cc top end assembled.
Rolling frame will be ready soon.
Pictures to follow

10-23-2014, 02:56 PM
Update to no one lol
Bike is almost ready to start

05-13-2015, 06:31 AM
Bike is now running and all electrics working

05-13-2015, 09:53 AM

06-01-2015, 06:28 AM
I have not been able to upload pics for a while, I am not sure why but when I try to upload it says it has failed.

Any suggestions?

Lights working now as well, but clutch isn't.

06-01-2015, 06:30 AM
old pic

06-01-2015, 06:34 AM
Slightly newer pic, but without seat, tank, lights ect.
Need to complete the following:
- Spray tank / panels
- Check ignition timing
- sort the brakes

06-01-2015, 06:36 AM
Current setup
Arrow expansion pipe and silencer
70cc polini kit
26mm PHBH carb

06-02-2015, 04:52 PM
Mine are still both in pieces, no plans for them yet here, especaily for the model you have as i do not have all the parts for it because it was modified for 50cc cup racing.

06-03-2015, 03:51 PM
How is it modified Patrick?

06-04-2015, 11:05 AM
lowered front and rear and clipon handlebars, missing oiltank, missing battery holder, missing airbox, race CDI with seperate coil, and a bunch of other stuff. but mainprobblem is the lowered front and rear (1 inch ground clearance) chopped top tripleclamp, missing oiltank, missing airbox and battery holder, all the otherparts i got.

06-04-2015, 03:03 PM
What does the race cdi do, is it programmable?

06-05-2015, 11:59 AM
They belong to a Race Stator with Lighter Flywheel, they where not programable though.

But if you want a good aftermarket CDI i think the Yellow Top Performances should be fine for you, bit more power on topend and can handle high rpm for a long peroid with out blowing a capacitor, fits straight on there same way the Original does.

06-09-2015, 01:47 PM
Have you tried advancing the ignition timing, checked mine with a strobe earlier and is less the 22deg btdc, it is prob in the region of 15deg, so bout 1.2mm. What are your thoughts?

06-16-2015, 06:29 AM
Lights on, timing sorted, started motor fixed,
Next job --> sort the brakes

06-22-2015, 04:16 PM
Patrick have you got a spare front caliper?

07-02-2015, 09:33 AM
This project has been on going for a while now!

07-05-2015, 12:16 PM
Yep, I am in no rush, I just build it when I have spare cash to buy the bits.
Basically finished now but I am trying to find someone to repair the fairing at the minutes.
Almost impossible to find panels for this bike.

09-03-2015, 06:07 AM
You'll all be please to know that I have decided to tackle the fairing myself.
I have already repaired all of the panels using aluminium plate, plastic bonding compound, and filler.
I have also purchased an original 80's sticker kit.
I expect completion in approx. 2 months (if its not too cold in my garage)

09-03-2015, 07:50 AM

09-07-2015, 06:38 AM
Thanks mattology

Unfortunately this project has dragged on slightly, but I am determined to complete it!!

09-23-2015, 06:45 AM
I thought I would share the latest status because I'm really please with the paint colour match. Once painting is complete, stickers will be applied.

09-23-2015, 06:47 AM
Im 50% through painting, it doesn't help that the standard bike has a red, white and blue paint scheme.

09-28-2015, 09:36 AM
This is an awesome project, I have only seen this model when I was 18 in tech college. Seemed so futuristic, great to see not all of them died a death. The engine looks like the one my friends Europa had, kinda squarish.

09-30-2015, 03:33 PM
Cheers, not many about so had to source parts from all over the place.
The engine is an rv4, I have replaced the top end with a 70cc aluminium polini kit, then fitted a bigger carb.
Just putting the laquer on the panels then should be complete

10-11-2015, 12:52 PM
Stickers are on and bike is looking more like it should, test run soon to see how well it runs with the 700cc kit

10-11-2015, 02:09 PM
Yeah it's looking great. :D

I wonder if there's something you can do to pull the fade from the seat.

10-12-2015, 06:12 AM
I have a feeling that it's not the correct seat. Most AF1's that I see are not set up to carry a pillion passenger and have a single seat
However I have seen some that are. Mine also has brackets for rear footpegs.

I might buy a single seat that I have seen on ebay Italy that is a much brighter red.

10-12-2015, 12:46 PM
Yeah a solo seat would look like it belonged on the bike. You could keep both around for those days when you have a Pillion around. :D

10-12-2015, 03:58 PM
I don't think it would move with two people on it, or the clutch would burn out

10-12-2015, 07:10 PM
Sounds like you need some stiffer springs, and a BBK. That bike looks like it would be a screamer! ;)

10-13-2015, 06:15 AM
I certainly hope it'll be a screamer but I am yet to try it out. I will probably ride it and be disappointed with the 10hp