View Full Version : RS50 Track Bike Project

05-09-2009, 03:37 PM
Instead of just asking a bunch of seemingly random questions, I figured that I would start a thread about the transformation of my RS50 (#2) into a track toy.

Here is what she looked like when I rescued her last fall...

05-09-2009, 03:43 PM
Yesterday, I took all of the plastics off and assessed the situation.

Needless to say, the previous owner (who said it was 99% finished) was less than honest. After a few minutes of contemplation, I decided to make her into a track only bike and lose the broken blinkers, mirrors, gauges, etc., etc...

05-09-2009, 03:45 PM
I spent last night (yes, Friday night) tearing down the bike.

05-09-2009, 03:53 PM
So far, I have replaced the top triple (yoke), seat lock, and and gas cap with a set from shannon. Thanks brother!

When the previous owner sent the "key" it was broken off (who knows where) and unusable. That made getting the gas cap off quite a PITA.

Then I went through and started removing all of the electrics that I won't need for a track bike (more questions on this to follow).

05-09-2009, 03:54 PM
The other major project I've been working on is removing the oil injection system.

05-09-2009, 04:14 PM
Now for some electrical questions...

1) If I'm not running lights, do I need the Voltage Regulator and/or Rectifier?

2) I am considering two options for the battery / electric start. What are your thoughts on...?
(a) Keep the battery and electric starter
(b) Fit a battery eliminator and therefore lose the electric starter

Thanks in advance,

05-09-2009, 04:15 PM
Responded to you other post....looks like you pretty much on it.:cheers:
Get rid of the starter,battery.

05-09-2009, 04:32 PM
Well here goes;
Stripped down entire bike to the bare frame. Replaced all the seals,bearings,bushings that needed it. Keep in mind the little swingarm on these bikes only has Nylon type plastic bushings. If you have a older bike they probably need replacing especialy if there was ever any play in the frame/swingarm end bolts. Replaced rear shock with an adjustible I-Shock unit and 850lb spring. But you can use alot of the newer pit bike shocks out there. Front forks rebuilt with new seals,springs,heavier oil. Ditched the speedo drive with an aluminum spacer. Cut the kickstand mount off. Had everything powdercoated at this point. Yes its not cheap but powdercoating takes alot more abuse than paint and in my opinion looks much better. The wheels were also stripped and coated and bearings replaced with race bearings,now they spin alot more free. RS125 Race Slicks can be found on ebay all the time for pretty cheap. 90-120 front rear is best bet. But you can run 110-130 front rear. Replaced the front brake rotor with Galfer,pads with EBC race pads,steel braided lines are a good idea at this point aswell but I had not done it yet$. While the engine is out replaced top end with TOP 73cc kit,21 or 24mm carb will be as big as you can go with this set up. Barnett race clutch kit,springs. Since its a race bike remove the starter and all the electrics,wiring.....everything. You only need the wires from the stator,coil and a kill switch. Removed the oil injection pump and tank..run premix. Reinstall engine with new Metrakit race exhaust,carbon silencer. Now that the bike is rolling around again it gets going a little faster,easier for you to stay motivated. Relaced the top clamp with AF1 race clamp. Woodcraft clipons,bars,whatever grips you like. Race levers aka; CRG,AGV would be nice but they are pricey and you will break them so????? The bodywork is really up to you. I really like a race bike to look the part plus for me it helps indulge my inner racer fantasy to look the part...dumb I know. You will crash so if you put alot into the bodywork it hurts everytime you crash$$$. I love the RS250 body so I bought the 250 front top,bottom and RS50 race solo rear,repainted all including the tank cover and there you go. Very minor trimming to fit very easy. Rear sets would help the riding position but good luck finding some TCM no longer makes them. I'v done three now and these little bike are loads of fun and easy to work on and a blast on the track or the local park lot. Well hope that helps...best of luck on your build and keep us in the loop. If you need any pics of the process I have plenty.

Thanks brother. What did you put in place of the huge oil tank / undertail?

05-09-2009, 04:37 PM
I have been wanting to fab up an undertail but at this time there is nothing under it.

05-09-2009, 09:47 PM
Thanks for the advice bikebike69... I keep going back through your old threads trying to see little bits and pieces. It helps a good deal.

Anyway, with the starter (and all of the subsequent wiring) pulled, there is quite a bit of room!

I ordered the starter and oil pump plugs from AF1.

Now my questions are as follows:

1) Do I need to do anything other than hammer the oil pump plug in where it fits? Which way is out? (Pictures please)

2) AF1 has a picture of the starter plug hammered in, but... What do/did you do to fill the two bolt holes that used to hold the starter in?


05-09-2009, 09:50 PM
One more question about the oil injector pump...

Can you pull/remove anything more than what I have already done (in the picture)?

It seems like there is probably some sort of drive/gear that is creating drag...


05-09-2009, 10:04 PM
As for putting on the Dell'Orto PHB6 21mm Carb...

I'm pretty sure I didn't get the intake manifold from the guy I bought the carb from.

Does anybody have one?


05-09-2009, 10:44 PM
The pump dive gears are little plastic gears,not really worth taking out unless you are in there to do some thing else like the clutch replacement. They can be removed by little c-clips. The plugs sold by AF1 are just little freeze plugs that can be picked up at any auto parts place for pennies. I used them the first engine I built but since have just cut small plate from aluminum or steel whatever I have around the shop,cut the two bolt holes,cut a gasket from gasket stock sheet and there you go. Also you dont really need anything to block off the starter hole just leave it as is but if your really worried about it just do the same as above....cut out plate to fit drill two holes(no gasket needed) and mount. Also check Dan at PodPerformance for a manifold.

05-10-2009, 08:12 AM
Thank you for the link, I sent Dan an email.

We need a shop like AF1 or Pod Performance on the East Coast!!!

05-10-2009, 09:08 AM
I posted a thread wanting to buy a plastic fuel tank cover, but haven't gotten any response yet.

Do you guys think I could repair this with some fiberglass? It will be my first attempt, so any advice would be appreciated.

The two main areas of concern are the hinge and the hole up front/top where the bolt holds the tank down.



05-10-2009, 09:28 AM
Here is the motor from my other RS50 that I drive on the street.

It has an AirSal big bore and a Dell'Orto 21mm carb.

The intake manifold is definitely different (no coolant hoses, etc.).

Do you guys think I should run the stock set up for a while? Or am I going to be ridiculously disappointed?

05-10-2009, 07:13 PM
Does anybody have a MALOSSI MHR Racing Ignition (or opinions about it)?

Does anybody have a different (lighter) flywheel?


05-11-2009, 08:16 AM
What kind of gas cap did you replace the stock one with? pics?

I've always used a standard aluminum plug from home depot and jb welded it over the oil injection hole. Only costs a dollar.

05-11-2009, 03:20 PM
What kind of gas cap did you replace the stock one with? pics?

I replaced it with another standard gas cap. But this time I have the key, and it matches the ignition and seat.

I've always used a standard aluminum plug from home depot and jb welded it over the oil injection hole. Only costs a dollar.

I already ordered the plug from AF1, oh well, it was only like $2!

06-14-2009, 04:43 PM
Alright ... sorry for the long delay, but I have a new baby boy since my last post!

I finally got the bike back together today and got it started on the first bump.

It ran for about 33" (with constant blurping of the throttle) and then died and wouldn't restart.

I let it sit for about 5 minutes with the fuel selector valve off and then tried again with the same result. (After putting it back to ON again, of course)

I can push it along in second gear and it gives a slow steady growl when I have the throttle opened, but it won't restart.

Any suggestions?


06-14-2009, 04:58 PM
Some pics for ya...

06-14-2009, 06:15 PM
tried the plug

Well, it starts and runs for about 30 seconds.

I figured that if it was the plug, it wouldn't start at all.


06-14-2009, 07:04 PM
On the matter at hand... hmmm.

You have fitted a new carb?

try to pour a little petrol directly into the spark plug hole, if it fires up, id say your carb's blocked or theres a prob there...

give it a wirl and get back.

I left the stock carb and cylinder on it for now.

I have a 21mm Dell'Orto Carb (but no intake manifold) and a big bore kit, but I wanted to wait on fitting those until the next top end.

The motor only has 500 miles on it...

The bike fires up and runs for about thirty seconds at a time right now. Do you think it could be a blocked carb still?

06-14-2009, 07:06 PM
Blocked jets?

06-14-2009, 07:12 PM
I mean its worth checking....

Give the carb a clean, easy enought. You dont seem the noob type, i take it you know how? lol ...

It's only gonna be one less thing that it isnt.

Process of elimination, only fuckng way to solve anything on the rs lol.

Good point.

06-14-2009, 07:14 PM
What you seem to have is trash in the carb bowl or trash in the petcock tube.

06-14-2009, 07:48 PM
What you seem to have is trash in the carb bowl or trash in the petcock tube.

I'm leaning that way now too.

Would switching to premix cause this?

06-14-2009, 08:50 PM
No,running premix would not cause it unless you had mixed your fuel in a dirty container. This just happens from time to time. The smallest little thing can cause a clog.

02-25-2010, 03:46 PM
thread resurected, any progress?

02-25-2010, 03:55 PM
LOL... nope, sold it

02-25-2010, 04:09 PM
aww rage :( was interested in seeing progress, seen that guy wiltek on some other forum's project, and went on the hunt for others.

makes me want to get mine fixed up a bit lol

03-01-2010, 06:11 PM
well for for some inspiration,heres mine as of yesterday. Rear shock was listed wrong and is 5mm too long need to switch up befor track time.




03-01-2010, 06:30 PM
Unbelievable bike, looks brand new. Shock looks very nice as well.

03-02-2010, 03:13 AM
What kind of pipe is that?

03-02-2010, 08:50 AM
Leo V

03-03-2010, 06:45 PM
aww rage :( was interested in seeing progress, seen that guy wiltek on some other forum's project, and went on the hunt for others.

makes me want to get mine fixed up a bit lol

I bought it from Mike. It is going to be my fiancee's street bike. It is 100% back to stock and runs ok right now. I'm waiting for summer to get the carb perfect and put the fairings back on.

It's going to look ugly as sin this summer figuring it will go down once or twice while she is learning in a parking lot but will be painted all pretty for her next winter unless she wants to move up to a bigger bike.

08-08-2014, 03:14 PM
Hi Guys,

Ken from BikeBuilds.net (http://www.bikebuilds.net) here. Nice RS50!

We were glad to add albrechtmj's (http://www.bikebuilds.net/builders/albrechtmj) bike to our database: http://www.bikebuilds.net/aprilia-rs50-track-bike-build-by-albrechtmj