2010 Aprilia RS50 only starting when jumped

[dshwasher]

Took a reading between pin 85 and 86 on the relay and got a reading of 25 Ohms. Should apparently be about 50-200. Since it is pretty cheap to replace i’ll be ordering a new one and working from there

[JRH]

Yep. The starter solenoid / relay is item 10 and it’s called electric fan remote control. .

[Grumpy Old Git]

Item 10 in the 3rd image is the starter solenoid (mis-titled as an electric fan control!!).

 

 

[dshwasher]

That explains a lot

I ordered a new relay as it was giving a low reading of resistance and was physically very beat about. Hopefully should be in by next week.

Looking ahead, could this have been causing the no starting-off-starter issue?

[Grumpy Old Git]

Possibly - Looking at the state of those contacts, it would not have helped!

[Mississippi Bullfrog]

I bet if you open it up it will be green and crusty inside. 

[dshwasher]

Fitted the new relay. It sounds like it is cranking a lot “harder” (a lot louder) now… but still no start. It is low on fuel so I’m going to fill it up to eliminate the obvious. 

[Fozzie]

I keep dropping off from this, and then I see stuff I could have helped with. That is indeed the starter relay, it's tiny as the engine is tiny and requires very little amperage to spin compared to other kit. 

 

A weird trick to try, that worked on mine. If you put the choke on full, and pressed the start button. It would *never* start on its own. It needed a touch of throttle to get it going. 

 

When starting try the following as exactly as you can. Press the starter, but twist the throttle to full and close it again in one smooth motion (should take 2 seconds to do this). Then leave the throttle but keep the starter button pressed. If it sputters into life, as soon as it does, release the starter. If it dies, try again. These bikes are very basic, and a little temperamental, and there's a *nack* to getting them. 

 

[dshwasher]

Thank you for this! I’ll be trying it out the next opportunity I get 

[dshwasher]

I’m not with the bike today, my dad is: I’ve told him to try out what you’ve suggested Fozzie. He hasn’t got back to me yet. 

 

I filled up the bike and it’s not starting… the mystery continues. 

 

I think it might be worth mentioning that the bike, when it is being jump started, must have the choke off or it will not start. The bike will die straight away if I put the choke on while it is running and wont start off the starter again (maybe this is normal). 

 

This slips my mind a lot as it was so long ago and I feel like i’ve been trying to get her running since I bought her: She originally started just fine. Her battery was dead so we changed it and I serviced her the same day and I had no issues. The next day I tried to start, it was just cranking. I don’t know what could have happened overnight so fast. 

 

It also rides great once it is has started.

[dshwasher]

Here is a video of it running

 

Bought her that colour… kinda grown to liking it though 

[Bianco2564]

You say if the choke is on it won't start when bumping it, this is from cold?

1 hour ago, dshwasher said:

I think it might be worth mentioning that the bike, when it is being jump started, must have the choke off or it will not start. The bike will die straight away if I put the choke on while it is running and wont start off the starter again (maybe this is normal). 

Just to check, is the choke a lever you can adjust to various settings, or a lever/button that's either on or off?

If you don't need the choke when bump starting it from cold, might suggest its too rich, check all the carb settings; needle position, float level, idle screw setting.

Does it have reed valves? If so, are they ok, not gone weak and not sealing?

Air filter clean? Is it a std filter, not some aftermarket thing?

Is the exhaust system clean? 2 stroke exhausts are prone to filling with oily grunge.

How many miles has the bike done?

[dshwasher]

Yes this is from cold. 

 

You can adjust the choke to various settings.

 

The carb I originally looked at a lot as I thought it was the root. Now I think about it, it is possible the needle position is set too rich. 

 

Reed valves are new and are in good condition. 

Air filter is also new (standard).

I’ll need to check the exhaust system

 

17350 miles on the clock 

[Fozzie]

Was there any joy with giving it some throttle with the start button pressed?

 

I dug about and there's a post of mine from 2012 where I suggest the same thing to someone else with the same bike. All little 2-strokes were a bit weird that way, you had to give a few tickles of throttle with the starter pressed. It would splutter and you'd feed it a little more throttle to get it going. 

My old mans RD400 is similar. By todays standards these are usually signs of bad fuelling issues. But with 2-strokes, it's just your average morning. Once you get the knack, you have a lot less problems. So try a few things around what I've said, and see what works. 

 

But as a side note, did you buy this bike with this problem? What's the exhaust on it? Standard or aftermarket? 

You wouldn't believe the amount of people who bought a performance exhaust, and then rejetted the carb. It produced this problem, and often they'd sell the bike on rather than fix it. 

 

 

[dshwasher]

The bike didn’t have this problem when I bought it. The first day I owned it I serviced it and changed the battery. After all this it was starting fine. The next day I tried to start it.. that’s when it refused.

 

The exhaust is aftermarket. Bought it with this one on. LeoVince V6. Photo attached. I think I have the original one however. 

 

I’ll need to have a closer look at the carb hopefully later today and before that try what you have suggested. I think it could be the source of the problem. The float pin (the one that holds the float) had actually snapped. I made a makeshift one the same day it was starting and it was working fine with it in (and works fine when it is jumped). I’ll take some photos and post them on here as I really don’t know what looks wrong and right.

I’ll see what jet is in it too.  

 

Thank you 

[Fozzie]

Is that Leo vince a full system or end can? You can usually tell as the expansion chamber is a welded stainless steel. Stock, it looks like a single piece and is often painted matte black. The Arrow exhaust was the favourite when I was 16, but the Leo Vince was better for the top end. A Peugeot XR6 (same engine) ran one, and it felt like it would just accelerate until it blew up, hopefully they tempered it a bit

 

Ok, if something was done to the carb that's the likely candidate. You can actually buy new 19mm carbs from ebay for the bike. But that's for the AM6 engine. Something to keep in the back pocket if the original can't be fixed. 

[dshwasher]

Looks like a full system  

 

I’ll open up the carb and take a look. If it’s too much work, i’ll just replace it. 

 

New problem… just came back from college to find the starter motor making very weird noises. It isn’t catching at all sometimes and makes some very loud cranking noises other times. It seems to sound fine first half second of cranking. After that you can hear it stop. I’ll attach a video https://imgur.com/a/XOibFeQ First 2 tries is without throttle. Rest are with. 

 

Opening it up to see what horrors I find. 

[dshwasher]

Can’t pinpoint what’s wrong with the starter motor. Teeth on both the motor and what it catches on seems good. Might have been a case of not being tight enough. 

 

Have the carb out at the moment. I’m going to try find a needle clip as my DIY one dosen’t look the trustiest. 

Everything else in the carb looked fine to me. Probably not going to replace it. Size 82 main jet. Suitable? 

 

I’m thinking.. if the bike runs fine when it’s jumped, how could the carb be an issue? It’s got to be the starting system right?

 

 

 

 

[Bianco2564]

Is that a bit of wire wrapped around the needle, rather than a circlip? 

I'd refer to the manual on what the main jet and circlip position should be.

Get the carb set up right and try again.

Have you got a good spark when the engine is cranking?  Leave the spark plug in the head to create the load on the starter, use a second plug resting on the engine and check for a fat blue spark. If not, you might have a voltage drop to the ignition system?

[dshwasher]

Got my hands on a circlip so needle has been

sorted. 

 

The starter motor or the starting system inside the bike isn’t working properly and makes loud cranking noises as if something is stopping it from turning. Took the motor apart and couldn’t find anything unusual so i’m going to test it and look into the starting system inside the bike. 

 

Thanks for now everyone 

[dshwasher]

I took a closer look at the starter cylinder and there’s this dried up oil? that had pooled up inside of it. 

 

This isn’t normal right..?

[Fozzie]

There are multiple circuits in the carb, so it can happen that it won't start without help but then run. These little bikes tend to need throttle to get going when starting, even with choke on. But other possibilities are battery, and starter circuit. 

 

That starter motor sounds like it isn't engaging. There's likely a sprag clutch that isn't engaging and it's just spinning the inner mechanism. Has it always been a bit funny? There's a chance it has burnt out if used too long. Have you held the button down for literally minutes at a time? 

Starter motors look quite cheap on ebay (under £30) so might be worth ordering a new one. 

[dshwasher]

Starter is actually the second one i’ve bought as the old one was completely burnt out.

 

I took out the fly wheel cover and it’s the bendix that is not engaging with the flywheel. It isn’t springing forward (only does once the starter is let go of). According to google it’s because of a possible voltage drop. 

 

The starter doesn’t seem to be spinning fast enough to launch the bendix forward to engage the flywheel. 

 

 

Everything with this bike seems to lead me back to the electrical system. At this point, would getting a whole new loom be of any help (or a stator?? maybe even both)

[dshwasher]

https://imgur.com/a/2VqENKJ

 

Video of the bendix here. 

 

Dad is convinced it’s something to do with the starter motor instead. 

[Fozzie]

Ohhhh I remember. It's been way too long since I had one of these apart, but I vaguely remember it. 

 

Give it a good clean first, they can also act weird if they get any ingress of dirt. Make sure the battery is fully charged. Hopefully that's your problem, and has been this whole time. It's quite uncommon though, it's usually the carb or battery. 

I wouldn't swap your loom unless you can find actual damage, like a worn through cable shorting against a metal surface. This issue is looking more simple now so it would be overkill. Same with the stator, if the windings aren't burnt out, it's probably fine. But keep an eye on battery voltage when it's running, if you get any weird readings you'll soon know if something in the charging system is awry.