RS125 2 stroke issues/how to remove carb for cleaning

unL33T said:
Hmm thanks for the info. Tried to play with the idle adjustment but found that after it getting stuck at high idle at every light on the way home (and using the clutch trick to knock it back down so I wasn't sitting at 4k RPM for the whole time), in neutral on the stand it would idle normally. I have a copy of that manual but couldn't find much about removing or cleaning the carb. Just about removing the engine (which included some stuff with the carb) and how to adjust certain things.

Also, half way home it decided it no longer wanted to let me know how fast I'm going. Looks like I've got another issue to deal with.

Think I'll be taking the 650R to work tomorrow. Good thing I haven't managed to sell it yet! Lol
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Always good to have a backup bike when you have a two stroke.

Idle adjustment is different from air screw.
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If you haven't found it yet, the AF1 apriliaforum has a rs125 section... probably the most updated one I've come across.
You'll want to sign up there, as they can probably best answer your questions specific to the ape rs125.
Think this is what your looking for on carb accessing : http://www.apriliaforum.com/forums/showthread.php?254137-Carb-help&p=3159907&viewfull=1#post3159907


 
gnatwest said:
Why would it be stalling, you never mentioned that before.
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If I lower the idle to a point that when it's stuck in its high idle condition that it idles at the proper level then when whatever is wrong gets unstuck (such as when I load the engine) it would allow the idle to drop too low and it would stall. As I mentioned it idles fine on the stand in neutral so if I adjust it so that instead of getting stuck at 4k it sits at 1.5k then when it's not acting up its going to be idling very low, if at all.

It seems like something is caught up to me, too. Maybe I'll just get a set of replacement cables and pull/clean the carb and get all that sorted out at once. Or just lube the cables I have. I tried to do that the other day with some lube kit I got that has syringes of oil with a thin end to shove into the cable sheath but I couldn't get it to go in and gave up.

Might just have a shop do it, though, because I'm not sure I'm ready to start playing with rejetting and all the other adjustments right now. The previous owner told me he had it tuned/jetted recently by some kind of 2 stroke expert in Peterborough but with the slack on the cables, chain, and everything else I can't see how they could've done much with everything so out of whack.
 
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unL33T said:
If I lower the idle to a point that when it's stuck in its high idle condition that it idles at the proper level then when whatever is wrong gets unstuck (such as when I load the engine) it would allow the idle to drop too low and it would stall. As I mentioned it idles fine on the stand in neutral so if I adjust it so that instead of getting stuck at 4k it sits at 1.5k then when it's not acting up its going to be idling very low, if at all.

It seems like something is caught up to me, too. Maybe I'll just get a set of replacement cables and pull/clean the carb and get all that sorted out at once. Or just lube the cables I have. I tried to do that the other day with some lube kit I got that has syringes of oil with a thin end to shove into the cable sheath but I couldn't get it to go in and gave up.

Might just have a shop do it, though, because I'm not sure I'm ready to start playing with rejetting and all the other adjustments right now. The previous owner told me he had it tuned/jetted recently by some kind of 2 stroke expert in Peterborough but with the slack on the cables, chain, and everything else I can't see how they could've done much with everything so out of whack.
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Have you checked for an air leak, or did a compression test? Seems to be a problem with the 125 by reading some forum posts online. As gammaguy said the AF1 forum is a good source. Here's a link I found that may help.http://www.125ccsportsbikes.com/forums/index.php?showtopic=70496
 
Generally speaking I hope your not letting it idle too long, blip that throttle!!
 
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2stroker said:
Generally speaking I hope your not letting it idle too long, blip that throttle!!
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I am not, except at lights. The previous owner did tell me he used to let it warm up fully at idle before riding but I've since read that 2 strokes don't like that.
 
This sounds more like you're sitting on the threshold of the timing advance. Above 2,000 (or thereabouts) the timing advances and brings the RPM up, below the advance drops out and lets the RPM drop.

A common problem I had with high strung snowmobile engines, except they would idle at 5,0000 RPM, slowly drop to 3,500 as the plugs loaded up, then drop precipitously to a stall requiring constant blipping at about 3,000.

Try lowering the idle speed just a little. You'll want it that the RPM just drops to below the advance speed, but still high enough to idle. You'll probably still need to blip the throttle to clear the plug.
 
What do you mean by "clear the plug"? Also, there's a fair amount of oil oozing out of the exhaust and it smokes a fair amount. I know the previous owner said it was tuned more rich because it was running very lean. Is that something I should be concerned about or normal for running a little rich?
 
What's the best way to check for an air leak? All the how tos I read say to spray carb or brake cleaner around the part but I've heard that stuff is terrible for plastic, rubber, and paint, and has potential to cause a fire.
 
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Just reading thru some posts.

Any resolution to this?
 
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Your dead nuts on, Snobike. His motor is a ticking time bomb, just waiting to detonate - no pun intended. Any 2 stroke owner needs to buy/build a pressure tester. This will tell you the true health of your bike. Without it, it's just guessing.
 
I didn't have time to address it before the cold came in and the speedo sensor broke (looks like someone in the past used a rear stand and caught the sensor, ripping it in two) so I couldn't ride it anyway.

I did borrow a pressure checker from a coworker but not sure it will do what I want. He says you just pull the spark plug and turn the engine over a few times and it tells you the compression. I'm thinking what I need is something that checks from intake to exhaust like I've seen on YouTube when Googling how to check it.

I also ordered all new control cables while I was at it. Tried to lube mine but couldn't get the nozzle for the lube thing into the cable so I'll just buy new and lube them off the bike.
 
unL33T said:
I did borrow a pressure checker from a coworker but not sure it will do what I want. He says you just pull the spark plug and turn the engine over a few times and it tells you the compression. I'm thinking what I need is something that checks from intake to exhaust like I've seen on YouTube when Googling how to check it..
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You borrowed a compression tester which is not what you need. You need to do a full leak down test to check for an intake manifold leak which you quite likely have.

Have a read at the links I posted as they will give you at least good direction of what you need to do.

Keep us posted.
 
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Snobike Mike said:
You borrowed a compression tester which is not what you need. You need to do a full leak down test to check for an intake manifold leak which you quite likely have.

Have a read at the links I posted as they will give you at least good direction of what you need to do.

Keep us posted.
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That's what I thought. Thanks. Hard to work on it out in my driveway over the winter. Considered hauling it up to my apartment but while it's pretty light, stairs and the turn at the top might be quite the challenge, lol.
 
Check you tube (or Google) for 2 stroke pressure tester. You should be able to find some how to info on building a pressure tester that will work with your bike, or at least give you a good idea. You'll have to take carbs out and exhaust pipes off to get some dimensions. That will be a PITA during the cold months. Maybe best left for the spring.

The idea is that once the all the orifices (inlet and exhaust) are plugged, you should be able to pressurize the engine (low pressure approx. 6psi) and it should hold that pressure for a couple of minutes.

Here's an example. Plug exhausts.
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Remove carbs and plug inlets. Need a pressure gauge and schrader valve
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This set up allows you to pressurize the cylinders/crankcase and watch any pressure drop. You should be able to hold 6 psi for 2 mins. If not, time to get out the soapy solution and find leaks.


Jeff
'87 RZ 350
 
+1 to jeff above. It really does sound like you have a leak somewhere. (my RS is of the HRC type not the Aprilia type but a two stoke are in principal all the same)
 
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