Motorbike Mechanics Look here!

[J12 WYT]

Sorry if wrong section.

I have just got my hands on a 2003 Aprilia rs125, It starts off the button first time, but when i rev the thing it doesnt respond. Just chugs and bogs down. Pulls away and moves, but only under the power of the gears.

This might not be of any use but, last night when i was out on it, I kept getting electric shocks and the rev counter not behaving properly?

Hope someone could help?

Thanks

 

[Graham Gooch]

Sounds like a dodgy earth to me.

 

[J12 WYT]

I was hoping something electrical and not mechanical. Would this cause the bike not to rev and just bog aswell?

 

[Graham Gooch]

Yeah it will, probably causing a poor spark which'll cause poor running. This is where I'd be looking at first. Maybe pull the plug out and see the spark condition?

 

[J12 WYT]

Thanks for your help mate, brand new to this sort of thing. Would you know how to resolve the faulty earth?

 

[Graham Gooch]

Check the condition of the earth strap, check the connections are tight. Might have worked itself loose.

 

[powey]

clean up any electrical connections, look for wires bolting to the frame and unbolt and clean these.

Has it recently started playing up or did you get it like it

 

[J12 WYT]

Bought it 4 days ago, private sale. Reasonably cheap. I expected something to happen really, they just feel to fradgile hah!

Last Night it happened, it lost power and just started slowing down, picking back up then bogging down. Managed to get home and it seemed fine. But started it today and this happened. Hopefully an easy fix.

Did give it a good blast with the jet wash yesterday to get the thick off the swingarm and wheels so might have something to do with it.

 

[Graham Gooch]

Did give it a good blast with the jet wash yesterday to get the thick off the swingarm and wheels so might have something to do with it.

Bingo! Lol.

Take the plugs out and let the engine dry out. It'll be fine.

 

[powey]

May be worth taking the bowl off the carb to incase any water has passed the airfilter

is the air filter clean AND dry?

 

[paul_h172]

Sounds like you have wet the CDI coil (think thats it name)and its shorting out on the frame hence the shock you got, its under the tank, take the tank off and let it dry out, take the plug out like Gooch said, also check the airfilter, make sure you have not wet it.

 

[millzzz]

It's not a good idea to use a jet washer on a bike. Don't be lazy next time, lol!

 

[J12 WYT]

Just taken the tank off and removed the plug. Plug looked to be in good condition. (Iridium plug it says?) Everything seems to be dry under there but will leave off over night and try in the morning. Put finger over sparkplug hole and pressed start button, lifted my finger clean off it. Is the a good sign for compression?

 

[paul_h172]

Just taken the tank off and removed the plug. Plug looked to be in good condition. (Iridium plug it says?) Everything seems to be dry under there but will leave off over night and try in the morning. Put finger over sparkplug hole and pressed start button, lifted my finger clean off it. Is the a good sign for compression?

Compression isnt your problem, but yeah shows its not bad. The make of the plug doesnt matter as long as it the right one.

 

[Pep]

The bogging down might be too much 2 stroke oil? Or am I looking too deep?
Seems to me like it needs a good clear out, give it a thrash!

 

[millzzz]

As well as the correct plug gap, but that doesn't sound like your problem. Have you checked all of your electrical connections and earths?

 

[J12 WYT]

Where are they located?

 

[powey]

Airfilter?

Also as mentioned about the 2 stoke oil, make sure to give the bike a really good shake side to side. Was the plug black and wet when removed? Ideally wants to be chocolatey brown

 

[J12 WYT]

Havent checked air filter yet, what should i check for?

The plug was black and dry, looked fairly new

 

[powey]

Airfilter should be clean not dusty and definately not wet.

Not sure if they oil roadbike filters, may be worth finding out

 

[Graham Gooch]

Clean the black off the plug, that won't help. From what you've said definitely sounds like wet electrics. Give everything a spray of wd40. Should help. Also sounds like it needs carbs setting up or at least looking at.

 

[J12 WYT]

Thanks for you help people. Appriciate it, Im going to get the carb looked at aswell. It runs as though it needs a good clean

 

[Graham Gooch]

Tbh a good long thrash will help!

 

[powey]

Im thinking though the plug may be black due to the fact that last going off if it was missfireing etc, causing the plug to foul.

I wouldnt touch the carb yet until the electrics are completely checked over.

 

[paul_h172]

if the plug is black its down to too much oil in your mix. only thing to adust on the carb is the mixture screw and idle, check these against factory spec, also check the carb jet is not blocked, these can get dirt in them, also are you running a fuel filter? check that to.

I think your fault is electrical.

 

[Paddy_g46]

water+electrics=fail! Check all the connections that would have possibly got wet!

 

[macrae99]

if its not the electrics then most likely dirty jets in the carb, is the carb and filter standard on the bike? has it boged since you got it or only after you washed it?

Callum

 

[Jamesstone]

Pressure washers & motorbike fuel tanks are normally the fault, good chance you have water contamination, When you take the float bowl off check to see if its more than just unleaded in there! if you rebuild the carb & runs fine briefly then returns with the same issue drain the fuel tank & start again.

 

[latza]

it sounds like the carb, mopeds and small 2strokes are notorious for the jets getting blocked as there so small,
small amount of petrol an get threw when its blocked but as soon as you rev it. loads more air is coming in and still the same amount of petrol.

you need to remove the carb take the jets out and simply blow threw them, take around 30 minuts and should sort it.

cant see it being an electrical problem lol. there so basic its unreal

 

[J12 WYT]

Its going into the garage tomorrow to get checked over.

Started it this morning after i had taken the plug out for the night, it all seemed fine until it started warming up then the revs dropped and started bogging and wouldnt rev again!

Turned the bike off and tried starting again, had to leave it about 15 mins until it would fire up again. Flooding maybe? Possible over fueling?

I just hope its the carb and not the top end!

 

[macrae99]

is the carb standard, any mods to it? has it been like that since you got it or only recently?

 

[J12 WYT]

Carbs standard, 28mm with standard air filter. I literally bought the bike 3 days ago! So havent had much time on it. Was running fine until this

 

[latza]

see ur from newcastl. just take it to westgate road.

 

[J12 WYT]

Got it running

Stripped the carb down and cleaned both jets and cleaned any debris from the air filter..

Still is a bit lumpy and i think it needs set up properly by a garage, also think the power valve needs a good clean. Does anyone know where its located?

Thanks alot

 

[Alexiooo]

i had this problem on my Honda NSR 125 a few years back... bought it brand new from a Honda garage, after about a month of having it, it became the most reliable thing under the sun, sent it back to Honda about 6 times in the following months, even they couldnt find the problem and offered to replace the engine if it happened again, then i realised i was using cheap 2 stroke oil, it caused the area near the spark plug to oil up but didnt actually affect the plug itself, so no evidence of it visually. My advice... only use Rock Oil Fully Synthetic, or Castrol TTS... neither are cheap but they both work a treat.

 

[paul_h172]

Got it running

Stripped the carb down and cleaned both jets and cleaned any debris from the air filter..

Still is a bit lumpy and i think it needs set up properly by a garage, also think the power valve needs a good clean. Does anyone know where its located?

Thanks alot

Power valve is located by the exhaust, were it meets the engine, the Solonoid that controls the valve might be sticking aswell which is common.

 

[J12 WYT]

Went to collect the bike tonight, He had replaced the cdi box with a new 1. Full power again like the last 1...

All running fine, no bogging down and no eratric rev counter needle.

But... When i was riding home, going thru all the gears warming the bike up. It got to the correct temperature and when i went to actually go for it, it gets to about 6,500 to 7,000 revs and then the power just dropped and virtually dies. I stopped and went off again. Everything, fine this time, a little hesitant and jerky it seemed but power valve kicked in and went. I took it back to garage and he is going to put it onto the dyno tomorrow and see whats up with it. He says it cant be much? so hopefully hes right.

Has any1 any ideas on what it could be? Maybe a faulty coil? or choked up PV

Thanks alot james