oil on my face?

[Matty]

ok, here's a classic.
Having been messing around with just about everything on my agility 50 for the last 4 months, I seem to have got it running ok.
Then on the way home last week it suddenly went from running fine to giving very little power and not revving to maximum. I rode it about 2 miles like that.

Scratched my head for a bit and realised I hadn't changed oil in forever. Turns out there was only about 250mm in there. Ouch. Changed it this morning (went from 10w40 semi synthetic to 15w40 mineral as it's all I had).

Took the bike out - it ran fine again for about 7 miles, then started failing again in the same way as before - poor power, won't rev fully.

Have I stuffed it?

[blue]

You said your messing around with everything can you explane that better. Did you do valve check and clean the carb and at one time did you cut the cdi box because if the cdi box got wet you may need a new one. how good is the belt and the rollers and did you take the clutch apart and clean it.

[Matty]

Valves - yes checked these. They're within service limits
Carb - checked, was clean. Replaced main jet with #82 (I have been trying to re-restrict as I think the last owner de-restricted)
CDI - not cut. Original
Belt - new.
Rollers - original 6.5g (I think). A bit dirty but I've given them a spit polish. Within service limits on diameter. Tried 5.5g but revved like crazy.
Clutch - not taken apart. Only taken apart the driven pulley of the cvt. Couldn't get the cluth nut off.

Bikes only done 5000k. Could all this be down to the oil type? Like I said it seemed fine for 7 miles after the change, then died again??

[blue]

wont hurt anything to try a oil change I would go with 15/40 full synthetic valvoline I have been useing that in my scoot for 5 years now.as far as restrict or scoot you need a bigger jet and change out the drive boss and cut the cdi box.    Good luck.

[REDKYMCO]

I would be intrested to know where the oil is going over half a litre in less than 5000km, i check mine every 1000km and change every 4000km and in that time never have to top up, i wonder if its getting into cylinder from pre worn valve guides or piston rings and fouling your spark plug, although with only 5000km on your scoot you should not have worn piston rings etc if your bike has ever ran leen/hot for any length of time this can cause your piston rings or valve guides to soften and wear faster, is your exhaust giving out much smoke otherwise to be losing that much i would think you have a leak somewhere, kymco recomend 10w50 or 15w40 mineral so you should be fine i use 10w40 fully syn as i want the scoot to last me as long as possible and 10w40 being a littlle thinner flows better especialy in winter....

[Matty]

Thanks, Kisbee
Yes it did seem strange to lose so much I did a full replace at around 3000km.
I can't see any evidence of smoke.

Where might a leak be? Could a leak be affecting pressure and therefore performance? Or does oil pressure not really matter for scooters?

[REDKYMCO]

Is there not oil on the floor where the scoot is parked over night if not i would guess its not from the drain or oil filter bolt other places could be crankshaft seals and it leaking down behind the variator pully but that amount i would have thought would have got on your drive belt causing it to slip and also found its way out of the cvt cover by now and if it was the stator/fan side would be leaking out onto floor if you cant see any oil drops under scoot or on floor then i would guess its being burnt up in the cylinder, have you checked the plug lately to see if it looks oil fouled could explain the poor running....

[sidthesloth]

If it runs fine, then goes bad, I doubt it would be a mechanical fault, unless it is something heating up.
For the losing power, I would be looking at the fuel system, Filter, hose, vacuum hose, and fuel cap vent as it sounds like it is starving for fuel. If it is running too lean, it could be heating up to the point of almost seizing, hence your loss of power. Did you have this problem before you changed to the 82 jet? What size jet was in there before? Is the air filter stock? Or has it been opened up for better flow?

[Matty]

No oil on the floor
No oil evident inside the clutch/variator casing, and no oil on the belt
Never opened up the crankcase so can't comment there.
Air filter stock
Don't know what jet was in there before, but suspect it was actually the stock 80 (the last owner doesn't know if it was rejetted or not)
No obvious leaking around the drain bolt or oil filter.

Plug always looks fouled to me but I checked and cleaned it immediately before the oil change so I can't imagine it's clogged up that quickly? Is it possible for a plug to foul up in only 7 miles of running?

What's odd is that after the oil change it was running fine for 7 miles (say 30 minutes) then slowed right down. Now when I start it it's already in the "go slow" state.

Maybe it is the spark, but that would mean either it's set waaay too rich, or there is too much oil in the cylinder ie. failed piston rings. Correct? Or possibly weak battery - I did briefly charge the battery before I started the 7 miles. Does it make sense that it would produce a weaker spark after 7 miles of riding? I thought they charged as they went?

Maybe that's it? Any thoughts?

[blue]

to much oil is just as bad as not enough. drain a little tell it shows on the dip stick the right amound.

[REDKYMCO]

If oil is getting into cylinder especialy the amount you are going through over 500ml in 2000km then i would say it could foul up the plug within 30 mins of riding, i dont think even my old peugeot 2 stroke engine went through that much oil LOL have you checked plug since your 7 mile trip. As for the batt after your 7 mile trip did you try the elec start if it can still turn engine over then it must be charging itself and yes it does charge when engine is running, are you having batt problems why did you need to give it a charge or are you just draining it because its hard to start?

[Matty]

Hi kisbee

Yes still turns over fine after the 7 miles with electric start and always has.
I just had a few people suggest it might be weak spark so charged the battery to see if this made a difference.
I also replaced the high tension wire/coil with new but that made no difference.

Think it's time to take it to a garage or put it in the bin...

[spidrgr]

Try reinstalling your original jet in the carb. Or, remove restrictors in the air box. How is the exauxt tip? Is it moist whith fuel? What color is the plug? When you say it slows down, is it the engine that is losing revs or is it just slowing down as if someone was applying the brakes? Have you checked the oil level in the rear transmission? Is the rear wheel spinning freely (normally) when the scooter is on the centerstand? Could be the transmission seizing up. Is the fuel properly reaching the carburetor? is the fuel filter clean if one is installed? Is the fuel petcock functioning properly? Does the engine regain its power after being stopped for a while? Is there gas leaking on the ground when it stalls?

What i'm trying to get at here is the fact that you are not clearly describing what really happens. It is therefore somewhat difficult to try to find some kind of explanatio to your problem!

[Matty]

Thanks for this, Spidrgr.
Interestingly, here's what just happened on my way home tonight:

0. As discussed, I left the bike at the office last night after it died, and when I tested it at lunchtime it still had poor power when I started it up.
1. I trickle charged the battery after lunch for 4 hours
2. I put the battery back in the bike this evening and it ran fine for 3 miles.
3. Then it died back again to low revs and low power. It stayed like that for about 4 miles whilst I rode slowly at lower revs
4. Then it suddenly picked back up again and worked fine for the last mile of my journey.

Mental. Could too much engine oil be the cause of this? Ie. when hot it expands and the power goes, then when it cools back down again, the engine runs ok? Anyway, I've drained some oil out, cleaned the spark, recharged the battery and replaced the fuel filter tonight so let' see what happens in the morning (UK time!).

Spidrgr to answer your questions:
1. I can't face reinstalling the original jet. I don't think it's this as the bike has been working fine with the current jet (if intermittently)
2. Restrictors in the air box...I didn't even realise these existed - probably one for later - I'd rather get it running normally first
3. The plug when I took it out tonight was black on the metal part around the white central "island", but the island was white, not black
4. Engine is losing revs. It's not as if someone was applying the brakes. Acceleration dies to super slow and top speed drops to around 28kph
5. oil level in the rear transmission - I replaced around 2000km ago, but you're right I will check this weekend
6. Rear wheel spinning freely when on centrestand
7. Fuel - I have thought this too, but I cleaned out the fuel lines, and fuel was flowing freely under gravity
8. Fuel petcock - Tested this a month ago and was fine, so don't expect this is the problem.
9. Does the engine regain it's power? Not after being stopped for a while. However if I recharge the battery, it will regain it's power after being stopped and the battery charged.
10. No evidence of gas leaking, plus have decent mpg still.

[blue]

mmmmmmmmmmm when you had the cab apart how was the diaphram. is everything in the carb working ok.