Losing power in third

The Cardellino runs fine in 1st and 2nd but runs out of steam in 3rd. So much so I need to drop it down occasionally to pick the speed up. I have been told the crankcase needs to be really oil tight to get good compression. Is this correct? I have a very small oil leak coming from where the clutch lever bolts into the crankcase (I think) Could this be causing the problem? If you have another suggestion please shout out. Steve

On a 2-stroke the air + fuel is sucked into the crankcase first, then ‘blown’ into the combustion chamber as the piston goes down, so crankcase sealing is quite important yes.

So yes maybe find out where the oil is coming from, might be a busted crankshaft seal. But we’re still not absolutely sure until then.

If the crank case was not airtight, then it probably would not run at all! The oil leaking through clutch lever would be from the gearbox, which is separate from the crank case. I have had similar problems from small two strokes and the first thing to check is if the exhaust port or any part of the silencer system is coked up. Take the silencer apart (small nut on end of can and withdraw cover from opposite side). There should be a long bolt with 2 baffle plates attached. Take the silencer off all together and check in the exhaust port of the engine too. If there is any blockage, this would cause your problem. Don’t forget, it is not very powerful anyway, and if you are used to a Cali, you would notice a big, big difference! An air leak between the carburettor and its fitting can also cause a problem. Check carb filter is clean and the choke mechanism is working correctly also. Good luck!

Sounds like sound advice. At the risk of insult, could try checking the spark plug is tight first.
Cabernet2012-09-12 20:14:04

Oh yay-yas.

At one point, just prior to 2nd (and much more betterer) rebuild, my Bantam was still sort of going with two cracked & perished crankshaft seals (old rubber), and one exceedingly knacked main bearing (balls were down to half their original diameter), so a fair bit of crankshaft whip, plus, swarf from the bearing etc. had properly kippered the big end too (roller), so you’d be surprised.

I will check the spark plug today. I will have to fab something because the spark plug socket for the cardellino must have been very thin. There is vey little space between the plug and the cyclinder and so I have never been able to tighten the plug as it should be tightened. Thanks for the tips Andy I appreciate it. But just so you know what a Cardellino looks like

That could be all it is then, also, sounds like plug maybe now getting very old. Treat it to a new plug & see what happens.

And, make sure spark gap is correct, to whatever it is supposed to be

Appendix ~ 2-stroke combustion does strange things to plugs, so they easily get crudded up with dross and conductive carbon which can cause electrical tracking down the insulator so it don’t spark, and no amount of cleaning gets it off properly.

Or they just stop working without warning.

Once I got a brand new just-come-out-of-the-box Champion for the Bantam, checked gap was correct (I always do) put it in, nuffink, wouldn’t start at all. Plug out, on top of cylinder head, kick over, yep sparking.

Put it back in, kick-kick-kick-kick-kick-kick nuffink.

Put old one back in, kick brrring-ding-ding-ding-ding-ding-!!!

Oh right so engine does work then.

New one back in, kick-kick-kick-kick-kick-kick…

lol …

Mike H2012-09-14 12:39:44

If you can get a box spanner type plug spanner, you can file the outside of these down to miss the fins on the head if space is limited.

Good idea. Most bike’s standard tool kit type ones I’ve seen tend to be like box spanners anyway.

The plug is quite new and I had it out today and it is fine, It is a Champion D19 and I think it needs a 24mm box spanner which is quite big. I thought exactly the same thing Don. I am also going to ask the Hispania guys in Spain what plugs they are using as well. It is a typical Guzzi and will probably take a few different plugs. Steve

You need to find out what is the original that’s specified, and match to that. Correct size of the electrodes is important.

I’m having great difficulty finding out about ‘D19’ on the web. (aka D-19, D^19 ??)

Length of plug is very important. if it is too short you won’t get proper combustion, too long and it will hit the piston - result dented piston and no plug gap!Stein Dinse seem to recommend an NGK B6HS in their listingDon-Spada2012-09-17 00:19:46

Hi Steve, I know what a Cardellino looks like, I have a 1957 Lusso and also a 1951 Guzzino! See my signature.

A choked up exhaust/silencer can also cause poor running. It did on my old Bantam, and it does on my 2 stroke strimmer too. Maybe worth checking.

Oh yay-yas. Good mench.

It is not the exhaust. The exhaust is like new. What plug are you using Andy? Steve

Fairy nuff, we can eliminate exhaust. Just checking

All the Cardellinos I ever rode didn’t do much over 35 with a tail wind anyway…

Hi Steve, The original plug should be a Marelli CW225F or Lodge HN.
I use a Champion L86C which nearly all the Guzzinos and Cardellinos should run on. NGK equivalent is B6HS. If you look on www.motocardellino.it that guy uses Denso W14F-U. Gap should be in the region of 0.5 - 0.6 mm. I think it’s just a small engine which would appear to be gutless to what you are used to!