Modern Vespa

Hello MVers,

I am about to drop the engine from my ET4-125 to change cylinder. I have watched the Scootwerwest-tutorial video carefully and taken notes. However, the nut for the back wheel was so stuck that I did not manage to loosen it and remove the wheel.
I guess it is not really necessary to take off the back wheel and drain the gear oil to change cylinder, is it?
I plan to take the engine inhouse and put it on my desk for the cylinder/piston change...

Thanks in advance!

your fine not draining the gear oil.

You can just leave the whole engine, transmission, final gear and rear wheel assembly intact and attached and remove it as a unit to work on replacing the cylinder.

As above - except that it's a lot heavier to move about. You're going to have to remove the rear wheel at some point to change the tyre, so why not persevere and get it off now. A wedge of wood to stop the wheel turning, a breaker bar perhaps with extension (metal tube of some sort) will get that nut moving.

Also you could have someone hold the rear brake lever, or strap the lever to the handlebar, to keep the rear wheel from turning.

That helps - but if the nut is on really tight (or the brakes are worn) it won't stop that darned wheel turning!

Best of course is an impact wrench for removal - but I'm assuming the OP doesn't have one, else he wouldn't have the problem...

Hello to Norway,

I'd suggest you should really try further to remove the rear wheel. If you're going the Malossi Route, the gearing should be changed also. Then the wheel has to come off.

I very recently went through the same ordeal. A couple of taps with a heavy hammer and all went well.

I feel when you take things down, then do all of the other things that can be easily attended to, then there is lesser to worry about later. So, bang the hell out of it and it will loosen.

Thanks for your answers to my post,

I left the wheel on for now, but have managed to drop the engine. Tomorrow I will clean it, so that I may bring it into the house (without my wife going crazy) and proceed with changing the cylinder (I am upgrading to the Malossi 190-kit). I totally agree with you that that nut on the back wheel needs to come loose, but I postpone it to when the engine is back in. I have put some penetrating oil on, and I will put a pipe or similar onto the wrench to get the required leverage to crack it loose.
The rear tire is good as new, so I do not need to change it, and the gear oil is only 2,000 kms old. As for the "Malossi-route" with higher final gear, I am not sure yet; I am looking forward to the increased accelleration and getting quicker to top-speed (at the moment 105-110 km/h stock with sito+pipe indicated on flat road with no headwind). For my daily commuting to work, I need to be able to blast past cars at roundabouts, trafick lights and junctions. On the return journey I normally stay 2 or 5 kms on the motorway (90 km/h speed limit), so getting to 100 km/h indicated quite quick is enough. I have read some reviews from people who have put the kit on and experienced wheelie-tendencies when giving too much throttle after stops...I think I AM looking forward to that. What are your experiences?

Hopefully, I will be able to do a lot on changing the cylinder tomorrow and maybe start breaking the kit in during the weekend.
Again, thanks for your answers and advice. This really is a friendly forum(!)

Also, If anybody has a leftover "ET4Cento25"-legshield badge to spare, please chime in!

FWIW, I put a 190 kit on an LX150 and didn't change a thing (it already had a Malossi variator). No re-jetting, no up-gear - and it hugely improved the get-off-the-line performance. Top speed was not an issue.

Since then I replaced the Malossi rollers with Dr Pulley sliders, and that added a bit more get up and go (the original rollers were well worn) and neither of us have yet taken it to its top speed - mainly because the roads it's used on aren't conducive to those sorts of experiments.

Good luck, I hope your roads will allow you to do some testing.

I'm looking forward to the info about not having to up-gear. I'll be doing the 187 deal soon. I want acceleration and have no interest in going over 100 km/h.

Thanks guys for posting.