Side casing Hot

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Simon2003
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hi
ive got problems with hot engine ,if im out and about for a few miles my sidecasing is very hot to the touch and also the hub but not quite as hot, (RT 225/30mm/BGMv4 )runs really well starts after a couple of kicks so at a bit of a loss as to the cause,tried a few things ,lefton tickover for 20 mins and casing is fine so i know the heat not from top end ,ive removed sidecasing and shimmed gearbox behind endplate and that was normal,rear brake seems fine wonder if anybody had any thoughts ?
Simon2003
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when i say shimmed i mean ive used feeler gauges to check gap
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nsaints
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Hard to know if you have an issue or not; not unless you have a reference temperature to measure your engine temperature against to actually determine if you have a real issue or an imaginary issue

This maybe a case of 'Lambretta paranoia' where perceived issues manifest themselves into problems when they're not. Don't worry all Lambretta owners (me included) suffer with this

Personally i wouldn't worry about it if it's just hot to touch, and not broken down - if you really believe you have an issue. or want to confirm it's not an issue you need to get some actual temperatures from a similar engine and compare
MightyGem
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My standard Li 150 Series 2 would occasionally seize up(it would free itself after standing for a few minutes)on a long run on a warm day. The side panels would be quite hot. Never did get to the reason why, but it hasn't happened since a 175 conversion, so it must have been something with the 150 cylinder/piston combination.
Warkton Tornado No.1
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It's very difficult to analyse a lot of the issues that come up on Forums such as this.

Often, the only effective cure is to dismantle fully & re-assemble to the best of your ability & the knowledge available.

Honestly, I can say that of all the engines that I have worked on, that apart from the very occasional untouched OEM unit, there has always been something that needs correcting. That's says something about the engineering prowess of the majority of UK Lambretta owners/builders.....

The gearbox should be relatively easy, but I have found them assembled with the wrong (unmatched) gears besides the wrong way around. Axial clearance to aim for IMO is 0.003".....see it as a challenge, which necessitates a huge variety of shims.

The clutch has two main characteristics that will contribute to heat build up, other that slipping during running. The top plate rubbing is one whilst the other is axial play, although that overlaps the function of sprocket alignment.

Sprocket alignment is important because without it, chains are virtually slewing sideways, rather than just doing their job. Alignment is always possible to achieve though it may often require swapping components & having the necessary shims.

The chain case in a well built transmission will not run hot. A 30+ BHP TS 70 x 60 running a CamLam six plate clutch in OEM Innocenti clutch parts can be caned mercilessly, yet you can put your hand on the the engine.

The only other differences to what many owners have is that I gave up the worship of HPC decades ago, likewise ridiculously small tailpipes usually to be found on 'sporty' box exhausts &, of course, I use ATF.
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