How tight should chain be?

[OzOAP]

Im putting an engine together with a 'pull down' tensioner.
Do you not run the lower chain guide?

[HxPaul]

With most pull down chain guides the chain catches with the back of it if you fit a bottom guide.

[fairspares]

it is advisable to always use a lower chain guide on anything other than a race engine which would be stripped on a regular basis and internals checked.

[alanscottj]

it is advisable to always use a lower chain guide on anything other than a race engine which would be stripped on a regular basis and internals checked.

I haven't got one and it isn't a race engine. What would the benefit of having one be? Thanks. Scott.

[eden]

I haven't ran a lower chain guide for over 25 years

[fairspares]

i didnt think it wise to advice someone whos not sure how tight a chain should be, not to use a lower chain guide and im sure those who dont use one check their engines regularly and only use high quality chains.

[OzOAP]

Differences of opinion eh?
Thought it would be a simple question...pleased i didn't ask what oil or tyres to use!

[OzOAP]

Sorted now...the coin landed on tails, so i fitted chain guide.

[coaster]

My view fwitw is that it is just something else waiting to break and wrap itself round the front or rear sprocket with possibly catastrophic results People will argue that Innocenti fitted them for a reason but ignore the fact that the engine was never designed for prolonged thrashing along at motorway speeds that we subject them to with double or treble the horsepower. If you are worried about scratching the inside of the case (I've not noticed this btw) then fit one of the Teflon lower guides too.

[andychain]

Tightness is only an issue where there is no tensioner. So although correct the 2-3% rule is for motorcycles.

The one in the picture will work fine, in fact it is good. There is a catena effect on chain chain
and the standard Lambretta tensioners work against it, the one shown works with it.

Andy