strange cyclical whirring sound NOW SORTED!

[bristolmod]

TV175 S3- totally standard

Noticed a weird "whirring" sound which rises and falls as the engines goes through its cycle.- it appears to be every revolution of the chain. Only happens in neutral.

The moment I put it into gear with the clutch pulled back it disappears.Does not affect performance.

Any ideas O wise ones before I remove the crankcase cover/ take a hammer to it/ crush the fecker?

Chris

[tomiskinky]

Funny you mention this, noticed it on my Special too. Odd thing is I can only hear it when wearing my davida lid as it knocks out the exhaust tone. Likewise it seems to be when going up through the gears, but maybe more a whine than a whir. Also disappears when clutch is pulled in. I was going to drain the oil and take a look last weekend, but ended up replacing my throttle cable and some other jobs, just finished when the monsoon hit, so never got around to looking.

If you pop you casing off let me know what you find.

Tom.

[coaster]

Slack chain I'd wager, the lower part pulls tight as you apply load i.e. when you put it in gear and it feels some clutch drag. This why a lot of folk leave out the lower chain guide as it doesn't really do anything most of the time.

[bristolmod]

thanks for that Gents- I will have a look inside next week and report back.

In all honesty, this problem started with the engine mounts..............................I had a couple of nice shiny engine bar nuts that I thought I would put on to replace the skanky old ones. The usual 2 minute job took an hour cos I couldn't manage to tighten them up so that the same amount of thread was showing (tighten one, then go to tighten the other, which moves the first one etc etc etc- you know the ******* Lambretta score) Eventually sorted that out then couldn't start the bike. Kicked it over and over and over before it would eventually start.

Then I get "the noise"..........................................

Ever seen that Faulty Towers episode when he thrashes the car with a branch of a tree??...................

Why oh why don't I ever learn- even after all these feckin years of Lambretta ownership............

[Muppet]

Me old li did that whirring nois thingy; the conrod snaped and the whirring noise stoped at just about the same time,
muppet,

[bristolmod]

Me old li did that whirring nois thingy; the conrod snaped and the whirring noise stoped at just about the same time,
muppet,

Interesting

I blew a hole in a piston once on the Motorway- I'll tell you what, the moment it blew all the vibration from the engine went as well..................quietest engine I ever had for the last 200 yards of its life

[goldeneye]

can you make the noise it does ...in an onamatapeia stylee..i.e."crash /bang/wallop" etc.? it may make it easier to diagnose.

[Muppet]

Me old li did that whirring nois thingy; the conrod snaped and the whirring noise stoped at just about the same time,
muppet,

Interesting

I blew a hole in a piston once on the Motorway- I'll tell you what, the moment it blew all the vibration from the engine went as well..................quietest engine I ever had for the last 200 yards of its life

200 yards that's further than i went on me li; I left me scooter just before it went quiet an i travelled the last ten yards slidin on me back,
muppet,

[bristolmod]

can you make the noise it does ...in an onamatapeia stylee..i.e."crash /bang/wallop" etc.? it may make it easier to diagnose.

sort of:-

mwa mwa mwa mwa

not as fast as each revolution of the piston; more slower like the chain or the clutch area rotating

[goldeneye]

is it not..."ning ning blang dang..riiiiiipppppp DONG"?