Harmonic Balancer

[Fatty Smalls]

My LN130 surf has been 'twittering' on tickover and gets worse as temp increases. After an hour drive it sounds like an avairy under the bonnet. I read all the posts about the Harmonic Balancer and tried the trick of spraying WD40 onto the bottom pulleys, and sure enough the twittering stops immediately and the motor sounds lovely. But within 5 mins the twittering is back. I tried the other trick of marking the pulleys to see if they have debonded and are moving independantly. I was expecting the back two pulleys (alternator drive belts) to be the bonded pair but its the front two pulleys that are independantly moving as in pic. A & B are the marks that have seperated on pulleys 3 & 4.

In other posts people have spoke about the Harmonic Balance debonding & cutting in the cam cover, so i thought the rear 2 pulleys were the harmonic.
1 - what pulleys are the harmonic balancer?
2 - should i change pulleys 1&2 or 3&4 or all 4?
3 - is this ebay harmonic the one i want as the roughtrax one is £110
http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=170342129618

Cheers

[NiftyNev]

The front two pulleys bolt to centre of the harmonic balancer. You remove these and bolt to the new one.

The Ebay one seems to be the right one. I suggest you get new keys for the crankshaft as well and replace the crank seal.

Nev

[Albannach]

1&2 are connected to the harmonic balancer. Buy from Roughtrax.

[NiftyNev]

BTW, the two pulleys 3 and 4 can't move independently. 1 and two are one piece as are 3 and 4.

Nev

[Albannach]

My 3 and 4 are separite?

[Fatty Smalls]

BTW, the two pulleys 3 and 4 can't move independently. 1 and two are one piece as are 3 and 4.

Nev

Thats what i thought Nev, but after placing marks on all 4 pulleys the front two 3 & 4 have moved!

Maybe its me , i will test again in the morning.

[NiftyNev]

My 3 and 4 are separite?

Now that I think of it you may be right. Been a while since I had mine off. What I should have said is that 3 and 4 can't move independantly of each other because they are bolted to the HB. They can move independently from 1 and 2 (which are a solid piece) if the HB outer and inner are slipping because 3 and 4 are attached to the centre section.

Hope that makes some sense.

Nev

[POPEYE]

Now that I think of it you may be right. Been a while since I had mine off. What I should have said is that 3 and 4 can't move independantly of each other because they are bolted to the HB. They can move independently from 1 and 2 (which are a solid piece) if the HB outer and inner are slipping because 3 and 4 are attached to the centre section.

Hope that makes some sense.

Nev

It does to me, mine went, 1&2 are bonded to the center part, 3&4 are bolted to this center part and will move if the bond goes, so 1&2 wont move indipendantly of each other but 3&4 will move in relation to 1&2
simple!!