celt wrote:Hoping you kind chaps can help me out as I've hit a brick wall.
As from the title getting clutch drag. Set clutch until ready to place into gear and all is well, ride to the end of my cul-de-sac, come back and clutch dragging quite bad even when lever is pulled in fully . Adjust clutch again and the same process re-occurs. Even shortened the the trunnion travel and again same problems occurs.
Stripped down clutch and got a friend to machine the crown-wheel so clutch flange and plates touch the crown-wheel unassembled. Now with the spider in place and clutch nut fitted, found the GP clutch flange is short to meet the crown-wheel by approx 3-4mm. The flange is hitting the clutch nut/top of xmas tree. Now is this supposed to happen
I have tried an LI clutch flange which sits flush to the crown-wheel, but the 2 GP flanges I have stop at the nut.
I understand that when springs are in, unless coil bound it would be unlikely that the flange would touch the crow-wheel anyhow. But unsure if this is correct.
The spider is riveted and not welded there doesn't seem to be any play.
The bronze bush is in good condition.
However when moving the clutch arm manually with a spanner it only travels about 10-15mm before it stops. My other scooters travel approx 25-30mm and seems to be under spring tension longer.
Any ideas please
Information for other Lambretta Owners with clutch issues.
Normally there is 20mm for the clutch to fit into.
A standard 4 plate clutch & steels set up is 18.2mm thick with 1.8mm to release with a 3.0mm top plate, more clearance by using the thinner 2.5mm or 2.0mm available for the 5 & 6 plate set ups.
Check that the top cork plate drive tangs still fit into the clutch basket & do not ride over the top!
Clutch springs that do not allow fee play when the clutch assembly is compressed will only lead to clutch drag as the engine warms up & all expands hence the 2-3mm clearance at the handlebar leaver! If too tight or the Li/SX clutch thimble will weld it's self to the pleasure plate & on GP's the bronze bush wear down!
The clutch spings that you use only have a maximum space of 14mm to fit into when coil bound or 16.5mm with the new Indian 5 plate pressure bells now being sold on ebay denoted by the full circlular top actuating plate whether Li/SX or GP type, which comes with a set of spings & a new GP brass plunger.
First dry fit the clutch (NO SPRINGS) to check that there is free play to release! Check again when the clutch assembly is being compressed with the circlip fitted!
Some times the cluster shaft protrudes though the clutch nut & stops the pressure plate from going fully down to touch the base of the clutch basket!
I have slimmed the clutch nut & moddified the cluster shaft before now to fit 5 & 6 plate clutch units so as to give clearance to release.
This is why new bepoke engine builds take longer than a simple strip & rebuild to do as none of the parts have previously been together!
It has taken me approximatly 1-2 hours to & build a new clutch set up into a motor from scratch checking clearances & chain alaignment etc.
I am using at the moment in the powerful RB & TS1 motors I build:
Italian 46 or 47 clutch basket with recesses cut to allow the first cork plate to sit below the sprocket teeth.
BGM 6 plate corks. 2.5mm thick (15mm)
Tino/CamLam 0.85mm heat treated & dimpled clutch steel plates x5 (4.25mm)
A square base spider such as that supplied by Tutto, MB, Tino & Foxhat, this stops the first steel going under the normal spider (Thats why the older 5 plate clutch sets had one steel bent up to engage into the spider!
2.0mm or 2.5mm top steel bevel Plate which ever give the best fit retaining the last cork plate.
My own special Taffspeed clutch springs that are fully compressed at 16.5mm or 14.0mm depnding on whether I'm using the Indian 5 plate GP style pressure plate for a 6 plate set up or Italian GP Pentagon top pressure plate for a 5 plate set up. Several other dealers do similar clutch springs.
Remember that using the Indian deeper pressure plate (2.5mm deeper) means that clearance between the bronze pressure release bush is now very close & a thicker chaincase cover gasket 2.0mm thick is adviseable to use or machine the clutch bronze push unit shorter & recut the lubrication groove into it!.
By using this thicher gasket the kickstart piston may sometimes have trouble extending far enough to engage the first gear fully! If this happens dremmel the slot deeper by 1-2mm.
Thinner gearbox oil Silkolene SRG75 or similar as this reduces the chain wear as it lubricates the chain & gearbox components far better than the original SAE90 gear oil!
Next we come to the clutch cable operation! Many people have fitted & use nylon lined cables, some of the sets have the normal wire cable & not a multistrand cable that can be wrapped arround your finger several times & when released go staight again with no kinks! These multistrand inners are the best to use as they give a lighter feel & do not stretch as much!
Next problem is the clutch arm on the top of the clutch cover, this should be fitted at 90' to the cable pull if possible so as to give the least force required to opperate!
If having done all of the above & you still have a clutch that drags then shorten the clutch arm by 10mm which will in turn make the lever opperation heavier but give the extra release movement against the brass plunger you are missing.
Remember to leave the 2-3mm at the handlebar as this allows for the clutch plates to settle in & wear normally.
Failing to leave this clearance will keep the brass plunger rubbing the pressure plate wearing it away! If using the Li/SX pressure plate then the thimble has been known to weld it's self to the center pin!
Best regards
