LCGB Forums

Hi All

Now that my RT195 is running properly, I am about to change the gearing on my LI150 box, currently I have a 46 rear and a 17 tooth front sprocket fitted and have ordered a 16 tooth to replace it. I don't want to fit a stretched 80 pitch chain, so to allow me to keep my 81 pitch I have also ordered a Casa OTT Chain tensioner that I intend to fit in the pull down option. The question is how tight do I pull it down ? Also is there any fitting tips I need to know.

Many Thanks

Thread lock everything.
Just check tension several times as you run the chain round to check for any tight loose spots.
plug out makes this easier.

Fundamental to the primary drive is having a decent chain in conjunction with good sprockets & crown-wheels in line & a good tensioner.

If you have the choice, use an old chain such as GENUINE Regina, Renold, TD Cross & Morse in preference to even a brand new Indian sourced type, such as Rolon as they are not fit for purpose, IMHO. I have seen the consequences of their phenomenal wear in several different engines to draw my conclusion.

Any decent Power Transmission Stockists will sell you 3/8" pitch duplex chain of a reputable make (& for far less than many Dealers charge!) & some will make it to length (if they have the basic facilities which cost me personally less than the RRP of a Rolon chain) Having said that, I've never witnessed a chain fail using connecting links either.

Just bought one of these and tempted to fit spring washers under the 2 dome head bolts, need to check clearance first, anyone else do anything other than thread lock.?
Thanks

I've never witnessed a chain fail using connecting links either.

I have, a few times with half links, with devastating results this was an 83 pitch Regina,in a TV200 Casing,Mallory Park flat-out in 4th round Gerards!
I've also had an Iwis let go on my road bike, the type with the black half link snap on route back from Kelso rally, also know of several other Iwis with black links snapping.

dscscotty wrote:

I've never witnessed a chain fail using connecting links either.

I have, a few times with half links, with devastating results this was an 83 pitch Regina,in a TV200 Casing,Mallory Park flat-out in 4th round Gerards!
I've also had an Iwis let go on my road bike, the type with the black half link snap on route back from Kelso rally, also know of several other Iwis with black links snapping.

I'll qualify what I claim further.

I have never had a chain that has been assembled with either split links, half links, one-&-a-half links or riveted by myself with the correct tooling fail. I acquire chain by the box, usually Renold.

I have only had a chain fail assembled by one of the country's top tuners. Upon closer inspection, it's understandable why. Over-zealous linishing of the riveted joint thinned the side plates. I still retain the broken pieces for 'posterity'

In that instance, I blame human error.

I have also designed & seen put into action machinery that utilises duplex chain in power transmission so have a reasonable understanding of the product enough not to ask more than it is capable of.

Anybody that has had chain or chain components fail, fitted correctly with alignment of the sprockets (I advocate better than five thou') bought from a reputable manufacturer should inform them. I would......

I have never had a chain that has been assembled with either split links, half links, one-&-a-half links or riveted by myself with the correct tooling fail. I acquire chain by the box, usually Renold.

Maybe you've just not had enough BHP to? Sorry couldn't resist, stay safe!

dscscotty wrote:

I have never had a chain that has been assembled with either split links, half links, one-&-a-half links or riveted by myself with the correct tooling fail. I acquire chain by the box, usually Renold.

Maybe you've just not had enough BHP to? Sorry couldn't resist, stay safe!

I never "had enough BHP" though always a tryer. Both shoulders broken, both dislocated (all @ separate times) & dislocated ribs are a legacy to that. But earlier this decade, was the highest placed racer running a Rapido, including a 'podium' place @ Snett in 2013, beating Edmonds prepared Mugello's in the process. That's considered mostly a 'power circuit' so feck knows how I did it, only my second weekend meeting following my return to the track. That was with a failed front axle bearing that made the (internal) hub rub on the disc which in turn boiled the fluid (AP race) but I kept going. Same year, same engine, the plug whiskered on the line @ Darley Moor. Left for dead but I bumped it WOT when allowed & it fired up. Red mist descended that got me up to fifth by the end of the race (too few laps!)

So, I guess you are winning races by now, with all of your BHP

It was a light hearted comment, hope you took it as that?
Yes we are winning races,championships and endurance events, bloody hard work as you well know.

Ive just fitted a casa chain tensioner ------Crickey, arnt they heavey . i weighed it at 1lb 3 1/2" oz ! Thought about fitting it without the "Over engineered "metal block but then realised it would then be at the wrong angle. I have an LTH in my other lambretta , which seems more than up to the job .

dscscotty wrote:It was a light hearted comment, hope you took it as that?
Yes we are winning races,championships and endurance events, bloody hard work as you well know.

Ha! My response was deliberately ambiguous in that it could mean I was well fecked off. Just teasing!

I actually meant how are you doing personally because you were doing Group Four, weren't you?

I actually meant how are you doing personally because you were doing Group Four, weren't you?

My racing days are long gone, about 25 yrs and 7 stone ago! Just prep and build scooters for the team and others now, its safer that way and don't hurt as much.
Apologies to the original poster for going off topic, just a note that we use Casa chain guides in our race scooters, great bit of kit, just a word of caution use loctite when fitting,

I snapped a half link chain in my production class motor after 2 miles. Half a mile was seeing what the jetting was like straight out of the box, which was horribly rich then half a mile home. The other mile was after I had rejetted it properly and give it a good handful. It snapped and wrapped around the front sprocket twisting the crank. I then had to push it home.
I hate scooters.

bsso78 wrote:I snapped a half link chain in my production class motor after 2 miles. Half a mile was seeing what the jetting was like straight out of the box, which was horribly rich then half a mile home. The other mile was after I had rejetted it properly and give it a good handful. It snapped and wrapped around the front sprocket twisting the crank. I then had to push it home.
I hate scooters.

Was the link branded in any way? Many of them aren't, in which case, they might just as well be made from old Blakeys or Segs. Or worse.....rejected Rolon chains

There's no reason as to why a cranked link or correctly fitted connecting links should have any tendency to fail, but should be fitted 'trailing' not 'leading' IMHO & I also prefer 'one-&-a-half' links rather than 'half' links. Duplex chains are an absolutely excellent concept, rarely failing in other uses, such as camshaft drives, where they are often fitted for life, by comparison with timing belts. Accurate sprocket alignment is essential though. Not as in any Lambretta manual, but as good as you can get.

Power transmission specialists will sell you a good chain in any length from a reputable manufacturer.