LCGB Forums

I should have my first lambretta engine running this weekend.

It's a gt186.

I've used rich Taylor's jetting advice plus a little bit so that I'm slightly rich.

I'm not sure what to do about oil. Do I go 4%?

I've also been advised to use mineral oil during running in.

I appreciate that there are opinions aplenty on subjects like this, but I'd like to hear them anyway.

dickie wrote:I should have my first lambretta engine running this weekend.

It's a gt186.

I've used rich Taylor's jetting advice plus a little bit so that I'm slightly rich.

I'm not sure what to do about oil. Do I go 4%?

I've also been advised to use mineral oil during running in.

I appreciate that there are opinions aplenty on subjects like this, but I'd like to hear them anyway.

If I were running in an iron barrel I'd go 4% on mineral oil.

Ditto. It will make for a shorter running in period.

But please please please remember, once run in and you decide to change to semi or fully, empty the tank and carb first. Never mix semi or fully synth with mineral because they wont actually mix.

Two lads I know with GT186 kits both run semi synth @ 4% at all times. Decent kits them.

thanks for all the advice gents.

from the various advice i've had, I'm going to do the following running in plan.

- 4% mineral oil during running in.
- start and run on blipped throttle for 10 minutes then allow to cool. start and run on blipped throttle then allow to cool again
- torque head up again
- after 100 miles replace gearbox oil
- do 250 miles with short bursts of wide open throttle but never let it rev out
- drain carb and tank and replace fuel/oil with synthetic at 3%
- enjoy my lovely new/old scooter

still open to advice if i've missed anything obvious

I can't believe how excited I am to start and ride an old shopping bike! I hope the bloody thing starts after all this work and near-divorce.

Sounds like a good plan if 250 miles is all that Rich T recommends? But most people would check the head torque at around 100 miles, not just after ticking over on the stand.

coaster wrote:Sounds like a good plan if 250 miles is all that Rich T recommends? But most people would check the head torque at around 100 miles, not just after ticking over on the stand.

In that case I'll do both. I've used nordlocks on the head, so I'm not expecting any significant change but I'll check anyway.

coaster wrote:Sounds like a good plan if 250 miles is all that Rich T recommends? But most people would check the head torque at around 100 miles, not just after ticking over on the stand.

He says at least 250 miles and I'm an impatient youth of only 46 (young on here) so I doubt I'll be able to hold myself back after that.

GT kits are well prepared when you get them. Do not compare the running in of an Indian 175 conversion, with variable bore clearance, to one of Rich's kits. As I have run in tight bores in the past I could tell quite quickly with the GT kit that I was in safe territory after very few miles really.

As has been said just don't labour the engine, particularly up hills, better to put it in a lower gear where the flywheel spins more and cools the engine. Up and down the years at every available opportunity. Have you got the porcupine head too?

Having once had to chisel nordlocks off an exhaust manifold I'd be loathe to put them anywhere near a cylinder head !

Thanks for the advice Storkfoot. I originally built this engine with a "tuned" Indian barrel but never tried to start it as I was unhappy with build quality.

I got my money back and decided to go for quality. Hence the gt186 kit. To make sure everything went together perfectly I bought the porcupine head.

The whole thing went together beautifully and I'm already thinking of buying another (gt200 though) for my next project.

Also, i think your nordlock issue was probably with carbon steel ones (I only use stainless). On an exhaust manifold the heat cycling with carbon steel could "fuse" the 2 halves together and be a nightmare. I use nordlocks all over deck equipment on construction ships and I've never had any issue. In fact I love them, yes it's real love.

Donnie wrote:Ditto. It will make for a shorter running in period.

But please please please remember, once run in and you decide to change to semi or fully, empty the tank and carb first. Never mix semi or fully synth with mineral because they wont actually mix.

I once used Shell SX mineral oil and changed to Exol semi synth,they both mixed ok and both mixed with the petrol.

OK, but it's introducing another risk that isn't necessary surely :-/

My memory is coming back. I recall we have had this conversation about nordlocks before LOL

Storkfoot wrote:My memory is coming back. I recall we have had this conversation about nordlocks before LOL

Aye, you're right and I reckon you'll never love them and I'll always love them. We'll never agree.

I've only ever used Rock Oil Groundsman semi-synth in my GT200 kit, 4% for 1st 100 miles and 3% thereafter.