Ron Moss - Avanti TT3 - Cylinder Kit - Review & Test.....

[soulsurfer]

I think the reed will be retro fitted Nigel, whereas the GT186 is a reed kit from scratch. Funny you say that though 'cos when I rode the TT I likened it to what I would expect from a large block GT if there ever were such a thing.

[soosh]

When i read the review in scootering i knew there would be a lot of comments.
I think the kit looks very good for what it is.
Lets look at some of the cons.......160 degrees is a long inlet timing and we all know you will get a fair bit of spitback with that duration.
Fair comment about about the bridged exhaust.....they can cause issues
It will not perform as good as a reed valve at very low revs simply because its piston port and not as efficient as a reed valve. This is generally well known in the world of two strokes, in fact it is pretty much agreed that piston port is the worst form of induction compared to crankcase and reed but the Lambretta is piston port as standard so it is not to say that the Avanti is not a vast improvement over the standard.
Not wanting to ruffle any feathers but everyone moans about the low transfer duration on a muggy 225 and guess what the Avanti is practically the same and has a long inlet again like the muggy 225.........
Things i like about the kit.......genuine attempt to solve cooling issues on the lambretta. Alloy barrel with nicasil lining. The amount of technical support supplied.
One small concern.......glass fibre head cowling.....i thought it was metal in the pics but i really dont think glass fibre is going to last very long with the vibration of a lamby and constant heating and cooling of the cowling.
All in all great value for money and looks a good kit for what it has been designed to do.
Good luck to all involved.

Is a160 degrees period long for induction? I thought that was about a proper stage 4 spec or roundabout that.
If spitback is that bad,one of those remote filters solves that.
The transfer timing may be about the same as the slugello but the actual area is bigger from what I've seen.

[nelson pk]

160 dgrees inlet is getting close towards race territory. The only downside of that is the spitback as it is not long enough to effect pulling away at low revs. I was just pointing out a couple of cons in the article, basically just to say the cons are not that bad!
I also think reed induction could be a better choice and that i do wonder about a glass fibre cowl but again i think it looks good value and a good kit.

[brmspeedwell]

on the subject of the fiberglass head cowl should be ok with temp as it has a high thermal resistance the mountings in the top of the head cowl are far stronger than the single mounting on the org steel head cowl .vibration should be less of problem to fiberglass than steel stress wise .i would guess that producing the head cowl in steel a major cost in tooling terms for minimum run would cost more than the whole kit imho :smug:

[mick1]

I've bought a kit and i'm not concerned about the fibre glass cowl. As stated above it looks adequate for the job and if it isn't i'm sure there'll be S/S ones available in the near future (far east ?).

[Muttley McLadd]

160 dgrees inlet is getting close towards race territory.

Are you drunk?

[nelson pk]

No mate. If you read the article in scootering it states that a well known race team favoured 160 degrees inlet and if you ever take a look at Mr Websters tuning maual, the inlet timings for the race conversions range from 160 to 175.
From what i have read on piston port motors, if you go over 150 degrees, its likely to be spit back city and it is harder to set a carb up with longer durations but that aside it will probably give more power.
I fear it is you who has been on the vino Mr Mcladd

[Muttley McLadd]

No mate. If you read the article in scootering it staes that a well known race team favoured 160 degrees inlet and if you ever take a look at Mr Websters tuning maual, the inlet timings for the race conversions range from 160 to 175.
From what i have read on piston port motors, if you go over 150 degrees, its likely to be spit back city and it is harder to set a carb up with longer durations but that aside may it may well give more power.
I fear it is you who has been on the vino Mr Mcladd

I think you should have another read of DMC's avatar.

My piston port motor has close to 180 degrees inlet, and barely spits at all. It wasn't difficult to jet either, even without a dyno.

[soosh]

I think some might have nightmares of the thought of smallframes with 220 degrees of inlet then?

[Chutney Brownlove]

No mate. If you read the article in scootering it staes that a well known race team favoured 160 degrees inlet and if you ever take a look at Mr Websters tuning maual, the inlet timings for the race conversions range from 160 to 175.
From what i have read on piston port motors, if you go over 150 degrees, its likely to be spit back city and it is harder to set a carb up with longer durations but that aside may it may well give more power.
I fear it is you who has been on the vino Mr Mcladd

I think you should have another read of DMC's avatar.