Avanti Upgrade

Anything related to Lambrettas... ask tech questions, post helpful info, or just read and learn.
dapper
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Warkton Tornado No.1 wrote: Sat Jun 29, 2019 6:50 pm
dapper wrote: Sat Jun 29, 2019 1:09 pm Any help appreciated
dapper wrote: Sat Jun 29, 2019 3:32 pm Warkton, if you had read the blurb on Ron's site properly, you would have seen this at the bottom

"Please Note:-

These are NOT for the Avanti TT3 Kit"
Yeah! That's the trouble with me! Reading stuff & taking it literally.

(Ron most likely added the note about the reed valve pistons just in case there were some tw@ts unable to deduce the difference between the piston ported TT3 kit & those modified to take a reed valve. Probably completely unnecessary........)

If I offer to hold your hand & take you to speak to Ron, don't take that literally either.
Warkton, no offence intended. Thank you for the link to Ron's site. However, I know I read that Ron didn't recommend cutting and drilling the standard Avanti piston. Perhaps if his blurb stated "These are NOT for the standard piston ported Avanti TT3 Kit" it would read better. Your totally uneccessary attempt at sarcasm belittles you and was, in my opinion, uncalled for.
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Warkton Tornado No.1
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dapper wrote: Sun Jun 30, 2019 12:09 pm
Warkton Tornado No.1 wrote: Sat Jun 29, 2019 6:50 pm
dapper wrote: Sat Jun 29, 2019 1:09 pm Any help appreciated
dapper wrote: Sat Jun 29, 2019 3:32 pm Warkton, if you had read the blurb on Ron's site properly, you would have seen this at the bottom

"Please Note:-

These are NOT for the Avanti TT3 Kit"
Yeah! That's the trouble with me! Reading stuff & taking it literally.

(Ron most likely added the note about the reed valve pistons just in case there were some tw@ts unable to deduce the difference between the piston ported TT3 kit & those modified to take a reed valve. Probably completely unnecessary........)

If I offer to hold your hand & take you to speak to Ron, don't take that literally either.
Warkton, no offence intended. Thank you for the link to Ron's site. However, I know I read that Ron didn't recommend cutting and drilling the standard Avanti piston. Perhaps if his blurb stated "These are NOT for the standard piston ported Avanti TT3 Kit" it would read better. Your totally uneccessary attempt at sarcasm belittles you and was, in my opinion, uncalled for.
Please do not state "no offence intended" after your initial response to my attempt to help.

Please do not attempt to patronise me by referring to my sarcasm, which was as the result of your own offensive remarks.

Hopefully, you can do what you should have done in the first place & speak directly to Ron, who will qualify the suitability of his products within each other, saving the likes of me attempting to be of any help.

(What may be 'helpful' to others if you can follow this Post of yours up with the facts as a guide to others in the same dilemma)
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coaster
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I have already been down this route and fitted an Atomic Ultimate reed valve to my Avanti TT3 a couple or so years ago. I had to remove some finage but not too much and I cut windows in the piston and cut a 3mm D section from the bottom of the inlet side of the skirt using an old TS1 Matica piston as a template. I did however have a LOT of trouble with frame clearance as the Avanti barrel puts the manifold further out. I already had an R1 shock (195mm) and fitted offset cones but I could only just get the shock on. Ended up grinding away at the reed manifold until I had about 1mm clearance. Scooter ran like dream for a couple of hundred miles, did the Derby 150 on it but then I blew a hole in the piston due to an air leak on the ScootRs manifold in one of the bolt holes.

Right, I looked on Rons website and I too saw the TS1 pistons so duly ordered one. Ron then emailed me to ask if it was for my Avanti and to give him a ring which I did. He said the TS1 pistons would not work due to the compression height and I would need to use a standard Avanti piston but without cutting holes/windows. Ron said the hole would eaken the piston and cause the skirt to crack. He did say it would be ok to cut a 3mm D section out of the piston skirt. Ron is of the opinion that the windows are not necessary.

I did all that but I have to say it didn't run like it had previously with the windows :( The only other thing I changed at the same time was fitting a 60/110 crank which I know would have affected the port timings but I think it more likely its the lack of piston windows. I WAS going to take the piston pout and cut the windows but then I blew hole in the new piston despite my belief that Id fixed the air leak (leak down test carried out)

I don't really undertand the concern about weakening the skirt tbh, the GT240 uses a TS250 piston modified by Richard Taylor which seems to be without such issues :?
Warkton Tornado No.1
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coaster wrote: Mon Jul 01, 2019 5:59 pm I have already been down this route and fitted an Atomic Ultimate reed valve to my Avanti TT3 a couple or so years ago. I had to remove some finage but not too much and I cut windows in the piston and cut a 3mm D section from the bottom of the inlet side of the skirt using an old TS1 Matica piston as a template. I did however have a LOT of trouble with frame clearance as the Avanti barrel puts the manifold further out. I already had an R1 shock (195mm) and fitted offset cones but I could only just get the shock on. Ended up grinding away at the reed manifold until I had about 1mm clearance. Scooter ran like dream for a couple of hundred miles, did the Derby 150 on it but then I blew a hole in the piston due to an air leak on the ScootRs manifold in one of the bolt holes.

Right, I looked on Rons website and I too saw the TS1 pistons so duly ordered one. Ron then emailed me to ask if it was for my Avanti and to give him a ring which I did. He said the TS1 pistons would not work due to the compression height and I would need to use a standard Avanti piston but without cutting holes/windows. Ron said the hole would eaken the piston and cause the skirt to crack. He did say it would be ok to cut a 3mm D section out of the piston skirt. Ron is of the opinion that the windows are not necessary.

I did all that but I have to say it didn't run like it had previously with the windows :( The only other thing I changed at the same time was fitting a 60/110 crank which I know would have affected the port timings but I think it more likely its the lack of piston windows. I WAS going to take the piston pout and cut the windows but then I blew hole in the new piston despite my belief that Id fixed the air leak (leak down test carried out)

I don't really undertand the concern about weakening the skirt tbh, the GT240 uses a TS250 piston modified by Richard Taylor which seems to be without such issues :?
Before the advent of 'special to tuned Lambretta' pistons came along complete with their 'special' price tag to suit, there was little option other than to look to the motorcycle, watercraft, snow-sleds & kart industry for selection of something that could be utilised.

That is still a very good route to consider, bearing in mind the quality & costs.

When there was not much option, then modifying pistons, such as the Suzuki TS250 by adding ports or cutouts proved to be reliable.

There are also options, as long as the correct ring material is available, to utilise pistons intended for iron or sleeved bores in nikasil cylinders & vice versa.

That's what I have done, as long as the clearance allows, several times. It also helps to have an account with a major two stroke piston supplier.....

Currently, I am building a TS1 70 mm bore with a Yamaha DT250 piston simply as a change to the Suzuki item. The compression height is 1.0 mm different, but the DT has a window on the inlet side. I have queried with the Gran Turismo 'team' as to why the DT piston was not selected rather than the TS but from what I gather, any questions as to the way things are done, is taken as a challenge or criticism.....
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OAP
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Hi all, first anyone wants to contact me : phone 07951952768
between 9 - 5:30 Monday - Friday 9 - 1 pm Sat.
email: info@supertune.co.

Just to clarify:-
Avanti Kit Pistons are just that, they are a different diameter size also the inlet skirt is the same thickness as the exhaust skirt un- like the original TS1 piston which is thicker on the inlet skirt which is stronger to take the cut outs.
I am not saying that you cannot cut a window in the Avanti Kit Piston it is just that I cannot recommend it, because if I did and the bottom of the skirt dropped off damaging your bore / crankcase or what ever then I get the blame. What I have said is to cut a half moon at the bottom of the skirt ( 10 - 12 mm arc) marked in the correct position.

The TS1 pistons on our web site are a different size as previously stated but that is not the only reason that they are not suitable for the Avanti Kit, they have "indents" around the gudgeon pin which are liable to bridge the exhaust port to the transfer posts this is because of the width of the exhaust port on the Avanti Kit.

All of our pistons are standard compression height and I have never said any different at any time, nor have I stated to take 3 mm from the bottom of the skirt!

Reed inlet manifolds, as Adam has stated there can be issues so please ring if anyone needs advice, it's free, some customers actually take it on board! Cheers Ron
dapper
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Thank you Ron. I knew there was more to it from previous threads. I'll give you a call shortly to arrange a visit. Your contact details now logged on my mobile for future reference.
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