LCGB Forums

Hi, I want replace the asso piston in my ts1 kit & was wondering if anyone has used one of the above pistons, my kit is totally standard with no tuning .I run it one of Ron Moss ex box exhausts & a 30mm phbh . I was going to purchase a wossner piston as a replacement but they are out of stock everywhere so was considering one of these. thanks for any info

al pushpak wrote:Hi, I want replace the asso piston in my ts1 kit & was wondering if anyone has used one of the above pistons, my kit is totally standard with no tuning .I run it one of Ron Moss ex box exhausts & a 30mm phbh . I was going to purchase a wossner piston as a replacement but they are out of stock everywhere so was considering one of these. thanks for any info

Got one running in a steel liner TS1
As long as your inlet boost port hasn’t been opened up these pistons are fine...

Wouldn’t a new set off rings for the Asso be suffice? Or is this piston damaged?

Hi Norrie thanks for the quick reply & info, the cylinder is totally standard with no porting, my asso piston is little scuffed but nothing major, I just fancied upgrading to a lighter piston

Be careful of piston to bore clearance- Avanti piston grades do not match nicasil TS1 grades i:e grade A avanti does not match grade A Asso TS1 The clearance will not be sufficient and will cause issue

Ok thanks, I think I will probably wait until the wossner pistons come back into stock as I was told by both AFR & Andy Francis that the wossner piston will be a straight swap for my " B " grade cylinder cheers

Why not use one of the MB Meteor reed pistons designed for the RT reed kit? These come graded, a, b, c, and d. I tried one of the Mitaka ts1 pistons on my RT and found it rather heavy compared with the Meteor or Wossner.

https://rover.ebay.com/rover/0/0/0?mpre ... 3988852292

Give Ron a Pm regarding grade/clearances for your TS cylinder
I thinks his username is grandpa on here

He doesn't need to I've told him! if you do contact him tell Ron I said hello and sorry i didn't make him that brew at Lydden!

dscscotty wrote:He doesn't need to I've told him! if you do contact him tell Ron I said hello and sorry i didn't make him that brew at Lydden!

The Matica pistons that Ron sells are not tyhe same as ther Avanti ones, I have used one in a standard TS1 and it worked fine untill an air leak killed it. I tried to buy another one to use in an Avanti with a rteed valve but Ron intercepted the sale to tell me it would be suitable for my Avanti as they were made for the TS1.


Hope that helps

RM pistons on ebay today noted as;
A - 69.97
B - 69.98

I'm sure they did a 69.99 - C shown on website

Having used only one, ring peg very close the inlet edge and made by KHC (Mitaka don't actually make pistons)

Only way to select one against a used nicosil barrel is have the barrel accurately measured.

When I last swapped a TS1 piston in a used barrel, it ended up been a C piston in a B barrel. That's was an asso and AF did the measuring etc. Done loads of miles on it.

Personally I don't think you can go wrong with Asso

Thanks for all your replies , think I'm going to wait til the wossner piston's come back into stock, nothing against asso piston's or Ron Moss piston's I just fancied using a wossner as they are said to be a lot lighter. cheers

al pushpak wrote:Thanks for all your replies , think I'm going to wait til the wossner piston's come back into stock, nothing against asso piston's or Ron Moss piston's I just fancied using a wossner as they are said to be a lot lighter. cheers

The MB reed piston is very slightly lighter than the Wossner. Last time I checked there were no spare rings available for the 70 mm Wossner, this was over 6 months ago and I’ve heard nothing since dispite being promised a call as soon as they are available.

Just had a look at the MB meteor reed piston's & they do look a nice bit of kit, I also like the fact they are lighter than the wossner piston. My next question is ( & please be gentle as maths isn't my greatest subject lol! ) that I have measured my cylinder with a digital Vernier gauge internally at several different points & the measurements I get seem to between 69.5 & 69.6 does this seem correct? thanks for any info ps as stated in my earlier post my asso piston is a grade B cheers.

Verniers can't be used accurately enough when measuring cylinder bores. You need a bore micrometer.

Thanks, just had a PM regarding the correct way to measure the cylinder will try & get it measured at a motorcycle cycle dealer near my place of work thanks again for all your input

I changed from Asso to Wossner on my TS in the summer , Wosner has a lower crown profile than the Asso , so the head needed reprofileing.

My well used grade B with C piston is back after an emergency loan to a friend to go Poland. Piston looking a bit tired so both off to be measured/checked on Monday. Hoping it will take the next piston before a replate.
I'll report back Monday.

Anyone ever used one of the Casa reed valve 70 mm pistons in their Ts1 ? cheers

I’ve a casa reed piston for my spare ts1 that mb had tuned for touring, turns out the ring peg position will only fit in a standard barrel and the crown has a flatter profile so ended up using mb meteor piston and head. Managed to get a standard ts1 barrel which needs a replate so the casa piston n black line head will be used for that as a spare spare

I thought the Casa pistons had the same crown heights as the asso's 39mm but then again all this piston malarkey has definitely been a learning curve lol!