LCGB Forums

Anyone any experience of using these?
Or are they a stay well clear of piston ?

https://rover.ebay.com/rover/0/0/0?mpre ... 2595389485

I've got a KHC yamaha DT175 and a Ron Moss reed piston here....Both have the same cast mark inside and are very similar in their make up and details... so make your own assuption.

The rings that come with the KHC pistons are poor competed to the RIK ones supplied with the RM piston.

RM pistons are claimed to be made by Mitaka. I rang Mitaka (Grampian) and they told me the only Lambretta piston they have been involved in were made for Harry Barlow at ProPorting.

Gaz

Torbay Lambretta do a Mitaka TS1 Piston, can’t be certain but i think it comes with Ricken rings at about £70.

Norrie Bodge wrote:Anyone any experience of using these?
Or are they a stay well clear of piston ?

https://rover.ebay.com/rover/0/0/0?mpre ... 2595389485

Mmmm from Beedspeed also I’d try Harry @ Pro Porting

I spotted these too and was wondering the same thing, cheap enough to buy as a get you home spare at that price.I was a bit confused by the '1mm chrome wire' rings, I though chrome rings were iron Also, does anyone know which grade .02 equates too?

coaster wrote:I spotted these too and was wondering the same thing, cheap enough to buy as a get you home spare at that price.I was a bit confused by the '1mm chrome wire' rings, I though chrome rings were iron Also, does anyone know which grade .02 equates too?

Here ya go Coaster
WHAT’S THE DIFFERENCE BETWEEN AN “A” AND “B” PISTON (this is for a 2 stroke)
.
To sum all below up A or B size will work 100% fine in all cylinders - Only if the cylinder is brand new (no hours) this is the only time it matters to use a A or B - Other than that A or B will work great in all cylinders.
.
In layman terms - If you pulled a hair out of you head and split it into 3 that is around what .01mm is, this is the difference between a A and B size piston (from the same manufacture). Let’s say if you could actual get a 01.mm feeler blade it would break the first time you pull it out with your fingers to use! If you have a feel blade set and it has a .03mm or 001” blade dived that into 3 and you will have .01mm. Now you will start to see how fine the measurement .01mm of really is.

People seem to think the measurement between A and B grade piston is huge. It seems like seems to lot of 2-stroke KTM or European bike owners are really concerned about this. We come to the conclusion a lot of people are getting misinformed from someone that does not know what they are talking about. Most likely that same person would have never even use a micrometre and have no idea of engine measurements.

I've used them several times, some last some don't, as Gaz stated the rings are crap and are best replaced, I've got a few in the naughty corner minus ring pegs! Just to clarify the rating on the piston as 70.02 which equates to 0.02mm,
Also clarification with regards to piston size grading A,B,C etc, be careful with this as this is often only relevant for the cylinder the piston is designed, e.g. Grade A -Avanti/Ron Moss piston may not be compatible for Grade A TS1 Cylinder, infact I've measured this exact combination with a little over 2 thou clearance, which is to tight!

dscscotty wrote:I've used them several times, some last some don't, as Gaz stated the rings are crap and are best replaced, I've got a few in the naughty corner minus ring pegs! Just to clarify the rating on the piston as 70.02 which equates to 0.02mm,
Also clarification with regards to piston size grading A,B,C etc, be careful with this as this is often only relevant for the cylinder the piston is designed, e.g. Grade A -Avanti/Ron Moss piston may not be compatible for Grade A TS1 Cylinder, infact I've measured this exact combination with a little over 2 thou clearance, which is to tight!

Interestingly, I was considering one for my Avanti which has a 69.67mm piston, it has a reed valve piston which has just popped.

coaster wrote:

dscscotty wrote:I've used them several times, some last some don't, as Gaz stated the rings are crap and are best replaced, I've got a few in the naughty corner minus ring pegs! Just to clarify the rating on the piston as 70.02 which equates to 0.02mm,
Also clarification with regards to piston size grading A,B,C etc, be careful with this as this is often only relevant for the cylinder the piston is designed, e.g. Grade A -Avanti/Ron Moss piston may not be compatible for Grade A TS1 Cylinder, infact I've measured this exact combination with a little over 2 thou clearance, which is to tight!

Interestingly, I was considering one for my Avanti which has a 69.67mm piston, it has a reed valve piston which has just popped.

Currently, I'm rebuilding & tuning a TS1 70 mm bore with a DT250 piston from Grampians. Non Dykes rings, of course. I wanted to try one for ages as an alternative to TS250 pistons.

(Either the Yamaha or Suzuki piston, in genuine or a 'good' pattern form are going to be a safer & better choice IMHO, but the gudgeon pin size needs taking into account, but I've been using the flanged Glacier bushes for years with no issues, which often help with the excess little end side play that may be encountered )

Warkton Tornado No.1 wrote:

coaster wrote:

dscscotty wrote:I've used them several times, some last some don't, as Gaz stated the rings are crap and are best replaced, I've got a few in the naughty corner minus ring pegs! Just to clarify the rating on the piston as 70.02 which equates to 0.02mm,
Also clarification with regards to piston size grading A,B,C etc, be careful with this as this is often only relevant for the cylinder the piston is designed, e.g. Grade A -Avanti/Ron Moss piston may not be compatible for Grade A TS1 Cylinder, infact I've measured this exact combination with a little over 2 thou clearance, which is to tight!

Interestingly, I was considering one for my Avanti which has a 69.67mm piston, it has a reed valve piston which has just popped.

Currently, I'm rebuilding & tuning a TS1 70 mm bore with a DT250 piston from Grampians. Non Dykes rings, of course. I wanted to try one for ages as an alternative to TS250 pistons.

(Either the Yamaha or Suzuki piston, in genuine or a 'good' pattern form are going to be a safer & better choice IMHO, but the gudgeon pin size needs taking into account, but I've been using the flanged Glacier bushes for years with no issues, which often help with the excess little end side play that may be encountered )

BTW. The bore clearance is good, otherwise I wouldn't be building it

I wanted to prove the viability of a reed valve piston rather than cut holes in a non reed valve piston & the DT & TS pistons are very similar apart from 1 mm compression height. Of course, the original windows will be enlarged, but I like the idea of using a piston designed for a reed valve as the design will have taken account of that. I hope......

DT 250 pistons are a decent alternative, infact an LCGB committee member does or did run one I did for him about 10yrs ago which was a reed converted/boost ported Rapido cylinder, he rang me to ask what the bore/ring size was and should he change them? When I asked what was the mileage he replied, 20,000! So yes they are a viable option to TS250 Suzuki and as I recall the ring pegs are in the same position so run so close to the boost port on TS1's like TS250 Suzuki types, also as I recall the piston dome height/profile is the same as Suzuki TS so the same head/profile can be used, this conversion used an 18mm small ended rod so bushes were not required, I've seen to many wear over the years so prefer not to use them, I tend not to use jap pistons now because of ring peg failure issues on high mileage/motorway pounding motors,