Can anyone ID this piston?

[SHELRACING]

Took the barrell of the TZ 50 to check the piston as they have a habit of cracking and even shattering at the back. Found the fitted piston is not standard definately not TZ 50.

Can anyone identify it from these photos and dimensions. Note it has cracked at the rear of the piston as do the TZ pistons.

The fiited piston is on the right and appears to be standard size. I have a brand new 0.5 TZ piston and rings which is way too small.

Cheers
Steve

[cowpoos]

is there a weight diff?? [just being curious...I have no idea!!]

[TZ350]

.

could that be a RG50 (TS GT 50) piston? will check when I get to work monday.
.

[SHELRACING]

.

could that be a RG50 (TS GT 50) piston? will check when I get to work monday.
.

Cheers TZ

On investigating, I had considered the RG piston, beceause i believe the RG piston is used in a number of Suzuki's 50cc bikes even thier kiddie quads. And pics I've found look like my sample.

[SHELRACING]

is there a weight diff?? [just being curious...I have no idea!!]

Don't have anything accurate enough to weigh the properly. I'd say they were closley matched.

[F5 Dave]

RG. or equivalent. Std RG is 41, with .5 & 42mm oversizes.

RD pistons look similar to TZ but pegs will be in different position as single transfer design.

They only break piston skirts when the bore is worn. Rebore.

[Pumba]

Can I suggest asking Dave Diprose, as I am sure he will know what he put in it:done:

[SHELRACING]

Can I suggest asking Dave Diprose, as I am sure he will know what he put in it:done:

Yep did that, bit of confusion but he's just come back to me this evening. As suspected and suggested by F5 Dave it's an RG piston.

[SHELRACING]

RG. or equivalent. Std RG is 41, with .5 & 42mm oversizes.

RD pistons look similar to TZ but pegs will be in different position as single transfer design.

They only break piston skirts when the bore is worn. Rebore.

Thanks Dave. So if I rebore and get a new piston kit. Would it be worthwhile cutting some transfer windows in the new piston ? any Idea what my Piston Barrell tolerance should be ?

[F5 Dave]

Suspect TZ piston will have them anyway. May have to check if spacer under barrel or whatever as the pin to crown is much taller on the RG piston. 1.5 thou will be safe, could try 1 thou with careful break in, but I'm not familiar with the TZ/TZR pistons.

[Buckets4Me]

if it's got an rg piston
I would put a new one back in and leave it verymuch alone :shutup:

the bike runs well very well why bother changing anything that you dont have to change ??????

you will only muck it up :laugh:

so as F5Dave say rebore it and put the next oversized piston in
checking that its the same as what came out

Dave D spent a lot of money on that bike and had someone do the work to it
so I wouldn't try and make it any better (Yet )

my 2 cents worth ( have seen a lot of good bikes stuffed up because someone thought they new better than the origanal builder )

ps I think all 50cc suzuki pistons are the same ???? at least the part number for the Lt50 quad and rgvr50 and any other kids stuff I have found where the same

[SHELRACING]

Suspect TZ piston will have them anyway. May have to check if spacer under barrel or whatever as the pin to crown is much taller on the RG piston. 1.5 thou will be safe, could try 1 thou with careful break in, but I'm not familiar with the TZ/TZR pistons.

I have more info on the motor now from Dave Diprose. The TZ motor was modified to take the Rg Piston and a 3mm spacer used to raise the barrell, so you're right on the mark there. The squish was also modified for the difference in the piston.

I have a second barrell which looks to have been unused since a rebore, and think it will take a 0.5 O/S piston. Getting some help from TZ350 as well.

Any comment on my question on cutting some windows in the back of the RG piston ??

Cheers

[one fast tl1ooo]

good luck on findy out wat it is

[F5 Dave]

I wouldn't go crazy, it is a full reed engine unlike the RG so some holes may be beneficial. Maybe carefully drill a couple of pilot holes working up to 8mm.

On the other side it is possible Dave was thinking about intentionally having a full skirt piston. If there are no other paths to the crankcase he may have been using so called 'power porting' (read up in Bells book in porting section near end of chapter).

[SHELRACING]

Has been quite interesting and valuable this thread. I recall Dave Diprose telling me that one reason for the RG piston was he thought it may be stronger because there are no transfer holes and his TZ pistons were cracking.

Maybe it was as you say F5 and bore wear was causing the breakages. I have half a dozen samples of pistons broken in the same place.

I hate to say It B4me but you're right, however name a bucket rider that would give up the opportunity to have a little tinker.

In saying that I'll get it back together as it was, then when it's going real good. I'll try and make it better :laugh:

[SS90]

I recall Dave Diprose telling me that one reason for the RG piston was he thought it may be stronger because there are no transfer holes and his TZ pistons were cracking.



Ignore the window just below the crown on this picture (the piston is designed for a very unique inlet set up (double intake, reed and disc), but on the piston on the right, you will see I have cut a small "relief" in the skirt.

When you are dealing with a "direct reed intake" like the TZ50, you are only looking for a pressure difference when it comes to intake.

My experience is that the small relief is all that is required.

The third picture is what I used to do with (similar) designs, and while it functions as I would hope, (the piston is VERY VERY high quality and lasts well even with such "cutouts"), however, the lack of material on the skirt acts like a "digger" and carves away the bore causing premature bore wear.

I now use the system (essentially) the same as the above right picture, but I use the better quality piston for reliabilty and the power is the same.

I would suspect that in the case of a TZ50, having such a wide intake area, a small relief such as this would be suitable,and (perhaps) may help with the cracking problem.

[SHELRACING]

Ignore the window just below the crown on this picture (the piston is designed for a very unique inlet set up (double intake, reed and disc), but on the piston on the right, you will see I have cut a small "relief" in the skirt.

When you are dealing with a "direct reed intake" like the TZ50, you are only looking for a pressure difference when it comes to intake.

My experience is that the small relief is all that is required.

The third picture is what I used to do with (similar) designs, and while it functions as I would hope, (the piston is VERY VERY high quality and lasts well even with such "cutouts"), however, the lack of material on the skirt acts like a "digger" and carves away the bore causing premature bore wear.

I now use the system (essentially) the same as the above right picture, but I use the better quality piston for reliabilty and the power is the same.

I would suspect that in the case of a TZ50, having such a wide intake area, a small relief such as this would be suitable,and (perhaps) may help with the cracking problem.

Thanks SS90, A very similar mod was suggested by TZ350. and appears to make good sense.