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rt 225 piston choice

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rt 225 piston choice

Postby a-teamlambretta » Tue Jul 25, 2017 2:20 pm

whats availbe other than the mb rt pistons for the rt225 kit ? was thinking wisco or wossner ?? cheers simon
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Re: rt 225 piston choice

Postby Warkton Tornado No.1 » Tue Jul 25, 2017 2:48 pm

Not quite “How long is a piece of string” type question, but piston choice is often limited by factors you need to take into consideration.

The first priority for you must be to select a piston kit that is compatible with a chrome bore, so therefore the rings need to be suitable. Also consider whether pistons are graded sizes for the RT kit.

Pistons suitable for piston porting narrows things further.

Compression height & crown profile also need to be taken into consideration along with gudgeon pin diameter.

There’s no doubt that you might be able to select an excellent kit intended for a motorbike/snowmobile/jetski @ a really good price that will serve well, but it all depends on how much compromise you are prepared to make ;)
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Re: rt 225 piston choice

Postby a-teamlambretta » Tue Jul 25, 2017 6:01 pm

Warkton Tornado No.1 wrote:Not quite “How long is a piece of string” type question, but piston choice is often limited by factors you need to take into consideration.

The first priority for you must be to select a piston kit that is compatible with a chrome bore, so therefore the rings need to be suitable. Also consider whether pistons are graded sizes for the RT kit.

Pistons suitable for piston porting narrows things further.

Compression height & crown profile also need to be taken into consideration along with gudgeon pin diameter.

There’s no doubt that you might be able to select an excellent kit intended for a motorbike/snowmobile/jetski @ a really good price that will serve well, but it all depends on how much compromise you are prepared to make ;)


i have swapped a favour for a used rt 225 kit . the kit is shagged , piston ring peg let go and ring dropped into the exhaust port. just the lining is damaged and not the cylinder by the looks of it ,anyway was thinking a wossner or wiseco piston and may be get one cheaper than the mb ones. will have to send cylinder off for replate so can go nicasil or chrome or steel liner and no problem then with size or grading as lancourts or who ever will hone to suit piston size if piston is supplied with shagged cylinder .

just wondered if anyone had used something different. cheers simon
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Re: rt 225 piston choice

Postby a-teamlambretta » Tue Jul 25, 2017 6:25 pm

a-teamlambretta wrote:
Warkton Tornado No.1 wrote:Not quite “How long is a piece of string” type question, but piston choice is often limited by factors you need to take into consideration.

The first priority for you must be to select a piston kit that is compatible with a chrome bore, so therefore the rings need to be suitable. Also consider whether pistons are graded sizes for the RT kit.

Pistons suitable for piston porting narrows things further.

Compression height & crown profile also need to be taken into consideration along with gudgeon pin diameter.

There’s no doubt that you might be able to select an excellent kit intended for a motorbike/snowmobile/jetski @ a really good price that will serve well, but it all depends on how much compromise you are prepared to make ;)


i have swapped a favour for a used rt 225 kit . the kit is shagged , piston ring peg let go and ring dropped into the exhaust port. just the lining is damaged and not the cylinder by the looks of it ,anyway was thinking a wossner or wiseco piston and may be get one cheaper than the mb ones. will have to send cylinder off for replate so can go nicasil or chrome or steel liner and no problem then with size or grading as lancourts or who ever will hone to suit piston size if piston is supplied with shagged cylinder .

just wondered if anyone had used something different. cheers simon



just to add , i will be using a 60/110 crank. cheers simon
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Re: rt 225 piston choice

Postby dscscotty » Tue Jul 25, 2017 7:01 pm

Wossner would be my choice!
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Re: rt 225 piston choice

Postby Warkton Tornado No.1 » Tue Jul 25, 2017 7:05 pm

a-teamlambretta wrote:
a-teamlambretta wrote:
Warkton Tornado No.1 wrote:Not quite “How long is a piece of string” type question, but piston choice is often limited by factors you need to take into consideration.

The first priority for you must be to select a piston kit that is compatible with a chrome bore, so therefore the rings need to be suitable. Also consider whether pistons are graded sizes for the RT kit.

Pistons suitable for piston porting narrows things further.

Compression height & crown profile also need to be taken into consideration along with gudgeon pin diameter.

There’s no doubt that you might be able to select an excellent kit intended for a motorbike/snowmobile/jetski @ a really good price that will serve well, but it all depends on how much compromise you are prepared to make ;)


i have swapped a favour for a used rt 225 kit . the kit is shagged , piston ring peg let go and ring dropped into the exhaust port. just the lining is damaged and not the cylinder by the looks of it ,anyway was thinking a wossner or wiseco piston and may be get one cheaper than the mb ones. will have to send cylinder off for replate so can go nicasil or chrome or steel liner and no problem then with size or grading as lancourts or who ever will hone to suit piston size if piston is supplied with shagged cylinder .

just wondered if anyone had used something different. cheers simon



just to add , i will be using a 60/110 crank. cheers simon


In that case, you have even greater choice as the diameter can be selected & the bore made to suit.

The Suzuki TS250 piston is a popular choice & reasonably priced as well as inherently strong. The gudgeon pin is Ø18 mm so you need to bear that in mind with the con-rod to be used, although I have used 'caps' with no issues.

Personally, I'd have no qualms about using an oversize (say Ø71 mm) kit & better still if you can select a longer stroke such as 62 mm. If a Rapido can cope with shedding the heat, then an all alloy barrel should manage even better.

BTW, Wossner make a Kawasaki H2 750 piston if you're limited to Ø16 mm gudgeon pin size.

If you need more suggestions, I have some data somewhere, but I'm sure you realise that cylinder base packings are now commonplace to allow for all the variations & fine tuning of port durations.... ;)
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Re: rt 225 piston choice

Postby a-teamlambretta » Tue Jul 25, 2017 7:47 pm

thanks for the info, i will be sticking to the 60/110 crank as thats what i have on stock , standard little end i presume . so which part number for the wossner ?cheers simon
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Re: rt 225 piston choice

Postby dscscotty » Tue Jul 25, 2017 9:30 pm

If converting to jap suzuki/Kawasaki pistons you would also need to re-profile head, also I agree suzuki pistons are very good quality, although they do occasionally chuck ring pegs in high mileage motors,
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Re: rt 225 piston choice

Postby bookertmgs1 » Tue Jul 25, 2017 9:43 pm

If its the ring peg - return to Scooter Centre - they are offering warrantys for ring peg failures on the RT kits. They changed piston suppliers at start of the year due to failures & offered replacement program
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Re: rt 225 piston choice

Postby a-teamlambretta » Tue Jul 25, 2017 9:57 pm

Do you need a receipt to exchange and yesterday was ring peg failure that caused the damage, piston is still intact with rings no doubt that this was the demise of the kit.
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Re: rt 225 piston choice

Postby Warkton Tornado No.1 » Tue Jul 25, 2017 10:25 pm

You'd be wise to try & seek redress for the failure of the piston as a failure is a failure, regardless of ownership.

Failing that, the link for a full piston kit (presumably comprising three pistons) is:

http://www.forged-pistons.co.uk/webshop ... iston-kit/
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Re: rt 225 piston choice

Postby Raveydavey » Sat Jul 29, 2017 7:15 am

The new replacement pistons are meteor I think. Just fitted one. Way better quality than those shonky originals. I had the ring peg issue. Either scooter centre or MB will have the right ones
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Re: rt 225 piston choice

Postby Scooterdude » Sat Jul 29, 2017 8:22 am

a-teamlambretta wrote:Do you need a receipt to exchange and yesterday was ring peg failure that caused the damage, piston is still intact with rings no doubt that this was the demise of the kit.


There is a FB page dedicated to this issue, it seems that MB and Scooter centre are replacing failed kits as well as exchanging undamaged kits/pistons.
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Re: rt 225 piston choice

Postby a-teamlambretta » Sat Jul 29, 2017 8:58 am

Scooterdude wrote:
a-teamlambretta wrote:Do you need a receipt to exchange and yesterday was ring peg failure that caused the damage, piston is still intact with rings no doubt that this was the demise of the kit.


There is a FB page dedicated to this issue, it seems that MB and Scooter centre are replacing failed kits as well as exchanging undamaged kits/pistons.


What about those who are not on faceache, this is as near as I get to social media lol. Will try mb as they are nearest to me.
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Re: rt 225 piston choice

Postby Adam_Winstone » Sat Sep 07, 2019 10:43 pm

dscscotty wrote:If converting to jap suzuki/Kawasaki pistons you would also need to re-profile head, also I agree suzuki pistons are very good quality, although they do occasionally chuck ring pegs in high mileage motors,


I note that the Wossner piston is a low profile piston, more like the Jap piston crown, but don't seem to see anything on-line about people reprofiling heads to suit. Are people fitting these with the standard AFR heads, regardless of profile mismatch?

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Re: rt 225 piston choice

Postby Scooterdude » Sun Sep 08, 2019 1:54 am

The RT piston shares the same 7mm dome height as the TS1/RB piston so if you’re running a reed on your RT any of the Asso, Mitaka or Wossner TS pistons of 39mm crown height would work without having the head reprofiled.

As for non reed look at the Rapido Wossner Piston.
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Re: rt 225 piston choice

Postby dscscotty » Sun Sep 08, 2019 8:34 pm

Hi Adam
RB20 pistons have a flatter profile, same as yam blaster, 66/70mm pistons are usual dome height
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Re: rt 225 piston choice

Postby Adam_Winstone » Mon Sep 09, 2019 2:03 pm

^... Hi guys,

Thanks for the replies.

I'm using one of the 72mm pistons (39mm compression height), which I am about to machine the head for, and have noted just how 'out' the AFR head's squish band profile is. Whilst I'm aware that these are not a great match for the standard dome profile, I'm surprised to see just how far out they are!

I machined a few of these previously, always reprofiling the squish to suit whatever piston I've used, but I'm wondering just what I can get away with as the high capacity means that I'll be increasing the combustion chamber volume to deliver the compression ratio that I'm after... and the more I remove to reprofile = the more that I then need to work out of the bowl.

If this is the standard profile piston then there must be a lot of people out there with the profile being a mile out... yet I don't read lots of threads about it, nor hear lots of people talking about running issues.

Cheers,

Adam
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Re: rt 225 piston choice

Postby dscscotty » Mon Sep 09, 2019 4:37 pm

RB 250@ 72 mm also have a lower dome height, around 3.50mm (i think) all 66-70 etc are 6mm height as per Asso etc
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Re: rt 225 piston choice

Postby Adam_Winstone » Mon Sep 09, 2019 5:20 pm

^... thanks
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