Need new pistons for your 4L0 RDLC ?

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2smoke
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Need new pistons for your 4L0 RDLC ?

#1 Post by 2smoke » Sun Mar 24, 2013 12:32 pm

Hi
This question comes up alot so i thought i would make a post about it.
You dont need to use factory Yamaha 4L0 pistons. You can use Banshee/ RZ350(same thing) aftermarket pistons instead. When looking these pistons up for purchase, if they are not listed under RZ350, look under ATV- Banshee 350.
To use them you need to remove the middle "tooth" from the middle of the skirt as it is simply not needed on the RDLC cylinders and could wear and break off with disasterous results.
Draw a straight line accross the cutout, stuff a clean rag inside the piston to keep the aluminum dust out. Grind away.
Take care to make a nice smooth straight line. Use a fine file to finish and to take the sharp burr off the edge.
If you are too lazy to do this, the machine shop who is boring your cylinders will. Also, i know HVC cycle offers this service for a fee when you buy your pistons there.

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Its really easy, just use a dremel or 3M mandrel with a sanding disk in a tool. Obviously be careful not to hit the outside of the piston.
Heres what i use:

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Colin
79 RD400F Daytona Special
81 RD350LC
89 TDR250
75 Kawasaki H1 500
77 Can-am Tnt250

silverstrom
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Re: Need new pistons for your 4L0 RDLC ?

#2 Post by silverstrom » Sun Mar 24, 2013 12:39 pm

Excellent post Colin. Would be great to have a "Technical" section where stuff like this could be accessed for the LC and the YPVS.

rdlclazy
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Re: Need new pistons for your 4L0 RDLC ?

#3 Post by rdlclazy » Wed May 22, 2013 8:36 pm

in the uk, we use the same pistons be it an RD400, 350lc or a powervalve (you call them rz350's)
1981 Yamaha RD350lc, pwk28 carbs, banshee racing coils, 6mm reed spacers, black chrome small can allspeeds

Bare
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Re: Need new pistons for your 4L0 RDLC ?

#4 Post by Bare » Tue Aug 27, 2013 12:05 am

Again: if unstated or someone forgot?
OEM yama pistons (use banshee or RZ) are THE best money can buy.
Unfortunately Yama only supplies those in the first 2 oversizes.

brg1200
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Re: Need new pistons for your 4L0 RDLC ?

#5 Post by brg1200 » Sun Nov 03, 2013 11:47 pm

Someone said somewhere that ART made Yam pistons, and their "retail" arm is ProX. Would that make them the same thing?

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2smoke
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Re: Need new pistons for your 4L0 RDLC ?

#6 Post by 2smoke » Mon Nov 04, 2013 10:31 pm

I can only repeat what I have read on the net. That is that ART made the aircooled 350+400 pistons but they are out of business.
And I have read that Mitaka and Pro-x are manufactured by the same factory in Japan.
I have both Mitaka and Pro-x here and they don't look the same at all.
So who knows. Lol.
Colin
79 RD400F Daytona Special
81 RD350LC
89 TDR250
75 Kawasaki H1 500
77 Can-am Tnt250

brg1200
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Re: Need new pistons for your 4L0 RDLC ?

#7 Post by brg1200 » Sat Nov 09, 2013 6:39 am

Well, if they don't look the same and theyre being sold for the same purpose at the same time I guess they are coming from different factories.

LC Cnd
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Re: Need new pistons for your 4L0 RDLC ?

#8 Post by LC Cnd » Sun Jun 01, 2014 8:12 pm

Completed cutting off the tabs, yesterday, and polished off each cut to a glean (64.5mm pistons). Purchased the pistons out of Quebec. Be interesting to see what the compression test will on them. Thx for the tip Colin. Scott

nzminis
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Re: Need new pistons for your 4L0 RDLC ?

#9 Post by nzminis » Sun Jun 01, 2014 9:03 pm

few months back i got Mitaka pistons for my Rzv 500 and rd400 from yambits

Mitaka box , pro x cast on the inside of the pistons

so yes Mitaka and pro x are the same

yam4l0
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Re: Need new pistons for your 4L0 RDLC ?

#10 Post by yam4l0 » Mon Aug 18, 2014 6:21 pm

nzminis wrote:few months back i got Mitaka pistons for my Rzv 500 and rd400 from yambits

Mitaka box , pro x cast on the inside of the pistons

so yes Mitaka and pro x are the same
I have recently purchased a set of Mitaka pistons for my 4L0 & they were cast TKRJ, go figure :smt017

They were also "proper" LC pistons, round windows with no cut outs on skirt.

Image

speedjunkie_69
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Re: Need new pistons for your 4L0 RDLC ?

#11 Post by speedjunkie_69 » Tue Jan 20, 2015 1:14 am

Hello,
looking into ordering the 1st oversize pistons for my '82 and I noticed on the Canadian Yamaha webpage that the Banchee model ran from '87 till 2007. Are the Piston sets all the same? I quickly scanned 2 years and there appears to be the same part numbers..
cheers
Norm

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2smoke
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Re: Need new pistons for your 4L0 RDLC ?

#12 Post by 2smoke » Tue Jan 20, 2015 1:52 am

Yep. All years Banchee the same pistons.
Colin
79 RD400F Daytona Special
81 RD350LC
89 TDR250
75 Kawasaki H1 500
77 Can-am Tnt250

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JonW
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Re: Need new pistons for your 4L0 RDLC ?

#13 Post by JonW » Tue Jan 20, 2015 4:06 am

Whats the biggest overbore a 350 LC cylinder can have? we all seem to know its 66.00 on the YPVS motor cos of the PVs and the thin liner, but the banshee will take a 66.50 i think, so would the LC barrels too?
80 XT500 Supermoto!
81 RD350LC Resto
82 RD421LC Hybrid
82 RD350LC decapitation project
82 RD250LC JDM '251LC' YPVS
83 RZ350 Resto
84 RZ500 Resto
85 RZ350 F1 Resto
86 RZ350 F2 Resto
86 RZ350 F2 Hybrid

Like Watches? www.PloProf.com & www.DeskDivers.com

yam4l0
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Re: Need new pistons for your 4L0 RDLC ?

#14 Post by yam4l0 » Tue Jan 20, 2015 5:02 pm

JonW wrote:Whats the biggest overbore a 350 LC cylinder can have? we all seem to know its 66.00 on the YPVS motor cos of the PVs and the thin liner, but the banshee will take a 66.50 i think, so would the LC barrels too?
2.5mm O/S is max on a 350LC (4L0) but the liner is left quite thin & the head gasket needs opening out to suit.

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JonW
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Re: Need new pistons for your 4L0 RDLC ?

#15 Post by JonW » Tue Jan 20, 2015 6:05 pm

Thats what I thought, cheers for the confirmation :)
80 XT500 Supermoto!
81 RD350LC Resto
82 RD421LC Hybrid
82 RD350LC decapitation project
82 RD250LC JDM '251LC' YPVS
83 RZ350 Resto
84 RZ500 Resto
85 RZ350 F1 Resto
86 RZ350 F2 Resto
86 RZ350 F2 Hybrid

Like Watches? www.PloProf.com & www.DeskDivers.com

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