KTM/Husky 2-Stroke Piston Ring End Gap

[@xhulkdieselx]

This guy is a gift to the dirt bike community, I learn some thing every time I turn this channel on. Bravo

[@ktmers]

Mark, thanks much for passing on your knowledge! Love your channel.

[@otmuppet]

Nice trick with the marked piston for depth measurement. I used my calliper extended at 15mm. Will correct to 20mm. It’s possible that the nicasil coating may not be consistent through out, ie thickness of nicasil My 21 TE 250, at 182 hrs showed (.6 to .55mm) on both rings. The higher end was the bottom ring. New proX ring shows .50mm. Thanks for the excellent vid.

[@aaronwowzree]

I was pretty excited when I found KTM has free service manuals on their site. But man are they terrible. Their maintenance chart say that all the engine bearings need to be replaced after 40hrs!! What a bunch of BS! Thanks for making these videos. They are much more useful than the service manual.

[@JayGee6996]

Very helpful video, thank you as usual!

[@ykruH]

There is some misleading information out there. I am right now changing the piston on my Beta RR300 and the Vertex piston says in it's manual to use .006 - .009 inches minimum ring gap per inch of bore, what in 72mm would translate to a 0,43 - 0,65mm gap. Beta, same as KTM, says in the workshop manual that the maximum gap is 0,40 mm. I measured both new rings and they are at about 0,25 - 0,28 mm new, if I file them as recommended by Vertex I would be out of spec for Beta.

[@bencain7881]

8:28 : where did you find this spec for Vertex? The instructions that shipped with my Vertex piston call for 0.42-0.65mm (newly replated 72mm bore on '15 Husky 300). My rings are at 0.28mm out of the box, so I'd love for your spec to be right! :)

[@Sellutin]

Very informative video again, thanks.

[@gupomper]

Thanks for this video!

[@Shecki603]

Very useful info. Great video!

[@CW-up7xv]

Excellent video!

[@janeali1174]

Sir i have two stroke cylinder i want to increase its rpm power please help me how i can increase the speed from its ports. Please help me tell me sir

[@Sam.Eliæson]

Fantastic 👍🏽

[@marcosvincius4899]

Hello everything is fine? I would like to check where I can get this engine maintenance manual.

[@TokyoOffroad]

The KTM repair manuals are available for purchase from the KTM website here: print.ktm.com/

[@Stonesmetalworkchannel]

I've been looking all over, can not seem to find the ring gap specs for a 2020 husqvarna tc 125.. could you help a guy out please

[@jamesshort5768]

Is 0.60 ring end gap okay? I tried a bigger size piston but I’m not happy with the clearance based of my bore measurements

[@TokyoOffroad]

What bike do you have? If it's a 250cc then 0.6mm ring end gap is a little large. If it's a 300 then it's close to the max spec that Vertex list (about 0.65mm). Having a larger end gap isn't a reliability issue, but it will cause performance to drop a little.

[@jamesshort5768]

@ it’s a KTM 125. The manufacturer spec is 0.40. A bigger size piston size C has correct ring gap somehow and both was the vertex. My cylinder is 54 but bore gauge reading 53.97. I’m not confident with my bore gauge readings. I bought the cylinder second hand and was told it was size B piston but I’ve been getting slap. The size C seems a better fit less movement in cylinder but off my bore size readings it should be much tighter.

[@michail1963]

Mark, great quality video guide as usual. Do you see however the need to check this? Or just doing top ends every 150hrs should be fine?...

[@TokyoOffroad]

Mikhail - My thoughts are that the OEM ring tolerances are controlled tightly so that for a new OEM kit you’d be extremely unlikely to experience rings with too little gap. And so long as you perform regular top end overhauls (100-200H depending on how hard you ride) you should be fine. Also compression testing will show whether the rings have excessive wear.

[@loganhamilton245]

Hi Mark you won't have any cylinder to piston clearance specs for the 2017-2018 non tpi 250 bike's by any chance? Cheers from New Zealand 🇳🇿

[@TokyoOffroad]

From the 2017 repair manual: Cylinder Bore Size 1: min=66.400mm, max=66.412mm; Piston Diameter Size 1: min=66.340mm, max=66.350mm. From these specs you can calculate the minimum cylinder to piston clearance=0.05mm, maximum clearance=0.072mm

[@googlesucks3520]

For my 300 boys, ring end gap min spec is 0.28mm. Max spec (worn out rings) is 0.40mm. Vertex 300 rings should come at 0.28mm from the factory, "trust but verify" ;)

[@178Schmitzi]

Cool Video! But if I see this. Why to change the whole Piston by Engine rebuild and not only the rings? Cheers

[@TokyoOffroad]

The piston skirt wears and will eventually fail, causing catastrophic damage to the cylinder. My recommendation is to change the piston and rings every 100-200H depending on how hard you ride.

[@jesserichter7560]

Thanks buddy

[@MrShaniqua42]

Could you do a video on clutch slave cylinder bleeding ? I’ve tried many times and can’t seem to get the lever feel correct.

[@TokyoOffroad]

MrShaniqua42 - When you tried what method did you use? I’ve reverse bled my clutch (to replace the fluid). The method is the same as shown in this front brake bleeding video: m.kzbin.info/www/bejne/bIamf4qcdpyXjNU

[@kyomondo]

Why is your company 【tokyo offroad】? 　製造メーカーより親切な動画です とても勉強になります ありがとうございます

[@TokyoOffroad]

Tokyo Offroad was chosen as the name because I live in Tokyo and love off-road motorcycles and riding.

[@kyomondo]

@@TokyoOffroad Thank you for a wonderful video & I support you

[@artisgrietens5535]

Hello how i can select right ring end gap? ,when i buy new piston kit from ebay ,lets say for used cylinder like 200h on it, i know how to messure cylinder to piston clearance to select right piston, but piston ring end gap to get correct i dont understand it can be to small gap or to big gap, only thing i dont know is gap size !! ,yes if i see that piston in shop then i can do like you in video to messure gap ,but my piston comes from ebay...

[@TokyoOffroad]

The ring end gap needs to be measured in the cylinder you will be using (as shown in the video). If using a KTM OEM piston kit no adjustment should be required.

[@artisgrietens5535]

Tokyo Offroad ok thanks 👌

[@arminiusrex3501]

Hey, maybe you read a comment on a that old video^^ I have the same markings on my cylinder from the bottom to the top every few cm, you know how that happens or if it is a problem? And can you maybe make a video for Ktm 250 to set the X-dimension? That would be awesome. best regarts

[@TokyoOffroad]

Yes, every cylinder I've seen has had the same marks, even zero hour take offs. The marks should not be deep though and you shouldn't be able to feel them with your finger nail. If they were deep it would be an issue... Yes, good idea regarding the x-dimension video. I'll be working on an engine soon so will be making some new videos soon and will be sure to make an x-dimension measurement and adjustment video.

[@mullaway5746]

hi mate my manual says end gap 0.3-0.4 , ktm 250/300 , I just got a new mikita piston kit ktm300exc 2007, new rings gap measures .25 mm is that too small or can I still put them in at that thanks

[@TokyoOffroad]

Your ring end gap is a little tight. Wiseco provide a minimum ring end gap formula which is 0.04" per inch of bore. For a 300 this gives a minimum ring end gap of 0.288mm. My recommendation is to open up the gap to 0.3mm. This Wiseco document provides some advice regarding filing rings. Great care should be taken to keep the ring end square, with no burrs, or damage. Only file one end of the ring. www.wiseco.com/PDFs/Manuals/RingEndGap.pdf

[@juanpabloecuador]

Primero ! Excelente canal !!!

[@mt1885]

What brand of feeler gauges you using do you got link?

[@TokyoOffroad]

The feeler gauges I have are made by RSK (Riken Sokuhan) which is a Japanese brand. The part number is 100MZ. It includes these thicknesses: 0.03、0.04、0.05、0.06、0.07、0.08、0.09、0.10、0.11、0.12、0.13、0.14、0.15、0.20、0.25、0.30、0.35、0.40、0.45、0.50、0.60、0.70、0.80、0.90、1.00mm. I could start selling them on the Tokyo Offroad webshop if there is some interest.

[@TokyoOffroad]

www.r-s-k.co.jp/99_blank.html

[@TokyoOffroad]

This page shows the specifications: www.r-s-k.co.jp/products2031.html

[@mt1885]

Thank you for fast replies.

[@nicknicky873]

Hey man I was just wondering if you can let me know how I can learn how to mess we with everything on a 2 stroke dirtbike, I dont want to rely on shops and I would rather work on my own bike but where can I learn all of this?? I know you have a degree for engineering or something like that and thats why I'm asking, thank you

[@NirHason]

Unrelated question: If you have to keep only one bike which one it will be the 250 carb or TPI? (engine and power delivery wise)

[@TokyoOffroad]

Currently my carb model (Keihin 38mm Air Striker Short + STIC) is performing better than the TPI, so I’d keep the the carb model. It will be interesting to see how much better the TPI performs when I change the ECU to PowerCDI (when it becomes available.

[@NirHason]

Tnx for the answer :) I'll consider changing my carb to Keihin + STIC combination (not a cheap upgrade for me) instead of upgrading to TPI (even though I'll love to stop mixing oil and fuel haha)

[@mansoorahamed5028]

which piston is good quality for yamaha rxz 5speed

[@TokyoOffroad]

I don't have any experience with the Yamaha RXZ 5speed so can't answer. Anyone else?

[@power.turbine4872]

Why in the world do they put one ring split over the other? The splits should be as close to 180deg apart as possible

[@TokyoOffroad]

The ring gaps are offset by about 4mm and positioned at the intake. I think this is done as the intake is the coolest part. I previously made a video which shows the ring gaps passing over the intake port which you might find interesting: kzbin.info/www/bejne/gWfKq6mdi52of9U

[@power.turbine4872]

Tokyo Offroad emailed Vertex and this is his reply “Thank you for your excellent question. When talking about ring end gap placement in most 2-strokes you have to consider the intake, exhaust and transfer port locations in the cylinder. The ring end gap needs to stay on bridges of the ports or else the rings may stick out into the port and get caught and then bad things happen. If you have any more questions just let me know.” Didn’t answer my question really

[@power.turbine4872]

Tokyo Offroad also just checked pictures of my cylinder and piston orientation...and the ring gaps are directly over, and in the middle of, one of the intake ports...not even close to one of the port bridges. Pretty much goes against his reply

[@TokyoOffroad]

power.turbine - Yes, for KTMs the ring end gaps pass over the intake port as shown in the video (link above).

[@daveb1963]

I would take more notice of the bike manufactuer rather than the piston manu because they stand to gain more by saying your rings are worn out...

[@Jrod_FPV]

Crap... 0.13mm ring end gap on 2017 300. 280 hrs on cylinder. B size piston

[@andreatreviso8049]

Subtitle in Italian please 🙏