CRANKSHAFT TRUING MADE EASY | How To True Two Stroke Crank | 2 STROKE TUNING 

Love it when a customer (friend) brings me a job that I have no experience with and I can find a 4 year old video that explains what I need to know. Cheers 🍻

Unify needle and actual movement. To reduce potential for confusion, adjust the dial indicator "0" position to, in this case, roughly 9 o'clock position. The needle and crank will move in unison, up=up, down=down. Deletes one line of brain code for use elsewhere. Thanks for the video. Cheers

Rebuilding a crank is the last thing remaining that I haven’t been able to do myself. (Just finished my first overbore). Gathering ideas and preparing now. Great information about what you may see and what it means.

I have been building motors for years and I've been taking them to the shop to be trued. This vid have made me a sub, so def gonna build a stand like yours!

Amazing art,even more amazing is effortless explaining of such a complex task of truing of crank

I like your explanation man, absolutely easy to understood. Thanks a lot!

I watched your video as a guide, before I trued my crank of an old Bike from the UdSSR. I measured 6/100mm difference while turning the crank. It took me LITTERALY JUST ONE hit with the hammer and the shaft ran true with bearly 1/100mm. Thanks for that video, apparently it worked more than well for me!

Excellent informative vid by a cool dude, off to tackle my 1951 Royal Enfield crank now!

Great explanation! Your tutorial will make my chainsaw Crankshaft straightening much simpler 👍😎

Excellent video, by far the most informative video I’ve watched so far on crankshaft truing!

best video ive found explaining where to measure run out and interpret what to do ti fix it!

Excellent guide It was not possible to do diy alignment on my crank shaft without watching your guide. Here are Couple of techniques that I discovered: You could use a lever or screw driver and pry in between crank shaft for minor adjustments, you would be surprised by how little effort is required when doing this way I use the above technique with a dial gauge still touching the shaft for avoiding trial and error If one web is true and other isn't, I try to avoid wedging action and instead hit only the web that has run out, this however applies to rare cases though When checking run out, I tend to use the extremities of the crank

I dont know you but i fing love you man. i have a twin cylinder yamaha which received a proper bashing to disassemble, it molly cobbled the crank ...,but with your instruction and a 2lb brass basher I got it to within .001mm. thank you for sharing your knowledge sir. To anyone reading or watching, this is very very easy to do .

Finally - an explanation why the end of that CR crank was spinning around like a space shuttle. Thanks

For sterters, dial indicator both sides, 2 dial indicators, same time. lead hammer, lead bed, fixture should have tapered centers. You are doing very good for what you have to work with.

Благодарение на този епизод успях да изправя един много стар колянов вал! Благодаря!

Great tips. I am sorting an old Velocette crank first time I’ve tried This job. Your vid helps a lot to understand the readings I am getting and how to rectify 👍👍

Love a good bit of diy. Been putting the crank rebuild job off for ages on my husky 250 and finally got it sorted today thanks to your vids. The truing rig works a treat! Got my crank down to 0.01mm run out. 20,000kms on my original crank and man was she flogged!

Great job explaining the process, but I'm most impressed with the tooling you built. When I started 51 years ago I was not so smart and bought (on payments of course) a 4" Sears lathe for truing. Why watch a video on something I already know how to do? There's always something to be learned.(I did one twin crank, that was enough for me) Cheers

Didn’t know how to balance a crank until I saw this. It was perfect, I now have a BSA Bantam 1963 crank assembled and balanced. A1

I've pressed hundreds of 2-stroke cranks and my rule of thumb is to always eliminate the twist first...Start with rod back and then rod front and find which is lower at the two readings, then rotate to the lower reading and hit the top of the cheek closest the indicator...HIT THE LOW...After rod back and forward is true, I then move to check rod up and down, spread or pinch as needed and then follow up by re-checking twist, as well as a full rotation reading....After it is true I also re-check the rod side clearance as it can change during the truing process...Copper hammer and aluminum jaws on the vise also...Good luck with it !

Thanks.. this is the best video on you tube for crank trueing.

Kick ass content especially this one. Is a huge help

Nice work. Very informative. I will likely have to watch this many times over.

After a few rebuilds on my kx500, I've noticed the vibration changes to different rpm at each time. I use a hammer to belt the crank out and heat/freeze on assembly. I can now see why I'm doing it wrong..... plus I'll need a very big vice and hammer to balance it 👌

I taught crank re-building as part of 'Machine Shop' course, That was pretty good explanation. Two and 3 cylinder cranks are not too bad to do, even without various special tools.(I've used centres or v-blocks-precision and home made) Multi cylinder just take longer to do and you have to make sure the phasing is correct. 180 and 360 twins are pretty easy. Most small single cyl cranks only use 1.5~3 tons of interference fit, 'newer' Harley Davidson use a minimum of 40 tons, (even though they say 50) I don't mess with them. Polaris/Bombardier use around 18 tons and they are more than dangerous enough for me. Use a lead hammer to prevent damage to flywheels when you have unhardened cranks, easy enough to re-melt in a can when it gets deformed too bad (just don't tell health and safety ;o) )

Thank you so much for this, I'll be doing it myself soon.

Great video thanks for taking the time.

Thanks, really interesting! Excellent explanation!

Great video so much knowledge made easy thank you

Very nice explanation thank you !

Thank you very much for a good explanation, buddy!

Amazing video thanks!

Very well done!! I appreciate the information & your help! I have an IT-465 that needs the crank rebuilt. Now that I've seen this, I think I'll just do it myself. (-:

10 thumbs up. Super easy to understand and made perfect sense. Thank you thank you thank you!

Brilliant, thank you!

Perfect explanation, thanks!

Very detailed, thanks.

Love this guy!

Tips for 2 cyclinder snowmobile cranks? Your videos have been helpful in rebuilding/modifying my single cylinder bikes. I'm digging into my sled motor next...

This was amazing thank you so much

Thanks helped alot my yz80 was out of tru

Very informative,thanks maan👍👍

Thanks. Awesome vid.

I always wonder how well built cranks are when they leave the factory. And what heat does to change the crank, whether it's welding at assembly or heat cycles while operating the engine.

Very helpful video thanks👍👌

Μπράβο ρε μάστορα!

I called nearly 30 people and was able to find one guy who can true a crank shaft. He worked on stuff for him sepf

THIS is the correct way to measure runout then reduce it to as little as possible. Note where he places the indicator on the shaft, not the bearing journal. Good video!

wow and I been paying a machine shop $60 to do this. Man your the shit!!

I love RU-vid. Thanks for the lesson

Thank You :)

You are a good teacher...thanks, professor!

thanks man, i screwed up my new stage6 crank, making progres..

Can you guarantee that after you install the bearings into your cases (I presumme using a method of heating-up the cases and freezing the bearings), and you then install the crank into your cases, it still will be true? Would the friction caused by bearing to crank journal interference fit, eventually not pinch the crankshaft? Even if you draw the each crank pin on each side into the casing with a puller, the very last tension from the tightening the casing screws would eventually put some axial stress on the bearings and crank itself leading to pinching it?

Excellent video! I'll go and destroy my crank now :)

英語の授業でもこんなに楽しい教材があったら、良かったなす(´ω｀)。ビジュアルとのバランスが良くて、有り難いす！。

Thanks❤

Hey, excellent explanation. I got to do this at the motorcycle mechanics Institute. I put together my Honda c r eighty Aftermarket pre built crankshaft didn't know i needed to check it for true Now I got some vibration at wide open throttle. Sucks!

I would love to see that china bike series, better than a good movie. That's very similar to what I am doing.

Brilliantly simple but tricky to master I bet?👍🏻

Thank you for this info. I only can afford to mess with the Chinese bike motors on Amazon. But I'm able to get a sweet running motor. I didn't even know you could true a crank like this without grinding. Idk if you ever messed with those motors but they are a pretty good/simple design. Just the parts are usually pretty bad.

Nice channel, great topic. Sorry that Eyvind Boyesen is not with us anymore, he would have enjoyed the interest you're generating in two stroke development.

Truly a great video. You were at the top of your game here . Very well explained . Where did you buy the tool ,name??? The indicator that shows you , true or not ?

Thanks for the Video(s), your channel is awesome, since I'm really interested in the topic of two stroke tuning and you can explain it really well. My only question is, in how far you could damage the bearing in the crank in this procedure.

About 10 years ago, I was living in northern Minnesota, and I worked at an engine machine shop. Up there, almost everybody has a snowmobile. Twin cylinder cranks are bad enough, triples really suck, but one time a guy brought in a 4-cylinder 880cc vintage King Kat engine. NEVER AGAIN....

if you get it in 0.1mm then you did good job!

Hi, nice video!! Could you please suggest, my Yamaha crankshaft has a key way made into it and i need to place the Dial indicator very close to the crank, will this setup work? would there be any issues if i place dial indicator right above the support? Thanks

Spooky timing. I'm just about to take on rebuilding a crank for my yamaha 350. Doesn't seem quite as intimidating now.

Question; would using a rubber mallet to separate 2 stroke cases possibly throw off a crank’s balance? Im putting mine back together and want to know if it is necessary to check or get a new crank thank you!

Hi love your videos. Really helpful. Though I have a question I'm hoping you could get back to me as soon as possible, I'm doing my big end bearing on my crank after it seized on my Honda Cr125 2000 model. And I'm doing most of it myself to save money, my question is a mechanic told me that once I split my crank I'd have to send it to a really good engineer with the right laser tools to get it true and that even if it's 1000th of a mm of true it will wreck my engine. Is that true and how much off can I be from my true point to wreck the engine? I'm asking cos I watched your videos and you were off as you said by 200th of a mm or something so please explain and help I'd really appreciate it!

So are there pros and cons to slip fit crank vs welding the crank pin besides the fact you can’t true it anymore when welded?

What do yoy suggest an acceptable runout..I trued my gas bike crank between .002" both sides felt that was pretty good after hours of messing around I see yours is a lot more accurate.

thanks for sharing friend, i think i will try it on a honda 4trax 350...Creator bless...doug

Hi! Very informative video. Just one question, after what you did, don't you need to check the other side of the crankshaft too?

Don't know if you still follow this post...I'm having a terrible time with an XL185 crank, so I got the TAG Z balancer and meter jig, I'm getting a high point just before the crank facing front of 55 and if I run the Conrod from 0 backward the Conrod gets to two 3/4 to the rear bottom side and negative/low 75 as in reading the meter backwards 90 as 10, I've got it to about 12 high same position 45 low same position then I had realised if I ran the Conrod around, the jig runs the crank to one side and the bearing rollers on the jig catch on the crank grinding and obviously move on the meter position and alter (hence why im reading it by running it / counting backwards....ah amazing starting to figure it out now, using a rubber mallet by the way, no dents and it works

After i true my crankshaft will the sudden changes in temperature (assembly) make it bend back or do they stay forever in the same position

I follow your instructions but the main problem is that once i align one side (not a big problem) on the other side increase the runout, why? in this case should i find an acceptable balance between the two sides ?? or is it possible to align perfectly both the sides also if one runout till the other is aligned??

What do I do if the crankpin is on top or bottom i have 2 dial gauges the left one is not moving and is true to the eye, only the right one is moving and looks woobling a bit, when the pin is on tdc the reading goes higher and when on bdc the reading goes lower ONLY ON RIGHT SIDE.

At 6:30 you came to the conclusion that the error was around the crank pin, but how do you know it wasn’t just the shaft that was bent? ie. no longer perpendicular in to the face of the web or on the axis of rotation? Sure squeezing it there might true the far end you were indicating relative to the apparent centreline of the crank, but you might have to just “robbed peter, to pay paul” and thrown your web into an unbalanced or less balanced state, just to make the end of your shaft appear to run true! Maybe get a micrometer across the webs to determine if they are running parallel, and then run one or preferably a pair of dial indicators on the outer diameter of each web to determine if their centres aren’t concentric, and then tap to rotate in the desired direction. Once both webs are parallel and concentric to each other, run your dial gauge on the side face of each web to determine if they’re perpendicular to the axis of rotation and assuming all is good, then a run the indicator on the end of the shaft to determine if the shaft is bent, or if it is true to the axis of the crank, not that it matters critically, since it’s outside the main bearings anyway

were can i buy the tool that u have used to calibrate?! thanks ;)

I think you made a mistake in nominating your high webs between 4:00 and 4:43. In both examples, you identified the right Web as closer to you when the dial indicator read high.

Do you need to worry about welding the crank pin? Can it twist when in the bike or walk out?

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I pressed the webs to far , resulting in to little clearence. Is it possible to somehow press it out again.. i need it 0,5mm out, and don't want to spend money in a new con rod kit. .

Thanks a million.I am not sure I have your patience though.

How does that knife edge feel when you are turning the crank? Is it frictionless enough for balancing? I want to make one but I was thinking of a 3 ball bearing arrangement to hold the one side of the shaft.

You do any Dio 2 Stroke porting?

What if we do not true crank properly, or if we true it with our eyes only without using dial indicator?

Hey man, love your videos! Would you give me a tip for exhaust for my setup on minarelli am6? The setup is Exhaust and intake port polished Airsal 77cc cylinder Metrakit pro race crankshaft Stage6 C3 crankshaft bearings Dellorto PHBG 21mm carburetor UNI air filter NGK BR9ES spark plug Stock derestricted exhaust Thanks for your respond.

Hello just started to watch your videos and have helped alot. I am trying to refresh my sons iame ka100 engine because bearings on crankcase were going bad. first time inside a 2t engine. the crank is true but i have a question about axial clearance. per the overhaul manual it say between 0.4mm min. to 0.6mm max axial clearance on the connecting rod to the crankshaft. i have 0.7mm. this engine was previously blueprinted by a well known builder and i'm wondering if this was done for performance or should i take it apart and fix this. I would really appreciate your thoughts on this.

muito bom amigo,so fautou ser com uma legenda em português do brasil.obrigado davi pereira sanches,sao Paulo brasil

could it be the crank is slightly out of true that causes swing-vibrations when i accelerate up to higher speed. wowowowoowowooowwwwwwoooowwwwoowowowow.. like that?

how are you timming inner webs 180° out from each other. the pin is not keyed . I use presision ground gauge blocks made just for this .

Can you do that with a triple?

If i am simply rebuilding my daily driver 125cc scooter that has failed bearing do i need to go trough all this or its tuning for racing or when you push it far into in red zone 12000+ rpm? What happens if i dont do it?

"ö kött bålt änd a nött". Är kul med språk och dialekter och då jag förstår norskan ganska bra och är så van med engelskan så glömmer man ibland att du faktiskt pratar engelska när man hör den norska dialekten.

ehhhh. My crank happens to have two different journal sizes, a simple V wont work. I went through some variations, making a stand that accommodated for the differences...then I found that my craftsman mini lathe makes a damn fine crank jig even if it struggles to turn parts. (Looking at some of the commercially available $900 crank jigs Im thinking, "Hey thats just a damn mini lathe without the cross slide". Used two indicators on the halves. Its within .001" now, taking a breather. Guess I will throw it on the stand that resembles your concept here and see what the runout is on the far end of the crank, I still cant get that thru my skull as to how/why that works at all. what about variations in the stand? Like if moving left to right one side is higher? Or if the left side is closer to you than the right? (the sides of the stand I mean). I guess a trued crank would still read true even if it was spinning off level or not parallel to the stand.

Do you have to weld it after it is trued?

Bigger heavier hammer made of softer material.