Simplest way to measure Exhaust Port Timing on a Two Stroke Engine

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Showing the quickest and easiest method to measure the exhaust port timing on a 2 Stroke Engine using a Degree wheel with the engine assembled.
You can get a printable degree wheel to use by searching google.
#2Stroke #PortTiming #ExhaustPort

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23 дек 2018

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Комментарии : 72

@driffbro3380 5 лет назад

You, 2STROKE STUFFING and Matt from the workshop are my favorite RU-vidrs. Merry Christmas btw!

@DevinderAthwal306 5 лет назад

Snap

@AuMechanic 5 лет назад

Glad to hear it, you have a good Christmas too.

@karriebhurgari3933 5 лет назад

Me too, love all their vids 👍

@gerryporter8510 5 лет назад

Thanks again for all you do!

@Matfyf90210 5 лет назад

Love your work mate, thank you for these videos

@AuMechanic 5 лет назад

Cheers Matt Got another to upload later on that covers some more on this engine and another way to measure port timing.

@frankierutherford1888 5 лет назад

This is great info. Thanks

@ChickenStripped 5 лет назад

Very nice video. Informative and fun to watch. I think I like this video format more, compared to the older, "screen view only" videos

@AuMechanic 5 лет назад

Some things like this it is better to demonstrate on an engine, but other things like the chamber i need to use diagrams etc so Ill try to mix more of this type into videos.

@mordantly 5 лет назад

Gotta love 5th grade ameteur engineering! Merry Christmas. Can't wait for other port vids.

@AuMechanic 5 лет назад

Yeah Id use the word engineering loosely with this engine. At 154 Ex and 104 Transfer it's pretty poor and the piston is a world of wrong. Reed intake though but direct to case so no boost port I can see..

@mordantly 5 лет назад

Very true. Either a piss-poor copy or scrap bin parts job.

@AuMechanic 5 лет назад

@@mordantly I'm sure they copied some engine and just did a real poor job of it. But for AUD 60 price it looks like i got what i paid for. Shame really because if they got the right cylinder and piston to use it might have been half decent.

@donaldellis9004 4 года назад

You ate definitely smart enough to install a stiyl m660 cylinder on an 80 cc China motor , others are trying to make videos showing how and failing miserably please take the time to build that motor I would greatly appreciate it thank you

@AuMechanic 4 года назад

Thank you for the comment. I would probably attempt that job however at this stage I don't have any useful purpose for the engine other than to use it in the videos to demonstrate various topic I'm covering.

@chiradip24 2 года назад

Very informative video. Thanks for uploading..

@AuMechanic 2 года назад

Thanks for the comment.

@joshuadulaney5559 3 месяца назад

Nice shirt love suzuki

@tyronep5611 5 лет назад

Best video ever!

@AuMechanic 5 лет назад

Thank's for the comment.

@timdryden3778 5 лет назад

thanks

@erikjohansson9039 5 лет назад

Wow that is a mountain of piston not "clearing" the port at BDC. Anyways nice video and Merry Christmas!

@AuMechanic 5 лет назад

Well spotted, 3 mm actually, Ill be doing a video on the other problems with this engine. So far I can see the cylinder they used does not match the stroke of the crank and the piston they used was a dirty fix to get the comp ratio high enough to run.

@frankg3278 3 года назад

I've got one of these an I'm itching to port it but I've made the same observations as you guys. Would raising the barrel then skimming the head fix the problems do you think? It is possible to get a separate head for these engines...

@robmiller1514 2 года назад

Hi Dave, great video's, I've learnt a lot along the way. Even downloaded the calculator and built my first chamber. I have a question relating to port mapping. As you explained in another video, trace the port, work out the area then calculate the effective diameter which is then used in the calculations for the expansion chamber. However, like in this video at the 4 minute mark, my piston sits up into the port at BDC by about 3mm or the top ring just disappears. Should I therefore be reducing the measured area by the amount the piston is masking the exhaust port? By the looks of the engine in your video it looks like the piston is masking 15 to 20% of the exhaust window. I haven't re-measured mine yet but I'm guesstimating it's around 7 to 10%. I've recalculated the pipe and it makes a small but noticeable difference to the result.

@AuMechanic 2 года назад

Yes, if the piston masks the port to any degree you would need to subtract that.

@colta51 5 лет назад

Merry Christmas

@AuMechanic 5 лет назад

Thank's Sean, you have a good Christmas too

@whiskeytangofoxtrot9403 5 лет назад

A trick that I've seen in the chainsaw world for mounting a degree wheel is using a keyless drill chuck mounted to the wheel then snug it on the crank end

@DevinderAthwal306 5 лет назад

Wow, great idea.

@AuMechanic 5 лет назад

Good idea, however you fit the degree wheel is good enough since its not that critical doing piston port timing where you are just reading one sweep on the crank Where doing cam timing its more critical since you have to set absolute TDC and any chance the wheel slips is not good.

@christopherknee5756 3 года назад

You can mount the degree wheel with mounting putty like Prestik. If your wheel is light, it will stay in place if you don't bump it. To center it, just align the outside circle or perimeter with a fixed point. No bolts required.

@ronchinoy 9 месяцев назад

I am looking for engines with the lowest Exhaust port duration. What is this engine ?. What is its stock power band. ?

@dyl.au1 3 года назад

Hi, I have a KX85 which I'm putting a 2mm stroker crank in, can I space the base of the cylinder to keep the port timing right. Thanks,

@noahriedel801 3 года назад

Did you ever figure out the answer to this

@dyl.au1 3 года назад

@phreaktor 3 года назад

If you are installing a rocket key to advance timing, this needs to be done with it installed right?

@AuMechanic 3 года назад

You zero the timing wheel anyway to begin with irrespective of the ignition timing.

@phreaktor 3 года назад

@@AuMechanic Ah silly question. However it helped me see the obvious. Many thanks again. You have a new subscriber. :)

@lorifilm 4 года назад

Hi Sir! Right now im fixing-rebuilding an old Fantic Lei moped from the 70s, with 49,6cc Minarelli engine, and i measured just 132 degrees on the exthaust port!!! its pretty far from the range you mentioned. Any idea why is the number this low... or suggestion what would a more experienced mechanic do in this case?

@AuMechanic 4 года назад

Being an older engine the fairly low timing number may just be the engine doesn't rev very high. Is it out of a scooter ?

@lorifilm 4 года назад

@@AuMechanic Thank You for your answer! You are right I watched a comparsion vid of three cylinders from Matt(the workshop) and there he measured an older OEM Piaggio with a similar difference between the Tr-port and the Ex-port(just 3.5mm).

@willacewallace5905 3 года назад

Doesn't it matter to know the degrees from TDC to when the port begins to open? The effective power stroke. Then, from there were would calculate the 154 degrees in to that?

@AuMechanic 3 года назад

In a 2 stroke the port open is the same degrees as the closing from TDC (symmetrical). So if you want to know how far it is from TDC then just halve the open period,. Also, measuring half the open period from TDC halves the precision of the measurement where measuring the whole open period is more precise and is simpler too so less chance of a mistake. Setting TDC on the degree wheel is done for 4 strokes because cam timing periods are not equal degree from TDC (asymmetrical)

@sumedhovhal8156 5 лет назад

How can I increase the port timing my factory timing is 165° I want to make up to 175°

@AuMechanic 5 лет назад

Basically you raise the exhaust port to increase exhaust timing. Either by grinding the exhaust port itself OR to increase timing on exhaust and transfers you can raise the barrel and then remove some off the top of it to bring the head clearance back to what it was to begin with.

@barris1233 5 лет назад

How do i mesure the timing on a two sylinder engine?

@AuMechanic 5 лет назад

Same as single cylinder, just measure exhaust port timing of one cylinder. As mentioned in the vid, exhaust and transfer timings are symmetric, meaning they open and close at the same amount of degrees from top dead centre, so you only need to measure the total open period in degree's you don't need to measure how far from top dead centre they open or close at.

@barris1233 5 лет назад

@@AuMechanic thanks dude

@hugojohansson9278 5 месяцев назад

Where can you buy those wheels

@AuMechanic 5 месяцев назад

Do a search for metal timing degree wheels.

@karriebhurgari3933 5 лет назад

I have a question, is there any way to calculate the required octane rating on a 2 stroke? Please try to make it as simple as you can because I'm not as advanced so to speak as you

@AuMechanic 5 лет назад

The octane rating will be based on the compression ratio so you would need to calculate that for the engine which you can do from the bore and stroke above the exhaust port which is called trapped cylinder volume and the combustion chamber volume which is with the piston at the very top that you measure with oil or some fluid to get the volume of it.

@karriebhurgari3933 5 лет назад

@@AuMechanic I know what my compression is, it's 205psi. So any way to calculate off that?

@AuMechanic 5 лет назад

There is no formula to give compression ratio from cylinder pressure since the pressure you get on the gauge is subject to a number of variations which is why it is better to measure the actual CR and then calculate octane required from that.

@karriebhurgari3933 5 лет назад

@@AuMechanic thanks

@f1dzo98 5 лет назад

What is the best piston blowdown degrees and how to calculate it..

@AuMechanic 5 лет назад

Due to the fact degree in crank angle is dependent on rod length etc blow-down is expressed as piston travel. So knowing the exhaust open period in degree and transfer in degree giving you blow-down in degree, you can then calculate piston travel during that period. As a general rule anything less than about 4 mm of piston travel time between exhaust open and transfer open you risk excess back flow down the transfers when they open.

@mumameahaha 5 лет назад

Awesome video love watching them. Thanks for sharing. If you watch my RU-vid you’ll see my chopper bike with a worked 66cc

@AuMechanic 5 лет назад

Had a look, does that have one of those Zeda engines ?

@phuongchau35 4 года назад

Would u port and polish my 32 cc engine I will pay u for it. Please let me know message me

@AuMechanic 4 года назад

I don't do outside work anymore sorry but keep watching the videos and I will be covering more on porting..

@balajiseptember 5 лет назад

Dear Sir, I am Basil from India and I am looking for 2 stroke exhaust pipe design software. So if you can help me with it, will be great full. Please provide your contact details as well Sir. Thanks

@AuMechanic 5 лет назад

Hi Basil See the most recent video I did, there is a link in the description section below it to 2 Stroke Exhaust Expansion Chamber software i wrote, it is freeware.

@jaap3265 Год назад

you tell about the opening time of the exhaust opening and show the intake opening really clearly

@dandungriszkysabara9158 3 года назад

Im subscribe Please subtitle Indonesia all vidio 🙏🙏🙏🙏🙏👍

@donaldellis9004 4 года назад

Here's the thing do you make money off of these videos, (that's your business) but if you do then I'm telling you if you advertise it and make a 4 or 5 part video YOU WILL GET 500,000 VIEWS, there is no other video on the whole world wide web you would be the first to do a video and do it right , please consider!! China motor 80 bucks , cylinder kit from AliExpress 25 dollars equals five hundred k views maybe a million views .

@AuMechanic 4 года назад

I don't do the vids for money (I'd starve), however that said I never pass up a chance to earn a dollar. Ill look at it and see what's involved.

@donaldellis9004 4 года назад

@@AuMechanic my friend you will find some imfo that is correct and some that is just false , I'm learning some , one thing is use 2 bushings on sides of 54 mm piston and use 10 mm wrist pin instsead of the 12 mm pin that comes with the cylinder kit. God I would just about send you a motor and cylinder if I could get it back when you are done for a decent price, PLEASE DO THIS PROJECT!!