Great video and very interesting. I’m still running a 300 kit you did just before you retired from porting and I have always been very pleased with the performance of it.
As a teenager, tuning my 50cc engine, i always wanted to learn how porting works. But never did it by myself - till last year. Got a cheap china cylindre and did some cleaning and minor changes to it before I installed it. Over the years I learned more and more about a 2 stroke engine, and how it physically works (still learning). So I just thought about how the engine runs and what could possibly make it run smoother or more efficent. After i installed the new topend i went on a little testride and even with bad jetting, the engine ran really good, and runs even better since it's jetted right. I owned a lot of scooters and modified each of them, so I got to know a few cylinders... I can't tell a big difference between original/racing 50ccs and the cheap one here, AFTER the "porting" (mostly "flowing"...). Btw: Really love the videos where you show something of your professional skills and experience. For me, this is the best way to learn things. :)
here is a little tip for the sand paper if you get one of those little grinding disk bars you can put a few stacks of very fine sand paper and you get a really nice polish,
love the fact that at 10:56 he says about being careful and having shaky hands and that he has 40 years of experience and then slips with the tool himself. its like ... Fair enough... i see your point ! :P
How about roughing up the inlet and transfers. Make shark skin.. it’s called little vortex generators in order to build a functioning surface layer of air to lower the general resistance of airflow. Some Honda riders do that with great success. It improves low end power. Tell us what YOU know about that technique please!
Very nice video. I have a question on polishing the transfers, won't that cause the fuel to stick due to surface tension? I always thought you wanted a nice textured finish on the intake and transfers and polish on the exhaust but I'm not an engine builder like you. If this bike is TPI it would make sense to me to polish the bottom of the transfers like that as the fuel isn't introduced until up higher in the transfers closer to the port windows.
Great video, what thickness base gasket are you going to run when you put it back together? Also what is the minimum squish you like to see with your s3 head.
Very informative,precise and watchable. I remember reading that You used to raise the compression on the 300s I believe by decking the cylinder. Do you still think it’s a good idea? Also do you recommend any of the aftermarket heads with interchangeable combustion chambers.?
Thank you for the info. Can the same process of just cleaning casting imperfections be used on other 2-strokes models as well? like YZ250, CR250, RM250 etc.
Do you feel there are much gains to be found by matching the case-cylinder transfers? I have found many to have 1/8-3/16" mismatch, not exclusive to KTM but also Yamaha, Suz, Honda...
Thank you for this video Jeff! Any other reading material you'd suggest for someone who's interested in 2-stroke tuning to take a look at? Also, what is your opinion on carb oval boring? Worth it for road use, or a waste of time?
Hi Jeff great video. Would re-coating the nicasil remove the wear in the bore from the rings at TDC or is the coating so thin it won't fill those sort of imperfection.
Hey Jeff, Im one of your dealers and can do this type of work, but if someone wanted more, who would you recommend? Pro circuit used to do all my stuff and it was great. Woods stuff is different though. Thanks!
But carefully cleaned up is even better. I did my Husky TE 250 2015 cylinder myself but I didn’t polish transfer ports. Just some clean up for the casting and polished exhaust etc. I have ported many cylinders but this video was good so I didn’t change port timing by altering port windows. I raised cylinder with 0.9 mm base gasket so this extends a bit transfer ports and exhaust ports duration. I have RK-Tek head, Wiseco 1-ring Racers Elite piston, Bill’s Pipes full exhaust, V-Force 4 reeds, Keihin PWK 38 carb with Suzuki RM NECJ needle and opened airbox as especially Husky’s are originally asthmatic... vs. KTM’s. I use red PV spring screw level with the case and a bit lighter main spring. This way PV opens sooner. This motor is just awesome!
you been doing this for forty years and you never made a fixture to hold the barrel ,one of the biggest no no,s is to knife edge port walls , there is a reason for this
Thank you very much for showing us what you could. It's very generous of you to share your forty years of experience with us
It's my pleasure
Great video and very interesting. I’m still running a 300 kit you did just before you retired from porting and I have always been very pleased with the performance of it.
Thanks for this, and all your videos Jeff. Makes having a KTM just that much better.
the best porting video I've seen ! great thanks from France
Thanks for the info. I love that you share your years of experience with us and don't cup cake anything. You tell things exactly how it is.
Cupcakes? I'm getting hungry.
Ok I have a question. I know the Ace cylinder is much smaller than the SR, so how different in port design are the 125’s? Thx
@@slaverace1 23
Really interesting video. Thanks for sharing some of your porting knowledge and expertise.
thank you,very helpful and informative, like the way you over emphasize caution,also liked your 5 best engine performance upgrades,.. big mike
Thanks for sharing, Jeff. That was really cool to watch.
You're welcome.
I love the brutal honesty.
Thank you. I don't know anything else. Just an old farm boy from central Illinois.
I find you very refreshing and intelligent. People like you are a precious commodity in today's world of liars, cheats, and thieves. Respect!
Well if you love brutal honesty,this bloke will give it to you in no uncertain manner lol🤗
"The use to look like someone left a cat turd in there or something" hahaha
Giving my dude a thumbs-up and subscribe simply for keeping it real. Hard to find people that don't BS you nowadays.
Thank you.
Great video Thanks! gonna go ahead and polish up all my ports when it's time to change piston and rings!
Good tips and explanations for what your doing 👍
I love my two stroke tuners handbook!!!!
Thanks mate .. next rebuild I'm gona give it a go ...
glad you made this video
great video, very interesting to watch. cheers
Thanks for these videos jeff, I have never thought about porting and prob will never do it but the entertainment is great thanks.
You're welcome.
Wouldn’t try this myself, but thanks for sharing the wisdom and knowledge!
Got the cc specialties porting tool with foot speed controller mine has to hang the motor don't have a base just say no to knife edjes
This is worthy of subscription.
Great porting tips.
Very cool.makes me want to get another kdx and get busy.
Thanks for your professional opinion.
You're welcome.
So cool. Thank you👍🏻
As a teenager, tuning my 50cc engine, i always wanted to learn how porting works. But never did it by myself - till last year. Got a cheap china cylindre and did some cleaning and minor changes to it before I installed it. Over the years I learned more and more about a 2 stroke engine, and how it physically works (still learning). So I just thought about how the engine runs and what could possibly make it run smoother or more efficent.
After i installed the new topend i went on a little testride and even with bad jetting, the engine ran really good, and runs even better since it's jetted right. I owned a lot of scooters and modified each of them, so I got to know a few cylinders... I can't tell a big difference between original/racing 50ccs and the cheap one here, AFTER the "porting" (mostly "flowing"...).
Btw: Really love the videos where you show something of your professional skills and experience. For me, this is the best way to learn things. :)
here is a little tip for the sand paper if you get one of those little grinding disk bars you can put a few stacks of very fine sand paper and you get a really nice polish,
thanks for sharing.
I have a round stick or dowel I got from Home Depot that I cut a slot in to polish the ports with a drill and sandpaper.
Very interesting thank you! So did you recognize any major improvements after porting ?
Thank you !
Jeff did my 08 250SX head was a night and day difference.
What percent of the bore is the central exhaust Port window?
love the fact that at 10:56 he says about being careful and having shaky hands and that he has 40 years of experience and then slips with the tool himself. its like ... Fair enough... i see your point ! :P
How about roughing up the inlet and transfers. Make shark skin.. it’s called little vortex generators in order to build a functioning surface layer of air to lower the general resistance of airflow.
Some Honda riders do that with great success. It improves low end power.
Tell us what YOU know about that technique please!
Where can I get parts for 1982 XC 250 husky
Very nice video. I have a question on polishing the transfers, won't that cause the fuel to stick due to surface tension? I always thought you wanted a nice textured finish on the intake and transfers and polish on the exhaust but I'm not an engine builder like you. If this bike is TPI it would make sense to me to polish the bottom of the transfers like that as the fuel isn't introduced until up higher in the transfers closer to the port windows.
I don't polish the transfers. They still have a rough texture.
just bought your 300 mule kit for my 09 xcw 250, so im kind of supprised that the piston is the same weights and its in balance
Great video, what thickness base gasket are you going to run when you put it back together? Also what is the minimum squish you like to see with your s3 head.
.25 mm base gasket
Jeff, thanks for all you great videos. Does it help to go farther and match the base ports to the cases also?
Not worth the hassle.
Very informative,precise and watchable. I remember reading that You used to raise the compression on the 300s I believe by decking the cylinder. Do you still think it’s a good idea? Also do you recommend any of the aftermarket heads with interchangeable combustion chambers.?
He uses a S3 Head on his bike, if i remember right. So I'd say he would recommend it :P
Yes, I use the Slavens Mule S3 heads. slavensracing.com/shop/slavens-mule-high-compression-component-cylinder-head/
I agree, Jeff.. I know too many do- it-yourselfers in the past that hacked up and worsened cylinders.
Thank you for the info. Can the same process of just cleaning casting imperfections be used on other 2-strokes models as well? like YZ250, CR250, RM250 etc.
Yes.
@@slaverace1 Thank you, would you recommend the same process on the intake?
Do you feel there are much gains to be found by matching the case-cylinder transfers? I have found many to have 1/8-3/16" mismatch, not exclusive to KTM but also Yamaha, Suz, Honda...
A lot of trouble for a very minor gain.
Good to know! Thanks for the reply. Excellent vids btw...
Rotax engines already have base gaskets cut undersized from the factory for that reason.
Hi, what is that rotary tool you are using? Obviously, not a Dremmel with a flexi shaft.
CC Specialty porting tool.
Thank you for this video Jeff! Any other reading material you'd suggest for someone who's interested in 2-stroke tuning to take a look at? Also, what is your opinion on carb oval boring? Worth it for road use, or a waste of time?
Two Stroke Tuner's Handbook by Gordon Jennings is the original bible on 2 strokes. It's out of print and expensive on Amazon.
All types of carb boring add top-end performance but take away low-end grunt.
Hi Jeff great video. Would re-coating the nicasil remove the wear in the bore from the rings at TDC or is the coating so thin it won't fill those sort of imperfection.
Re-plating brings the cylinders back to stock.
Help can you tell me I Have KTM 380 2002 The skirt broke Can I Put a 250 Cylinder What would you doAny advice would be appreciated
The crank, conrod & head also differs.
Hey Jeff, Im one of your dealers and can do this type of work, but if someone wanted more, who would you recommend? Pro circuit used to do all my stuff and it was great. Woods stuff is different though. Thanks!
No idea.
I would be scared to have that kind of bitt rigth nexto nicasil
can really see how easy it would be to make a meal outta the cylinder !
how much in terms of horsepower does this type of cleaning up the ports do?
KTM/HQV castings are very good so the gain is minimal.
@@slaverace1 its all the minimal things that come to make a god machine.
Stock is perfect,my opinion. Just ride it!
But carefully cleaned up is even better. I did my Husky TE 250 2015 cylinder myself but I didn’t polish transfer ports. Just some clean up for the casting and polished exhaust etc. I have ported many cylinders but this video was good so I didn’t change port timing by altering port windows. I raised cylinder with 0.9 mm base gasket so this extends a bit transfer ports and exhaust ports duration.
I have RK-Tek head, Wiseco 1-ring Racers Elite piston, Bill’s Pipes full exhaust, V-Force 4 reeds, Keihin PWK 38 carb with Suzuki RM NECJ needle and opened airbox as especially Husky’s are originally asthmatic... vs. KTM’s. I use red PV spring screw level with the case and a bit lighter main spring. This way PV opens sooner. This motor is just awesome!
Any experience with bultaco astro 250cc cylinders/cases?
Yes, about 50 years ago.
Hi I’ve got a 1999 Ktm 300 exc/egs. I was wondering if you could port it for me please if I send you the cylinder many thanks
Sorry, I retired from porting 10 years ago.
I’m returning to the Hodaka hobby. Do you have any experience with the 125.
Yes, about 40 years ago.
Can’t blame you for retiring from porting. It can be monotonous and hard on your back and butt staying in the same body position all day long
You cant polish transfer ports
You can take the casting flaws out of the ports that’s all I do
Can i send you a cylinder to work on?
Sorry, retired from porting.
Jeff Slavens 👌
Have you had a chance to see kody kopp Head
I'm familiar with the flattrack racer but not a head.
Hogging baby hogging
you been doing this for forty years and you never made a fixture to hold the barrel ,one of the biggest no no,s is to knife edge port walls , there is a reason for this