Jeff's Top 5 Engine Performance Mods 250/300 - Slavens Racing

[@carlatamanczyk3891]

Thanks. Jeff, for all the great recommendations on these bikes. I aslo appreciate you putting in the pitch for riders to join a club or organization that fights to preserve OHV opportunities. As a founding member of the Blue Ribbon Coslition, the Idaho Falls Trail Machine Association, and two snowmobile clubs, I have been preaching and recruiting since 1981. Too many riders believe that if they do join, our battles will be over in a year or two. Everyone needs to realize that their help is needed eternally and they are involved in this fight whether they want to be or not. Thanks again, Jeff.

[@GoViking933]

I appreciate it too, we are having to fight more for our places to ride now up here in Canada and joining the groups helps.

[@mikewampler3161]

I did the carb, pipe, and reeds on my 09 250xc. What a difference!! I installed the red power valve spring as well. Head is next but this thing came alive after the upgrades I did already. Thanks for the video. Keep up the good work

[@slaverace1]

Hey guys, checkout out our new video on the Top 5 Performance Engine Performance Mods for KTM and Husqvarna 250s and 300s. Here are links to the products in the video. slavensracing.com/shop/slavens-mule-high-compression-component-cylinder-head/ slavensracing.com/shop/slavens-mule-hv-lectron-17 slavensracing.com/shop/fmf-fatty-2-stroke-pipes-ktm-husaberg/ slavensracing.com/shop/vforce-4-reed-valve-system/ slavensracing.com/?s=SX+CDI+unit

[@waynemodesitt3445]

Thanks Jeff for another great video. I did these exact same mods on my son's 17 250XC and (except for the Lectron carb) on my 2010 250XC with very good results. I recently picked up a new 2019 250XC, so am looking forward to your video on that one. The sooner you post it, the sooner I'll be buying the parts from you!

[@1320PNY]

In 2014 I did the S3 head, SXS CDI and eventually (after destroying the stocker) FMF Fatty on my 300 XC-W. The bike came with VForce reeds and a Keihin carb stock. I have to agree that the head and cdi are well worth the investment. I’m building my 2019 300 XC now, in phases as I have time to play. Stock, the bike was really off, and after some carb tweaks I was able to ride it around the yard. I then added only the SXS CDI and the throttle response is amazingly better. I have bought the S3 head and plan to upgrade the reeds for reliability. It’s a shame KTM went away from Keihin. With how reliable, consistent and low maintenance my 2014 was, I can only hope the 2019 performs as well.

[@carlatamanczyk3891]

I agree... what got into the mind of the people at KTM to leave the Keihin behind. Bad mistake.

[@jay_motocombat]

“Really off” I’m on a 19 300xc and man is that an understatement. JD kit helped a lot, but I’m still looking to find the KABAAAM of my old 15.

[@stevetdesigns]

STIC Metering block!!! I'll be testing mine when the snow melts ('17 300).

[@A1soldiersaint]

Eric Gore cylinder porting is a great way to alter power band to your liking. Suspension is the number one worst thing on a KTM that needs to be fixed (still). The Lectron is too cool, lots of people getting great results with them.

[@Jacare1973]

Good mods, though I would swap out the mukuni for a keihin air striker any day over a lectron.

[@Darco712]

good content. i only disagree with the carb change, my mikuni with the graham jarvis mods on it is absolutely phenomenal

[@beverlyboys73]

What were your carb mods?

[@grantflewwelling1260]

What is your opinion on fly wheel weights for harescrambles?

[@richardcurtis114]

This is coming from another angle....I've got a xc 300 2018 carburetor. So it's used for motocross. The mods I've done are....deb pipe and silencer. Had a go with them v force reeds . But they kept breaking. So a rad valve was used. Jd jetting kit. And the rear shock. A bladder kit. Now it pulls like a team of horses ... well happy with it

[@WK12345-z]

Hi Jeff, Thanks for all the information in your Videos! It really helps to hear it from a true expert. I currently have a 17 250SX I use mostly in the woods and trying to figure out how to make it lug more like a 300XC. Looking to see if your S3 Head works on a SX and what it would change. It is stock with a Fatty Pipe Thanks Will

[@johninwv807]

Is there any additional benefit going with the SX CDI on an XC? I thought they were the same.

[@andrewfrankl8184]

I switched to the sx cdi box on my 17 xc and it seemed to help. It goes well with the slavens s3 head and a kehein carb.

[@Kurosaki990Ichigo]

Thank you Jeff for sharing your knowledge. You said to use an SX CDI. So when I have a 300 EXC i use a 250 SX CDI?

[@motonack]

They make a 300SX kit for the 250SX that comes with a unique 300SX CDI.

[@kyleharbison8110]

Jeff, do you have a head recommendation for the 150s? If so, what is the rule of thumb for octane rating vs compression vs squish band clearance?

[@michaelselix8817]

It is odd that Jeff hasn’t commented, he might not like them, I just got a 19 150te.

[@carlatamanczyk3891]

Jeff, a.re the CDI units all different for the KTM SX, the XCW, and the XC? Different between the 250 and 300 also?

[@wesmorey6167]

Wondering if there's any premature wear and tear on motor with the high compression head-have always heard engine mods are bad in this regard

[@slaverace1]

Definitely no premature wear.

[@brianmetzger8607]

Jeff, would you recommend similar mods for the pre-17+ 250/300 XC’s like the 16?

[@claudioteixeira5917]

Don’t you use the clutch wheith?

[@VARocketry]

Jeff - Would you offer any advice on any mods possible on Paramotor two cycle motors? I fly a 280 cc Air Conception Tornado 280 motor. It has a WALBRO 37C carb. How does one evaluate whether head mods or porting would improve this engine. Principal complaint is rough mid-range performance. Cruise is 5100-5600 rpm. Max rpm is 7400-ish. Midrange in the 4200-500 rpm is rough.

[@slaverace1]

Sorry, not familiar with that engine but rough running sounds like a fueling issue, too rich in the mid-range.

[@stevebaum]

Jeff, if I add an SX cdi, should I expect to need to adjust my Lectron? (I have a high compression head & gnarly pipe on my 17 3-0 xc-w. ) Thanks.

[@slaverace1]

No. Just install and enjoy.

[@mhilde7744]

👍...thanks, Jeff!

[@brucewayne8408]

Where can I find a performance head for my 2020 ktm 250sx

[@slaverace1]

SX models already have a high compression head.

[@brucewayne8408]

Jeff Slavens thank you

[@huntermageau9173]

best ways to add some bottom end on my 2002 KTM 300 MXC? would a performance head help?

[@slaverace1]

Heads are not available for your year model but you can send your head to us to be machined.

[@GoViking933]

Jeff, what are your thoughts on needles? I have a JD jetting needle in my bike and love it!

[@Mad-Max171]

JD Jetting kits work awesome not everyone wants to / has the money to spend 100s on a lectron carb

[@slaverace1]

GoViking If it works for you, gets you out riding with your buddies, I’m all in. We sell a lot of JD kits and hear mostly positive feedback.

[@GoViking933]

I have been riding the venerable KTM 300 2stroke for over 10 years now, and the latest one I bought, a '13 300XC had such a strong engine (even over my last '13 300XC, which I put over 400 hours on), I finally figured out what made it so different: it turns out the previous owner installed a JD jetting needle! Love it..

[@ardhorenaissance1580]

Are U putting on kick starter on 2022 XCW 300

[@slaverace1]

No.

[@maxapollo1]

Would all those mods apply to a 2013 Husaberg TE250 ?

[@slaverace1]

Yes

[@grahamsampson769]

Jeff - How would a 1982 Husqvarna 250XC compare with a KTM 250SX?

[@jay_motocombat]

Basically the same bike 🤣🤣🤣

[@FROGMAN524]

Got a 2019 300 XC and wondering where I can get the SX ignition box?

[@slaverace1]

Where else? The KTM candy store. slavensracing.com/shop/sx-cdi-unit-for-ktm-husaberg-husqvarna-300/

[@abumusaryan4697]

@@slaverace1 lol what a question hey!!! Slavens are good to go, I made an australian purchase and honestly it was surprisingly fast, Installing and testing after the rain clears. But will be great

[@devonrose888]

Predictable with the lectron

[@goinhot9133]

Really surprised you didn’t speak of any flywheel weights?

[@slaverace1]

Flywheel weights have their pluses and minuses like many products but they are not in my top 5.

[@CW-up7xv]

Which power valve spring at what setting do you run on the 250/300?

[@slaverace1]

Stock spring, stock setting.

[@Chris-uh3cm]

Jeff, can a SX250 CDI be put on a 2014 200 xcw?

[@slaverace1]

No

[@johnsgroi1026]

Any overheating or pinging issues with the high compression head?

[@slaverace1]

I wouldn't use it if it caused those issues.

[@graham68ktm]

man that pipe hangs out alot , its about the only thing i don't like about 2bangers !