ktm/husky 300. whos spent time making more power?

2smokin

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keep us posted, I may have to try the raised cylinder out once i get my pipe. If its not the curve isn't narrower id imagine its going to be a good setup!
 
Dec 20, 2007
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Defiantly not narrower just moved up and to the right. Even as low as 5k power is still as good as stock. It will never be as wide as a 450 but the power is there and easy to use. For snow biking this type of power is a no brainer. Buy his spare head and try it. I promise no regrets.
 

portgrinder

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Had some time to do some more tinkering. think we are pretty much wrapped up. did some work in the cylinder to make it rev out farther and was able to not lose any bottom. if anyone wants the details, shoot me a note and i can explain what we did. first pic is where we ended up vs stock (gn is tq, red is pwr), second pic is the difference between a stock cylinder and one with some work done.

NPP snowbike pipe
Lectron 40mm with 6-2 @ 2.055 PJ 1.75
15/1 compression machined stock head
Red spring all the way out on the stock jug, 1.5 turns in on the tweaked cyl
C111 @ 30:1

pretty economical build. making more power than some high dollar 4 strokes

Dyno run vid


IMG_9715.jpg
IMG_9710.jpg
 

portgrinder

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Super cheap trick you can do at home with a dremmel. If you modify the ign pickup (make the bolt holes slotted) and move it all the way to the right, you pick up 3 in the midrange and 1 peak. At your own risk of course. I’m running c111 straight.

looked at a programable ignition but they sure are pricey.

we’re at 45tq now vs ~30 stock.
 

wwillf01

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Super cheap trick you can do at home with a dremmel. If you modify the ign pickup (make the bolt holes slotted) and move it all the way to the right, you pick up 3 in the midrange and 1 peak. At your own risk of course. I’m running c111 straight.

looked at a programable ignition but they sure are pricey.

we’re at 45tq now vs ~30 stock.
Nice... thats what I am getting out of the 450 with a lot of work!

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dooman92

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Portgrinder, thanks for sharing this info on the 300. At some point I would like to do a 300 two stroke. Will these mods work on the tpi 300?

Also, should have pm in your inbox.
 

wwillf01

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3 seasons on the yz250 platinum pipe no issues... cr500 fmf cracked 2 seasons .

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wwillf01

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Well here is a crude drawing of the power curve of my 18 450sxf that runs 1/2 u4.4 . The red line is the hp curve and the green line is the torque curve. I put all 4 pictures here so you can check my finger drawing overlay;) as always 2 different dynos in 2 different areas of the USA. Similar elevation. So all this is for nothing more than talking than proving anything... let it be noted the 450 does not really sign off by a lot till 11500 ..... so a ton more overev work with. But man the 2 stroke is a torque monster.


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portgrinder

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Can’t really see much from your pics.

the lectron guys are super, but they will tell you to get the 38hv (which is a 36), or the 38. My opinion is you want an actual 40. Likely a 4-2 for summer and prob a 5-2 for winter. Get a 6-2 as well. Cheap to get when you order the carb if you end up needing it. 6-2 will be needed if your pipe is working significantly better than stock + you have more timing/compression. They will give you starting height for each of them and they are usually bang on. A couple times I had to richen them by one notch.

put a colder plug in too. Like a 9eya or 9ecmix if you don’t have room
 
Dec 20, 2007
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Hello,
Since I just got my 300 cylinder back I figured I'd post some pics and get your guys thoughts.

TMR "snowbike porting"
Head set up for 50/50 110
.5mm base gasket
Will be running a 38 lectron

Getting excited with this build!
Did they tell you if they raised the ex port timing? Just curious because that seems to be what the 300s need most and there is a huge misconception that the 300 need to have low end grunt for snow biking. Grunt does nothing without some peak power to go with it.
If they won't tell you the timing measure down to the top of the port from the top of the cylinder. What year is it?
 
Sep 18, 2018
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Did they tell you if they raised the ex port timing? Just curious because that seems to be what the 300s need most and there is a huge misconception that the 300 need to have low end grunt for snow biking. Grunt does nothing without some peak power to go with it. If they won't tell you the timing measure down to the top of the port from the top of the cylinder. What year is it?

The cylinder is a 2015 xc 300, the bottom end is a 250xc.

I did specify to TMR i need top end increased for snowbiking, when asking i got this response " The port areas and open durations have been increased slightly. It is all in the balance of intake and exhaust area. You will notice better top end as long as everything else that you add compliments more top end"

I do trust TMR, as he did my YZ300 and it ran hard with never yz450f. So hoping it pans out on the KTM

Any specific measurements or pictures i can take to help indicate whats going on with the cylinder.

Thanks guys!
 

portgrinder

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I’m sure it will be fine. The stock cylinder is pretty good and hard to improve on a whole bunch. The gains are everywhere else. Timing, compression, pipe, carb etc.

FYI if you oval the holes and move the ign pickup over all the way you gotta run good fuel. With straight c111, 15/1, 0.049 squish and the advanced timing you can hear a little chatter at high rpm on setting #1. #2 has slightly less timing and works fine.

Quick vid of where we ended up.
 
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