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

portgrinder

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Anyone played around to get more power out of the 300?

Carb is too small, more compression for sure. gotta be enough room for a larger bore.

Curious what can be done instead of spending $7500 on a BRC that's still going to need some work to make decent ponies.
 

Zad

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I’ve put on a 40mm billet smart carb, RK Tek head and procircuit pipe and silencer and while I don’t have any before or after dyno testing (I suspect the difference is small) I can say it runs perfectly, has crisp throttle response, good power and I’m having a helluva lot a fun with a CMX 129”. I haven’t been able to take the same lines on long steep deep hills as my friends on 450’s and long tracks but it’s not for lack of power, the bike has lots of jam, I just don’t have the floatation/traction that they do and end up trenching. Having said that I’ve mistakenly had the rear shock set with very little preload and I’m hoping to get out tomorrow to try the setup with 3.5” of preload (I’ve got the 2016 Raptor shocks and updated cmx track) which I’m told will significantly help with deep snow performance. We’ll see. I’m 195 neked and carry 4.5 gallons of fuel on the tunnel at the start of a full day of riding...big carb, head and open exhaust makes for a thirsty rig. I’ve heard from a couple guys who’ve done the 330 big bore through Eric Gore and they seem happy too with a bit more torque and overall power increase.
 
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2smokin

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I’ve put on a 40mm billet smart carb, RK Tek head and procircuit pipe and silencer and while I don’t have any before or after dyno testing (I suspect the difference is small) I can say it runs perfectly, has crisp throttle response, good power and I’m having a helluva lot a fun with a CMX 129”. I haven’t been able to take the same lines on long steep deep hills as my friends on 450’s and long tracks but it’s not for lack of power, the bike has lots of jam, I just don’t have the floatation/traction that they do and end up trenching. Having said that I’ve mistakenly had the rear shock set with very little preload and I’m hoping to get out tomorrow to try the setup with 3.5” of preload (I’ve got the 2016 Raptor shocks and updated cmx track) which I’m told will significantly help with deep snow performance. We’ll see. I’m 195 neked and carry 4.5 gallons of fuel on the tunnel at the start of a full day of riding...big carb, head and open exhaust makes for a thirsty rig. I’ve heard from a couple guys who’ve done the 330 big bore through Eric Gore and they seem happy too with a bit more torque and overall power increase.
Hey ZAD does your bikechoke if your at top speed for a few minutes? I have a 40mm billet on my 18 and when cruising through a field wide open in 5th or 6th for a few minutes she eventually just acts like you hit the kill switch, let off and hit it again and its good for another 2-3 min. not a huge issue but makes me wonder if the carb ices a bit or what. Also on the wet days I sometimes get a little peice of ice formed that keeps the slide from closing the last tiny bit and makes for an awkward bit of throttle stick.
 

eric82930

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My experience with the 330 kit wasn't real good. But honestly didn't get much time to tune it and it had a gnarly pipe so it was a dog on top end.

I made a few good 300's though. Best bang for the buck - raise cylinder with thickest base gasket or two. shoot for .075" to .080" then shave the head to get the squish back to 050-060 (for high altitude).
Then if budget allows use a pc2 or fatty pipe, vforce and a bigger carb. A $50 pwk39 from ebay is fine. You can even drill and tap in the electric heater to it, just wrap the carb good with something to keep snow from touching the outside and it will be fine if you have the watts. If you do a lectron or smarty don't be bamboozeled into thinking you don't have to tune it. Tuning is where the power comes from and so far all my PWK's have run better then all the lectrons I've seen but I tune my arse off and I have 20 plus needles in my quiver.

The 300's won't rev if the main jet is too big. And the cutting out thing at WOT seems to be rich related combined with plugged filter. But for some weird reason only the 300's have the problem. The 250sx isn't nearly as picky and makes same peak power, just less torque. Try not to focus on making torque, you just can't ride a snowbike in the range where any torque gains can be made.
Make sure the PV is getting all the way open. Some oils will cause them to stick and sometime they get adjusted too low (for more torque) and they don't open all the way its like sticking a banana in the tailpipe! If your not sure, unscrew the pv turn buckle one turn and try it. You might be amazed.
 

portgrinder

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interesting stuff. thanks

I have found the lectrons are pretty darn close out of the box. what sizes are you guys running? the lectron guys always try to convince a fella to go smaller but that's not going to make peak. i'm thinking a 40mm

tested the pc2 on other bikes and they always work good

good to know that more exhaust duration responds well
 

Zad

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2Smokin', I had the same bike-suddenly-die experience too and at first I thought I was getting carb freezing as suggested above, turned out to not be the case for me.

The billet smart carb has tip over valves (brass nipples seated in the fuel bowl, see photos) that have balls in the cylinder part of the nipple. The stock smart carb for summer use comes with a steel ball and a plastic ball in each nipple. When the bike tips over the steel ball closer to the fuel bowl pushes the plastic ball toward the fuel hose and seals off fuel flow preventing a tip over leak.

If you are running carb heat for winter use, the added heat eventually causes the fuel to boil and the gasses push the balls up and seal the nipple stopping fuel flow and cutting out the motor even with the bike upright. Even without carb heat I suspect this may happen if the motor heats the carb enough to cause fuel vapour to lift the plastic balls. After shutting down, as the carb cools the pressure subsides, the balls fall down and fuel will flow again.

Solution is two fold: 1. Put a valve in the carb heat line so you can regulate heat to the carb and 2. Call Corey at Technology Elevated and he’ll send you tip over valves that only have the steel balls which are heavier and don’t get pushed up to seal fuel flow as easily.

You might already have the valves with steel balls only (call TE and they might be able to tell you from your carb SN) in which case turn off all carb heat and don’t use a carb jacket. You can also pull the carb and shine a light down into the valve...the plastic balls are red and can be seen when you tip the carb over and they move closer to the nipple end of the valve.

I’ve learned that I only need carb heat when the weather is cold and that, even with steel balls only in the tip over valves, added carb heat will cause them to be pushed up and seal. I use a neoprene carb jacket as well which likely makes it so I need less carb heat than I would without the jacket.

Removal of the valves is pretty easy, use a #10 or #12 (can’t remember which) one inch wood screw, wrap it in Teflon seal tape and screw it into the fuel hose end of the valve nipple until the valve just starts to turn. Then gently clamp the carb in a vice with soft jaws or wood blocks, clamp a vice grip onto the end of the screw and use a hammer to gently tap up and out on the vice grip to remove the valve that is press seated into the body of the carb. To install the new valve add a bead of red locktite to the valve sleeve, place a long socket over the nipple and tap into place.

While you’re at it, also order from TE a stiffer throttle return spring which makes it less likely the throttle slide in the carb will stick from freezing water vapour.

The steel ball valves and stiffer slide return spring have completely solved the same issues you’re having for me and the carb now runs flawlessly right from cold start up to operating temperature and at all elevations I’ve been at...it’s a beast. Pack extra fuel and hang on!
 

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M5-

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If a guy was starting from scratch and had the $$ is a FI 300 worth the price of admission? I've never ridden one but I must say I am pretty happy with my FI 4 stroke over my carbed 500 even thought the 500 never gave me any issues. The thing I like is the tuning not using wrenches, its so simple.


M5

Edit, never mind answered my own question, wrong tranny XC-W only in TPI
 
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eric82930

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If your fuel is boiling from too much carb heat it will run like crap even if the float vents don't stick. This crappy new fuel we have boils at just over 100 degrees at high altitude. Have to figure out a way to throttle back the heat. The electric heaters are nice because it can use a toggle switch. If I was ambitious I could get a 80 degree bimetal switch and zip tie to the carb to toggle it automaticlly.

You have to remember none of the TPI bikes are made for motocross so they just don't put out like you guys are used to with the 450s. Yes they are smooth and tractable in dirt but they don't wheelie in 5th like a snow bike should. All my 2 stroke clan keeps talking about trying one but right now its a $10000 gamble that might not work any better than a clapped out 2003 250sx.
 

2smokin

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2Smokin', I had the same bike-suddenly-die experience too and at first I thought I was getting carb freezing as suggested above, turned out to not be the case for me.

The billet smart carb has tip over valves (brass nipples seated in the fuel bowl, see photos) that have balls in the cylinder part of the nipple. The stock smart carb for summer use comes with a steel ball and a plastic ball in each nipple. When the bike tips over the steel ball closer to the fuel bowl pushes the plastic ball toward the fuel hose and seals off fuel flow preventing a tip over leak.

If you are running carb heat for winter use, the added heat eventually causes the fuel to boil and the gasses push the balls up and seal the nipple stopping fuel flow and cutting out the motor even with the bike upright. Even without carb heat I suspect this may happen if the motor heats the carb enough to cause fuel vapour to lift the plastic balls. After shutting down, as the carb cools the pressure subsides, the balls fall down and fuel will flow again.

Solution is two fold: 1. Put a valve in the carb heat line so you can regulate heat to the carb and 2. Call Corey at Technology Elevated and he’ll send you tip over valves that only have the steel balls which are heavier and don’t get pushed up to seal fuel flow as easily.

You might already have the valves with steel balls only (call TE and they might be able to tell you from your carb SN) in which case turn off all carb heat and don’t use a carb jacket. You can also pull the carb and shine a light down into the valve...the plastic balls are red and can be seen when you tip the carb over and they move closer to the nipple end of the valve.

I’ve learned that I only need carb heat when the weather is cold and that, even with steel balls only in the tip over valves, added carb heat will cause them to be pushed up and seal. I use a neoprene carb jacket as well which likely makes it so I need less carb heat than I would without the jacket.

Removal of the valves is pretty easy, use a #10 or #12 (can’t remember which) one inch wood screw, wrap it in Teflon seal tape and screw it into the fuel hose end of the valve nipple until the valve just starts to turn. Then gently clamp the carb in a vice with soft jaws or wood blocks, clamp a vice grip onto the end of the screw and use a hammer to gently tap up and out on the vice grip to remove the valve that is press seated into the body of the carb. To install the new valve add a bead of red locktite to the valve sleeve, place a long socket over the nipple and tap into place.

While you’re at it, also order from TE a stiffer throttle return spring which makes it less likely the throttle slide in the carb will stick from freezing water vapour.

The steel ball valves and stiffer slide return spring have completely solved the same issues you’re having for me and the carb now runs flawlessly right from cold start up to operating temperature and at all elevations I’ve been at...it’s a beast. Pack extra fuel and hang on!
Thanks man! I am pretty sure i'm steel only as me and cory talked about that when I ordered but i'll double check. I'll have to add a valve and turn down my heat, I was all worked up about the ice on the bottom of the slide and figured that less heat would make it worse. What would happen with absolutely no tipover balls, At first i thought tats what cory was saying he was going to do but after hearing what your saying Im assuming he just took out the plastics. I think my exhaust needs to get seperated from my intake area, as the moisture must be whats killing me. other weird part is whenever the piece of ice forms it runs funny across the board. I'll try the throttle spring too, he had mentioned trying my mikuni's spring as well.
interesting stuff. thanks

I have found the lectrons are pretty darn close out of the box. what sizes are you guys running? the lectron guys always try to convince a fella to go smaller but that's not going to make peak. i'm thinking a 40mm

tested the pc2 on other bikes and they always work good

good to know that more exhaust duration responds well
I talked to neil like your always recommending and im definitely going to buy a pipe from him for next season. Sounds like your kx500 is a beast you should post some videos of it ripping!

If your fuel is boiling from too much carb heat it will run like crap even if the float vents don't stick. This crappy new fuel we have boils at just over 100 degrees at high altitude. Have to figure out a way to throttle back the heat. The electric heaters are nice because it can use a toggle switch. If I was ambitious I could get a 80 degree bimetal switch and zip tie to the carb to toggle it automatically.

You have to remember none of the TPI bikes are made for motocross so they just don't put out like you guys are used to with the 450s. Yes they are smooth and tractable in dirt but they don't wheelie in 5th like a snow bike should. All my 2 stroke clan keeps talking about trying one but right now its a $10000 gamble that might not work any better than a clapped out 2003 250sx.
Not sure about the tpi myself either, especially if it has to be wide ratio for now.
 

2smokin

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Anyone played around to get more power out of the 300?

Carb is too small, more compression for sure. gotta be enough room for a larger bore.

Curious what can be done instead of spending $7500 on a BRC that's still going to need some work to make decent ponies.
Also to address the original point, I've never been so sure that the 330 is really worth throwing the motor off square, especially on a 17+ not sure how it would work with the balancer. Seems as though the real issue is how much hp can you make without it being painfully peaky. by old 250gp bike standards we should be able to get near 80 hp if you went all out but im sure its only in a couple hundred rpm increment. 70 hp with enough spread to roll into the power band without clutch would be awesome. I think its possible with neils pipe, a lot of compression and good porting. possibly in the race gas realm though. Anyone heard of the PowerCDI? Cory said it helped a lot on one of their bikes mated with a TPS billet to get rid of pipe band. I dont know how much it would offer for overall performance though. For $1000 or so it would have to be significant for me.
 

Zad

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Jan 8, 2017
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I was all worked up about the ice on the bottom of the slide and figured that less heat would make it worse. What would happen with absolutely no tipover balls?
Add a neoprene carb jacket and a ball valve to the carb heater. Turn off all carb heat unless is friggin' cold and put in a stiffer throttle slide spring and you should be good to go. With no tip-over balls when the bike gets upsidydowny the fuel keeps on flowing, floods the motor.
 

portgrinder

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Nov 26, 2007
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If a guy was starting from scratch and had the $$ is a FI 300 worth the price of admission? I've never ridden one but I must say I am pretty happy with my FI 4 stroke over my carbed 500 even thought the 500 never gave me any issues. The thing I like is the tuning not using wrenches, its so simple.


M5

Edit, never mind answered my own question, wrong tranny XC-W only in TPI
You already knew the answer anyhow...
 

portgrinder

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I found those electric heaters didn’t do anything in my application. Seemed like it had to be coolant above 75f to make it run well and no throttle sticking
 

Zad

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If your fuel is boiling from too much carb heat it will run like crap even if the float vents don't stick.
This is not true wth the smart carb, it runs perfectly right up to the point where it vapour locks and then the motor dies suddenly when the fuel flow stops.

Too much heat to the carb even with just the steel balls and the vapour is enough to lock up the carb for a few seconds. With the plastic balls it can take 10-20 minutes for the vapour lock to let go.
 

M5-

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You already knew the answer anyhow...
You know the old saying, no replacement for displacement. I think a 300 would be a downgrade from your 500 since you already have modern ergos with the AF. If you are looking for a more nimble feel maybe the answer lies in the a new back half of your bike. The new narrow rail Yeti might be up your alley.

M5
 

byeatts

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You know the old saying, no replacement for displacement. I think a 300 would be a downgrade from your 500 since you already have modern ergos with the AF. If you are looking for a more nimble feel maybe the answer lies in the a new back half of your bike. The new narrow rail Yeti might be up your alley.

M5
300 is a Great dirt bike . I have owned a new xc 300 every year for 10 years but it will not run with a good setup 450 sx which has closer ratio tranny ,The weight of a new KTM 450sx is 221 lbs, and the 2019 300xc 218lbs, The 300 has to carry much more fuel therefore the ride weight is heavier. Keep the 300 for the dirt, 450 rules on the snow .
 

2smokin

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I found those electric heaters didn’t do anything in my application. Seemed like it had to be coolant above 75f to make it run well and no throttle sticking
I had a lot of throttle stick with no heat as well, not sure if that was partially just from the amount of moisture my intake setup is getting though.

This is not true wth the smart carb, it runs perfectly right up to the point where it vapour locks and then the motor dies suddenly when the fuel flow stops.

Too much heat to the carb even with just the steel balls and the vapour is enough to lock up the carb for a few seconds. With the plastic balls it can take 10-20 minutes for the vapour lock to let go.
agreed, so if the vapors keep the balls held up why does the quickest let off of the throttle get you going again? releases the pressure somewhere?

300 is a Great dirt bike . I have owned a new xc 300 every year for 10 years but it will not run with a good setup 450 sx which has closer ratio tranny ,The weight of a new KTM 450sx is 221 lbs, and the 2019 300xc 218lbs, The 300 has to carry much more fuel therefore the ride weight is heavier. Keep the 300 for the dirt, 450 rules on the snow .
Lets not forget the rotating mass difference, the 300 feels light and nimble which is worth mention. And we'll see where production snowbikes end up, i'd bet it wont be a 4 stroke. the 450 is the best option we have from the dirt world for most people. I have a feeling the 450 wont rule the snow too much longer a 600ish v twin fuel injected smoker will sh*t on 450's IMHO.
 

byeatts

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I had a lot of throttle stick with no heat as well, not sure if that was partially just from the amount of moisture my intake setup is getting though.



agreed, so if the vapors keep the balls held up why does the quickest let off of the throttle get you going again? releases the pressure somewhere?


Lets not forget the rotating mass difference, the 300 feels light and nimble which is worth mention. And we'll see where production snowbikes end up, i'd bet it wont be a 4 stroke. the 450 is the best option we have from the dirt world for most people. I have a feeling the 450 wont rule the snow too much longer a 600ish v twin fuel injected smoker will sh*t on 450's IMHO.
Rotating mass on a snowbike is not an issue , Ewe have a 10 foot long 35 lb rubber track spinning and a simple timing chain wont change the feel. A good running 450 will destroy any 300, When a large Two smoker becomes reliable with fuel injection and starter that could be fun,The new 19 450 feel as lite as my 300,s. even less fueled and ready to ride since the 300 needs to carry more fuel. I love 2 smokes and someday hopefully we get one.
 

capulin overdrive

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Not measured down to the nitty gritty, but my 300 smoker seems to use about the same amount of fuel as my 500 4stroke.
 

Zad

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agreed, so if the vapors keep the balls held up why does the quickest let off of the throttle get you going again? releases the pressure somewhere?
Good question, the answer to which is beyond me, next time I talk to Corey at TE I'll ask and post here.
 
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