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SmartCarb for 2008 KTM 300, experience/suggestions, Avid?, Lectron, which works???

B
My BIL also has a 2008 KTM 300. The carb kept on icing Saturday night. The conditions for icing were probably about perfect, real humid, right around freezing. It just kept dying after riding around for a few minutes and after letting it sit, the bike would re-start but would die again after the carb had iced.

We want simple and easy and wonder which "simple" carburetor would be best for this completely stock 2008 KTM 300.

Which carb heater as well?
 
M
Jan 14, 2004
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You need a carb heater plain and simple, you don't need a Lectron. Its a two stroke. Pick a heater that fits it doesn't matter which one.


M5
 
B
If the carb keeps leaking fuel, I take it the float tang needs to be adjusted to make the float needle press into the needle's seat to stop the overflow, correct

It is little stuff like this, and a now 11 year old carburetor that has us thinking new carburetor.
 
M
Jan 14, 2004
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You can rebuild the whole carb for thirty bucks. Don't waste your money. Put in new brass, set it up add a carb heater and be done with it. My experiences with the Smart carb are all bad, no experience with the Lectron.

I'm telling one last time, we've all run two strokes for years, you need carb heat.

M5
 
B
You can rebuild the whole carb for thirty bucks. Don't waste your money. Put in new brass, set it up add a carb heater and be done with it. My experiences with the Smart carb are all bad, no experience with the Lectron.

I'm telling one last time, we've all run two strokes for years, you need carb heat.

M5

It is not that I'm not listening, I am.

What should I get to get the carb to stop leaking, needle jet and seat?

Which carb heater will clamp right on. I have read that the KTM one that I'd have to drill into the carb to install blows. I am willing to spend the money for the clamp on one that will plumb into the coolant.
 

2smokin

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Oct 17, 2018
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Bozeman MT
granted the decision was easier for me because my 18's carb was a pos from day one even in the summer. I know they made some changes to the smartcarb somewhat recently and anyways mine has worked far better than my stock carb from about 4-9k elevation so far. its no cheap date but i needed a carb that would at least be consistent for me.
 
B
SmartCarb, thanks!

I just did some reading on the PWK 36 that is on this 2008 KTM 300 and it seems that it is a leaker. That no matter what some have tried, like me, with messing with the float bowl tang, the bike either leaks or won't start no matter what the adjustment. It sure is a PIT MF-in A.

Once I get the carb heater on and get the carb on the bike, to have to tell every rider that they have to shut the fuel off then turn it back on after every stop or all the fuel will leak out the carburetor.
 
C
Mar 9, 2017
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Lethbridge, AB
ever ridden much with a Lectron? ive got 150 hours on my ktm 250sx in the summer on a Lectron and know the feeling of it quite well. the power delivery is sure different and im not sure if it would help on a snowbike at all??



they make the power in a 2 stroke (and 4 stroke im sure) more linear, its not so violent and aggressive, it doesnt want to rip your arms out when it finally takes off. its tame, its not snappy, its almost "weaker" in a way... but its not actually weak by any means. it makes it feel more like a 4 stroke. consistent (but weaker) power throughout the RPM range.



im the summer, when youve got almost perfect traction all day, the lectron taking away the hit and taming the bike down is awesome, it reduces arm pump and allows you to ride wayy longer. sometimes its almost too tame... I miss that instant, aggressive, crazy raw power when you need it to lift the front tire or something. I dont know if id like that feeling on a snowbike... I think it would hinder you more than it would save you. we dont got traction and arm pump problems as bad on the snowbikes I feel.



maybe its just me. I havnt ridden a 2 stroke snowbike yet, and I havnt ridden a lectron snowbike yet.... but with the summer ridden Lectron hours in super tight single track ive got under my belt, I dont think id like it on a snowbike and no way id personally ever put one on my machine. to each their own though. maybe my experiences in the summer are completely irrelevant here.:face-icon-small-sho
 
M
Jan 14, 2004
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If the bike leaked fuel in the summer out of the overflow then you probably should change out the float and the seat and the plunger on the end of the float, don't just reset the float buy a new one. Follow the specs in the manual for setting the float.

If its only a winter thing then once the carb ices all bets are off. The jets will be fine, if the idle hangs thats more of and indication of a physically worn carb, but that is typically more of a 4 stroke FCR kind of issue, the slides wear on those.

You could pick up a PWK 37 from a YZ250, or RM or whatever they are all the same off of Ebay or they aren't that much brand new. The Lectron and Smart carbs have features you don't need because you don't really change elevation very much and temps are fairly consistent. Once you set up a PWK or ??? you will never need to touch it again.

I have a few guys who want my carb heaters, maybe I can make some up in the next few weeks but no guarantees. Its not hardly worth the effort for what I make on one.

M5
 

Sheetmetalfab

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Oct 5, 2010
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……..
I ran a smartcarb in my 300 snowbike and it really sucked.
One tiny drop of moisture or humidity making its way into the carb makes your carb stick. (This is a smartcarb only problem) summer or winter.

Lectron does not have this problem.

If you call lectron and give them exactly your temps, conditions and bike info they can set up a carb that will run perfect.

Avid carb heater (made for the lectron) and you will be pleased as punch.

Stock carb powerband is like bog, braap
Smartcarb is clean flat low power with ok mid top power.

Lectron is tunable for top end fueling separate from the low mid. (Unlike smartcarb)
You can make the power whatever you want.

They will send you a summer needle (smooth mellow traction)
And a winter needle (enough fuel, big power etc)


Pwk can run right if you know how to set it up. (Considering its not your bike ?)
Lectron is kick and go.

Smartcarb was never quite right even in the summer. (Chasing lean then rich depending on conditions) worse than the stock carb.
 
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T
Feb 1, 2010
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Entiat, WA
As stated earlier, carb type will have no effect on icing, but that's been pretty well settled.

I have a Lectron on my 300 with 3 summer seasons and 2 snow rides on it in the upper 20's. Very little humidity, so icing wasn't a problem. The power with a Lectron is very linear. Not as peaky as a conventional carb. There's actually more power down low, but because of that, the transition to the top end is more gradual, and you don't get the arm-ripping steep power curve. Peak power isn't any less with the Lectron, it just starts building power sooner and increases more gradually. I reeled 450s in during climbs last spring with my 300 (I bought one of those bikes to put on my kit actually), so I'd say there's nothing wrong with the Lectron on snow. It's still a 2 stroke, and needs to be shifted and clutched, but it runs great.
 

HalfBrit

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Dec 26, 2013
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nw oregon
I run the new Lectron 38hv on my 02 ktm 300 exc good low end and top end. no bogging. just smooth all the way into the power band. They have a snowbike specific build kit for it also, but, I have no experience with that kit. Also it's not just elevation changes that affect pwk also temp changes and lectron addresses temp and altitude.
 
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CATSLEDMAN1

Well-known member
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Nov 27, 2007
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Missoula, Montana
carb"n up

I been running Lectons for over 20 years, well actullay I bought the first one to put on my modded 1979 ski doo wooped brand new Nordic. Burned her right down, but..........then I leared the do's and don't on sleds, they aren't bikes.

On a 2 stroke in the snow with a Lectron you will increase gas mileage a bunch, better throttle response, less effected by elevation/weather condtions and you will need a carb heater. They can set one up pretty good from the factory in Texas, but perfection will only be realized by more adjusting as you become familiar with how your bike runs.

Bought smart carb as the latest and greatest when they came out, they are still going through the same teething problems that Lectron had in 1981.

I bought a new model Lectron and ran it on my wr450 snow bike for two years.
Not as big a step up from running the Keihin as you find on a 2 stroke, better and cleaner but I wasn't as overwhelmed.

I put the Lectron on my WR partly to improve starting with the button, it didn't, but what I found was both carbs are toooo lean at idle to start easily. I installed a primer bulb on the WR, one little squirt of gas cold, count to 20, hit the button, instant start. Big long climb,engine blistering hot, turn it off and hard to start on the buttom. One push on the bulb, instant start, both Keihin or Lectron. Hot four stroke hard to start, THERE'S NOT GAS IN THE COMBUSTION CHAMBER, its instantly evaporated by the red hot motor.

Anyway, I run Lectrons on 3 2 stroke dirt bikes, a Ktm a Yam and a Kawasaki, the Kaw has a 30 year old Lectron off E bay for $20. The only real change in Lectron's in 30 years is the addition of power jet and more needle selection. So any old Lectron body and slide can be updated with plumbing parts or Mikuni parts to be as good as.

Have fun.
 
P
Nov 28, 2007
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Yukon Canada
Lectron on my 2017 xcw was perfect right as they send it for my application never toughed it for 2 seasons just runs perfect.

One buddy of mine runs one on the snow on a 300 xc works good with carb heater. They run a tad lean cruising down the trail-- make sure to get the snowbike needle as well as summer.
 
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