Crawdaddy adds a 2 smoker to the stable after a 12 year hiatus

[daijones 0]

Sorry to hear something like this.

I don't think your jetting was full cause of this failure, what you have should be close enough, and as I mentioned JD needles for KTM 2 stroke seemed too rich for my liking, and my experience with KTM jetting guide is they are always on the rich (safe) side, so a good starting point but I've always had to go leaner 1 or 2 steps from what they recommend.

At last top end rebuild 75hrs ago did they put in piston or just rings?

As you say somewhat suspicious it blew up shortly after filling with gas, my guess is that Slavens mods included high compression head as that's standard for his work as 300 is low compression stock and most of his bikes are ridden at altitude in CO/UT etc. So with high compression head at low elevation you get very high compression and with potentially lower octane gas you may have had bad detonation which caused temperature to go up and meltdown. The higher compression heads are great and give substantial boost but if you go too far and at low elevation and lower octane gas can give issues so have AAK measure head volume and squish as you may want to go with higher x dimension (extra base gasket) to lower compression closer to stock to use in the desert, or I have couple of stock 300XC heads if you want to try/compare.

Definately wise to do the bottom end with that many hours and the possibility of damage from the piston bits then you can happy for a long time.

When you get it back start with rich jetting and go through plug checks and lean off bit by bit until you get it right

[Spaugh 1]

Sorry to hear something like this.

I don't think your jetting was full cause of this failure, what you have should be close enough, and as I mentioned JD needles for KTM 2 stroke seemed too rich for my liking, and my experience with KTM jetting guide is they are always on the rich (safe) side, so a good starting point but I've always had to go leaner 1 or 2 steps from what they recommend.

At last top end rebuild 75hrs ago did they put in piston or just rings?

As you say somewhat suspicious it blew up shortly after filling with gas, my guess is that Slavens mods included high compression head as that's standard for his work as 300 is low compression stock and most of his bikes are ridden at altitude in CO/UT etc. So with high compression head at low elevation you get very high compression and with potentially lower octane gas you may have had bad detonation which caused temperature to go up and meltdown. The higher compression heads are great and give substantial boost but if you go too far and at low elevation and lower octane gas can give issues so have AAK measure head volume and squish as you may want to go with higher x dimension (extra base gasket) to lower compression closer to stock to use in the desert, or I have couple of stock 300XC heads if you want to try/compare.

Definately wise to do the bottom end with that many hours and the possibility of damage from the piston bits then you can happy for a long time.

When you get it back start with rich jetting and go through plug checks and lean off bit by bit until you get it right

i was going to mention that too dave. the head mods slavens does are for high elevation riders. you should do a compression test on the new top end and keep it below 185-190 max. Mine run decent at 160 and have mega bottom end boost with 190.

Have them set the piston level with the deck and do a compression test. if its above 190, buy a stock head or have the bowl on that one cut to give lower compression.

[Crawdaddy 96]

Dave/Brad - Thanks for the input.......perhaps you're right......compression ratio may be set for 5K-8K......

I highlighted the applicable portion from the Slavens website.....

"Slavens Mule Port/Polish/Decking/Head Mod

$629 – KTM 300EXC/MXC/XC/XC-W ‘04 -’10

$589 – KTM 300XC/XC-W ‘11-’12

The Mule Port & Polish/Cylinder Decking/Head Mod combination offers a significant boost to the low-end and mid-range torque and horsepower. It’s NOT a minor change that you can barely notice, it’s a major boost. The increased torque and horsepower produces smooth power delivery which makes it much easier to ride, increases traction, and enables using a taller gear in most situations. These mods, when combined with a Slavens Mountain Jet Kit, increase fuel mileage.

All cylinder decking and head mods will have the compression ratio adjusted to work in the elevation range in which they will be ridden. (example: engines to be used at low elevation will have a lower compression ratio than engines designed for mountain use only)

Major increase to low-end and mid-range torque and horsepower with good top-end power

Smooth power delivery

Increased torque makes it easier to ride

Pulls a taller gear in most situations (climb hills in 3rd that you used to climb in 2nd)

Increases traction

Makes it easier to re-jet

Increases fuel mileage

Does NOT decrease engine life

Runs on pump fuel"

[Covered in Dust 163]

I had my 490 yamaha seize on me years ago and after I rebuilt the engine she still would not run. Figured out that the gas filter in the tank was plugged from dirty gas that I bought in Mexico. No gas, bike leans out end of piston.

CiD

[daijones 0]

Dave/Brad - Thanks for the input.......perhaps you're right......compression ratio may be set for 5K-8K......

I highlighted the applicable portion from the Slavens website.....

"Slavens Mule Port/Polish/Decking/Head Mod

$629 – KTM 300EXC/MXC/XC/XC-W ‘04 -’10

$589 – KTM 300XC/XC-W ‘11-’12

The Mule Port & Polish/Cylinder Decking/Head Mod combination offers a significant boost to the low-end and mid-range torque and horsepower. It’s NOT a minor change that you can barely notice, it’s a major boost. The increased torque and horsepower produces smooth power delivery which makes it much easier to ride, increases traction, and enables using a taller gear in most situations. These mods, when combined with a Slavens Mountain Jet Kit, increase fuel mileage.

All cylinder decking and head mods will have the compression ratio adjusted to work in the elevation range in which they will be ridden. (example: engines to be used at low elevation will have a lower compression ratio than engines designed for mountain use only)

Major increase to low-end and mid-range torque and horsepower with good top-end power

Smooth power delivery

Increased torque makes it easier to ride

Pulls a taller gear in most situations (climb hills in 3rd that you used to climb in 2nd)

Increases traction

Makes it easier to re-jet

Increases fuel mileage

Does NOT decrease engine life

Runs on pump fuel"

Thats my guess, the high elevation compression ratio with poor gas was most likely cause. I do like the higher compression on 300 and my 2012 XC on pump 91 octane gas at >3000ft is totally awesome, needs more skill than I have to control it fully in anything but deep sand but so much fun

[Crawdaddy 96]

Thats my guess, the high elevation compression ratio with poor gas was most likely cause. I do like the higher compression on 300 and my 2012 XC on pump 91 octane gas at >3000ft is totally awesome, needs more skill than I have to control it fully in anything but deep sand but so much fun

For the record, the pump gas I put in at Borrego was 91 octane (per the pump), the jetting was set for sea level to 3K in accordance with JD kit instructions (without consideration for Slaven Mod), and the mix was ~55:1.

Input from previous owner after reading this thread/seeing pics (his "local jetting" was set for 5-8K which is why we changed it to adjust for local So. CA. conditions. I plan on calling Slaven for input/suggestions):

This all makes sense about the compression and high altitude etc. The mule mod does increase the compression and it is true that at high altitude the higher compression makes a big difference. I rode that bike with my local jetting at 13,000 ft in Colorado and it still had OK power. When I did the top end, I replaced all the parts i.e. piston, rings and wrist pin and gaskets. It was a vertex piston. For what it’s worth, I would not mess with the compression. The bike has been great for me. I think that the jetting was too lean for your conditions.

Jeff Slaven is a good guy. If you call the number, he will answer the phone himself and have some good advice for you.

[Bagstr 287]

Does Aprilla or anyone make a Fuel Injected smoker?

[Crawdaddy 96]

Check out the new Ossa: http://translate.google.com/translate?sl=es&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fwww.ossamotor.es%2FES%2Fmodels.php%3FidMoto%3D337

[Bagstr 287]

Hokus Pokus Injectors?? My bike could use some of that.

213 pounds

[paulmbowers 236]

Hokus Pokus Injectors?? My bike could use some of that.

Heck, *I* could use some of that.

The heck with the bike.

[Spaugh 1]

Thats my guess, the high elevation compression ratio with poor gas was most likely cause. I do like the higher compression on 300 and my 2012 XC on pump 91 octane gas at >3000ft is totally awesome, needs more skill than I have to control it fully in anything but deep sand but so much fun

For the record, the pump gas I put in at Borrego was 91 octane (per the pump), the jetting was set for sea level to 3K in accordance with JD kit instructions (without consideration for Slaven Mod), and the mix was ~55:1.

Input from previous owner after reading this thread/seeing pics (his "local jetting" was set for 5-8K which is why we changed it to adjust for local So. CA. conditions. I plan on calling Slaven for input/suggestions):

This all makes sense about the compression and high altitude etc. The mule mod does increase the compression and it is true that at high altitude the higher compression makes a big difference. I rode that bike with my local jetting at 13,000 ft in Colorado and it still had OK power. When I did the top end, I replaced all the parts i.e. piston, rings and wrist pin and gaskets. It was a vertex piston. For what it’s worth, I would not mess with the compression. The bike has been great for me. I think that the jetting was too lean for your conditions.

Jeff Slaven is a good guy. If you call the number, he will answer the phone himself and have some good advice for you.

do "mess" with the compression. have RJ do a compression test. You want to be around 170-185 in Ramona. And run a big main like 170 and 38 pilot with needle in rich setting. Then work down from there.

This was not your fault chris, just an expensive learning experience that happens to all of us. Dirt bikes are expensive money suckers!!!!

I want you to have a look at this link: This is an "SXS" head with "lower compression" to combat "high thermal impact" of "sand tracks"... High compression heads are for torqing around single track, you want lower compression and fat jetting for mashing around the desert.

http://www.ktmcyclehutt.com/ktm-parts/ktm-parts.php?sku=SXS10150051&title=SXS-cylinder-head-144/150&year=&ktm-model=&category=Engine-Parts&fitment=bigbikes

[Spaugh 1]

here is something they MIGHT make for the 300 as well, this is for a 250 and older 300s but you get the idea. low compression insert for warm and sandy conditions:

http://www.ktmcyclehutt.com/ktm-parts/ktm-parts.php?sku=SXS03250010&title=KTM-Cylinder-Head-Kit-250-SXS&year=&ktm-model=&category=Engine-Parts&fitment=bigbikes

two strokes are a pain in the ass to get jetted right, elevation, temperature, compression ratios, they all make a big difference. The best thing is get the head milled for your lowest elevation riding area and jet fat and live with a little oil on the silencer, its cheap insurance.

[dirt dame 559]

I never try to get jetting perfect. I would always err to the side of being rich...as long as the bike runs without loading up or fouling plugs, it's all good.

[DustyRock 0]

Thats my guess, the high elevation compression ratio with poor gas was most likely cause. I do like the higher compression on 300 and my 2012 XC on pump 91 octane gas at >3000ft is totally awesome, needs more skill than I have to control it fully in anything but deep sand but so much fun

For the record, the pump gas I put in at Borrego was 91 octane (per the pump), the jetting was set for sea level to 3K in accordance with JD kit instructions (without consideration for Slaven Mod), and the mix was ~55:1.

Input from previous owner after reading this thread/seeing pics (his "local jetting" was set for 5-8K which is why we changed it to adjust for local So. CA. conditions. I plan on calling Slaven for input/suggestions):

This all makes sense about the compression and high altitude etc. The mule mod does increase the compression and it is true that at high altitude the higher compression makes a big difference. I rode that bike with my local jetting at 13,000 ft in Colorado and it still had OK power. When I did the top end, I replaced all the parts i.e. piston, rings and wrist pin and gaskets. It was a vertex piston. For what it’s worth, I would not mess with the compression. The bike has been great for me. I think that the jetting was too lean for your conditions.

Jeff Slaven is a good guy. If you call the number, he will answer the phone himself and have some good advice for you.

I love the way my 300 runs. Red Spring, PV Brass Screw turned out, Boysen reed cage, FMF pipe & sparky. Honestly the thing doesnt need any more power or low end. Its like a tractor when I need it & a powerhouse when I want. No need to do any other mods. Some always want to tinker to push things to the ragged edge. "play with fire & you will get burned" We all know the saying if it aint broke dont fix it......... Just sayin....... KTM spent lots of $ designing these things to make them last for Joe Consumer.........

[Crawdaddy 96]

I love the way my 300 runs. Red Spring, PV Brass Screw turned out, Boysen reed cage, FMF pipe & sparky. Honestly the thing doesnt need any more power or low end. Its like a tractor when I need it & a powerhouse when I want. No need to do any other mods. Some always want to tinker to push things to the ragged edge. "play with fire & you will get burned" We all know the saying if it aint broke dont fix it......... Just sayin....... KTM spent lots of $ designing these things to make them last for Joe Consumer.........

Agreed. I'd rather drench a $3 plug by guessing rich than fry an engine trying to squeeze out cutting edge performance. I didn't realize I was (apparently) running so lean after following the stock JD settings.

The Slavens work has already been done......now I need to learn how to deal with it accordingly.....winter riding 0-4K......summer riding 4-8K.

I mean, come on......my "go to" bike for dualsporting is a WR250R.....I'm clearly all about reliability/dependability NOT cutting edge performance

[daijones 0]

I love the way my 300 runs. Red Spring, PV Brass Screw turned out, Boysen reed cage, FMF pipe & sparky. Honestly the thing doesnt need any more power or low end. Its like a tractor when I need it & a powerhouse when I want. No need to do any other mods. Some always want to tinker to push things to the ragged edge. "play with fire & you will get burned" We all know the saying if it aint broke dont fix it......... Just sayin....... KTM spent lots of $ designing these things to make them last for Joe Consumer.........

Sounds like some tinkering there to me, all good but just saying.

The higher compression head is just another nice improvement on 300's which if your running decent gas works great and makes jetting easier/more consistent, and even bigger gains at altitude. Now if your riding in Mexico with unknown gas at sea level unless you carry octane booster or running race gas its not a great idea so it depends on your situation, KTM and others design bikes to be reliable over worst case conditions so are seldom optimal for anyone and can almost always be improved for specific cases.

FYI my philosophy on jetting is simple, get main right on for lowest elevation and temp you expect so will always be bit rich (and adjust by season or specific riding areas as necessary) then get pilot/AS and needle as lean as you can go to get best response. This way you have a great responsive engine that can run WFO easy and evey time you are WFO even for a second it gets a bit extra gas to keep it cool.

[DustyRock 0]

I love the way my 300 runs. Red Spring, PV Brass Screw turned out, Boysen reed cage, FMF pipe & sparky. Honestly the thing doesnt need any more power or low end. Its like a tractor when I need it & a powerhouse when I want. No need to do any other mods. Some always want to tinker to push things to the ragged edge. "play with fire & you will get burned" We all know the saying if it aint broke dont fix it......... Just sayin....... KTM spent lots of $ designing these things to make them last for Joe Consumer.........

Sounds like some tinkering there to me, all good but just saying.

The higher compression head is just another nice improvement on 300's which if your running decent gas works great and makes jetting easier/more consistent, and even bigger gains at altitude. Now if your riding in Mexico with unknown gas at sea level unless you carry octane booster or running race gas its not a great idea so it depends on your situation, KTM and others design bikes to be reliable over worst case conditions so are seldom optimal for anyone and can almost always be improved for specific cases.

FYI my philosophy on jetting is simple, get main right on for lowest elevation and temp you expect so will always be bit rich (and adjust by season or specific riding areas as necessary) then get pilot/AS and needle as lean as you can go to get best response. This way you have a great responsive engine that can run WFO easy and evey time you are WFO even for a second it gets a bit extra gas to keep it cool.

Great tips, good info on jetting, cant go wrong with that.

From the Factory: Red Spring, PV spring adjuster. Add-ons: Spark arrester, Pipe & Reed cage (bought it with these items) Cant imagine that the pipe or the reeds are major engine mods that would affect longevity.......

PS: Sure would like my 300 to have a 6th gear for higher speed. But from what I have read it really isnt that much faster on the top end, 5% or so. I will have to defer to diajones to confirm. Thanks

[daijones 0]

Great tips, good info on jetting, cant go wrong with that.

From the Factory: Red Spring, PV spring adjuster. Add-ons: Spark arrester, Pipe & Reed cage (bought it with these items) Cant imagine that the pipe or the reeds are major engine mods that would affect longevity.......

PS: Sure would like my 300 to have a 6th gear for higher speed. But from what I have read it really isnt that much faster on the top end, 5% or so. I will have to defer to diajones to confirm. Thanks

The 6th gear makes little if any difference to XCW 5 speed gearbox top to bottom, you just get the same sort of overall spread but with closer ratios between gears. I disliked my 09 300 EXC (XCW basically) gearbox as ratios were too wide 3/4 and 4/5 for it to pull the next gear properly especially under load in mud/sand/loam, I experimented with PV settings etc and was never fully happy. In comparison I got 2010 300XC and was blown away how good the gearbox was, no gaps, always the right gear except when you want to go real fast or just cruise along road without screaming it. 2011/12 XC gearbox is now basically perfect, it's low enough for anything, no gaps amd 6th is good enough for 80mph+ which is plenty fast enough for me off road, now I will say 2011/12 XCW gearbox may be even better with lower first and second so greater overall range, on 300 at least wider gaps of XCW wont be an issue, I prefer XC more because of suspension than gearbox.

[Crawdaddy 96]

It's back.....rebuilt and tuned properly by All American KTM

Millennium Cylinder work

Rebuilt Crank

Previous owners machined head replaced with stock head (previous owner had head reduced .025 - more squish margin now with stock head)

35 Pilot

Stock KTM needle

3rd clip

168 Main

"COREified" graphics

[TrophyHunter 15]

Merry Christmas! Good to see it back.

[dsfox 0]

Sure is a Sweet Looking Bike, and I like the personalized touch!!

and All Great things to say about All American KTM - they are Awesome!

[Beezzz 6]

sweet ride chris!!!