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Discussion Starter #1
long discussion with KTM tech department on the SX-F engines.
Huge power improvements by retiming the cams !


Lobe centres

· 103 inlet stk is around 107

· 105 exhaust stk is around 108

Now lets be very very clear here, there is no way I can validate or verify this, use at your own risk.

There is some variation in the stock cam settings from the factory and an engine with flat power delivery is often found to be out of spec on the cams (boy I sure hope so !!!)

Cams are pressed onto a taper and held with a retaining nut , no keyways, very easy to retime. KTM make a special tool that inserts into the crankcase (remove allen headed inspection bolt) that then engages into a recess in the crank to lock it at TDC, nice. Procedure is in the 450 SX-F dirtbike work shop manual.

Extreme care to be taken with the camshaft towers, these must be torqued to factory settings with a quality torque wrench and cams checked that they easily moved in end float.
Problems have occurred with excessive tightening leading to seized cams / ruined heads

Recommend KTM 505 setup. This information was provided based on a typical recent 505SX-F build with the emphasis on mid range muscle rather than top end shriek...............

Reliable 58 hp @ 9000 with strong over rev to 11,000
37 ft lbs at 7000 rpm
3 hp improvement over stock at 4000 rpm and stronger through out the power band from there after.
Stock Cams, Cam Shaft Lobe centres
· 103 inlet
· 105 exhaust

Full Akro exhaust, Akro head pipe  SX-F type is the key to the gains. Good power also seen with full FMF systems.

Head work; mild port and clean up, porting is aimed at mid range torque improvement not top end increases.

41mm carb is plenty. Bigger only favours top end, emphasis on this build is mid range muscle

limited - minimal gains with CDI changes (Wolf or Vortex) tends to tame power down rather than add more power.

Unplugging the CDI brown wire, no to nominal change in peak power but slows acceleration in the low end - mid range - softens the hit. Marginally better in low traction greasy conditions.

13.5:1 compression. Machine 0.3mm ?? off base of cylinder to get 13.5:1 from stock piston. Apparently no problems with valve clearance with these engines. Minimum 98 octane race fuel. Would not go higher as detonation can be an issue inthe 2 wheelrs, quad with the higher loads will be more prone to deto risk

Recommend CP or Wossner pistons. CP  450 only at this stage. Wossner does both 450 and 505 pistons.

http://www.woessner-kolben.de/english/indexenglish.html



Piston change out 20 hours at pro level use, 10hrs desert racing with extended wide open throttle / hi ambient temperatures. High risk of piston cracking if engine life is pushed out past 20 hrs in fully built race engines / sustained high rpm usage.

Guess what I'm going to be doing in the new year.................. ;)
 

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You have way to much time on your hands. LOL

Killer info. I plan on doing most of that myself
 

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long discussion with KTM tech department on the SX-F engines.

Huge power improvements by retiming the cams !



Lobe centres

· 103 inlet stk is around 107

· 105 exhaust stk is around 108



Now lets be very very clear here, there is no way I can validate or verify this, use at your own risk.


There is some variation in the stock cam settings from the factory and an engine with flat power delivery is often found to be out of spec on the cams (boy I sure hope so !!!)



Cams are pressed onto a taper and held with a retaining nut , no keyways, very easy to retime. KTM make a special tool that inserts into the crankcase (remove allen headed inspection bolt) that then engages into a recess in the crank to lock it at TDC, nice. Procedure is in the 450 SX-F dirtbike work shop manual.



Extreme care to be taken with the camshaft towers, these must be torqued to factory settings with a quality torque wrench and cams checked that they easily moved in end float.

Problems have occurred with excessive tightening leading to seized cams / ruined heads



Recommend KTM 505 setup. This information was provided based on a typical recent 505SX-F build with the emphasis on mid range muscle rather than top end shriek...............



Reliable 58 hp @ 9000 with strong over rev to 11,000
37 ft lbs at 7000 rpm

3 hp improvement over stock at 4000 rpm and stronger through out the power band from there after.



Stock Cams, Cam Shaft Lobe centres

· 103 inlet

· 105 exhaust



Full Akro exhaust, Akro head pipe – SX-F type is the key to the gains. Good power also seen with full FMF systems.



Head work; mild port and clean up, porting is aimed at mid range torque improvement not top end increases.



41mm carb is plenty. Bigger only favours top end, emphasis on this build is mid range muscle

limited - minimal gains with CDI changes (Wolf or Vortex) tends to tame power down rather than add more power.

Unplugging the CDI brown wirs, no . moiminal change in peak power but slows acceleration int he low end - mid range - softens the hit. Marginally better in low traction greasy conditions.


13.5:1 compression. Machine 0.3mm ?? off base of cylinder to get 13.5:1 from stock piston. Apparently no problems with valve clearance with these engines. Minimum 98 octane race fuel. Would not go higher as detonation can be an issue inthe 2 wheelrs, quad with the higher loads will be more prone to deto risk



Recommend CP or Wossner pistons. CP – 450 only at this stage. Wossner does both 450 and 505 pistons.

http://www.woessner-kolben.de/english/indexenglish.html



Piston change out 20 hours at pro level use, 10hrs desert racing with extended wide open throttle / hi ambient temperatures. High risk of piston cracking if engine life is pushed out past 20 hrs in fully built race engines / sustained high rpm usage.



Guess what I'm going to be doing in the new year.................. ;)


craig man, you never cease to amaze me with the info you come up with. that is excellent information!!!
 

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Kiwi craig
You wouldnt have spec on cam intake open and closing, and ex would you or can you get

Re cam sprokets i asume you need a tool to remove gear from cam shaft ???

Also seems you have info galore...the wire map change, would you know what rev limit on each setting is ????
 

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Discussion Starter #5
moogie

no one seems to want to give out the stock cam values, frig it, i'll map em out my self in Jan

brown wire on cdi, no change in the rpm limit, just reduced timing in the mid range to soften the hit.

Cam sprockets, apparently just press off / press on with a small hyd press ? I'll get more info when I can.
 

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can you do the same with a 450sx or just 505.
 

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Same. Only diff is the piston and Jug.
 

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Discussion Starter #8
craig man, you never cease to amaze me with the info you come up with. that is excellent information!!!
LOL, hey I'm a Consulting Engineer, i get paid to know all the techncial stuff and to advise clients !

but in this case rather than design and manage construction of airport expansion projects as a civil engineer it's figuring how to make engine roost and chassis handle as an off road enthusiast :D

Thinking things through and figuring stuff is my speciality; facts, figures, data, then making your own interpretation and havin the nads to then go for it and implement it !
 

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long discussion with KTM tech department on the SX-F engines.
Huge power improvements by retiming the cams !
[/font]
Lobe centres

· 103 inlet stk is around 107

· 105 exhaust stk is around 108

Now lets be very very clear here, there is no way I can validate or verify this, use at your own risk.

There is some variation in the stock cam settings from the factory and an engine with flat power delivery is often found to be out of spec on the cams (boy I sure hope so !!!)


Kiwi. Do these settings apply to the 450 sx as well. I used the cambridge and shifted my exhaust cam slightly to stock and seem to have lost about 3hp between 5 and 8k revs. How do you measure the timing (lobe centre) so accurately?
Cams are pressed onto a taper and held with a retaining nut , no keyways, very easy to retime. KTM make a special tool that inserts into the crankcase (remove allen headed inspection bolt) that then engages into a recess in the crank to lock it at TDC, nice. Procedure is in the 450 SX-F dirtbike work shop manual.

Extreme care to be taken with the camshaft towers, these must be torqued to factory settings with a quality torque wrench and cams checked that they easily moved in end float.
Problems have occurred with excessive tightening leading to seized cams / ruined heads

Recommend KTM 505 setup. This information was provided based on a typical recent 505SX-F build with the emphasis on mid range muscle rather than top end shriek...............

Reliable 58 hp @ 9000 with strong over rev to 11,000
37 ft lbs at 7000 rpm
3 hp improvement over stock at 4000 rpm and stronger through out the power band from there after.
Stock Cams, Cam Shaft Lobe centres
· 103 inlet
· 105 exhaust

Full Akro exhaust, Akro head pipe – SX-F type is the key to the gains. Good power also seen with full FMF systems.

Head work; mild port and clean up, porting is aimed at mid range torque improvement not top end increases.

41mm carb is plenty. Bigger only favours top end, emphasis on this build is mid range muscle

limited - minimal gains with CDI changes (Wolf or Vortex) tends to tame power down rather than add more power.

Unplugging the CDI brown wire, no to nominal change in peak power but slows acceleration in the low end - mid range - softens the hit. Marginally better in low traction greasy conditions.

13.5:1 compression. Machine 0.3mm ?? off base of cylinder to get 13.5:1 from stock piston. Apparently no problems with valve clearance with these engines. Minimum 98 octane race fuel. Would not go higher as detonation can be an issue inthe 2 wheelrs, quad with the higher loads will be more prone to deto risk

Recommend CP or Wossner pistons. CP – 450 only at this stage. Wossner does both 450 and 505 pistons.

http://www.woessner-kolben.de/english/indexenglish.html



Piston change out 20 hours at pro level use, 10hrs desert racing with extended wide open throttle / hi ambient temperatures. High risk of piston cracking if engine life is pushed out past 20 hrs in fully built race engines / sustained high rpm usage.

Guess what I'm going to be doing in the new year.................. ;)
 

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Registered
Joined
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55 Posts
long discussion with KTM tech department on the SX-F engines.
Huge power improvements by retiming the cams !
[/font]
Lobe centres

· 103 inlet stk is around 107

· 105 exhaust stk is around 108

Now lets be very very clear here, there is no way I can validate or verify this, use at your own risk.

There is some variation in the stock cam settings from the factory and an engine with flat power delivery is often found to be out of spec on the cams (boy I sure hope so !!!)

Cams are pressed onto a taper and held with a retaining nut , no keyways, very easy to retime. KTM make a special tool that inserts into the crankcase (remove allen headed inspection bolt) that then engages into a recess in the crank to lock it at TDC, nice. Procedure is in the 450 SX-F dirtbike work shop manual.

Extreme care to be taken with the camshaft towers, these must be torqued to factory settings with a quality torque wrench and cams checked that they easily moved in end float.
Problems have occurred with excessive tightening leading to seized cams / ruined heads

Recommend KTM 505 setup. This information was provided based on a typical recent 505SX-F build with the emphasis on mid range muscle rather than top end shriek...............

Reliable 58 hp @ 9000 with strong over rev to 11,000
37 ft lbs at 7000 rpm
3 hp improvement over stock at 4000 rpm and stronger through out the power band from there after.
Stock Cams, Cam Shaft Lobe centres
· 103 inlet
· 105 exhaust

Full Akro exhaust, Akro head pipe – SX-F type is the key to the gains. Good power also seen with full FMF systems.

Head work; mild port and clean up, porting is aimed at mid range torque improvement not top end increases.

41mm carb is plenty. Bigger only favours top end, emphasis on this build is mid range muscle

limited - minimal gains with CDI changes (Wolf or Vortex) tends to tame power down rather than add more power.

Unplugging the CDI brown wire, no to nominal change in peak power but slows acceleration in the low end - mid range - softens the hit. Marginally better in low traction greasy conditions.

13.5:1 compression. Machine 0.3mm ?? off base of cylinder to get 13.5:1 from stock piston. Apparently no problems with valve clearance with these engines. Minimum 98 octane race fuel. Would not go higher as detonation can be an issue inthe 2 wheelrs, quad with the higher loads will be more prone to deto risk

Recommend CP or Wossner pistons. CP – 450 only at this stage. Wossner does both 450 and 505 pistons.

http://www.woessner-kolben.de/english/indexenglish.html



Piston change out 20 hours at pro level use, 10hrs desert racing with extended wide open throttle / hi ambient temperatures. High risk of piston cracking if engine life is pushed out past 20 hrs in fully built race engines / sustained high rpm usage.

Guess what I'm going to be doing in the new year.................. ;)



Kiwi. Do these settings apply to the 450 sx as well. I used the cambridge and shifted my exhaust cam slightly to stock and seem to have lost about 3hp between 5 and 8k revs. How do you measure the timing (lobe centre) so accurately?
 

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Discussion Starter #11
Bob

tools Dial guage and bolt on arm
degree wheel http://www.motionpro.com/motorcycle/partno/08-0092
and a two or three sections of high tensile wire to make crank and cam "pointers" - a way of accurately determining where you are rotation wise
Dirt tricks cam chain tensioner (to replace the stocker)
KTM TDC lock
Plenty of time, this is not a job you cannot rush.

you need to get a degree wheel from your local speed shop
Remove the stator cover and attach to the flywheel with blue tack or similar or bolt on usingthe central flywheel crank nut,
lock the crank at TDC using the lock pin in the crankcase, and fit a piece of wire somewhere using one of the stator case screws for example and align the pointer to 0 degrees / TDC on the degree wheel, you now have TDC mapped - confirmed and can now check timing from here.
replace the stock cam chain tensioner with a dirt tricks unit - stocker uses the engine oil pressure and goes slack when trying to rotate - degree in the cams.
Open up the cam cover and fit a dial guage to the rocker arms to measure when the cam is at max opening. Remove the camshaft locking bolts off the end of the cams, you need to expose the end of the camshaft so you can mark the camshaft and edge of the cam sprocket.
Rotate the engine through a few cycles and find the pojnts where the cams intake and exhaust are fully open, do them one at a time is easiest.
you need to rock the crank back and forth to find the max dial guage readings.

[attachment=3049:cam_timing.bmp]

Once you find the valve fully open position note the degrees on the dgeree, and find a convient method of marking the camwheel / end snout of the camshaft, bugger all room there, again a wire pointer bolted on somwhere sturdy is best, then rotate the crank to the desired fully open position based on the crank degree wheel and remark the cam wheel via the cam pointer you have made. Then you have the existing full open position and the newly required full open position.

Remove camshaft and press off gear and realign to new mark, refit cam gear and torque down end nut, reinstall and rotate crank to recheck timing.

It's alot of work and you need to be patient and most importantly, take your time and check check and recheck. Once you have done it a couple of times you'll get the hang off it real quick.



Kiwi. Do these settings apply to the 450 sx as well. I used the cambridge and shifted my exhaust cam slightly to stock and seem to have lost about 3hp between 5 and 8k revs. How do you measure the timing (lobe centre) so accurately?
 

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Bob

tools Dial guage and bolt on arm
degree wheel http://www.motionpro.com/motorcycle/partno/08-0092
and a two or three sections of high tensile wire to make crank and cam "pointers" - a way of accurately determining where you are rotation wise
Dirt tricks cam chain tensioner (to replace the stocker)
KTM TDC lock
Plenty of time, this is not a job you cannot rush.

you need to get a degree wheel from your local speed shop
Remove the stator cover and attach to the flywheel with blue tack or similar or bolt on usingthe central flywheel crank nut,
lock the crank at TDC using the lock pin in the crankcase, and fit a piece of wire somewhere using one of the stator case screws for example and align the pointer to 0 degrees / TDC on the degree wheel, you now have TDC mapped - confirmed and can now check timing from here.
replace the stock cam chain tensioner with a dirt tricks unit - stocker uses the engine oil pressure and goes slack when trying to rotate - degree in the cams.
Open up the cam cover and fit a dial guage to the rocker arms to measure when the cam is at max opening. Remove the camshaft locking bolts off the end of the cams, you need to expose the end of the camshaft so you can mark the camshaft and edge of the cam sprocket.
Rotate the engine through a few cycles and find the pojnts where the cams intake and exhaust are fully open, do them one at a time is easiest.
you need to rock the crank back and forth to find the max dial guage readings.

[attachment=3049:cam_timing.bmp]

Once you find the valve fully open position note the degrees on the dgeree, and find a convient method of marking the camwheel / end snout of the camshaft, bugger all room there, again a wire pointer bolted on somwhere sturdy is best, then rotate the crank to the desired fully open position based on the crank degree wheel and remark the cam wheel via the cam pointer you have made. Then you have the existing full open position and the newly required full open position.

Remove camshaft and press off gear and realign to new mark, refit cam gear and torque down end nut, reinstall and rotate crank to recheck timing.

It's alot of work and you need to be patient and most importantly, take your time and check check and recheck. Once you have done it a couple of times you'll get the hang off it real quick.
Thanks Craig

Those dgree settings you spoke to KTM about do they apply to the 450 sx as well??
 

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Discussion Starter #13
yup all the same 450 - 505
 
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