- Joined
- Feb 6, 2006
- Messages
- 10,626
- Reaction score
- 4,316
- Location
- Cape Town, deep in the lentils
- Bike
- KTM 990 Adventure
I have a thing about getting my bike to run at its best and like to work up a bit of a knowledge about it for myself.
I recently bought a set of Bosson Pipes. The prime reason is not for louder pipes but I think the OEM ones are dangerous because of how hot they get. I had visions of me falling, being knocked unconscious and waking up with a very overdone leg. Just brush them and they cause bad burns. Along with this they are heavy beasts. Also if truth be told, I don?t think the OEM stuff is the best in terms of performance. The new ones are free flow but not unduly loud. Along with them I got a DNA air filter, it is expensive but in just 2 filters? time it will have paid for itself.
I installed them but did nothing to the carbs, this change alone bought along a slight increase in torque and power as measured though the arse-o-meter. Response was better but, technically if the original stuff was running right then it would be running a little lean from the better breathing ability.
After following the huge jetting thread on ADVrider I ordered one size up on the main jets from 155 front and 160 rear to 160 front and 165 rear and down one size on the idle air cutoff (IAC) jets #80 to #70. This IAC move is a little controversial as most people on the Jetting site go up from a #42 to a #45 on the Main jets to get to a similar result. But as pointed out by more than one of the guru?s, KTM provides a whole range of IAC jets but only the one main jet in its parts list so you have to wonder why. Then once there was evidence from the forum that the IAC thing works I decided to try. Also you have to get the #45?s through an aftermarket business.
The main jets arrived but the IAC jets took a while to get here from KTM Austria.
I couldn?t wait for the latter so I put the former in, raised the needles to the third clip position and balanced the carbs. Things appeared much improved except for the dreadful fuel consumption (from 300 plus to 230k?s max). It was more responsive but I could tell it was overly rich; didn?t need much if any choke to start and on very warm days was affected slightly.
This weekend I got my hands on the IAC jets and put them in, lowered the needles to 2nd clip and turned the Mixture Control Screw to 1.25 turns out on both carbs and rebalanced them. Also, I removed all the SAS and EPC stuff, fabricated some aluminium blanking plates for the holes left from the SAS removal. Plugged the airbox holes and capped the carb vents that went to the EPC.
The effect is amazing.
The needle races around the clocks incredibly quickly now. There is no hesitation anywhere; I was in some deep sand this morning and from low revs in second it did not bog at all ? very clean pulling. It will lift the front cleanly in second and care needs to be used in first. Any ham fisted movements in first will result in tears. There is less vibration from the engine and it seems as if gear changes are easier/cleaner (although why that would be affected from a carb tune stumps me?). The torque is huge between 2500 and 7000. If anything, I think the very top end has only very slightly improved but not a radically as the low and mid range.
I want to see what happens to the consumption and I am going to take it to get AVR?s analysed as I am curious to see technically what my modifications have done.
I might jump back into the carbs to fiddle but for now life is very good.
If you have a carb?ed 950 and live at the coast, I would definitely have a go at this. If you are in the Cape and own a 950 and are keen to check the bike out you are more than welcome to PM me to organise a quick ride to feel the difference. Unfortunately if you don?t currently own a 950, sorry, I won?t let you on it.
I recently bought a set of Bosson Pipes. The prime reason is not for louder pipes but I think the OEM ones are dangerous because of how hot they get. I had visions of me falling, being knocked unconscious and waking up with a very overdone leg. Just brush them and they cause bad burns. Along with this they are heavy beasts. Also if truth be told, I don?t think the OEM stuff is the best in terms of performance. The new ones are free flow but not unduly loud. Along with them I got a DNA air filter, it is expensive but in just 2 filters? time it will have paid for itself.
I installed them but did nothing to the carbs, this change alone bought along a slight increase in torque and power as measured though the arse-o-meter. Response was better but, technically if the original stuff was running right then it would be running a little lean from the better breathing ability.
After following the huge jetting thread on ADVrider I ordered one size up on the main jets from 155 front and 160 rear to 160 front and 165 rear and down one size on the idle air cutoff (IAC) jets #80 to #70. This IAC move is a little controversial as most people on the Jetting site go up from a #42 to a #45 on the Main jets to get to a similar result. But as pointed out by more than one of the guru?s, KTM provides a whole range of IAC jets but only the one main jet in its parts list so you have to wonder why. Then once there was evidence from the forum that the IAC thing works I decided to try. Also you have to get the #45?s through an aftermarket business.
The main jets arrived but the IAC jets took a while to get here from KTM Austria.
I couldn?t wait for the latter so I put the former in, raised the needles to the third clip position and balanced the carbs. Things appeared much improved except for the dreadful fuel consumption (from 300 plus to 230k?s max). It was more responsive but I could tell it was overly rich; didn?t need much if any choke to start and on very warm days was affected slightly.
This weekend I got my hands on the IAC jets and put them in, lowered the needles to 2nd clip and turned the Mixture Control Screw to 1.25 turns out on both carbs and rebalanced them. Also, I removed all the SAS and EPC stuff, fabricated some aluminium blanking plates for the holes left from the SAS removal. Plugged the airbox holes and capped the carb vents that went to the EPC.
The effect is amazing.
The needle races around the clocks incredibly quickly now. There is no hesitation anywhere; I was in some deep sand this morning and from low revs in second it did not bog at all ? very clean pulling. It will lift the front cleanly in second and care needs to be used in first. Any ham fisted movements in first will result in tears. There is less vibration from the engine and it seems as if gear changes are easier/cleaner (although why that would be affected from a carb tune stumps me?). The torque is huge between 2500 and 7000. If anything, I think the very top end has only very slightly improved but not a radically as the low and mid range.
I want to see what happens to the consumption and I am going to take it to get AVR?s analysed as I am curious to see technically what my modifications have done.
I might jump back into the carbs to fiddle but for now life is very good.
If you have a carb?ed 950 and live at the coast, I would definitely have a go at this. If you are in the Cape and own a 950 and are keen to check the bike out you are more than welcome to PM me to organise a quick ride to feel the difference. Unfortunately if you don?t currently own a 950, sorry, I won?t let you on it.
