OzVMX Forum
Clubroom => Tech Talk => Topic started by: evo550 on January 16, 2009, 08:01:26 am
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A friend of mine has recently bought his son a '09 ktm 65 (the ones with the "husaberg" type motors)
He has been having a lot of trouble keeping plugs up to it, with a new plug the bike runs fine for about half an hour then starts spluttering, bogging, loading up, coughing, sneezing, then eventually gives up the ghost. Fit a new plug and away we go again.
He has had it back to the dealers a few time to ensure all the setting are as they should be and been given the all clear.
He received a call from his dealer yesterday saying ktm were about release a bulletin reccommending 65 owners NOT run any higher than 91 octane fuel in the bikes ??? ???
He has always run BP Ultimate.
What do you think?
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My son has a 09 KTM 50SX same new motor styling, KTM Reccomend to run it at a fuel ratio of 60:1, does your mate know that this is the recomended fuel mixture for these new style engines? this maybe the cause if he is running it at a much richer ratio.
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What heat range is the plug?Type of plug?
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yep i would be looking at that, std heat range may not suit the riders riding style and they are not getting enough heat in the engine to burn off the carbon. see this sort of thing all the time and have to tune bikes to run on the fuel we have today. i find that i can ride bikes on their std heat range plug but many old guys who really ride gentle/easy need to have a hotter plug, but sometimes i wish they would just give the bike some more revs and ride a bit harder because they think their bike will break but by riding the bike so gentle and letting it idle long periods is doing it more harm than good. Im not sure why they would recommend such a low octane fuel? usually its better to go as high as possible and use octane booster. 91 is shit. std carb jetting should be set up for oil ratio in owners book so do what that says.
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Hmmmm, if I was gunna muck with an engine I would have a base of known settings which I know that works. The manufacturers recommendation including recommended fuel would be a good start ;). Try it and see. If it doesn't work you know who to blame :). If it does work what more could you want ;D.
Hmmmm, rhetorical question :P. If you want more higher octane fuel is an obvious. 91 octane does seem low for a racing two stroke (is that a fair dedscription of the 09 KTM 50SX?). The cycle you described, 96 BP ultimate, runs fine, misfires, new plug, 96 BP ultimate, runs fine, misfires, sounds like a fowling plug to me. Suggests one ot two things to me,
1/ wrong plug heat range (is the kid particularly novice and lugging the engine - if so try 'hotter' plug) or
2/there is something in BP Ultimate that the bike/engine/plugs does burn off and accumulates on the plug. This is possible. Oil ain't oil, Soul and fuel ain't fuel, mate. There are lots of additives and they vary from brand to brand. Try another high octane fuel such as Shell Optimax or whatever.
Is the bike gonna be a paddock basher or a race bike? If its gonna be a race bike and you want the max, ask the KTM dealer if there are various thickness base and head gaskets. KTM use to offer various thickness base and head gaskets for its two strokes and you could use them to good effect slightly raising and lowering ports and compression ratios to your hearts content or your ultimate frustration ;D.
(60:1 seems lean on the oil to me ::). I would go with OEM specs).
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I think the problem with the higher octane pump fuels is the higher the octane the more additives they have these additves tend not to be carb friendly. I've seen a lot of bikes chewing thru plugs when run on high octane. These fuels are designed for fuel injected cars and don't work that well in carby motors. You can really notice when you pull apart a carb that has been run on Shell (VIC) high octane because of all the crap in the carb bowl.
On a 65cc two stroke there should not be any issues with detonation so running 91 should not have any effect anyway
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That's a symptom of SHELL there Mick, have easily tuned a Rotax Max kart engine at the point of detonation, each and every time it hits the track.Fuel is control of BP98, it NEVER varies from location to location or one batch to another.No waxy deposits in carbs, tanks or anywhere else.
Make sure you are NOT using an ethanol blend fuel either.
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(60:1 seems lean on the oil to me ::). I would go with OEM specs).
THAT IS THE OEM SPECS!
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you have to re-tune to suit the fuel being used. different fuels burn at different temperatures. if you tune for one fuel you will have to re-tune if you go to another fuel.
the only problem i ever experience with high octane premium is that the volitile chemicals dissapear quick and the fuel goes stale quick. usually best to drain float bowl after ride ( if your not riding bike ever couple of days) and keep fuel tank topped up. it has a shelf life in drums of about 3 months.
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i use caltex 98 in my dt360 and my 70hp yamaha outboard.my dt is used for dirttrack.it gets flooded with fuel as i have a 38 mm carb.at one stage it ran with no rhs crankcase seal in it.nothing wrong with fresh fuel.a mate of mine has a few us mussel cars and if let sit with shel ultramax for 4 or 5 weeks they wont start.change fuel fires up straight away.the cars are perfect condition he has won 3 summernats with a few of his cars.old fuel high performence engines dot mix.
cheers
jim
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Thanks guys,
Yep he is running as factory reccommends 60;1 with motul oil, the plugs aren't fouling as such (with big oil and carbon deposits on the tip) instead they just stop sparking. I understand this is a build up something over the insulator around the electrode which allows the charge to travel from the electrode over the insulator and to the earth, instead of jumping the great divide.
He has tried all of the heat ranges and from $2 plugs through to the $40 only get through your dealer genuine ktm ones. Same results.
It's a race bike and the kids no novice.
I just find it a bit hard to swallow the high octane fuel senerio, when you would expect it to effect a most bikes if the fuel was the problem.
He's getting slightly pissed off....not what you want when you hand over $6500 of your hard earned.
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probably means nothing in this context but I usually run Silkolene oil - ran Motul when in Tassie as I couldn't ship any oil with the bike and this was the best I could find - my bike smoked a lot more?
Rossco
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I can understand your frustration. I went through the same thing with the WR250F when it first came out (involving some looong pushs on some hooot days up in the Watagans :-X :(). It wouldn't run more than 30 minutes on Shell without fouling a $15 ubeaut plug (just long enough to get you deep down a single wheel track trail deep in the Watagans :o - Tojo's revenge ::)?. A change to Caltex, a couple of minor needle and jet changes, and then no probs 8).
I know some of the high performance (high compression) sports multi's have had similar 'teething' probs.
Good luck.
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Heres my two bobs worth, had a very similar experience with My Pe 400- and it drove me insane to point the that I had the stator rewound , changed CDI -coil -plus timing set , changing jets didn't work ???
Must be the Fuel ---Shell to BP no good
Hmmm, ok change brand of plugs form NGK to Champion same heat range problem solved Why ????
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check the fuel breather tube isn't blocked (just a thought)
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I can understand your frustration. I went through the same thing with the WR250F when it first came out (involving some looong pushs on some hooot days up in the Watagans :-X :(). It wouldn't run more than 30 minutes on Shell without fouling a $15 ubeaut plug (just long enough to get you deep down a single wheel track trail deep in the Watagans :o - Tojo's revenge ::)?. A change to Caltex, a couple of minor needle and jet changes, and then no probs 8).
I know some of the high performance (high compression) sports multi's have had similar 'teething' probs.
Good luck.
I had one of them that did exactly the same thing, pissed me of that much that I punted it and went and got a new 400 berg, Hhmmm..Much Better ;)
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I had a similar problem years ago, running NGK B8EV plugs. I couldn't get more than 5hr out of them, changed to the B8ES which are heaps cheap and lasted forever.
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some have said the EGV (NGK racing plugs in red box) have been suspect. these type have a gold palladium electrode. maybe the fuels are reacting with this metal? it doesn seem to happene everywhere as many people throughout the world use these plugs in PE's with no problems.
by the way, just because you foul a plug it doesn mean its rubbish and time for another one. just clean it and put it back in again and fix the problem that is causing the fouling. some people dont realize this and go through dollars woth of new plugs.
i have never had to replace a plug because it was causing a problem. Only reason i replace plug is part of service/maintenance procedure or for peace of mind to know 'its new'. One or 2 times i have had a faulty plug out the box and it was a loose insulator or loose center electrode, i cant remember.
These days iridium plugs fix many problems and are far superior to other basic $4 plugs or other top of the range platinum or racing plugs from 20/30 years ago.
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check float level ;D
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Does your KTM use a PVL ? if so PVL only suggests one plug type.
use that over any Ktm books spec, if its digital it needs a 500 ohm plug and if i remeber its a gv not a egv or somthing similar.
Was the bike pre delivered correctly ? as in is the earth on the coil on metal or is it not earthing propery somwhere under there and shorting out the plug only to re-earth properly when you mess about under there , then moves back to an unearth when its ridden over bumps etc again.
I like the thinking on the blocked carby pipe, come unstuck a few time on that one. if the plugs not fouled then it could also be just ign problems, tell the dealer you want to borrow another coil and black box to eliminate it, my gut feel is there is a gremlin in the ign and its shorting plugs. i know if i over rev my 360, particulaly if its in neutral trying to clean out the pipe, it kills my plug, it will missfire and wont rev out during a race, new plugs fine, and only ever happens if i over rev the dam motor, if i dont it goes for eva.
just some thoughts ???
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I think the problem with the higher octane pump fuels is the higher the octane the more additives they have these additves tend not to be carb friendly. I've seen a lot of bikes chewing thru plugs when run on high octane. These fuels are designed for fuel injected cars and don't work that well in carby motors. You can really notice when you pull apart a carb that has been run on Shell (VIC) high octane because of all the crap in the carb bowl.
Quoted for truth, but - like Lozza - I'd place more emphasis on the particular brand of fuel being used... ;)
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The word is that Caltex or Mobil (use the same fuel i think) are the way to go. That is what i use. BP seems okay as i have used it a couple of times myself. Stay away from Shell.
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Have had same problem with 380 sx when trail ridden . if plug is race egv etc then unless it is getting its beans it will foul up.
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Problem solved...at least I think.
Dropped the clip down 1 notch on needle
ran 7 series plug (8 standard)
ran 96 octane fuel as manual recommends.Not 98
plus he had an extremely over oiled air filter ( three coats of molassis)
Went out to MX mountain on the weekend ran two days no probs.
The young fella's smiling again.
Thanks to all for help.
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if that dont work you can allways buy the young fella a kx 65