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17' 250RR coolant loss..

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Question for you guys, noticed my coolant level is quite low after my 5th ride on the bike.  10 hours total.  I checked the coolant after the 4th ride and it was still full so it must of happened on my last ride.  The last ride was the hottest and most technical to date.  When I lean the bike way over to the left, I still don't see any through the cap whole.  I never noticed the bike boil, leak or act strange on that ride.  I have since looked for any visible leaks and found nothing.  The overflow tube is not blocked.  One other thing I have noticed since new is that pressure remains in the rads hours (or even days) after a ride.  When I remove the cap air and sometimes coolants splashes out.  Any suggestions on what you guys think this could be would be great.  I have some Engine Ice at home that I was thinking of replacing the stock stuff with.  Anyone know what the stock coolant is if I was to just top it off?  Something I can get at an auto store?  Looks kinda dark green in color.  One final thing, the transmission oil is clear and shows no signs of coolant in it.

Edited by NW_drZ

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1 hour ago, ohiodrz400sm said:

Are you noticing any white smoke or a "sweet" smell when the engine is running?

The bike smokes like crazy when I start it and its cold.. white smoke.  But goes away once warm.  Ill fire it up when I get home and see if that smoke has a sweeter coolant smell.

1 hour ago, GP said:

Head orings. 

On a bike this new?! That sure would be a bummer.. Is there a way to check and confirm this?

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There have been some cases of bad orings slip through, exact symptoms.  Take it back to the dealer.  If your a DIY guy, get new ones and verify they are Viton (flat black).  Any doubt get KTM orings.  I did my 250 conversion and had no problem with the new supplied parts.  While your at it check the thermostat hose clamps or scrap the tstat with a hose kit.  The motor is awesome and never gets hot and boils if set up and jetted properly.

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Pretty good video from one of the members here about a similar problem. He had coolant puddling on the floor however.

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What I would do is just get some known good orings from Steve at Afterhours (motoxgiant) here and DIY, its faster and cheaper than going to the dealer unless he is close.  Smoking is normal for a cold 2stroke on the choke.  For smooth, strong power jet with the NE** series needles, run the PV adj out to 1/2 turn, and use a G2 throttle w/#200 cam especially if your new to 250 2strokes.  Gear it 13/50.  It doesn't get any better for a 250 woods motor than this. 

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2 minutes ago, GP said:

What I would do is just get some known good orings from Steve at Afterhours (motoxgiant) here and DIY, its faster and cheaper than going to the dealer unless he is close.  Smoking is normal for a cold 2stroke on the choke.  For smooth, strong power jet with the NE** series needles, run the PV adj out to 1/2 turn, and use a G2 throttle w/#200 cam especially if your new to 250 2strokes.  Gear it 13/50.  It doesn't get any better for a 250 woods motor than this. 

I have the bike geared at 13/51 now.  Thought it was a little gappy (13/49) when I first got it. Are the NE needles part of the JD jet kit?  An extra needle and a few jets came with the bike when I got it new, not sure what they are.  I have only tried the PV in from 1.5, not out towards the flush side.  I going to try this next time I'm out as the 250 2 stroke is definitely a learning curve for me.  I was on 250F's before this.  The G2 throttle tamer was actually something I was considering to tame down the off idle twitchiness of the bike.  Good suggestion there.  And I appreciate all your info.

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3 minutes ago, NW_drZ said:

I have the bike geared at 13/51 now.  Thought it was a little gappy (13/49) when I first got it. Are the NE needles part of the JD jet kit?  An extra needle and a few jets came with the bike when I got it new, not sure what they are.  I have only tried the PV in from 1.5, not out towards the flush side.  I going to try this next time I'm out as the 250 2 stroke is definitely a learning curve for me.  I was on 250F's before this.  The G2 throttle tamer was actually something I was considering to tame down the off idle twitchiness of the bike.  Good suggestion there.  And I appreciate all your info.

13/51 is fine.  The NE series are the Suzuki needles, not JD.  Better fine tuning options.  Running the PV out more moves the hit a bit lower in the rev range,  and works great with the needles suggested.  At the risk of starting a debate I'll also say scrap the oil injection and premix, it can't fail. 

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2 minutes ago, GP said:

13/51 is fine.  The NE series are the Suzuki needles, not JD.  Better fine tuning options.  Running the PV out more moves the hit a bit lower in the rev range,  and works great with the needles suggested.  At the risk of starting a debate I'll also say scrap the oil injection and premix, it can't fail. 

would you say having the PV out makes the bike more linear since the hit is lower?  I like to lug the bike a gear tall so this could be good for me.  Are you running the G2 tamer on yours?

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Mine started pissing a small stream from the top of the right radiator hose connection on slow technical trail, even though the clamp was plenty tight. I installed a Samco thermostat elimination hose kit and haven't had the problem since. 

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would you say having the PV out makes the bike more linear since the hit is lower?  I like to lug the bike a gear tall so this could be good for me.  Are you running the G2 tamer on yours?


Yes, but I'm running different jetting which is part of it. The head on my bike is also modified, but the jetting is smoother regardless. I'm running the G2 w/#200 as I have for years on all my bikes.

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Interesting as my 17 250 next day after a hot 3 hour race i found coolant next morning and rad was pressurised, never had it with the 300, have there been reporting on failed head Orings? Iy was a dusty race and there seemed to be some darker dirt around the head/cylinder joint, warmed bike up and let it cool i put a load of talcum powder around engine but no lost coolant and no pressure once cooled down.???

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1 hour ago, Retromlc said:

Interesting as my 17 250 next day after a hot 3 hour race i found coolant next morning and rad was pressurised, never had it with the 300, have there been reporting on failed head Orings? Iy was a dusty race and there seemed to be some darker dirt around the head/cylinder joint, warmed bike up and let it cool i put a load of talcum powder around engine but no lost coolant and no pressure once cooled down.???

Probably didn't get it hot enough.  External coolant could also be from a leaky tstat housing/hose dripping on the head.  When I built mine I addressed all this nonsense and would do the same with a new bike considering the reports.

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I found the o  ring will leak when you first fire the bike up and pressurize the cooling system ( leaking at the thermostat housing and junctions, then once the bike warms the head o-ring seals and all is ok .

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My 17 300 has just started to be a pig to start and is smoking way more than normal but when warm running mint, I'm running NECJ needle and S3 head. 40 hours with no issues until last couple of rides.
Think I will order Ktm O-rings and change out the current ones.
Cheers for the idea
I will report back if it solves the starting/smoking from cold..

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