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FX Problem after overheat

How do you guys even get these things on a trailer without it overheating then?
Still doesn't seem right to me the more I think about it.........
No direspect, just thinking out loud.......
Thanks !!
 

If it's overheating that fast after the idle comes down, something is not right. The three things that come to mind are the thermostat, air pocket in the cooling system and the sensor as being the least likely as I have not heard of any failures of these although anything is possible. If it's not too expensive, could be a quick way to eliminate that.

When you fill the system, do you remove the bleed plug in the top pipe? It's a small rubber plug with a spring clip holding it.

I've had mine idle for 10-15 minutes to when the fan kicks in and off in a 20C garage. The only time I ever overheated was when I was running in very low snow and the radiator couldn't keep up. Let it idle for a bit, came back down, no problem.

No diss taken. We realize you inherited a basket case so there are a lot of unknowns here.
 
Thanks, I didn't want to come off as arrogant or anything like that, I really appreciate the help a LOT. I was just listening to my gut instinct.
I bled the coolant through the little rubber plug at the high point there, twice now actually.
Thermostat is brand new Yamaha. I replaced that because of the overheat issue when it was brought to me.
The sensor, I have not replaced, but it matched the actual temp in diagnostic mode when I used the infrared gun on it.
I'm SURE I would've seen the overheat light on because I have glanced at the display to look for codes now that I think of it. I took a look at the display today and I don't think I would have missed that.
Maybe the trigger is going bad when it gets hot?
 
Okay then it sounds like YOU are not overheating it.As for the SPI coils.No I havent had trouble since I never needed any and I would use OEM if needed.I have used a SPI coil/ecu on a 340 Polaris and banged my head against wall trying to figure out why it would break up on top end.Two SPI cdi/coils and a month later put a stock Polaris unit on and problem solved.I would not take chances with aftermarket electronics unless there was a performance gain involved.Sucked trying to figure that one out and no way I could charge guy by the hr for that one since charge could have easily bought a whole sled!
 
I couldn't stand it anymore, so I put the sled back together and tried everything again.
Had the idle way up and started it up. Again it ran for a while, idled down and just cut out. No overheat light and I had a shop-vac blowing on the rad.
Changed the plugs and got it started again after much cranking. Didn't run for long. Plugs didn't look wet.
What I did notice was that the engine seemed pretty stiff to turn over with the clutch by hand when warm, even with the plugs out.
I'm wondering if the blown head gasket puked a bunch of coolant into the engine (there WAS coolant in the exhaust) and there's some bearing issues or something like that.
Maybe even the cams are seizing beacuse the cylinder head was so overheated.
I also saw somewher on the site somebody that had an output/clutch bearing go bad?
:o|
 
Some of the very early 2007 production had a reduction gear defect that grenaded fairly quickly. I can't imagine one of those still out there unless it's a very low mileage unit. One member tore down one of those and it was a mess with metal everywhere and unusable. Here's a link to it: http://www.ty4stroke.com/viewtopic.php? ... e+teardown

And as far as turning it from the clutch, it would be more difficult as you are turning it through a gear, making the engine spin faster than the clutch.

Since it doesn't have a fan, it is possible that it did overheat to the point of warping the head. The ECU should have shut it down but it may not have had the time to if the right conditions were present. Anything is possible. But to have the camshaft saddles also warp to the point of seizing the cam is not very likely as it would have been a more catastrophic shutdown, more like a seizure.

I hate just having you throw parts at it without really knowing what is causing this. Here's something that you could try. Try swapping relays around. Maybe one for the fuel pump or ECU might be overheating and losing contact. Another possibility is a flaky fuel pump. I saw a similar issue in my truck where it would not supply enough fuel when the tank was below half. Maybe after running a while the fuel pump stops. Have you tried re-starting it right after the shutdown? At this point, it doesn't look like it's overheating. When it stops, does the display also turn off, as if the key is turned off or stop switch is activated? When mine stalled while trying to start it, the display stayed on.
 
The head was warped, actually kinda "dished" the center was around -.003" and I resurfaced it .004"
That's where the head gasket was blown out, in the middle towards the back a bit.
I have been running it with a fuel pressure guage hooked up and I haven't seen less than 45 lbs yet.
It will not start after it shuts down, it sometimes catches like it's trying to start and even sounds like it's starting on one cylinder, loping around 600 RPM but it will not usually start.
Display stays on when it stalls.
 
Anyone else near you with a phazer willing to swap coils to troubleshoot?
 
Do the 3 & 4 cly sleds use the same coils? I might be able to get ones off a Nytro or maybe a RX-1.
I put new ones on because the old ones were melted, by the way.
I was thinking that would be one thing I wouldn't have to worry about............
Last time i had it running it seemed as though somebody hit the kill button. I wonder if I can un-plug the "kill" switch? It seems as though it's connected to a few things because it also disables the starter. I'm not at the machine right now, so I can't check till tonight.
 
The Nytro has a different model of coils. It would just be nice to have been able to rule out the coils.
 
You got a real head scratcher here!

Do you happen to have the codes that where in the computer written down somewhere? Or any codes it may have now?
 
I wrote all the codes down that were on it before I erased them. There were 14, but I don't have them with me right now.
No codes since I put it together other than the two I caused myself ( 1-TORS -I had the throttle cable too tight, and 2- the cam position, when I had the connector undone when I did a compression check)
I should've bought some starting fluid for troubleshooting before I took it back apart.
I did have trouble with the cam chain tensioner, the chain wasn't tight the first time I put it in, but other than that everything went together smooth.
 


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