650/X-2 Two different temperature readings..Which one is right?

[KawiKid]

Hey guys,

ive searched in multiple locations, forums, threads, FB, you name it, haven't been able to get a solid answer. It's actually a two part question:

after riding for about 20 min, I pulled up shore to lift the hood to Check the hull. ( I recently replaced the head pipe to the coupler style, and also ran a new thru-hull pump fitting tube)
although the pisser was pissing normally, when I took the hood off after I shut the ski off, I noticed the motor was really hot, and the pisser line was extremely warm. No water was sizzling anywhere.
so I got it home and flushed on hose.

1) so, what is NORMAL OPERATING TEMP on the hose for a 650sx, stock, single cooled?
The front head area and cylinder were at 139*F and the rear head area and cylinder were between ONLY 92-97* F.

2) is it NORMAL to have such a difference in temps from the front cylinder to the rear?

Again, nothing was sizzling, but was super hot to the touch. The head pipe was completely COOL and so were the manifold areas and the rear cylinder.

just replaced the thru hull fitting/tube for the pump, so that is clear, pisser line and hull fitting are clear, both head pipe fittings are completely clear, air flows right thru, hose from head pipe to cylinder head is clear, air blows all the way through.

while making sure these paths are all clear, I took the pisser line off from the head pipe, and I saw this...this cant be normal...looks melted to me.

 

[TaintlessEd]

I think you may have plumbed it wrong.
Take a few pictures of your cooling setup and post it.


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[KawiKid]

hey taintless, I was actually JUST reading your replies to the other guy regarding his pump questions.

ok I will. keep in mind, its how I got it from the Previous owner.

 

[KawiKid]

Hey Taintless ed,
ok, heres my cooling setup. 1) the hose flush is no longer there, I capped it off and just use the backflush tool from the pisser. (have been doing this for a while with no issues)

2) if you see my pipe drain and pump thru hull fittings, theyre switched, the PO snapped one of them off on the pump side a while ago, so he had the pump routing entering on the exhaust side, then he used broken one for the passive exhaust drain fitting. The third fitting goes to the stock/passive bilge that exits the pump

 

[Vumad]

How do the plugs look? One thing about a single carb is you can't tune for cylinder differences. Is the hotter cylinder looking lean?

 

[KawiKid]

hey VUMAD I am going to double check again today when I get off of work, but from a while ago, I think I remember the front plug looking leaner. what would that mean?

 

[Vumad]

hey VUMAD I am going to double check again today when I get off of work, but from a while ago, I think I remember the front plug looking leaner. what would that mean?

On a twin carb you can make adjustments to each carb to the needs of that cylinder. On a single carb you have to tune to the leanest cylinder. This shouldn't be making such a big temp difference and is unlikely your problem. 140 is pretty normal operating temp in my experience.

 

[KawiKid]

ok, yea I think the 140 is ok, but what concerns me is why the front cylinder runs 50+ degrees hotter, and why the inner sleeve of the pisser hose was melting. It IS butted up completely flat against the head pipe and then clamped down. Even so, I wouldn't think that it was so hot that it would singe the hose like that. I believe its the colored hose from Blowsion.com , I wonder what their temp threshold is on these.

 

[KawiKid]

thought maybe it could be the head gasket....
Unfortunately I didn't find anything that looked alarming, meaning there was no sand or clogs anywhere. And from what I see, head gasket looked fine. Besides a few thin flaps of black carbon or an adhesive (?) no holes were covered or clogged, unless I'm missing something.

What do you guys think of the head gasket and the head?

i don't know WHAT ELSE could possibly cause two drastically different temperatures between the front and rear cylinder.

any other ideas?

 

[KawiKid]

here are a few more

 

[Freakie]

the piston that is almost clean on top and the dome from the head look like they are been steam cleaned by a small leak in the head gasket ...I think that would lower the temperature of that side of the cylinder due to the cooling effect of the steam...(i think)....so which piston is that....the cooler side or the hotter side......either way......check if the head is flat and not warped....new gasket and test again....I run my TPE at 140 degrees measured on the head using the stick on temperatures strips....that from checking out most of what the forum members run their AM motors at.....the cooler cylinder in your motor is too cold imo

 

[KawiKid]

@Freakie yea the cleaner one is the front piston (the one that is running hotter). ok I'm going to order a new head gasket today and check the head for warping. im hoping it was some sort of microscopic leak that I cant notice and at this point, I will check the temps again after running it, and if theyre not over like the 150's mark, ill just run the ski until it runs no more. its running fine with no issues besides that. what I haven't checked are the temps on both cylinders after running out on the water.. the temp difference was only noted while on the hose.
I just found it odd that one would be almost 50 degrees cooler

 

[KawiKid]

Ok well,
Head is NOT warped, dead straight..
Deck is NOT warped, dead straight..
Just went through ALL OF THE COOLING LINES AND FITTINGs again, no blockages AT ALL,
No blockages in water jackets anywhere.

Only thing left is to hope that there were some microscopic inefficiencies in the head gasket that weren't noticeable, so a new head gasket is on its way, second, in going to Richen the low speed screw a little more, then check compression, if compression is still around 150/150, I'll just ride it and then check temps right after a long ride. As long as BOTH cylinders don't go over the 150-160*F mark or don't sizzle, not going to worry about one cylinder being hot on the trailer/hose

I'll just ride it until I can't..

Also, I read up on a few people mentioning airlock in the front cylinder while on the hose, but that was usually occurring when the persons trailer was on a pretty drastic angle. Mine is always basically straight when I flush though...

 

[kevbo]

With a single inlet line, water flow between cylinders are controlled by the small holes in the exhaust manifold gaskets. It is common for gravel to block the lower passages at the exhaust manifold gasket. This will make one cyl cooler than the other. Its best to increase the size of all fittings and lines from the stock 7mm to 5/16" or 8mm. This will ensure plenty of cooling.

 

[KawiKid]

@kevbo i actually retapped and went with the bigger water fitting on the head pipe..

Ok well, I think I may have found my problem.. and I think it's a BIG one.

Went to put the head back on, started the tightening/torquing sequence and 4 bolts just wouldn't tighten and then I noticed those studs were sticking out of the head much more than the others..
Well, so far one of the studs just pulled completely out.
Looks like the previous owner had a problem and then helicoiled the studs..

Well now the helicoils were stripped and pulled right out.

Can I recoil them again with the same size? Or do I have to go even bigger now? And if I did, I'd have to use a bigger stud too, right? And if I did that, I think a stud even a tiny bit thicker Won't allow the head to slip over it.

Can I do this, or do I need to buy a whole new block?

Thanks guys

 

[TaintlessEd]

@kevbo i actually retapped and went with the bigger water fitting on the head pipe..

Ok well, I think I may have found my problem.. and I think it's a BIG one.

Went to put the head back on, started the tightening/torquing sequence and 4 bolts just wouldn't tighten and then I noticed those studs were sticking out of the head much more than the others..
Well, so far one of the studs just pulled completely out.
Looks like the previous owner had a problem and then helicoiled the studs..

Well now the helicoils were stripped and pulled right out.

Can I recoil them again with the same size? Or do I have to go even bigger now? And if I did, I'd have to use a bigger stud too, right? And if I did that, I think a stud even a tiny bit thicker Won't allow the head to slip over it.

Can I do this, or do I need to buy a whole new block?

Thanks guys

If you have the knowledge/ability I would just get new cases and start fresh instead of trying to fix something that broke twice already.
Plus you'll have that peace of mind that it's not going to rip back out.


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[KawiKid]

Yea that's what I'm going to do.. looks like I don't need to open up the bottom end.. as long as nothing crumbles and falls apart when I pull the top case off, I can basically do it with just taking the exhaust manifold off. (Not looking at the ski right now, I think the intake manifold is attached to the bottom end?)

So, hope to find a good clean case