This melt down just might have me stumped..

[Dartman]

As for roseand's issue: A single 44 should be easier to tune

but my guess is needle and seat is too small or popoff is too high and you were running lean at that 2/3-3/4 mark you feel is "safer" to not blow your engine. You probably would have been safer at WOT with that 150 main in there than the cruising speed.

plus im betting the piston to wall clearance was too tight for the mods done
although he not believing it because it ran last season like that-don't rule out some of the things i pointed out
ported engine will run different piston and egt's temperatures

 

[Mike W]

I had the same thing going on with my plugs a few years back ('08-'09). Can't remember what it ended up being but I took it to Chuck at XScream and be sorted it out. At the time I was running a 62t/61x with a single 48 Novi. I will see if I can dig that thread up.

 

[Roseand]

You know @amitchell was having a sorta similar issue @15 seconds of 3/4 to wide open, he also had one cylinder leaner than the other but It was a dual carb 38 set up. You might review that thread.

For me 3/4 throttle is the same as wide open, I notice no speed increase beyond 3/4 so 15 seconds is too long. After you get her fixed you might limit your throttle more

My skis been driving me crazy too, Electrical issue effecting the Cdi. Sucks some times. Hope you get to the bottom of it

http://www.x-h2o.com/index.php?threads/dual-38-fuel-delivery-problem.150494/

Yes it makes sense for one cylinder on a dual carb setup to he leaner for sure.
And for me I notice a difference between 3/4 and full throttle. My ski keeps pulling.

 

[Roseand]

If 3/4 and full throttle is the same you aren't jetted correctly.

38's usually have a lean spot that's hard to tune out at 2/3-3/4 throttle. Cruising around for 10 minutes there is no good and a quick way to blow your motor.

As for roseand's issue: A single 44 should be easier to tune but my guess is needle and seat is too small or popoff is too high and you were running lean at that 2/3-3/4 mark you feel is "safer" to not blow your engine. You probably would have been safer at WOT with that 150 main in there than the cruising speed.

You could be right about running lean at cruising speed. But isn't it odd to have one cylinder on a single carb setup lean out/sieze and have the other cylinders plug look dark and have perfect compression?

 

[BruceSki]

Not if you are right on the cusp of running fine and not running anymore. You said it yourself the rear cylinder has more load on it than the front.

 

[Roseand]

plus im betting the piston to wall clearance was too tight for the mods done
although he not believing it because it ran last season like that-don't rule out some of the things i pointed out
ported engine will run different piston and egt's temperatures

The reason it surprises me is because I feel like that's something so many people over look, and I know of other people who've gotta there cylinders ported and kept their same clearance. I have a hard time believing I coulda gotten that unlucky. Water temps are still fairly cool and I doubt that porting makes the temps that much higher, and the cylinders were clearanced for dual cooling and cast pistons before..

 

[augustaf]

And the rear piston experiences more of a load and would show deto first.. Awesome info guys! I really appreciate it. Just gotta clean up the aluminum transfer and give it a hone and I should be game for a new piston and rings. No scoring from what I felt so far.

Is muriatic acid on a q tip the way to go for removing aluminum deposits?

And what could I soak my assembled cases in to make sure the bearings are free of any aluminum/metal dust?

Yes, muriatic acid will work and I don't think it's necessary to wash out the case- there is no dust or debris.
Be advised that torque values are specified for dry threads- unless specifically mentioned "lubed"! Example: if 20 ft/lbs dry is needed and you lube the threads, then your 20 lbs torque wrench pull might give you the equivalent clamping of 30 lbs. Loctite is not quite as slick.

 

[Roseand]

Yes, muriatic acid will work and I don't think it's necessary to wash out the case- there is no dust or debris.
Be advised that torque values are specified for dry threads- unless specifically mentioned "lubed"! Example: if 20 ft/lbs dry is needed and you lube the threads, then your 20 lbs torque wrench pull might give you the equivalent clamping of 30 lbs. Loctite is not quite as slick.

Just to be sure though, is there any chemical I can use to flush them without disassembling?

 

[augustaf]

Your Klotz oil might be too pricey, Walmart , Advance Auto, Amazon . com sells Pennzoil 2 stroke oil for about $21/ gal. , maybe you feel comfortable to wash the case out with that? Whatever might have been there prob. already left,

 

[CRJ]

it was ported, was it re-chamfered? Unless they didn't change port timing or catch the stock chamfering? Usually after a chamfer you should hone it, it may of had a bur that started the problem. Also remember that you dont read plug readings by the tip of the plug, its buy a ring inside at the base of the electrode. I would guess reeds, having one lean and one rich looks like the front cylinder broke a reed and is pulling the majority of the fuel. Have you checked them? you said they were new, which is usually the best time for them to shatter

 

[Roseand]

it was ported, was it re-chamfered? Unless they didn't change port timing or catch the stock chamfering? Usually after a chamfer you should hone it, it may of had a bur that started the problem. Also remember that you dont read plug readings by the tip of the plug, its buy a ring inside at the base of the electrode. I would guess reeds, having one lean and one rich looks like the front cylinder broke a reed and is pulling the majority of the fuel. Have you checked them? you said they were new, which is usually the best time for them to shatter

Chamfer looked beautiful. Builder knew what he was doing. I'll take a look at the reeds.

 

[badvinny]

Zack is right, an air leak has developed, that plug isn't light, it's white! You may have an underlying problem of too tight of cyl clearance, ported requires minimum. 005", measure it now since stock pistons usually don't shrink like Wiseco. Also post better pictures of the piston top and the head, the pics you posted are hiding alot of info.

 

[Big Kahuna]

Oil on gasket to me does not tell you much. If there was any buildup for fuel/oil in the cylinders, when you loosen the studs you are breaking the seal. The fuel mixture can start to bleed out, and again when you pull cylinder.........

 

[Roseand]

Zack is right, an air leak has developed, that plug isn't light, it's white! You may have an underlying problem of too tight of cyl clearance, ported requires minimum. 005", measure it now since stock pistons usually don't shrink like Wiseco. Also post better pictures of the piston top and the head, the pics you posted are hiding alot of info.

Will do. If it's an air leak it only leaks when running...static leak test passes. And spraying carb cleaner around the gaskets of the engine and carb when running does not show signs of a leak.

 

[Jakobi86]

I sat next to you when you had the head off and we were trying to figure out what went wrong. I could have sworn that the grayish plug came from the rear cylinder. That was my first thought when you pulled the plug out and it was gray, same as the dome and cylinder wall on that rear cylinder. (Aluminum). Maybe I'm
Mistaken, but I could have sworn that was the case. If so and your white plug was actually the front cylinder, then maybe they were both very close to going and the rear one just went first. Either way, the extended long pull is what I think did it. On any two stroke I have, I never hold a throttle position, it's alway varying because of those lean spots that seem notorious to two strokes. Just my take at the situation... You'll get it going again!


Sent from my iPhone using Tapatalk

 

[Pro-pulsion]

I may have been told hogwash about this, but I believe iodine will also lift separated aluminum from cylinder walls.

 

[Roseand]

I sat next to you when you had the head off and we were trying to figure out what went wrong. I could have sworn that the grayish plug came from the rear cylinder. That was my first thought when you pulled the plug out and it was gray, same as the dome and cylinder wall on that rear cylinder. (Aluminum). Maybe I'm
Mistaken, but I could have sworn that was the case. If so and your white plug was actually the front cylinder, then maybe they were both very close to going and the rear one just went first. Either way, the extended long pull is what I think did it. On any two stroke I have, I never hold a throttle position, it's alway varying because of those lean spots that seem notorious to two strokes. Just my take at the situation... You'll get it going again!


Sent from my iPhone using Tapatalk

When I pulled the plugs I think I ended up swapping the rear for the front tho..

 

[speedysprocket]

Likely not the cause of your issue, but there's no reason to run race fuel when you have an engine designed for pump gas. Local 964 owner decided to try mixing 110 50/50 with 93. I rode that ski and was like what happened to this thing?! Put some more 93 in and came back to life. He tried adding 110 again and it ran like crap again. If you don't have the compression and timing to account for the higher octane, it's wasted money, and sometimes even a performance loss!
Also, 45:1 on oil...? Just saying...

 

[Roseand]

Likely not the cause of your issue, but there's no reason to run race fuel when you have an engine designed for pump gas. Local 964 owner decided to try mixing 110 50/50 with 93. I rode that ski and was like what happened to this thing?! Put some more 93 in and came back to life. He tried adding 110 again and it ran like crap again. If you don't have the compression and timing to account for the higher octane, it's wasted money, and sometimes even a performance loss!
Also, 45:1 on oil...? Just saying...

I've always mixed in a little race gas, usually I do 20% race.
What's wrong with 45 to 1? Last season I noticed a little more sludge by the exhaust ports and exhaust tube/b pipe chamber than I liked,and I was at 40:1. It's klotz ski craft as well which is really good oil,and I know plenty of people that run their ported motors at 50:1

 

[speedysprocket]

I like 40:1. Just saying. Remember too- less oil means it'll run rich on fuel, so you should lean it out which means even less oil. I believe it's a balance to get just the right amount of oil.
And for the fuel- told you my recent experience. Use it as you like.


Sent from my iPhone using Tapatalk