Super Jet Blowing O-rings all the time. ADA

[rossthaboss11]

I keep blowing o rings on my 701 after about a full day of riding. About an inch of the compression o ring blows out in the same spot pretty much every time. Front cylinder at the 7-9 o'clock position when sitting in the tray. I switched the two domes last time and the problem didnt go with the dome so its not that. I had the cylinder bored last summer and the guy said my cylinders were dead flat when he got done with it. Do these head shells ever warp much or does it sound like a cylinder drop? im torquing the head bolts to 21 lbs and the girdle bolts to 30 lbs. Its a 701 62t bored to a 727. Ported with 175psi on an ADA girdled head.


Also, how do my pistons/fuel mixture look?

 

[BruceSki]

head shell is most likely worn out. They are made out of soft metal and the dome will bounce/vibrate around in there once the wear happens. This destroys the Orings.

A member on here fixed his by shimming the problem dome. I would recommend an entire new head shell and domes though if you want a trouble free fix.

 

[waxhead]

Make sure your sleeve has not dropped in the alloy casting.
If it has you will need to remove the cylinder and have it machined

 

[rossthaboss11]

ok. Im hoping its the head shell vs the cylinders. how do you check to see if the cylinders dropped other than looking at it? i physically cant see anything or feel any difference between the cylinder and sleeve.

 

[onedumbtrucker]

I wouldn't be surprised if the exhaust mount pulling on the head was twisting it and making the problem worse.

 

[Idok]

sounds like the head is warped...

 

[Freakrider]

This is why some engine builders use 1211 on the backside of the domes where it makes contact with the headshell, to prevent vibration/wear...You could try a semi-dry coat of it before installing the domes to create more crush onto the bores...You could also add a little 1211 in the o-ring groove where it is blowing out...how old is that headshell ?

 

[rossthaboss11]

Not sure how old the head is I bought the ski from another guy 2 years ago. I added some high temp sealant to the o ring grooves last season this happened and it did hold up longer but still blew out. Wasnt sure if I was supposed to do that or not. But if you guys say I can then ill add some to the entire compression O ring groove. I may just order another shell though to hopefully eliminate it all together.

On a side note, the O ring kit for these heads seems odd to me. mainly the fit of the dome to the shell with the two different sized small o rings. They kind of smush together and doesnt seem like a great fit. I place the smallest one around the top of the dome and the other one in the top of the shell groove then put it together. That is correct right?

Thanks for the replies

 

[grahammy]

This used to happen to me a lot. Cut some circular shims out of some beer cans and put them over the domes above the o rings.

 

[200%Absolut]

just go to a workshop to check flatness and mill the head and top of cylinder.

Last winter i've blown the front o ring like that . after the check and rectification no more problem .

 

[Freakrider]

Not sure how old the head is I bought the ski from another guy 2 years ago. I added some high temp sealant to the o ring grooves last season this happened and it did hold up longer but still blew out. Wasnt sure if I was supposed to do that or not. But if you guys say I can then ill add some to the entire compression O ring groove. I may just order another shell though to hopefully eliminate it all together.

On a side note, the O ring kit for these heads seems odd to me. mainly the fit of the dome to the shell with the two different sized small o rings. They kind of smush together and doesnt seem like a great fit. I place the smallest one around the top of the dome and the other one in the top of the shell groove then put it together. That is correct right?

Thanks for the replies

yes smallest o-ring on domes second largest in the headshell groove...Try sealant on the backside of the domes where it makes contact with the headshell, let it dry some before install...you need more dome crush...shims or even beer can shims work lol so I would think dried sealant would add a bit more crush.

 

[rossthaboss11]

ok I will try some shimming with sealant. I did have the head shell checked for flatness and there was disparity which we flattened down but I dont think theres a perfect test for the headshell. The domes are really pushed down by the inside and top of the shell so checking the (bottom to top) of the shell for thickness variations doesnt do much besides making sure the outside water sealing O ring is good. I will try this and let you guys know how it goes.

How do my pistons and tune look?

 

[Freakrider]

piston wash looks good because you are slightly rich/ safe...I use yamabond on the backside of domes to secure them and then upon removal you have to tap the plugs lightly to pop the domes out (holds them good)....yeah let us know how it works out.

 

[Waternut]

I asked this a couple months ago because I was having the same problem. I laid a straight edge over my cylinder and it was good and the shell seemed good too. Before the fix, I had blown an o-ring after 3-4 gallons. Thinking it was a fluke, I changed them and it happened again in the same amount of time. I added little strips of stainless steel tape (0.004" thick) between the head and the shell. Bought the stuff from mcmaster carr and haven't blown an o-ring since. The shell gets worn from twisting and vibrating and doesn't squash the o-rings like it used to.

 

[rossthaboss11]

Welp, blew another O ring. I added in the shims with sealant. It did last a little bit longer this time but only a couple times of riding. I am just going to buy a new head shell. How do I check to see if the cylinder dropped? I cant really see it dropping at all by looking. The cylinder and sleeve seem flush to me. Once again it blew in the same cylinder, most likely the same spot but i didnt rip it apart yet.

 

[Waternut]

Before you go and spend hundreds on a new head shell, might want to put a nice straight edge across the top of your cylinder and check to make sure it's not warped.

Just to make sure... Were you shims made of sealant or did you use a shim and held it in place with sealant? There is a big difference.

 

[BruceSki]

if you are going to buy a new head shell, buy domes too. If the shell is whooped the domes are too.

 

[rossthaboss11]

I did use sealant to hold the shims in place and I also used sealant on the compression O rings. I would of originally thought to get new domes too but ive swapped the domes between front and back and they are always rotated to different positions and the problem doesnt follow the domes its always in the same spot no matter what. Is it possible the big heavy Factory Type 4 dry pipe is pulling on the head causing this?

 

[chriselmore_1]

That's an ada head fer ya.on The blowsion.protection.greater.commander.cool.unit. 2 piece style shells you can just deck the top piece and call it a day.... also the domes lock in place unlike ada

 

[Waternut]

I did use sealant to hold the shims in place and I also used sealant on the compression O rings. I would of originally thought to get new domes too but ive swapped the domes between front and back and they are always rotated to different positions and the problem doesnt follow the domes its always in the same spot no matter what. Is it possible the big heavy Factory Type 4 dry pipe is pulling on the head causing this?

The pipe would not cause the issue unless your are using drastically low torque values but even then it looks like your blown o-ring is on the pipe side of the cylinder which definitely means no. If you know exactly where the o-ring keeps blowing then you know exactly where the problem is. So take a ruler or some kind of straight edge and see if that spot on the cylinder is lower than the rest. If it's low you can take it to a machine shop and have them machine it flat.

The other option is a simple self fix. You first have to remove the cylinder from the engine. Then tape some 300-400 grit sand paper to a fairly thick piece of glass (more than 1/8" thick so that it can't warp). Move the sandpaper back and forth over the cylinder in straight motions taking care not to tip the glass as that would cause rounded edges on the cylinder. Go forward and backwards at first. You'll be able to see high and low spots really easily if they exist since the high spots will be very clean and the low spots will still be black/dull. If you have a low spot on your cylinder in the problem area, keep sanding until it's gone. When getting rid of low spots, you'll need to go side to side as well. When changing directions, you want to make sure that all of the scratches in the opposite direction are gone before changing directions again. Hopefully this helps solve the problem and you won't have to buy a new head but let us know what you decide to do.