Lost bolt now losing my mind

[BigAl57]

I have a 97 GSX with 787 engine. Had a guy replace a blown piston and a few other things last summer. Got it back and the engine blew in l 1 ess than an hour. Machine also sank and filled engine with water. He had replaced wear ring and I think he didn't reseal the impeller unit when he put it back in. Now I am out money and trying to redo it myself as he had it for 3 months and said he would fix it but just left it sitting outside. By the time I got it back the crank was almost seized as there was still some water in it. I filled crank with oil and kept turning it over 3 weeks, then drained the oil and refilled and did again. Everything is moving smoothly. Ordered a new piston and watched some youtube videos and read the manual so felt I could do the job. Here's the problem. During all of this I had put all bolts removed in a tupperware container. When I sorted everything out I am missing a M10 x 75 for securing the jug to the crankcase. I am in Canada and called dealer but they say these are all out of stock. Saw one on Ebay but delivery was $25 U.S. on top of the price of the bolt. If anyone has an extra bolt, and can ship it for a reasonable price I would appreciate it. I bought two stainless steel bolts on line and thought that would solve the problem but today I tried to put everything together and the head of the bolt is too big to allow me to use a socket to put it in. The original bolts take a 13mm socket, the one's I was able to get were 17mm heads so no space. Anyway, I think the machine is cursed as I have looked everywhere for the missing bolt with no luck, and can't seem to find one on line. I may have to bite the bullet and pay the exorbitant shipping fee unless someone can help me out. thanks.

 

[Lee.Harrison]

I definitely know the feeling of dropping bolts into the abyss of the ski, and are you doing a full rebuild or just the piston, if your doing just the piston I dont know how well that's going to work, and also you need to figure out why it blew in the first place, you dont want to spend even more money and have it throw another piston, I would say you need to rebuild carbs and make sure it's not running lean, best of luck!

 

[Sandman251]

Don't worry you can find that bolt at any hardware store for 50 cents. I've done it many times. Your only concern should be if you dropped it into the crankcase. Even if your replace just one piston, make sure you follow the proper break-in procedure. Good luck.

 

[BigAl57]

Don't worry you can find that bolt at any hardware store for 50 cents. I've done it many times. Your only concern should be if you dropped it into the crankcase. Even if your replace just one piston, make sure you follow the proper break-in procedure. Good luck.

If I get it running what should the break in be? I only ran 3/4 throttle last time and ran a little richer fuel mix. Should I do this for a certain number of hours? thanks.

 

[etemplet]

Man !! So sorry to hear about your ordeal !! That happens a lot though. I've taken some engine apart that have had Allen Head screws for Cylinder Base Bolts. I like to use the factory stuff but.... people get buy without incident. I applaud your tenacity and resolve to get the ski back together and reliable.

Check the crank case for metal parts. clean it out really good. Check the connecting rods for play. Make sure the pistons are installed correctly. Put some good assembly lube on all the parts. I use the SBT engine break-in method and modify it a bit. I am impatient. LOL I always add extra oil to the fuel whether Pre-Mix or injection system.

I ride the ski at idle for 5 minutes and let it warm up. Come back and check for leaks and cylinder temp. Then I ride for about 15 minutes and come back. remove the seat, check temperatures and inspect the engine compartment. check cooling water flow, etc.

So, if it isn't gonna sink... I ride a 1/2 hour to 45 minutes at no more than 20% throttle varying throttle position. I blip it every now and again for a 2 or 3 second pull from idle to about 3500 rpm.
Let it cool a bit.
Then ride at no more than 50% throttle for another 45 minutes but vary the throttle often and do several pulls from idle but keeping the throttle position low. no more than 4500-5000. Sometimes I pull in and let it cool a bit and inspect.
The third session I pretty much ride at no more than 50% throttle but I clown around to some tight turns and such.... put a some load on the engine. I consider 6k wide open range but it isn't. I cool it down again and the 4th session.... 50-75% throttle and of course, I gotta do a wide open run, however short. LOL I rarely run my engines wide open for long periods (more than a few minutes). I inspect the hell out of the ski and listen, pay attention to what is going on, monitor the spark plugs, etc.... ***** nobody rides these skis but ME ****

Generally I accomplish this over two separate days of riding. I still baby the ski for 3-5 hours. Then every time they skis go out.... I warm them up slowly for the first ride of the day. No dropping that hammer with a cold or cool engine. This is just my way of break-in. To each his/her own. Good Luck !!

 

[GGuillot]

I don't have an extra M10 bolt laying around, if I did I'd send it to you since you asked. Some on this thread and forum have a dozen skis or more, tons of parts, I only have 2. Three months is a long time for it to sit with water in the engine. Bearings that rusted up on the crank, now free, is what you're working with. You need to plan that crank will need to be replaced sooner than later.

On both my 787 skis, (97' GTX and 96' GSX) I'd say a couple tanks of premix is what I ran for a break in (50:1) which is about 10 oz per 5 gallons. No WOT on the first tank and brief WOT hits on the second tank. I also set about 1/2 turn out on the HS needles for the first 20 hrs or so, slightly rich on WOT is what I strive for during this time. Removing the plugs and checking will tell you rich or not.

I run Marine Sta-Bil full time, every time I add fuel. I do it for good measure and a cheap insurance for the fuel system.

Before firing up another engine, I personally would double check the fuel system, the carbs need to be perfect, if it's been awhile rebuild them with some OEM kits, test them, sync them and tune them at factory needle settings. Be through and attention to detail, this effort will reward you with trouble free times on the water.

 

[mikidymac]

I’ll say it.... with the engine sitting for weeks or months with water in the bottom end you crank and balancer are trash. Once you get a little rust on the crank bearings they will eat themselves in a very short time even minutes. Once it goes its going to take everything with it.

If you just want to see what happens then go for it but if you actually want to ride it you’re going to have to split the cases and replace the crank and balancer.

 

[BigAl57]

I’ll say it.... with the engine sitting for weeks or months with water in the bottom end you crank and balancer are trash. Once you get a little rust on the crank bearings they will eat themselves in a very short time even minutes. Once it goes its going to take everything with it.

If you just want to see what happens then go for it but if you actually want to ride it you’re going to have to split the cases and replace the crank and balancer.

Thanks for the info. I wish I could do the crank but I don't have enough experience or cash to do it all. I have a 96 Polaris that is running fine so if the gsx runs I will sell it whole and if it blows I will part it out. Before I took it back to the "mechanic" I did put oil in the crankcase to try to save it. When I looked at setting the rotary valve I thought it looked like it had been put in backwards as it lines up much better when I flip it over, but I don't have a timing wheel. Could this explain the piston blowing? I still have the old piston and could post pics if someone thinks it might help identify the cause.

 

[mikidymac]

No. Without a timing wheel you can’t install the rotary valve correctly.

99.9% of the time the pistons go from being lean caused by dirty carbs and/or fuel systems.

 

[etemplet]

Well.... I've seen

When I looked at setting the rotary valve I thought it looked like it had been put in backwards as it lines up much better when I flip it over, but I don't have a timing wheel. Could this explain the piston blowing? I still have the old piston and could post pics if someone thinks it might help identify the cause.

Post some pictures. What did the cylinder look like?

 

[BigAl57]

This is what piston looked like.

 

[BigAl57]

Sorry about the 3 copies. Not sure what happened. Burned on exhaust side

 

[etemplet]

I was told once that the result in your picture is the piston melting into a liquid state. The metal is pulled away, deposited on the head and vise versa. I see this often as in this picture of a 717 that I felt was nothing but abused by the owner who allowed anyone and everyone to ride this 1998 GS. Wide Open all the time and never paying attention to the engine or performance just gas n go. I think this little fella would have lasted me a really long time but C'est Lavie..... this happens all too often. This is only half the story. Check your fuel system thoroughly.

 

[BigAl57]

Thanks for the info. Since the carbs are off I will check the filters and see what I find. I will double check for any free play on the road while I wait for the new bolt. Ordered one off ebay as a Canadian dealer wanted $24 for the bolt plus shipping on top of that.

 

[etemplet]

Wow they are sure proud of those bolts. Sometimes I don't fully appreciate the value of a large pile of parts and components at my disposal.

 

[mikidymac]

Just so you know that’s not a stock piston. That’s a WSM 0.25 overbore piston. And... since it caught a ring on the exhaust side there could be a number of additional reasons why like not enough piston to bore clearance, not chamfering the ports, not trimming the RAVE valves.

Also you can see where the shrapnel peppered the top of the piston and now that’s in the crank bearings too. Seriously that engine is done and needs a full top to bottom rebuild.