Middle Cylinder Blown

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cajones2

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Cedar Rapids, IA
99 600sx - Middle Cylinder Blown, crank work needed?

Hello Everyone,

I was riding my 99 600SX this season and blew my middle piston. I think i got into some bad gas and too much isopropyl. Interestingly, the middle cylinder had a gray sludge material coating the head, spark plug, the transfer ports and in the crankcase for that middle cylinder. I am my cylinder in for repair since it was scored up pretty good and will replace the middle piston and all new rings across the top.

My concern is the gray sludge and am wondering if it is from the piston, the nikasil, or is it a crank bearing. Either way my next step is to split the case and examine the crank. My question is:

1. How do i inspect/test the crankshaft to ensure the bearings are good.

2. At the least, i will need to wash the middle bearing, is there a procedure for that?

3. Worst case scenario, i will have to rebuild the crank and would like to learn how to do that. Are there step by step instructions and specs on how to do that?

4. Finally, since i will have case apart, what other things should i service or replace?

I tried to attach some pictures, but wasn't able to do so successfully, so here is a link to my google drive with some pictures:
https://drive.google.com/drive/folders/1mkdZ_8-2NstRJ-30wRdH0sbf32Rl5W0c?usp=sharing

Thanks All!

-Craig
 
Last edited:
cajones2 said:
Hello Everyone,

I was riding my 99 600SX this season and blew my middle piston. I think i got into some bad gas and too much isopropyl. Interestingly, the middle cylinder had a gray sludge material coating the head, spark plug, the transfer ports and in the crankcase for that middle cylinder. I am my cylinder in for repair since it was scored up pretty good and will replace the middle piston and all new rings across the top.

My concern is the gray sludge and am wondering if it is from the piston, the nikasil, or is it a crank bearing. Either way my next step is to split the case and examine the crank. My question is:

1. How do i inspect/test the crankshaft to ensure the bearings are good.

2. At the least, i will need to wash the middle bearing, is there a procedure for that?

3. Worst case scenario, i will have to rebuild the crank and would like to learn how to do that. Are there step by step instructions and specs on how to do that?

4. Finally, since i will have case apart, what other things should i service or replace?

I tried to attach some pictures, but wasn't able to do so successfully, so here is a link to my google drive with some pictures:
https://drive.google.com/drive/folders/1mkdZ_8-2NstRJ-30wRdH0sbf32Rl5W0c?usp=sharing

Thanks All!

-Craig
Click to expand...

You images need to be 1024x768 to attach them.
 
cajones2 said:
Hello Everyone,

I was riding my 99 600SX this season and blew my middle piston. I think i got into some bad gas and too much isopropyl. Interestingly, the middle cylinder had a gray sludge material coating the head, spark plug, the transfer ports and in the crankcase for that middle cylinder. I am my cylinder in for repair since it was scored up pretty good and will replace the middle piston and all new rings across the top.

My concern is the gray sludge and am wondering if it is from the piston, the nikasil, or is it a crank bearing. Either way my next step is to split the case and examine the crank. My question is:

1. How do i inspect/test the crankshaft to ensure the bearings are good.

2. At the least, i will need to wash the middle bearing, is there a procedure for that?

3. Worst case scenario, i will have to rebuild the crank and would like to learn how to do that. Are there step by step instructions and specs on how to do that?

4. Finally, since i will have case apart, what other things should i service or replace?

I tried to attach some pictures, but wasn't able to do so successfully, so here is a link to my google drive with some pictures:
https://drive.google.com/drive/folders/1mkdZ_8-2NstRJ-30wRdH0sbf32Rl5W0c?usp=sharing

Thanks All!

-Craig
Click to expand...

After looking at your images I would just clean it out really good and make sure the carbs are clean and put it back together for new parts. You would do rings on all 3 and all new gaskets. Be sure to take a good look at the connecting rod bearings.
 
Thanks a lot for the information! I will plan on doing that. Do you have any suggestions on how to wash out the crank bearing...i suspect some of the gray got inside the crank bearing.

Thanks again!
 
cajones2 said:
Thanks a lot for the information! I will plan on doing that. Do you have any suggestions on how to wash out the crank bearing...i suspect some of the gray got inside the crank bearing.

Thanks again!
Click to expand...

Also since your down there, if u split the cases I'd at least replace the crank seals and rebuild my water pump. Cheap and easy to do just be careful with the mechanical seal on the pump. It can be a bastard.
 
I was my cranks with break clean and carb clean then compressed air. Just go easy with the air. And do spin the shizz out of the bearings with the air gun lol I also heard diesel fuel works good. Then luber it up super good, I used a little squirt can to get right into the bearings
 
Thanks again! I am still waiting for my repaired cylinder to come back from US Chrome via Hauck. Hopefully it is this week. Before i ask for instructions, i will check the documentation for splitting and reassembly of the cases. ;)
 
If that was mine I'd split it. It isn't a burndown. Some sort of foreign material has caused this damage imo, which could be from a bearing going bad. Is the wrist pin bearing in good condition?
Also, be sure to put a new seal-washer under the impeller bolt as these are known to cause leaks eventually.
 
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