Super Jet Dangers of riding with leaking front crank seal?

[mcibmw533]

I did a leakdown test today and my front crank seal leaks like crazy! Goes from 8psi to zero in about 90 seconds. Did the soap bubbles test and bubbles form along the entire seal on the front. I'm thinking that if I'm going to do this work on the motor I might as well do some engine work and get some more hp out of it as well. My question is what type of damage is possible if I were to continue riding out the rest of the season (probably about 3 weekends) with the motor in its current state? I've never done this repair before, but I'm assuming I'll be half way to doing engine work by the time I replace this seal and the other two common seals to replace at this time as well, right? (If these questions seem stupid, please be patient, my level of knowledge on these engines is complete motor swaps and pipe installs - nothing in regards to internals.)

Also, this is a stock 701 out of a 2000 SJ with the only mod being a coffman exhaust (it performed great least weekend). I pulled the flywheel cover and flywheel to replace my bendix and was greeted by an abundance of sludge.

Thanks

 

[Cannibal]

Oh, well you need to get rid of that thing right now. I've got a crisp $100 bill for you and I'll be at your house to pick it up tomorrow :biggrin:

Seriously, you need to get that fixed. I toasted the front cyl on an engine because of a leaky front seal. It takes it too lean and can cause detonation, then you are looking at new pistons and a head (or a dome at least) at a minimum. You need to replace all 3 seals while you are in there. You have to split the cases to do it, so engine is coming completely apart. Get a gasket set, new wrist pin bearings and circlips. Might as well hone the cyl and install new rings while you are at it unless they are fresh. Most will recommend OE only on the above parts.

And come out to the Grayland Open this weekend. Going to be a blast!

 

[Tyler Zane]

my level of knowledge on these engines is complete motor swaps and pipe installs - nothing in regards to internals.

hey, if it helps there is a really good write up on how to assemble a 701. if your like me its easy to take things apart but a little directions is nice for putting them back together.:439:

here is the link; http://www.x-h2o.com/threads/68398-How-to-assemble-a-701-motor

 

[mcibmw533]

Thanks for the heads up, guess the ski is out of commission for the rest of the season. That link looks like it spells everything out pretty well, that will be very useful to not have a pile of extra parts when I'm done reassembling everything. Thanks for the shopping list, it's always easier to find the right parts when you know what to call them.

Yeah Grayland does look like it would be great (I've yet to see surf riding in person), unfortunately I'm tied up on the east side of the mountains for this coming weekend - perhaps next year.

Thanks again guys

 

[djkorn1]

Get it fixed asap! It should only take about 6 hours to rip it down and replace the seals and put in new gaskets....I wouldn't call it a season.

If you keep riding it, you could take out the cyllinder and the cases and that's big bucks...

 

[Dustin Mustangs]

Oh, well you need to get rid of that thing right now. I've got a crisp $100 bill for you and I'll be at your house to pick it up tomorrow :biggrin:

Seriously, you need to get that fixed. I toasted the front cyl on an engine because of a leaky front seal. It takes it too lean and can cause detonation, then you are looking at new pistons and a head (or a dome at least) at a minimum. You need to replace all 3 seals while you are in there. You have to split the cases to do it, so engine is coming completely apart. Get a gasket set, new wrist pin bearings and circlips. Might as well hone the cyl and install new rings while you are at it unless they are fresh. Most will recommend OE only on the above parts.

And come out to the Grayland Open this weekend. Going to be a blast!

Why new wrist pin bearings and circlips? If you've got good compression just stick new seals in there and call it a day.

 

[Cannibal]

Why new wrist pin bearings and circlips? If you've got good compression just stick new seals in there and call it a day.

I stick new ones in every time I take mine apart, cheap insurance. If he needs to get it on the water for cheap, new seals and gaskets is all he really needs. No need to hone the cyl and install new rings either, but if the engine has had a few years on it (as I suspect by the owner not having the engine apart before), then it would probably be a good time to freshen it up. Just my opinion.

 

[tor*p*do]

no worries, first the seal can blow taking out the stator like this:

while leaning out the cylinder and maybe cracking a piston like this:

 

[AdamOntario]

Since you are fairly familiar with taking complete engines out, take it out, flip it over and replace the seals without disassembling the top end. fairly quick process with removal of the engine being the longest step.

 

[Tyler Zane]

Since you are fairly familiar with taking complete engines out, take it out, flip it over and replace the seals without disassembling the top end. fairly quick process with removal of the engine being the longest step.

is that really the best way to do it? i understand its the fastest but most relaible... not so sure. most of the time taking shortcuts only creates more problems down the road. just saying if i was gonna go threw the hassel of taking the engine out and replace the seals i would do the base gasket as well as head gasket (if stock)... that way i knew it was all straight. just my 2cents

 

[AdamOntario]

is that really the best way to do it? i understand its the fastest but most relaible... not so sure. most of the time taking shortcuts only creates more problems down the road. just saying if i was gonna go threw the hassel of taking the engine out and replace the seals i would do the base gasket as well as head gasket (if stock)... that way i knew it was all straight. just my 2cents

He would be touching the base gasket. only re sealing the cases. I think this is a lot better than blowing the engine and gives him few more weekends, of course all this is assuming that the seals are the only things need of replacing.

Of course proper way is to do a full disassemble and check on ALL components but that would not stop at the base gasket either.

 

[smoofers]

Even if you are just going to replace the 3 crank seals (which I have done, it's not that bad) you MUST remember to take the FLYWHEEL and COUPLER off before you take the bottom half of the case off. Otherwise, you'll be real pissed when you gotta put it back together to remove the coupler so you can change the rear seals....