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4tec Exhaust Valves: A necessary Replacement?

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IDoSeaDoo

IDoSeaDoo

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If you just bought a 185hp supercharged ski with 200 hours, would you change out the hollow exhaust valves? I hear only bad things about them... particularly the phrase "Time Bomb" I'm going 4-stroke because I hated the exhaust valves on the 787's. I REALLY don't want to have any related issues (it's a sore subject now-a-days). So is replacing them really necessary? I've rebuild plenty of 4strokes and never heard of exhaust valves going bad before. Is it worth the $400? (including head gasket and bolts) Is this as likely a failure as those flimsy timing chains?
 
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I'm shocked that they lasted 200hrs to be honest. You're on borrower time in my opinion as far as the hollow valves go. Should you spend $400 to save a $3000 motor? You tell me. I'd do it in a heartbeat if I was in your place. Since you've rebuilt 4 strokes before then you know what a mess a timing chain failure can cause. That said I'd replace that too.

I'm curious what you mean about the 787 "exhaust valves"? The 787 is a 2 stroke and does not have valves (intake or exhaust). Do you mean RAVE valves?
 
I thought later motors received an engineering change to address this, not sure when it began, sometime in '03-04? A dropped valve will toast your engine before you can shut it down, could be none of the OEM valves are good as far as I know..
 
Yes, later ski's have updated valves.

And officially, you do not need to swap them out. However, when you weigh the cost of the MAJOR repair if one of the valves does fail compared to replacing them before a failure it is a bargain to swap them out.
 
And this problem was just with the exhaust valves? So far, I plan on rebuilding the supercharger, and getting a new, updated timing chain. Hearing this, I'll probably also get the exhaust valves too. Anything else I should know about?
 
Good point. Any way to tell? Are the exhaust valves the only ones affected by this malady? Are there any other things I should change while I"m at it? Any other weak points?
 
As I read this post it got me thinking and I thought it would be good to clarify...

I understand that the exhaust valve issues are mainly related to the supercharged engines, has anyone heard of issues with the N/A (155hp) engines? I had always thought that the lower compression of the N/A engines made them a somewhat immune to this syndrome and never came across posts describing valve failures in the N/A engines.
 
There is a way to tell but don't recall off hand. I will do some digging and see if i can find my notes...
 
the issue is mostly on the 215hp motors, the 185 is much less common and the 155 is even less common but still can happen if they are left to rust. it really depends on how it has been maintained and the conditions as well as a little luck. much more common in saltwater environment. I see 100 good ones that are still running fine for every 1 that dropped a valve on the 215s here in Ohio.

the timing chains problems are for the most part isolated to around the 08-11 years, seadoo changed something(probably a cheaper supplier) but I'm sure they would never admit to it.
 
My foggy understanding is the early (bad) valves have the number 72 or higher stamped on the end of the valve just above the keeper grooves, the late (good) valves are stamped 75 or greater.

I should say, we aren't a seadoo dealer and we don't service SD's aside from perhaps an odd-ball that might be traded in on occasion.
 
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Ski-doo...so the earlier motors (before 08) had better timing chains?

I highly appreciate this thread and the replies....this 4stroke stuff is all new to me.
 
Do the earlier 2003 valves have this issue? I seem to read in places that it only affects 2004 and up. It sounds more and more like something to leave alone, as it'll cost roughly $500 just in parts. What about the timing chains, is there a replacement interval? Should I even mess with it? At this point, I'm afraid to buy a weaker chain from the "Bad" period that someone's been shelving.
 
SPORTSTER is correct.

A bad valve will have a number that starts with 72

A good valve will have a number that starts with 75 :cheers:
 
So I guess I'll pop my valve cover and take a peek. Can those VC gaskets be reused? Also, what's the verdict on the timing chains, are the earlier years (2007 and earlier) good to keep? 200 hours on a 4 stroke engine is NOTHING in the auto-world, does any part of "If it ain't broke, don't fix it" apply to jet skies?
 
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Not really. Typically a 4tec if maintained properly can run 4-500 hrs. I've seen them as high as 6-700 but that's the exception. Safe to say yours is halfway through its life if it was maintained properly.
 
Last summer I saw a pair of 2005 supercharged RXPs with 550 and 475 hours that had never had the SCs rebuilt (according to the original owner) and were still running good. They were professionally maintained but not dealer maintained. These things looked like they had been through a hurricane, beat, cabin toys that the grandkids had free reign to use. The trailer was mint.

Here's the thread I started on it
http://www.seadooforum.com/showthread.php?66528-What-s-the-longest-you-ve-seen-an-engine-survive-without-the-supercharger-rebuild
 
If it ain't broke, don't fix it, doesn't really apply to seadoos, maintenance is a must. I occasionally see 4tecs that go 500 hours without any real maintenance but I see plenty more where the sc blew up at 200 hours because of lack of maintenance. the 4tec motors are very different than automotive engines. the 4tecs run at 8k rpms continuous, don't know of many car engines that are designed to do that other than super cars. the 4tec is much more similar to motorcycle engines but those as well don't have a huge life span when compared to cars that go thousands of hours at 2500 rpm.

the flywheel bolts are kind of similar to the timing chains but not as isolated, the early years seemed to be very reliable and something changed. not sure if it was the higher hp and rpms of the 215 in 04 or if seadoo changed suppliers but the 02 and 03s were pretty bullet proof.
 
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Ok so I'm looking at a 05 RXP with 150 hrs on it. So from reading this post the two main things that need to be done are the sc washers the valves and timing chain?
 
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