Srx 780

Shafner79

Shafner79

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Joined
Dec 27, 2008
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316
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45
Location
Etters, PA --- Ride in Potter/LH
Just picked up a 99 SRX 700 cheap. Needs the center cylinder and pistons. Haven't dug into it yet, but I will be trying to diagnose the burn-down.

He told me that the motor is not stock, it has 52mm pistons and is 200hp??? My 98 is bad fast with only 140, but 200hp? Really? He didn't say it was a 780, so how can I visually tell if it is? I have really not even looked at the thing, besides loading it on my trailer in the dark tonight with a flashlight. But for the price, I wanted this thing in my possession a.s.a.p.. It has stock pipes, cold air kit, brand new track, skid is all re-done/serviced, was kept inside, and came with a ton of parts and a cover!

I'll look at it during the day tomorrow, and see what i find.
 
well I hope it isnt 52mm pistons or its a pretty small engine, as stock is 69mm bore for 700 and a 780 is 73mm.

I can guarantee its not 200hp, thats a bunch of smoke...lol

take off a head, if it is a big bore it will have wiseco pistons in it.
 
I knew it wasn't 200hp, just wondered where he came up with it. He also said it was the fastest sled in NY at line time....but it looks pretty stock to me.
Guess he was just hyping it up. Heads are off already. I'll be checking those pistons soon. But it's cooooolllllldddddd out this morning!!

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its not a big bore either.....stock 700

if you got it cheap its no big deal but the guy was full of BS!!
 
that sled came from n.y. ? no wonder you got bull shited. 200 hp LMFAO. and thats no burn down, thats either a ring broke or a wrist pin bearing let go. 3:16 (yammie tony)
 
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I would have to disagree, it is a burndown with the typical front crown being burned back off the piston. When this happens it exposes the ring to the flame front , turns it orange and soft and parts come off it and trash the cylinder. In your center cylinder pic I outlined it with red paint, the yellow paint shows the loose debris thats mashed into the head and piston top, parts of the ring are missing as well.

In your mag side cylinder the piston crown looks to be rounded off as well.

too lean of jetting, lousy fuel octane, dirty carbs are all the things that lead to the problem.

98-99 srx sled the bigger main jet goes into the mag cylinder.

next step would be to take off the carbs and see what jetting is in them. They are going to need cleaned anyways.

Does the sled have a cold air kit or anything else on it, like gutted airbox, etc. make notes of all that as it effects the jetting required.

One thing Tony hit on is I would replace the wristpin bearing in the center cylinder for sure as once the piston is subjected to that kind of detonation and damage the bearing takes a good beating.
 

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ya don thats what i get for not getting my glasses lol. saw all those gouges. no doubt melted so bad ring blew apart. 3:16 (yammie tony)
 
I did get it cheap, and I haven't torn into it yet, so I haven't seen the carbs to see if they were cleaned or to see what jets are in it.
I don't believe they were cleaned because he told me that he has never touched the carbs on his other sleds.
it does have a cold air kit. Not sure if box is gutted, haven't checked. I originally thought lean condition first, because of the exhaust side damage to the pistons.


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Did you drain the coolant? Complete absence of anti-freeze, doesn't even look like it was wet recently. Maynot have anything to do with burn down but where did it go and why?
 
The previous owner planned to rebuild it and originally removed the heads and drained the coolant. That middle cylinder is just sitting there.

I think I might part out my 98 and swap motors. Anyone think that's a bad idea? Never pulled a motor, but it shouldn't be that hard. I know my way around srx's a bit. Rebuilt my 98 about 3 years ago.

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I would pressure test the cooling system prior to making that decision. Leaky front exchanger found after you put the work into swapping everything over would be a PITA. Everything else is easy peasy.
 
You may want to finish tearing down that engine after you pull it out and give that crankshaft a good going over. The engine bay looks like it was exposed to the elements and/or not stored properly as there is a lot of white corrosion on the clutches and the piston ring pieces are all rusty, among other things. Also the coolant in the case isn't helping the crank. Check the bearings over closely, visual and by moving/spinning them, for rust and roughness/noise. If the crank is still ok, oil it down good and store out of dirt & humidity, even back in the cases after they are cleaned out. Might as well try to preserve whatever good parts are left.
 
total mess. like mr viper posted earlier. ring grove destroyed from heat and away we go. this motor should be totally take,in apart. 3:16 (yammie tony)
 
Devilin AblueDress! said:
Good looking sled overall, don't know what you paid but those ohlins front shocks are worth a buck or two! Whats in the rear?
Click to expand...

Got it chhhheeeaaapppp! I think I'm going to completely tear the motor down, and put my 98 motor in it. The 99 is in better shape than my 98 and the skid has been completely re-done along with a new track and studs. It was kept in a barn, and it definitely needs gone over. Saw some mouse evidence, which means possible wiring issues.

Going to start tearing into it tomorrow morning. It is a good looking sled and has potential. I got extra shocks, clutches, skags, radius rods, a trailing arm, springs, chain case cover, sled cover and a bunch of other things with it. Also came with new foot pads, and a complete gasket kit.
 
bADa$$ SRX said:
silver trailing arms on a 99?
Click to expand...

No decals suggest aftermarket or re-painted. 01-02 Silver is dimensionally identical to Blue 98-00. Blue pans/tunnel could be 99 or 00, single bulb narrows it down to 99.

How bad is the mouse damage? Especially the wiring harness. That's the only major difference in the two engine bay wise due to servo behind carbs on 98s and and left side of cowling on 99.
 
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