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'03 GasGas 400FSE Need Help!

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Recently purchased an '03 GasGas 400FSE. Bike tested ok, ran strong, and pulled hard. As this was my first experience with GasGas I'd say from perfomance they are a force to be reckoned with. Parts though is another story. It recently blew a head gasket and suffered a major meltdown. Took it to the local GasGas dealer who said it needed a top and bottom rebuild and ballparked at $2,200 and said he figured high since he's never rebuilt a GasGas before. Needless to say we were both in shock when the estimate came in at $4,200 with nearly $3,500 of that in parts alone and him salvaging as much as possible. Needless to say I didn't even pay that much for the bike. So now I'm in dire need of a motor, advice, someone interested in a street legal thumper that needs a rebuild or a big rock to smash my head against.

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Recently purchased an '03 GasGas 400FSE. Bike tested ok, ran strong, and pulled hard. As this was my first experience with GasGas I'd say from perfomance they are a force to be reckoned with. Parts though is another story. It recently blew a head gasket and suffered a major meltdown. Took it to the local GasGas dealer who said it needed a top and bottom rebuild and ballparked at $2,200 and said he figured high since he's never rebuilt a GasGas before. Needless to say we were both in shock when the estimate came in at $4,200 with nearly $3,500 of that in parts alone and him salvaging as much as possible. Needless to say I didn't even pay that much for the bike. So now I'm in dire need of a motor, advice, someone interested in a street legal thumper that needs a rebuild or a big rock to smash my head against.

What Parts Do You Need? Why Did It Come Out So Exspensive???

If Its Bearings Then I'd Look On The Net At Bearing Suppliers. VOR Listed A Cam Bearing At £35 Plus Tax,Found A Bearing Supplier Online That Sold The Same Bearing For £5.89 Inc Tax And P&P. Theres Only A Handfull Of Gaskets The You'd Need. I've Said This Before But The Motors Very Close To That Of A DR-Z,I Know This Because When I Had Mine In Bits I Was Using A Mates Garage As I Had No Where Else To Do It,He Was Changing His Clutch,Cam Chain Tensioner And Valve Lash,Nothing Was Interchangerable But Its Was Ssooo Close.

Unless You've Rubber Ducked Your Head/Cams/Barrel/Crank Then I Cant See It Being That Sort Of Money!

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Yep, head, barrel, valves, crank. Complete top end rebuild clutch plates, fuel pump, and on and on. Thanks all for the good tips, gradually making progress.

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With all the parts your listing, i could probably sell you a new 05 FSE450 for not much more $$

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That Engine Isnt Rocket Science To Do. Like I Said,Its No More Complicated Than A DR-Z.

I Would Be Inclined To Do Most Of It Myself. You Can Get WS Manuals Online From Gasgas,Just Follow The Instructions.

The Only Thing That You'd Need To Take To The Machine Shops Are Rebuilding/Balancing The Crank And Maybe My Valve Guides And Seats And To The Dealer To Set Up The Mapping/Fueling

What Does It Need All This Stuff???.

This Sounds Very Fishy To Me,I Should Know I've Dealt With Dealers Who Didnt Want To Sort My Bike Out.

Mechanically Speaking The Engines A P.O.P To Work On,Just Getting To It Xan Be A Pain With All The Different Size Fastners.

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Why does a fuel pump need to be replaced because the head gasket blew? Something's fishy here.

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I don't think the fuel pump is related to the head gasket problem. Just prior to the head gasket the bike had been dying when coming to an abrupt stop. Not sure if they determined the problem or were just hoping to solve the problem by replacing the fuel pump. Seems to be the pattern...it looks like it was easier for them to replace everything than to sort out what was actually wrong. Needless to say, it's no longer in their shop and is in pieces in my garage until I can figure out what parts I really need.

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I don't think the fuel pump is related to the head gasket problem. Just prior to the head gasket the bike had been dying when coming to an abrupt stop. Not sure if they determined the problem or were just hoping to solve the problem by replacing the fuel pump. Seems to be the pattern...it looks like it was easier for them to replace everything than to sort out what was actually wrong. Needless to say, it's no longer in their shop and is in pieces in my garage until I can figure out what parts I really need.

Thats How Mine Was,The Valve Clearances On Mine Were Way Out,Had Broken Wire Just After Startor Plug And A Duff TB.

First Get A Good Straight Edge,Somethings Thats Wide And Has A Very Flat Edge,Like A Pane Of Glass,Lye That On The Face Of The Head And Look Across The Mating Face Of The Head In Various Places,If You See Light Beween The Head Face And Straight Edge Get A Feeler Guage And Find Out What The Distortion Is,This Will Determin If You Need A Skim Or New Head. Look For Signs Of Discolouration On Head Face,Particually Around The Water Ways,If All Looks The Same Then Its Likely That Its A Good Head And Not Porious.

Do The Same With The Barrel,Look A The Bore,Heavy Scratches And A Very Shiney Bore Will Require Bore/Plating And Over Sized Piston.

Best Go Get A Manual From The Web For The Bike And Follow What It Says. These Are Easy To Work On.

Crank Bearings I'd Check What The Manual Says But That I Would Send Out To A Specialist.

I'd Replace The Cam Chain/Sprockets And Tensioner Along With The New Exhaust Cam,Which I Think Is Of A 450. Its Said To Help Starting And Gives A Stronger Power Band.

Replace Valve Stem Seals And Shim Up As Required.

A LTR Alloy Water Pump Impellor Would Be A Good Move At This Stage,Think They Made Them For The 4T.

New Coolant Sensor Is Another Good Idea.

Check The Throttle Body Very Closely,Make Sure Its Not Worn.

Thats About It Cant Think Of Anything Else.

If I've Missed Anything Or Got It Wrong Somebody Will Tell You So

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After taking the bike from the local dealer I did some tinkering in the garage with a straight edge. Couldn't see what the problem was with the top end since things appeared to be within spec. Piston and sleeve were a little scarred but nothing too serious so I took it to another mechanic. He's got it all apart and said that everything is within spec and the only things that I need are a new piston, rings, and a gasket kit. The sleeve isn't bad but will need some bore plating. Unfortunately, we are caught in the transition period where GasGas isn't taking or shipping orders yet so we are unable to do anything until we can get a piston in. Thanks again for the help. It will be interesting to see just how far off the Dealer's estimate was since a good portion of the parts order wasn't justified.

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