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My 2004 LTZ400 was stolen 14 years ago and was recovered a week ago. (I was 22 and now I'm 36) crazy right? I received the quad with the motor out. It only came with the bottom end, no cylinder or head or piston. Im assuming they pulled this out because it was seized up? This bike was missing for so long and to finally get it back I feel like I just owe it to myself to get it running again. Plus I have a family now and would like to get them all into riding. So my questions are, how would you approach this? The bottom end of the motor (crank case) is completely out of the frame. Do I go for upgrades or just slap all stock parts back on? Cams? Drz base gasket? Should I buy a manual? I was hoping I could get an idea where to start with this project. The bike does still have a Dyna FS and a yfz 39mm fcr keihin carburator. Oh yeah, no exhaust either. Can you guys help me out?
 

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Well I thought I'd get more responses that. I think I'm going to keep it simple and maybe just install a drz gasket and upgrade the cams. Do I buy a after market cylinder/head? Or should I just keep it factory? What cams should I buy?
 

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I guess it really depends on what you want it to do. If the crank is bad, no better time than to put a stroker in it.Same price as aftermarket. That would give you more compression with the stock base gasket. You will lose some bottom end with cams, does that matter? If you have to buy new cams, aftermarket is the way to go though. I don't think there is such a thing as an aftermarket head. Piston and barrel kit is the way to go, just go to decide on big bore or stock, same price really.. I have some used NSHC, might let them go..If you do bump the compression, it will be high test only...
 

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I think its incredible that this was even found, truly amazing! How did it end up getting found?

I also agree that you should get that bottom end checked out. Since your top end is gone I would go with a cylinder kit and go big bore. They are some good kits out there that I hear are pretty reliable. And since you are missing an exhaust its a perfect opportunity for a full system!
 

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How much are we talking if I were to go big bore? I thought I'd keep it simple with a thinner base gasket and sone upgrades cams.
 

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Wow. Glad you got it back. First of all, you need to decide what you are going to do with the machine. Are you going to have younger ones/Wife ride it? Do you want to keep it tame for them? If so, I would look for some good used parts. You can get a lightly used cylinder and piston for very cheap. Stock exhaust is a dime a dozen. You can always upgrade it later.
If you are keeping this for yourself and getting other machines for the family, then build it right now. As said above, check the bottom end out and build off that. Maybe you can find a used mother with a cracked case. Use your case and the other top end.

Good luck
 

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What are your opinions on that Niche big bore kit? Is it off brand? Shold I spend more and buy cylinder works or something?
 

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I liked it. Comes with a cast piston. Some people like to upgrade to forged, and some kits are more expensive that include forged, among the cheaper kits.
 

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I liked it. Comes with a cast piston. Some people like to upgrade to forged, and some kits are more expensive that include forged, among the cheaper kits.
Hey thanks! Looks like I'll be buying that big bore kit. I bought a used head on eBay here https://m.ebay.com/itm/2003-SUZUKI-QUADSPORT-Z400-LTZ-400-ENGINE-TOP-END-CYLINDER-HEAD-CAMS-VALVES-GOOD-/292394265219?txnId=1521729365019

I guess im searching for knowledge at this point. Do I run this big bore kit with the factory cams? I was planning on buying the DRZe base gasket kit but being this big bore kit comes with gaskets, do I just use those? Do I need to buy upgraded cylinder head bolts? Do I need to upgrade the cam chain? Which one do I buy? Do I need a piston sleeve tool to install the piston into the cylinder? Will I need to pull off the right side crank case cover when installing the head? Got any other tips?
 

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Start off by going to rmatv and llok at some of the engine assembly vids. All motors are basically similar Then get a manual and follow the instructions.
Factory cams will work, but won't fill the cylinder like larger cams will. Bottom end will be strong, but will run out of breath at top end, IMO..

You have to use the big bore gaskets. Stock Cylinder bolts are fine.
I would not build a motor with an old cam chain. Stock or DiD are ok in my book, I think wisco has one as well.
Don't need a sleeve but it is awkward. some find it easier to put the c-clip in one side of the piston, insert piston past the rings in the cylinder, then put the pin in and the final clip, then finish lowering the cylinder. Other wise you will be talking in tongue trying to hold the cylinder steady while trying to coax the rings in without breaking them, especially alone.
When doing c-clips they can fly away for miles, I recommend doing this in a confined clean space. When working on top of the cylinder, plug all holes that parts can fall down in the motor with paper towel..same with the barrel off
Cover stays on for the cylinder change, but would come off for the cam chain.
You need an inch /lb torque wrench, as well as a ft/lb.
 

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Thank you very much, that should get me going at least for now. I'm sure I'll have more questions soon. Oh yeah, I have the crank case out right now. Can I just build everything on my bench and install everything all at once or should I put the crank case back in and install the cylinder+ head individualy? Also, if I do decide to upgrade the cams? Which ones did you buy? Do you have a part # and where to buy? I was reading about upgrading the valve springs to the DRZe springs, is this wise? Should I port and polish or get a valve job or replace the valves? Who would do this? Would I ship the head to someone or can I have any local machine shop do the valve job/ port polish? Or do I leave the head alone?
 

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I havent tried to install a complete motor, may someone could chime in. You could try a search for that as well.
Read this thread about cams. http://www.suzukicentral.com/forums/15-performance-parts/80764-cam-specs-all-major-aftermarket-brands.html
I have used NSCH and have OSHC equivalent 536 Webs in now. As you go up in duration, you trade low end for high end power, so it's really a choice.
Definitely upgrade the springs, they get tired, and the dual springs will handle more lift and rpm if you need it.
Personally, I wouldnt spend the money on porting. You will have a torquey motor when you are done. If you have to beat you'r buddy's then maybe.
IMO this is the time to do the valves as well. You will get new ones, aftermarket stainless, and have a machine shop cut the seats, for best results. You could probably get by with out cutting, just lapping them, but this way you are sure.
http://www.suzukicentral.com/forums/15-performance-parts/80764-cam-specs-all-major-aftermarket-brands.html
 
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