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I have a 2007 kfx 700 and I want to do the 730 big bore to it. What do I need to be able to do so?
 

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I'm getting ready to install a 84mm big bore kit on an '05 KFX. It has a blown, rear head gasket and melted rings on the front cylinder. Honing is not an option for repair and the rust / pitting in the rear cylinder is bad enough that I'm just going to have it bored out and use an oversized piston.

I'd highly recommend a complete 2004 - 2009 repair manual. Physical copies are about $100 if you can find them on eBay or used book sites. Digital, PDF copies can be had for around $15 on sites like tradebit.com. I'm pro, "right to repair" so if the dealers / manufactures are no longer offering printed manuals for sale (Kawasaki no longer offers them on the owner's website) then I have no qualms about buying a PDF version.

You'll need to do top-end tear down, so be prepared with the proper tools, some plastic bags, and marker for "bagging and tagging" everything. Trust me, you don't want to skip doing that or it will be a nightmare trying to determine the proper home for all the fasteners when you get ready to re-assemble. You've got the rocker box covers, rocker box, and cylinder heads to remove. It only takes about an hour per cylinder if you follow the procedure in the manual. Clean and detail at least the top portion of the engine before starting; you don't want dirt and debris falling down into the engine case and getting into your crank bearings.

Pulling the rocker box will allow you a chance to inspect the cams, valves, and springs for wear. You can pickup a cheap set of digital veiner calipers on-line or at the local auto parts store for checking components against the factory service limits.

There's really no spec in the repair guide for the timing chains. However, when you remove the auto-tensioners, if you take it out in as one unit (don't remove the center bolt, just the outer mounting bolts) you'll be able to see how far the tensioner has moved since it was last installed. If it's nearly halfway out, it might be time for new chains. One for each cylinder of course, along with a intermediate chain for running the oil and water pump. All three should be replaced at the same time. About $100 for all those from HotCams or another vendor.

Also, while you have the cylinders off, you can easily check the rod (big-end) to rod web clearance through the rear case opening using a feeler gauge. It'll at least give you some idea of how close it is to the service limits. Don't forget to stuff some clean rags around those case openings. You drop one bolt in there and you'll be splitting the cases if you can't fish it out with a magnet! Also, as mentioned before, dirt particles are a no-no down in the case. Your oil screen and oil filter will eventually pick it up, but most likely not until after it's found it's way into a main bearing.

You'll need to find a reputable machine shop / engine builder near you. Take in the cylinders and the piston kit in so they can spec everything out and do it right. If you need valve work, now is the time to do it. Check the for valve wobble to see how worn the valve guides are. Kibblewhite offers new valve guide sets for about $100. The shop should be able to press out the old ones and install a new set for you. If you valves are burned up or you just want to replace them as insurance, you can get a set of stainless steel Bronco valves for about $130 (original size.)

If you're inclined to do so, you can get a small valve spring compressor, remove the springs, and check the spring height against the OEM specs. That's another part worth considering to replace while you have it torn down.

If you cams are ok, you can run with the stock set. If you want stage 1 or higher, now would be a good time to do it while it's torn down. If not, it's not to difficult to get the rocker box covers off and install new cams down the road.

The PK1823 kit from Wiseco will get you to 732cc. The kit retails for $500, but many eBay sellers have them on sale right now for about $375.

The complete job can get pricey real quick; just depends on what you're needing / willing to replace while it's opened up and how much the machine shop charges for their work. Looking on-line, most shops charge $75 to $100 per cylinder. I'm not sure about valve work. I'm about to find out, so I'll try and post an update of what I spent total, out the door.
 

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Just a couple of quick notes. You'll want the following tools on hand. This is just from my tear-down experience so far:

  • Piston pin puller (Something like Motion Pro 08-0472)
    • May not be needed if you're pulling aftermarket pistons out, but the original piston pins are in there pretty good. Not press fit, but enough that you'll want a puller so you're not banging into the piston and putting pressure across the small end of the piston rod. Break a piston rod and you'll be splitting the cases!
  • Primary clutch puller (Tusk KK704-091796330002)
    • Need to remove the primary converter if you want to replace the cam timing chains
  • Valve spring compressor if you're inspecting the spring height
  • Magneto Rotor 35mm x 1.5mm Flywheel Puller (Same that's used for Yamaha Warriors) -
    • Be very careful with this tool; you can easily mushroom out the end of the crank with to much force on it. Maybe it's the tool I ordered, but the bolt on the puller is just small enough to slide into the opening on the crankshaft and it really shouldn't. I'm sure the OEM Kawasaki puller would be best, but difficult to find and way expensive (like $180.) If I have to pull the flywheel again, I'm getting this one. It's a much better design than the generic ones for the Yamaha quads:
Flywheel Puller 35mm x 1.5 RH Male for Honda Suzuki ATV Suzuki Kawasaki Motorcycles 1978-2007
 
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