400 swap

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mopar

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the big bear shares the same top end as the warrior, now i noticed the older 400 kodiac engines are a 400 air cooled engine and the cylinder and cylinder head look the same as the 350
i looked at the part numbers on yamaha site and the crank and all top end parts were the same part number, except the timming chain, is this a parts book mistake or is the 400 actually a 350?
 
I've thought of this myself.My cousin has a 2000 Big Bear and the cylynder and head all look the same from the outside. I looked at the specs on Yamaha's web site and according to them the stroke is different but the bore is the same.83mm x 64.5mm for the Warrior. 71.5mm for the stroke on the Big Bear. This is for 2002 models. THey say the Big Bear is 386cc as well, but it is common for manufactures to round up for thier madel names. I don't think they're the same part because the Warrior's crank assembly is almost 200 dollars more than the Big Bear on Alba OEM part finder.
 
Base and head gasket are exact same parts so top end should bolt on but if its the same bore thats not gonna do anything for you. Cam and most of the other parts in the head are exact same also, I would bet the head is actually the same with a different part number.(alot of companies will use different part numbers for the same part so they can charge more for different model vehicles) Cam chain is the same only 2 links longer so either the cylinder is a few mm longer or the or the crank sits further down in the cases.

I really don't think the 36cc's gained would give you a noticeable hp increase to justify the cost. But if you could get the parts really cheap it would be interesting to give it a try.
 
Im not sure of the cost of this or if it would even work but add 36cc's and your gona notice a hella difference.
 
Im not sure of the cost of this or if it would even work but add 36cc's and your gona notice a hella difference.
its not gonna be a high compresion stroker like the aftermarket stroker kits. since it would be the stock low compression with a longer stroke you feel more low end torque but the engine would rev slower than a stock warrior. yes its a 10% increase in displacement but I doubt it would give you a 10% increase in hp.
 
cant you get high compression pistons for the 400 like the wiseco i have in my 350?
 
Wiseco doesn't make one for the 400, if they don't I doubt anyone else does.
 
The bore I think on the bigbear is the same as the warrior, just a longer rod I think, with a lower compression hight piston, I think even the crank stroke is the same? I'll have to dig in.
 
Alright I found it here it is. It has a 7 mm longer stroke, I'm not sure if the piston is exactly the same. If it is then the Big Bear has some sort of cylinder spacer, which would constitute the lower compression.


Engine 400 Big Bear
Type 386cc, 4-Stroke Single, Air/Oil Cooler w/ Fan, SOHC
Bore x Stroke 83mm x 71.5mm
Compression Ratio 8.6:1
Carburetion Mikuni 33mm BSR
Ignition DC - CDI
Starting System Electric w/ Auxiliary Pull
Transmission 5-Speed Automatic Clutch w/ Reverse
Engine Braking Front & Rear Wheel

Engine Warrior 350
Type 348cc air-cooled, SOHC 4-Stroke Single
Bore x Stroke 83mm x 64.5mm
Compression Ratio 9.2:1
Carburetion Mikuni 36mm BSR
Ignition DC - CDI
Starting System Electric
Transmission 6-Speed manual clutch w/reverse
 
I just checked riva racing, the #s for the piston and cylinder are different then the Warriors, The cylinder is about $100 more and the piston is $25 more, so I would guess their different.
 
Double check the base-gasket and head-gasket part#'s. Its pretty common to use thicker ones to change the deck/stack height.
 
I'm not understanding the part #s but the middle #s are the same, example Big Bear 5FU-11310-01-00 and the Warrior # is 1UY-11310-03-00, whats the deal with these part #s, I know the first 2 #s describe the model, the second is probly the actual part number, then after that Im lost. Both PNs are from a 2002 kodiak and warrior.
 
All this comparing, Hot Rods makes a 7 mm stroker crank and piston that bolt right in, for like $500, to $600, gaskets an all. The kodiak 450 uses the same style crank also, but has a 75mm stroke,
10.5mm longer.
 
You cant just go dropping cranks from diffrent machines into your motor..



Ohh yea it may drop in, but you are not figuring for your piston to head clearence.

A stock warrior piston will sit to high in the cylinder and hit the head... high compression would be even worse..

Maybe it wont hit but thats cutting it close..

In order to make this all work you are better off just buying the 400 stroker kit from hotrods. The piston and crank are matched to work together, if you do it the other way its going to be a guessing game, of what works and what doesnt.
 
I was wondering about the same issue. I got a old yamaha i think its a big bear. On the head it says 386cc and on my warrior it say 348cc. Could i use the crank and rod out of the yamaha that i have that say 386cc in my warrior
 
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