# one question before I big bore



## RYAN.

I got my big bore (450 FST) almost lined up one concern before I pull the trigger.

my engine is oil cooled so I'm a little concerned with cooling I have my oil cooler racked so it doesn't get nasty and in return I get more airflow to my cylinder I plan on running Lucas in it because im a firm believer in all Lucas products. anybody have any input


2006 ARCTIC CAT 400FIS
29.5 SKINNYS
JUG GOING OFF FOR BB SOON
NO LIFT SOON TO BE 2.5 
15" GROUND CLEARANCE 
LOW REVERSE MOD 
EXHAUST MOD WITH SWAMP PIPE
SNORKED AND RACKED


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## redneckrancher420

Maybe putting a small fan in front of the motor? Wired up to the batter and a switch.


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## RYAN.

well I dont have the kit yet I was just wondering if anybody has had heat problems with a big bored a oil cooled engine


2006 ARCTIC CAT 400FIS
29.5 SKINNYS
JUG GOING OFF FOR BB SOON
NO LIFT SOON TO BE 2.5 
15" GROUND CLEARANCE 
LOW REVERSE MOD 
EXHAUST MOD WITH SWAMP PIPE
SNORKED AND RACKED


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## JPs300

Buddy of mine had the FCP kit in his 400 suzuki eiger(same motor). No heating issues, but it ate up the one-way bearing for the starter drive a few times and the resulting starter kick-back destroyed the starter, the drive gears, and the side cover twice, the second time it also took out the engine case.

The zuki starter drive system is a bit under designed for the stock engine, added the big bore & big compression and it can cause some grief.


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## RYAN.

JPs300 said:


> Buddy of mine had the FCP kit in his 400 suzuki eiger(same motor). No heating issues, but it ate up the one-way bearing for the starter drive a few times and the resulting starter kick-back destroyed the starter, the drive gears, and the side cover twice, the second time it also took out the engine case.
> 
> The zuki starter drive system is a bit under designed for the stock engine, added the big bore & big compression and it can cause some grief.


I have heard aftermarket cams caused this never the BBK its self


2006 ARCTIC CAT 400FIS
29.5 SKINNYS
JUG GOING OFF FOR BB SOON
NO LIFT SOON TO BE 2.5 
15" GROUND CLEARANCE 
LOW REVERSE MOD 
EXHAUST MOD WITH SWAMP PIPE
SNORKED AND RACKED


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## RYAN.

also I wanted the fcp kit bc he is kind of local an I could just take him the bike but he never called me back after a couple of messages


2006 ARCTIC CAT 400FIS
29.5 SKINNYS
JUG GOING OFF FOR BB SOON
NO LIFT SOON TO BE 2.5 
15" GROUND CLEARANCE 
LOW REVERSE MOD 
EXHAUST MOD WITH SWAMP PIPE
SNORKED AND RACKED


----------



## JPs300

The cam was the initial cause due to being advanced something like 10* due to Web grinding it wrong. We modified a cam gear and set the IC correctly and it helped a ton, but still wasn't enough as it eventually hurt the one-way again and started kicking back again. - Put a stock cam back in, still had some shut-down kick back and eventually ripped a couple teeth off the starter(but didn't hurt anything else that time). Pulled the entire BBK set-up, put the stock stuff back in and sold it, bike has been perfectly fine since.


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## RYAN.

maybe FST kit doesn't have quite as much compression as my whole build was around this bbk


2006 ARCTIC CAT 400FIS
29.5 SKINNYS
JUG GOING OFF FOR BB SOON
NO LIFT SOON TO BE 2.5 
15" GROUND CLEARANCE 
LOW REVERSE MOD 
EXHAUST MOD WITH SWAMP PIPE
SNORKED AND RACKED


----------



## RYAN.

or use the pull cord lol


2006 ARCTIC CAT 400FIS
29.5 SKINNYS
JUG GOING OFF FOR BB SOON
NO LIFT SOON TO BE 2.5 
15" GROUND CLEARANCE 
LOW REVERSE MOD 
EXHAUST MOD WITH SWAMP PIPE
SNORKED AND RACKED


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## Roboquad

run some engine Ice if you have heat concerns. it pays for itself in the long run.


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## RYAN.

its oil cooled not water


2006 ARCTIC CAT 400FIS
29.5 SKINNYS
JUG GOING OFF FOR BB SOON
NO LIFT SOON TO BE 2.5 
15" GROUND CLEARANCE 
LOW REVERSE MOD 
EXHAUST MOD WITH SWAMP PIPE
SNORKED AND RACKED


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## RYAN.

I suppose I could get a waterproof inline blower to help on the slow trails


2006 ARCTIC CAT 400FIS
29.5 SKINNYS
JUG GOING OFF FOR BB SOON
NO LIFT SOON TO BE 2.5 
15" GROUND CLEARANCE 
LOW REVERSE MOD 
EXHAUST MOD WITH SWAMP PIPE
SNORKED AND RACKED


----------



## JPs300

I really don't think you'll have any heat related issues. My bud never did, and we're in SW Florida riding year round(100+ degree summer days). 

Compression will help some, but honestly I don't think it will be enough either. The starting system on those motors is under-engineered factory; people have had problems with it on stock motors. - If you can deal with cranking it from the pull cord it definitely makes a very notable power increase. 

There is a clutch pack starter drive gear used in the AC bear cats from the late 90's/early 00's that the 500+ cc bikes have used to negate the starter kick-back issues, but the pieces to get it swapped in are a few hundred $ and I haven't been able to confirm if they will fit the 376 motor. - Kinda of expensive just hoping for the best as a test dummy.


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## greenkitty7

i wonder if anyone has tried to do the starter gear mod from the 454 bearcat in the 400? ive seen it done in the 650s and it almost completely eliminates the kickback...


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## JPs300

^ thats what we looked into on my bud's bike. It's been done to the 650's and 500's, but the 400 is a different engine and I haven't been able to confirm if it would work. - Not an overly cheap list of parts to "test dummy".


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## greenkitty7

I would think if it works in the 500 that it would work in the 400. Both are very similar engines and also have a good deal of parts that transfer.


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## RYAN.

what if I tapped in a compression relief into my head?

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## JPs300

They already have a compression release, it's built into the cam. - Does the same function as a lever type one; cracks the exhaust valve open slightly on the bottom side of the lobe.


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