Hey esonnen, let me know how the big bore kit works out. BTW who is doing your ports?

 

Thundercat11- I got the big bore and cam in about a week ago. WOW!!!! This thing is like a whole new bike! I want to run it against a 400 just to see how it does. It is very peppy now. Before I had a hard time getting the front in up, but now it will come right up (this is without popping the auto-clutch and in second gear) I put 20" tires on the back and it handles so much better (thanks to Gregs advice from CWR) I am not getting it ported. Maybe some day but for now I am happy with this thing. I just put on a 14 T front sprocket but I havent tried it out yet. With all the stuff it just wrapped up too quick and it seemed capable of a lot more top end. It pulls very hard through all gears. BRAG BRAG BRAG. Money well spent and still cheaper than a new ATV. Did you port yours at a different time than putting in your big bore kit? If so, did it make a big difference and about how much did it cost to do it? Do you have any other significant mods?

 

To give you the whole story I got my Lakota for free. Was looking at an Acat 400 when my father in law said that I could have his lakota. The machine was a wreck, it had been stolen, run without oil (knocked out rod bearing) and then recovered by the law in pieces. When he gave it to me I pulled it down and sent the crank, to greg along with all of the other pieces he needed to make the big bore kit. In the meantime I discussed some things with greg re: porting and did the valves and porting myself (I have a head shop setup). When I put it back together It had the BBK, stock cam and a DG RCM exhaust. I had to do a lot of tuning with the jetting and actually had to go richer than what greg recomended (possibly due to the ports). When I put the bike back together I went against greg's advice on the tires. He wanted me to go smaller, I wanted to go bigger because some of the areas I ride in are very rough and I need all of the ground clearance at the sprocket I can get. It's a little tippy and hooks up the rear very hard under power but I like it. Because of the 24" tires I was able to keep the stock gearing and If I did the math right your final drive with the 14T driver and 20 inch tires is still lower than mine (better acc. less top end).

No lie I could start from a dead stop at idle in THIRD gear, (no playing with the clutch or anything) sit on the seat in a normal riding position, punch it and the fronts would lift about a half foot off the ground and carry for a good 10 feet. However it would run out on the top end a little sooner than I wanted.

Having said all of that The RCM was too loud for where I was riding and had no spark arrester. I put A Supertrapp IDS2 on it and rejetted. It no longer pulls as hard from a dead stop but it did pull more on the top end. Still I can pull the fronts from a dead stop in second and have more top end. Over the winter I had Greg grind my cam to .390 and that livened it up even more. I've outrun 200 cc 2 stroke bikes (not sure how good the riders were but it was pretty smoth terrain) and a couple of blasters. Not saying it's the fastest thing out there but I like it---a lot. Oh yeah I lost the stock air box in favor of a K&N with an outerwears. Not sure if that helps or not but I was too lazy to keep messing with the airbox and kinda figured I'd be doing a lot of jet changes. So deep water is out of the question for me.

 

thundercat11-That is awesome that you got your kota for free! I am not sure how much of a difference the 14 T will make or even if it will let the lakota reach its potential. who knows, I may be ordering a 15T sprocket soon. What size of jet are you running on yours? I have a direct to carburator clamp on filter and I just put on a 138. I am running race fuel and the 135 I had on it seemed a little lean. I havent even touched the pilot jet, starter jet or raised/lowered my needle (I have a dyna jet kit on it) I know that the all out rev up a hill then killing the engine and checking the plug will tell you if you have the right size of main jet, but is there a good way to check the other settings? I am curious what you came up with, also what is your altitude? I am 900 to 1000 ft. Have you put your bike up against a stock 400 sport atv? I think I will have a chance in the next couple of weeks. Your bike sounds like a beast. Do you have any pictures of it or you in action on it? I need to get some of me on my machine and post them on my profile here.

 

I'm running a 142 Main jet. I run Amoco Super 93 fuel with lucas octane boost(1/2 bottle to 5 gal). When I first started I ran 110 oct race fuel but the super with octane boost works just as well. Depending on where I ride alt is 700-1000 ft. I have the dynojet kit with the needle in the fourth groove down from the top. BTW what part of the country are you in. Im in NC

 

My friends 96 lakota has been running great since new, Its a quick light fun ATV.

 

esonnen-I see you have the 420 cam. Looks like the main dif in our engines is you have a higher revving cam and I have probably a little better port setup. I did the math your 14 T driver with a 42 tooth rear would just about match the final drive i have. Since you have a little higher revving cam you ought to be good. Oh yeah I played around with my supertrapp and jets and I have all 18 discs in it.
Cant say I've raced any stock 400's hard but have ridden a few and if they have anything on mine it's not enough to notice. When i get back to PA where I have a long smooth 1/2 mile stretch to run I's like to put the GPS on it and see how fast I'm really going wound out in 5th. Where I'm at here I rarely get out of third, of course wound out in third now is basically what wound out in fourth was when the machine was stock.

 

91Warrior357- did you ever decide if you are going to get the lakota? Thundercat-I am going to try to see what this thing will do this weekend as far as the top end goes. The hard part is to keep the eyes on the road and not on the MPH on the GPS. Grin... I dont remember if I have 12 or 18 disks with my supertrapp- I put that in about 3 years ago and havent touched the silencer since. I put all of them that came with it. How long does it take to do the porting? Did you just smooth it out or did you actually enlarge the ports and valves? I am in north - eastern ND and there aren't really many cool places to go riding so I am going to start looking at taking the trails in Minnesota. If I ever head east I will contact you up and maybe we can do some riding. Thanks for the info on the jets - I need to spend some time playing around with mine.

 

The porting was fairly easy. The intake side of that head is pretty good basically I just gave it a good 3 angle valve seat and refaced the valve--you don't do anything to the valves basically. On the exhaust side I removed a considerable amount of material in the "bowl area" directly underneath the valve. I used a valve seat cutter and about an 80 degree cutter if I remember. I also opened up the radius a little by hand. Then I gave it a good 3 angle valve job refaced the valve and back together it went. I'll tell you more specifics if you decide you want to do it and if I can find my notes, but I'm guessing you'll probably want to ride it for a while before you tear it apart. Give them 400's hell. BTW how fast are you going on that thing?

 

I am hoping to find out tomorrow maybe how fast it goes- we will see what garmin has to say. I dont have the tools or the knowledge to do porting but it is good info if I take it in somewhere. I am not planning on tearing it down for a while. If (when) I go to get it ported, about how much should I expect to pay? Can shops that do porting on cars typically do it on small engines as well? You seem to have a wealth of info on engines. Thanks for all the info.