416 or 425

[Blackguywithouta400]

I’m trying to figure out what bore to go with on my 400; both of the bores are easy to do so, im tying to find out what people have and what they think.

So its 425 or 416 I don’t really care about he bores left in sleeve so mainly I guess my question is what would you do? And what compression I plan on running a 93 octane
Plus octane boost or 100 octane trick race fuel

This is the current setup
Xr400 Cam
Stock Carb
Dmc Alien
K&N no lid

[400exJOE]

i am putting in a 440 by the end of the month. What i can tell you is this. If you want to run pump gas, stay under 11:1 compression. I am going to run 10.8:1 and use 93 pump. I know the 416 is probably faster revving and the 425 probably has more low end. A 416 is boring the sleeve .080 over so you're safe with the stock sleeve. I know the 440 requires boring the actual cylinder and putting in a bigger sleeve. I don't know about the 425 boring situation. It seems to me a lot more 416s and 440s exist than 425s but I don't know why. Either should give you some real nice power! Good Luck:D

[Dave400ex]

What kind of riding do you do? I would get the 416 or 440 for MX racing. For XC I would get the 425 kit. I`m going to get the TC racing 425 because I want to race XC. It kind of depends on what kind of riding you do.

[Blackguywithouta400]

My goal is to have my quad setup for racing in the woods or XC fast, agile, and dependable i think the 425 is going to be what i want, not quite a 440 but revs out fast for the sand and has some good top end. Does this make sence?

[Wheelie]

Does the 425 use an overbore sleeve like the 440, or does is use the stock sleeve punched .100 or .120 over?

If the 425 kit uses the stock sleeve stay away from it and go with the 416. Punching the stock sleeve that far will be sacrificing reliability and cause heating problems, and possibly distortion in the sleeve.

If the 425 uses an aftermarket oversized sleeve similar to the 440 setup, it would be the way to go.

[Dave400ex]

The TC 425 kit uses the stock sleeve. I asked TC about reliability and he said it was fine with the stock sleeve. 465stroker had the TC 425 kit and had no problems with it. He loved it. The TC 425 has won the GNCC four stroke open championship the last 3 years. I don`t think you need to worry about reliability and over heating. If they won the championship the motor must not of had any problems.

[Taco]

i would think the topend would rely mostly on which cam you decide you should run.

[Dave400ex]

I just got off the phone with TC. The stock sleeve is fine with the 425 kit. He said the reliability would be fine that it mostly depends on what kind of air filter you run. He said the stock filter is the best filter you can run. I told him I just got a K&N. He said the filter will give it more power, but not block as much mud and dirt as stock. He went on and said he could run the stock filter for a year on the motor and not have any problems, but with a K&N or any other aftermarket air filters you could not. I ran a K&N on my Warrior for over a year and didn`t have any problems. A lot of you guys on here run K&N and I haven`t heard anything bad about them. I know Rico has had his for over a year and he hasn`t had any problems. Just make sure you get a Outerwear. The 425 sounds like the way to go.

[51]

yea the 425 was alot of fun that tom put together for me... he is awsome and knows what he is doing with motors....

[Dave400ex]

Tom knows what he`s doing. 51, how do you like your 250r? My brothers is about done.

[51]

welp i only have 1 tank of gas threw it so far but as for now i can say i am in love soo much top end ... i really like it... but i am going to an actual tract to see what i think...lol i miss the traction of the ole thumper though... tell you bro to have fun

[Dave400ex]

My brother went to a MX track and loved it. Since his engine blew up he hasn`t been able to ride for months. Now it`s getting so cold around here he will not be able to ride it when he gets it back. Tom told him not to ride in the real cold weather. The bad thing about his engine is that after every race he has to change oil and it costs $9 a quart. All he needs is some different shocks and he will be set.

[stevengates45]

How much do yall pay for race gas? A drum down here costs around 70 bones i think.

[Chef]

a 50 gallon drum costs 70? ours is a hella lot more than that. and i think im out again....

[CBRSLIDER]

Warriorman,

How much did Tom quote you for the 425? Not counting shipping. Does this also include a cam?

Thanks
Ray

[wyndzer]

If I was going to build a bike to trail ride, well I would buy a 416 piston from GT Thunder, and put the XR cam in. I would still use the FCR carb no matter what I did. I think that was my biggest gain, even on a stock bike.

[Dave400ex]

A 5 gallon drum of VP race gas is around $35 here.

CBRSLIDER, The TC 425 piston kit is $120, the XC Cam is $179, and his Pipe is $319. That`s the setup I`m going to build. I might have him lighten the flywheel for $85 too.

I`ve heard to much good stuff about the 425. Not many people have a 425 motor. I don`t want the 416. Everybody has that. Plus the 425 has more lowend. The 416 is more for motocross. It`s more rev happy. If the TC XC motor has won the Four Stroke Open GNCC for the last three years I don`t want to run anything but that kit. His cam is a drop in, so I would rather have that than the XR400 cam. The FCR carb is the best carb though. I would buy it over any other carb.

[51]

my pap runs avation fuel in his race cars and i though i'd give it a try...wroks just as good as vp or cam2 but it alot cheaper... i pay like $2.12 a gal so i get a 15 gallon jug fuilled for like 33bux or so...and works fine... you guys should try this !!!!!! ohh and burns great too

[CBRSLIDER]

Warriorman,
So are you just going to buy the parts and put it together yourself? Or are you sending him your motor?

Ray

[Dave400ex]

No I`m going to have Jason Orr do it. He owns Orr Motorsports and does everything by himself. He`s doing my brother`s 250r motor. I will just have him do it.

[400exBro]

So your saying that the 416 is a better engine for mx???
Well i guess i will settle for the 425 do to i do trail riding a little bit, but mx most of the time .. should i stayed with 425 or go with the 416?

[knighttime]

Call Marcums and get a JE 416 10.8:1 piston kit, gasket kit, viton valve seals, and an xr400 cam. This will run ya about $300 dollars. You will need to get your cylinder bored. You will be able to still run 93 octane gas.

This is the best and easiest way to go. I guarantee you will love the set-up. I use it for woods ridin' and I'm gonna do some racin' with it. It's all you need (unless you are a really big/heavy guy), and is very reliable.

Good luck.

mike

[Dave400ex]

If you MX a lot I would get the 416 kit. The 416 revs faster and that`s the way most of the motocross guys are going. I know the set-up Knighttime talked about is very popular on this site. If you want a lot of power I would ask Tom (TC) about his 416 National motor kit.

The 416 will be just fine for trail riding, but if you were going to race XC the 425 would be better because it has more torque.

[Chef]

the 416 probably wont have a noticable difference in how fast it revs, because my quad revs faster than any quad ive ever ridden/ridden with. it may rev faster, but you wont be able to feel it. and also, when your racing up some serious dunes or hills, you will notice the difference in torque and horsepower between say a 416, 425, 440, and stroker bikes, because i pull comp hill in 4th gear (300 feet,about 50 degrees, maybe 60) in 4th gear with 14/38 gearing, where the 416's i ride with pull it in second with the same gearing and identical paddle tires (8 paddle haulers) but the 416 can do anything you want it to, there is no stopping a 416 from doing what a 425 or 440 will do.