Reliability of 426?

[hosted]

I am going to go look at a 426 built by Pro Fab ATV tomorrow and I was just wondering how reliable the 426 is compared to stock? I will probably just be using the ex for lots of trail riding and a little bit of MX when I have time. It has Stage 2 cam, but I can't remember what compression it was at. Does it need race fuel? I think that if it is going to require to much more maitnence than stock, I might end up swapping motors. I have a built banshee now, and I don't want another motor where I am rebuiling it a lot. Thanks


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[cals400ex]

i know the sleeve is pretty thin in the 436's unless you swap sleeves. reliability should be pretty good though. i don't know much about pro fab. it should definately open up a lot compared to stock. the compression ratio will determine if you need race gas or not. you should probally tell them whether you want to run race gas or not. if you don't want too, the compression ratio will have to be lower. i would hope it is more reliable than a banshee. :eek2: all in all, it should treat you well. just keep up on the simple things like changing oil, adjusting valves, cleaning the airfilter, etc.

it should be fairly good...jus like cal said...take care of it and it will take care of u :macho

[hosted]

Well, I ended up buying it. I am kind of worried about that motor though, it has a 12:1 piston in it. A little much for what I'm going to be using it for. I went to my local track today and bought a five gallon can of race gas :eek2: That stuff sure is going to hurt the wallet. The motor runs great though. With the 12:1 do I have to run straight race gas or do you think I could run 50:50? I was playing around with it tonight and there was a little tick with just premium, but seemed to run good 50:50. I really really really don't want to have to run straight race gas if possible. With the price of race gas, I will probably end up doing a motor swap here pretty soon and get it closer to stock, if it is possible with this to just get a lower compression piston and put it in and change the necessary things, or would I have to redo a lot of stuff? Sorry if I sound really stupid, this is my first 4-stroke, so I don't know much about them. Other than that, I am very happy with it.

It is a 2000 with:
426 motor
Works Triple Rate Fronts
Revalved Rear
Denton +2 +1 Arms
Brand new durablue axle
2 sets of plastic
beadlocks
aluminum air box
white brothers pipe
dg nerfs
pro taper handlebars
guessted and powdercoated frame
the brakes are new, and has all new bearings in it.


For a grand total of $3200 :D
I think I did pretty good

[cals400ex]

you should probally be fine with 50:50. you could just put in a 10.8 or so and you will be fine with premium fuel. you dont need to change too much. heck, it might even be possible to shave part of the dome off of your piston to reduce the compression. you willl have to send the piston out to get that done though.

[Natertot426ex]

My 426 hasn't given me any troubles and I have had it in for over a year now. I will sometimes run 50:50 race gas and other times run supreme. I am very happy with mine. The compression I went with is 10.8:1

[Quadzilla]

Originally posted by Natertot426ex
My 426 hasn't given me any troubles and I have had it in for over a year now. I will sometimes run 50:50 race gas and other times run supreme. I am very happy with mine. The compression I went with is 10.8:1

Do you notice any significant difference in power when running 50/50 vs supreme pump?

[Natertot426ex]

I do a little, plus the motor runs a tiny bit cooler.

[stupid driver]

i have an 11.3:1 compression ratio on my 425.(11:1 and a flx steel head gasket) i run 50/50 112 leaded octane and 92 premium gas. I havnt had any problems with pinging at all. The temp guage hardly ever moves once it is warmed up. also, did you have heavy duty head studs installed on your 425? thats the only problem i have had on mine. There is a TON of torque on with these engines. It stretched the stock studs like rubber bands. I would suggest that you look into some heavy duty studs. Rocky Ridge Racing has a pretty good set if your interested.

[mack400ex]

lets say i got a 426 piston with 10.8 compression? will i be happy with it for x country? and what other parts should i get to help the engine due to the upgraded piston?? gaskets etc.?

[stupid driver]

you shouldnt have a single complaint with a 10.8:1 piston in your 426. Im guessing that it is a JE piston? if so, that is a great piston. Very high quality. Ross is top of the line as well. The 10.8:1 motor will give you the bottom end power you are gonna want in a XC racing bike. Accompany the piston w/ a good cam, and that will make one torque monster. I have a TC924 mx cam in my 425 ( emphasizes top end) and i still have awesome bottom end power.

[xc400ex]

Yeah i race harescrambles I run 11:1 JE 426 with stage 2 hotcam and a HMF slip on. Has lots of lowend but still pulls really good on top.