Need help with reliability, 450cc compared to a Big Bore Kit

[reptikes]

I was considering a big bore kit. Say maybe 470-511 and was wondering how reliable my engine would be afterwards? I have an 04' 450r and have done nothing engine wise except change my oils and filter and it runs perfect. I don't race. I ride woods, hill climbs, and jumps, practice on a track or two here and there. I know nothing about working on quads so reliability is a big issue.

Thanks,
Mike

[TRX450RACER174]

IMO these engines can be made reliable by many reputable builders, I don't think just cause they are big bore makes them any less reliable it's all in the person riding the bike and doing the maintenance, let me ask you why you want one of these motors if you are not racing?

[reptikes]

I race my friends and i refuse to lose. And i have a graving for power. I'd like a lot more low to mid range power.

[MR.BIG]

Well before I went with a bigbore kit I would do some bolt-on mods first.Pipe,cam,piston and then go from there. If that isn't enough I would look into porting or call Chad from DRG he is doing my motor right now and is very knowledgeable about all types of builds.:macho

[TWISTED DINLI]

yea i would go with the pipe, cam and piston and stuf like that before you go to a big bore kit then if you need more, which you proly wont, then go to a big bore kit.

[reptikes]

Thanks guys, i think i'll work on the pipe, cam, filter, jetting ect.

And MR.BIG where is DRG.

Thanks,
Mike

[MR.BIG]

Originally posted by reptikes
Thanks guys, i think i'll work on the pipe, cam, filter, jetting ect.

And MR.BIG where is DRG.

Thanks,
Mike

He is located in MD! He is on here all of the time his name on here is chad502ex. He is doing my motor right now and I can't wait to ride it. I would definately do a pipe first that will make a huge difference over stock. I just ordered the rossier pipe they are one the top pipes for making the most hp.Good luck!

[pro-rider46]

well if your looking for low end i recomend a hotcam stage 1, either a rossier pipe, dasa pipe, or a sparks pipe. and then a cp 12:1 piston. after these three mods, if you buy them brand new you will be looking at $775,00, plus shipping. it will smoke all of your friends and you will be very happy. trust me. and if you do decide to go big bore you will have to buy all these parts anyway.

[sandmanblue]

Don't let anyone fool you. When you add power to these 450's, then tend to stress the weakest link in the power chain. On the 04/05, it's the rod and crank bearings. If you take a well broken in motor and start adding stuff to make it faster, it will grenade after a while. It's a rare occasion that these TRX motors get modded and last more than a year or two.

There are countless ppl out there that took older motors and stuck in cams, high comp pistons, etc, and many of them have found out the hard way that the bearings and crank won't hold up.

If you are even thinking about this, you need to seriously think about replacing the crank and bearings. The HotRods replacement cranks are a reasonable cost and are built better than the OEM cranks. Start there (maybe even add the +3 stroker crank while you're thinking about this), then build the top end to do what you want.


How do you all think the 450's got such a reputation for grenading? From ppl doing what you're talking about.

Better safe than sorry.

[400exrider707]

Originally posted by sandmanblue
Don't let anyone fool you. When you add power to these 450's, then tend to stress the weakest link in the power chain. On the 04/05, it's the rod and crank bearings. If you take a well broken in motor and start adding stuff to make it faster, it will grenade after a while. It's a rare occasion that these TRX motors get modded and last more than a year or two.

There are countless ppl out there that took older motors and stuck in cams, high comp pistons, etc, and many of them have found out the hard way that the bearings and crank won't hold up.

If you are even thinking about this, you need to seriously think about replacing the crank and bearings. The HotRods replacement cranks are a reasonable cost and are built better than the OEM cranks. Start there (maybe even add the +3 stroker crank while you're thinking about this), then build the top end to do what you want.


How do you all think the 450's got such a reputation for grenading? From ppl doing what you're talking about.

Better safe than sorry.


I will agree somewhat, I didn't do anything but add a slip on, filter, and a stage 1 hotcam, and mine grenaded.

I say if you are thinking of doing the power mods, go ahead and just replace the crank and bearings now, might as well do it while its apart.

[chad502ex]

imo estimating the 'reliability' of two different engine builds is near impossible.

i suggest look into components that perform great, but also work well with other performance parts. Simply bolting on a BIG Bore crank and high compression piston on top of the OEM crank without harmonically balancing the crank to the new assembly is a mistake, as the increase pounding on the crank would surely take its tole on the bottom end...

good luck.