I am pretty decided on getting a 450, but i wanted to know how much up keep they require? that and what mods to get and how easy/cheep/expensive the mods are. do they make the quad less reliable? also, can you use race gas in a stock motor? thanks for any help, i am a total noob

 

For maintenance, you HAVE to keep the oil changed and air filter cleaned every few tanks of gas and valves adjusted every 50 hours or so. The top end(piston/rings/etc.) needs replacing more frequently than a lower output 4 stroke too. That is going to be dependent on how you ride and how reliably maintenance is done.

The basic mods such as exhaust/air intake/jetting are fairly easy to do although you should seek help with jetting if you are unfamiliar with doing it. Motors jetted to lean can go BOOM and cost lots of $$. Price for most things is across the board for other 4 strokes as well. The Yamaha 5 valve head design is a little more costly to upgrade due to the extra valve.

If you are going to run the stock motor don't bother with race gas, 91 octane is all you need until you start bumping up compression with internal mods. Race gas is only going to be a waste of money on a stocker and I wouldn't bother.

 

<div class="FTQUOTE"><begin quote>Originally posted by: menthox

I am pretty decided on getting a 450, but i wanted to know how much up keep they require? that and what mods to get and how easy/cheep/expensive the mods are. do they make the quad less reliable? also, can you use race gas in a stock motor? thanks for any help, i am a total noob</end quote></div>



Welcome to the forums menthox. [img]i/expressions/face-icon-small-wink.gif[/img]

Nice choice. [img]i/expressions/face-icon-small-wink.gif[/img] Doesn't matter which one you buy, they always take money. lol[img]i/expressions/face-icon-small-wink.gif[/img]

Scooter86 eplained the race gas question for you. [img]i/expressions/face-icon-small-wink.gif[/img]

Good Luck and enjoy. [img]i/expressions/face-icon-small-smile.gif[/img]

 

so how much do u think i would be looking at to get the exhaust/air intake/ and jetting done? also, what kinda of high compression mods can i do? are they expensive? and how much hp and mph gain will i get from the exhaust, intake and fetting? and from the high compression mods? also what is "the cam mod" and is it a good hp/mph gain?

thanks alot. and do u think me being 6'2" and 190lbs is to big for the yfz450?

 

190lbs is no problem. At 6'2" you will probably want to put taller bars or a taller steering stem on it eventually. Try it out for a bit first though. A slip on exhaust will run around $300.00, $500.00+ for a full system. Intake will be $100-$150.00 depending on make an filter type. That is for the kits which change how the filter mounts. You could just go with only a filter for $50.00(K&N) or less for a foam style. Taking the quad to get it jetted you are probably looking at least an hour labor + maybe $20.00 for jets. My guess for a full system+intake+jetted= 7-9HP gain at least. You will have to do some research as to where different systems make those gains over stock though. If you are a trail rider you wouldn't want a predominantly top end pipe for instance. There is a lot of power to be had once you open up the motor, but it costs. Once you have it, ride it for a bit and then mod the engine if you really NEED more power than a pipe/filter gets. The cam mod is simply retarding the exhaust cam one tooth. This gives the engine the same cam timing as the dirtbike motor and adds a bit of oomph across the powerband. Some people like it, others claim it did little. I have it done on mine and like it. It is free if you can do the work yourself and reversible. If you are going to pay someone to do it, wait until a valve check as you would save a bit on labor that way. None of these mods will give you much in the way of top end speed unless you change gearing to. You will get to top speed faster though!

 

what kind od engine mods could i do? and would that make the motor less reliable? i read somewherer that the yfz motor is already pushing realy close to its maximum... is this true?

 

Menthox, the YFZ 450 is an excellent choice. Great on the track from what I have heard. I really don't think that any modifications that you add to the ATV, as long as you aren't hammering anything onto it or jerry-rigging anything on, and as long as it is made for that quad, it should be good to go. Personally, I wouldn't toy with it unless you know what you are doing when it comes to opening the engine or rejetting the carburetor. Cosmetic modifications or small exterior mods should be easy enough.

Good luck and enjoy it.

 

If you get one, just ride it for a while and get used to it, then decide what upgrades might be needed. They are pretty zippy even bone stock. Definately enough motor to keep a new rider happy for a while. When the upgrade bug hits, do the pipe and filter. That is usually enough for the masses unless you are one of the rare people that races in the higher classes. Even then most endurance type racers do little to no internal mods on these engines. The place I would go after the pipe/filter combo would be to redo the suspension. At least get the stock shocks revalved and maybe add wider a-arms and an axle if you have the cash. This will make the quad ride and handle better. In turn you will ride faster without having to add engine mods.