New to thumper...need some help with what to do to four strokes

Hey all, new to the forum and new to the thumper world. I've ridden 2 strokes since i was 6, but a friend was ditching one of his bikes and after some research i picked up an '00 yz426 for a grand. He was told the bike was a former factory race bike, not that I believe it but it does have oodles of aftermarket stuff. I rode the bike last presidents day weekend (this ride is what led me to thumpers) and the thing is a beast, I was sold. So now I have a bike that I don't know the maintenace history on, and have never dealt with a 4 stroke before. What should I have checked, obviously oil, filters, plug, etc will be changed. The bike runs (does not like starting or idling anymore, but has been sitting since presidents day so I know a carb clean is in order) and rides nicely. Do thumpers need top end rebuilds as often as 2 strokes? What needs to be checked in that top end? Any input you guys have would be great, as well as any suggested mods to use or avoid. :thumbsup: Thanks!

bump for a newb

Valves, Valves, Valves. Learn how to check them and adjust them. If you don't already have a manual, get one or at the very least, download one from the one of the stickies at the top of the YZ Page. I would recommend that you tear the bike down and grease the steering head bearings, wheel bearings, and swingarm/linkage bearings. Change the oil often and pay attention to any metal that may be in it. Learn how jetting works with these 4-strokes and it will save you a lot of time in the future. Also understand that your engine is probably on borrowed time. This is not to say that it will let go soon, but eventually it will need some tlc. If you don't catch the valves going in time, then expensive engine damage will result. If the bike seems loud, repack the muffler and keep the damn thing quiet. We all want to keep our riding areas open. Ride every second you get the chance and welcome to the crazy addiction that is 4-strokes.

Chad

Awesome man, that's exactly what I was lookin for!

Learn how jetting works with these 4-strokes and it will save you a lot of time in the future.

Chad

im a noob to carbs, where can i learn how to jet my bike? link will be helpful

my shop do a realy bad job on it so i just let it run rich.

Also, accept the fact that your gonna need an inch-pound torque wrench. I broke down and bought one when I did my top end last weekend. They're not cheap, but worth it if you plan on doing some maintenance yourself (which will save you alota $$).

Go to the TT store and get a new cam chain for your bike. It should be about 15 bucks. They should be changed every year or so. They stretch, which can cause the engine to jump time, which means alot of costly engine work.

I typically change my oil every 6 hours, and my filter every 2 oil changes.

Grab a set of feeler gauges and check the valve clearence too!

Also, accept the fact that your gonna need an inch-pound torque wrench. I broke down and bought one when I did my top end last weekend. They're not cheap, but worth it if you plan on doing some maintenance yourself (which will save you alota $$).

Where did you get it? What kind? How much?

Where did you get it? What kind? How much?

I got one from MSC Industrial Supply, at their online store. This one: http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=20281356&PMT4NO=60668163

Sears also carries that wrench, but it's more expensive at sears. MSC is cheaper and they offered free overnight shipping. The wrench itself is quite nice, very nicely built, and it fits fine between the head and the frame.

be forewarned that they will cost more money and will mandate a hell of a lot more time working on them than a 2smoke

When i bought my 426FM (2000) It had a wierd noise. it wasnt oober loud.. but sounded like there was some clanking on the inside.. after hitting Little Sahara Sand dunes racing it pretty rough, it made even more noise.. sounded like my clutch basket was coming apart.. wasn't comforting at all! I had a mechanic do a teardown and it tured out there was 2 teeth missing off of my crank, and another gear with a chunk out of it resembling a pie with a large slice taken out of it. the cranks are NOTORIOUSLY bad in these things.. and hot rods doesnt make an aftermarket for our loved 426. OEM was expensive as hell. use the TT store it is VERY essential to saving some dough! good luck hope your buying experience is better than mine!

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