Well, after my old sprocket had worn and my chain had become real loose, I bought new sprockets (14 Front, 38 Rear) and a new chain. We had to cut the chain because it was too long. I don't know if I'll regret doing this because the gearing feels much lower now. 1st is great though because I have plenty of power even when I'm at the low RPM. But my gears have become much shorter and 5th feels much too slow on long stretches. I think I should have went for a 15/39 Combo or 15/40. Only problem now though is that I cannot enjoy this extra torque because my parents do not want me to pull wheelies because they blame the wheelies for stretching the chain. They say I am too rough when I pull a wheelie and that it is the cause of me needing a new chain. Also while changing the sprockets/chain, we noticed that we can shake the back wheels. Is this normal or are the bearings done?

So I've got a few questions:
1)Will the 400ex blow up with a 14T front sprocket held wide open in 5th?
2)Are my bearings finished?
3)Are wheelies really that bad on the chain?

I've also got a quesiton about my spark plug. We took the old plug out (it was a Champion) and I bought a plug from the dealer today. The dealer plug is an NGK plug and it is about 1-2 mm longer than the Champion. What could the reason be that the person I bought the bike from had a different kind of plug in?

 

what do you mean shake the back wheels? do u mean the rim or does the whole axle shake?

 

The whole Axle.

 

More than likely the bearing are gone if the whole axle shakes...recently had the same problem with my 450 and if you arent quick to fix it you could loose your carrier like i did

 

So. I have pity on you because your parents are making up stuff and accusing your driving techniques of destroying your bike. No, wheelies won't hurt the chain any more than a hard controlled accelleration would. "gear slam" wheelies will destroy your transmission before your chain stretches before your eyes. (that's when you let off the gas, and let all the backlash out in one drection, then nail it to get a wheelie and hear a clunk as your tranny unloads it's lash in the other direction) Any properly clutched/pure power wheelie is perfectly fine for both chain and gears. (chains are considered expendable items anyway. Smoke 'em while ya got 'em.)

Unless you have a rev box or any other means of engine self destruction, pinning in fifth won't immediately destroy your bike, but it sure sounds bad and I wouldn't do it for long periods of time.

Your bearings are probably toast. They're not that expensive and wear out because they're sealed and greased, not running in lubricant, like on a 250ex-type setup. DO NOT buy the OEM wrench. Go to rocky mountian atv and buy their 45 and 56mm set of axle nut wrenches for like 15 bucks. I just did mine so I can walk you through if you need it.

As for the spark plug thing, IMMEDIATELY stop running it if the threads are longer than your old plug and do a thorough investigation of the situation. If it's only the electrode tip, don't worry too much. (so long as it's not slapping the piston or anything) Good luck.

 

Do you know where I could find a diagram for the rear end of a 400ex? Oh and as for the spark plug thing, I put my old one back in (The Champion). I put the new one back in the box. But when I do get aroudn to putting the new one in (NGK), should I listen for any sort of knocking?

Thanks,

-Jed

 

about the sprocket question here is a cool site where you can calculate in your gearing and find out the speeds.

http://www.ljsoftware.com/DS/GearSpeedCalculator.html

When selecting sprockets: for more LOW END, go larger on the rear, or lower on the front. For more
TOP END, go lower on the rear, or larger on the front. Also if you go for more low end it should increase your accel alittle and give you some nice torque but yes your gears will be shorter and seen on the link for the website. I hope this helps your undestranding of sprockets

steve

 

Check that your axle nut isn't just loose. Had to tighten mine a bit the other day. Takes a very large crescent wrench.

I found that a 14 in front was to much! It would wheelie at the most inopertune times, like powering out of a trun. Went back to a 15/39 instead.

Your chain is going to stretch anyway, no matter what. Things like chain and sprockets are disposable, just like tires. They need to be replaced now an then, just from normal wear.

What part of your quad has the most moving parts???? The Chain!

 

My bike's rear end is currently apart so I haven't driven it in a while. Also, sometimes when I drive the bike, it just starts "dying". Like when I give it full throttle or even 3/4 throttle, the engine sounds like it is about to stall. However, if I pull the clutch in, it'll rev right up. My dad and my friend both suspect that because the bearings were messed up, that it put a strain on the engine and that is the reason for it...

comments?

 

The first sign of shot axle bearings is that you adjust the chain, but it won't stay adjusted.