Motor Rebuild

[Xtreme4Wheeler]

I am looking to buy a 400 or 450ex but a few things to consider...just how often should a motor have a complete rebuild or at least piston and rings? How much scheduled maintenance internally to the engine shouuld be done and what components? I am trying to get an idea of how much $$ it cost to maintain a ride. And of course what shoud i look for when buying a older model?

Thanks in advance for any feedback!

[aviator4]

There's not a whole lot of expense in maintaining a Honda. They're built like tanks! The info below is based on a stock bike:

As far as rebuilding, it all depends on how much you ride. the average guy riding a Honda can go YEARS and YEARS without having to reuild the engine as long as it's maintained. I check the valve clearances on my bike every 30 hours or so of riding. It's an easy maintenance thing.

Other things to consider are:

Oil and Filter - Change it, at a minimum, according to the specs in your manual. I think they say 100 hours. I change my oil after every ride, I just don't want to risk it. The biggest expense you will probably have is the oil filter, which will be around $5 individually. I buy them by the case off of E-bay and save money.

Air filter - clean it OFTEN. I clean mine after every ride. If you wait until it looks dirty, you've waited too long. Getting crap in your engine is a sure fire way to ensure you need to rebuild it!! Ditch the stock air filter and get either UNI or a K&N. There is great debate over which is better. I have both and run both from time to time. Both offer better performance over stock.

Chain - keep it adjusted, clean and properly lubricated. Change the chain and sprockets at the same time. Don't power wash an o-ring or x-ring chain as you will force the oil out of the seals and water into them, rusting the chain.

Sprockets - Watch for tooth wear. Teeth that look like "shark fins" are worn out and should be replaced - I've gone three seasons on my stock sprockets before I had to change 'em.

Brake pads - typically need changing before the start of every season, but if you ride EVERY weekend, they may need to be changed mid season too. It's a good idea to "eyeball" the wear indicators before you ride, that way if you have a stuck caliper or a bad pad (that has thrown it's pad medium) you catch it before doing damage to your rotors. If the caliper is fine and the pads are good but the rear seems to be wearing down REALLY fast...make sure you're not riding the rear brake with your foot when you ride.

I know this may sound silly, but a CLEAN bike requires less maintenance than a DIRTY bike.. PLUS you can catch problems (like cracked hoses) faster.

As far as things to look for on a used bike:

FRAME: make sure it's straight, it should be symmetrical from side to side. Chipped paint at the joints and welds typically means that the frame is bent. Look at the welds closely. Any weld that seems "out of place" (either looks different, or in a strange spot) should be scrutinized closely. Some racers have their frames gussetted to make them stronger which means welding, so don't worry about those. Also, the lower A-arms on a 400 are also pretty weak, check them closely.

Plastics: Check where the plastic mounts to the quad. Tabs that are broken can mean rattles. Broken tabs are common, but shouldn't cause the rest of the plastics to crack.

Handlebars and stem: Stock 400ex stems are notorious for bending. If a quad has a set of aftermarket bars on it, ask the seller why. if they were replaced because of a wreck, inspect the stem for bends. Don't be surprised if you find one.

Engine: Honda engines that leak oil should tell you that there's something terribly wrong. Don't worry about how easily it starts... to a point. All air cooled engines are harder to start than water cooled engines. Check for smoking when the choke in the OFF position. Engines that "puff" when you first start them up may indicate worn rings or leaking valve guides. blue smoke means it's burning oil. black smoke means it's running rich. Listen for valve noise. A little is okay and can be adjusted. a Lot of tapping means that there may be cam,rocker or valve damage.

Air Box: check inside for crud. If the seller takes care of his bike, he will take the time to clean the air box out when he cleans the air cleaner. If the air cleaner is brown, as him to remove it to inspect inside the intake tube. If you find dirt in there, move on to a different quad.

Shocks shouldn't make noise when they are compressed (except a little hissing sound, which is normal). If they feel "gritty" or "springy" they will probably have to be rebuilt.

Check the wiring harness for cut wires. If you find any, ask the seller why they were cut. There are many good reasons for cut wires... things like an aftermarket clutch lever and pertch that eliminates the "clutch engage starter lockout" switch and therefore the wires going to it are wired together. etc...

Check the axle for bends as well as the rims.

Find out when the last oil change was. If he doesn't remember... move on.

ALWAYS ask to see a "statement of origin" on the bike (or title in some states) to make sure you're not looking at a stolen quad.


Sorry the post is so long, but you asked some big questions! Hope this helps.

[Aceman]

Originally posted by aviator4
. Check for smoking when the choke in the OFF position. Engines that "puff" when you first start them up may indicate worn rings. black smoke means it's burning oil. White smoke means it's running rich.

Blue smoke means it's burning oil, black smoke it's too rich, and white smoke it's burning coolant. But other than that--GREAT POST:D

[aviator4]

Thanks for the correction. Thats what I get for typing too fast. LOL. I made the changes to the original post. Maybe the moderators of the board could use this post on the site somewhere.

[RideRed250ex]

Nice... you may think that this will take a long time to do especially when the owner is standing over you but... It is definitally worth it. These checks can save you a lot of money down the road...This should go in the FAQ section for first time quad buyers...;)

Oh and sorry but i had to do this it is a 400ex and a 450R, just for later reference...:)