I would like some opinions on my 99 xplorer 400 2 stroke. The machine has 255 hours on it and about 1900 miles. I has been used to mow my lawn with mostly over the years pulling a trail-mower in low range. I cant remember the last time I greased it and I have never changed the fluids. Recently its been leaking gas sitting and also doesn't' run well at high speeds. Decided to go through the thing and grease it up and change all the fluids.

Discovered that it has a counterbalancer and I changed that oil out..it was milky. I never loose any coolant and there is no discharge from the overflow.

My question is, knowing that I have never changed this oil or ever even looked at it since 2000, with the hours and miles I have on this using it to mow, do you think the milkiness could just be from coolant migration that happened over that long of a time, or do you think its a bad seal?

If my carb cleaning gets this back to running good, maybe I'll sell it off and get something new (if the counterbalancer is going to start being a problem). Thanks for any insights.

Todd

 

If its the least bit milky then some coolant has passed through the water pump cavity into the counter balancer area. Counter balancer only holds 75cc of oil so it doesn't take much to change the color.
I've had some that just gushed coolant out of the counter balancer vent hose,to just a little milky color as you say yours is. Its hard to keep coolant completely out of the area even with two water pump seals! Over time age alone will distort seals and will seep a little! If you don't show any major loss of coolant and you DON'T want to go to the trouble of changing water pump seals right now,then just change counter balancer oil every 50 hrs,BUT if you let it go too long then you could face balancer bearing damage (inner and outer), scoring around where the balancer seals ride,etc. PLUS at least change your transmission fluid and give it a good greasing! And sounds like you need to clean the carb and replace the needle and seat to stop the leaking. Its like the old Fram commercial PAY ME NOW OR PAY ME LATER! OPT

 

Thanks, I think doing what you said is my plan A..Keep an eye on the CB oil and see how quickly it picks up coolant. I'm way ahead of ya on the maintenance. Changed out the front gear oil, front hub oil, antifreeze change, Transmission fluid (had the quart to change this for about 5 years but never got around to it). Cleaned and lithium greased the chain and adjusted it also. Greased every fitting and pulled the carb and soaked in a gallon of carb cleaner. Made the mistake of buying an aftermarket rebuild kit. The only parts I used from it was the float valve and the gasket. Everything else cleaned up good and didnt look worn. Well, guess what...tiny seepage of gas from the overflow tonight. The new float valve wasnt' rubber like the original. Before I put it together I might just go get a polaris valve (wasted 20 bucks on the kit).

I still need to pump through the brake fluid and get it changed since its 10 years old too.
My only other item to check is the belt and two clutches. The drive clutch was bumping the housing a bit and so I figured it was worn. It all looks pretty good and tight in there though so I think that my wifes mom, when she rode it, stepped where it as NO STEP.

Here's some shots of the clutches...they all seem tight and the friction disks seem to still be good. No wear to mention on the weights (against the roller bearing).

Please, if anyone can take a look at these pictures and tell me if they see anything wrong but I'm thinking its all still good in there.
https://picasaweb.google.com/grimsha...eat=directlink

The drive clutch seems to be worn down deep and I think that is from idling with it in gear too much. you might be able to see it from the shots. The belt apprears in good shape also but I didnt' measure width..no cracking or anything that looks like distress. I always used this in low range for any slow driving or mower pulling.
Thanks for any help and or advice...

 

"The drive clutch was bumping the housing a bit and so I figured it was worn."

These were defective, the plastic they are made of shrinks over time with heat and age. I replaced mine with a new one a couple years ago and it has been fine since.

 

What usually wears out over the years depending on how its treated is the front clutch buttons and the rear clutch ramp buttons,plus if the belt has more than 1 1/2" slack when you push down on the top middle of the belt,(use a straight edge across both clutches to measure) might be time to replace.Also the older clutch covers were prone to overheating and would rub the front clutch at idle. If it isn't making noise at idle then cover is probably ok. Pics don't look bad,doesn't look abused as you said. Also if you have an air blower and an open area,blow out any belt residue from the clutches. WILL make a mess and don't breathe in the dust! OPT

 

How much is a new outer cover...Mines was only hitting at low speed and not all the time....the fit is very close and it started doing it after someone stepped on the "no step" sign..haha If its 100 bucks I'll probably try and rig it to it sits up a bit higher.

I'll look for that deflection on the belt when I go to put this back together. Did you see the wear at the inside of the driven clutch? Is that a problem? I didn't know you weren't' supposed to idle with it in gear so I'm sure I did it often.

 

The cover is $84 + shipping at Cycle Parts Warehouse. You can run a brace from the frame down tube at the front and mount it to stabilize the cover Or some of the later models have an L bracket under the cover on the frame which lifts the cover up a little. They finally got wise and made the covers oversize to eliminate this problem. OPT

 

There are two things one has to do in order to keep the 400 two stoke engine running for the long run.

The first thing is to check the oil in the counter balancer VERY regular. When I rode them it was checked every two weeks and change the oil if it appeared to even have a trace of water or coolant in it.

The next thing is the top end. If you do not rebuild the top end between 3 and 4 thousand miles you ae asking for MAJOR problems. The piston WILL bust and when it does there is a good chance it will destroy the engine cases. Same thing with the counter balancer.

As long as your engine cases and counter balancer remain in good shape it does not cost much to keep these engines going.

If you have to buy both the cases and the counter balancer it is going to get very expensive.

 

Changing the water pump seals is not that bad of a job. I had to do that on my '96 400 as well. Pull the side plate where the pull cord is, then the stator and pick up. then unbolt the case and you can see the counterbalance and drive gears to see if you have any damage. The job can be done i a couple hours. Takes longer to pull the plastic out of the way. Seals and gaskets are cheap - (ebay). I paid around 50$ for seals, gaskets and new water pump impeller. Just food for thought if you want to tackle this yourself....

fire3096