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steade

Overfilled with oil and ...

27 posts in this topic

1998 WR400 - I checked my oil the other day before my ride and it seemed low so I added about 250-300ml (probably too much). Started perfect, ran perfect for about 5-10 kms. Stopped for 20 minutes, started it back up and 5 minutes down the road it started to cut out at cruising RPM ranges and then it would start back up and keep running. When I stopped and let it idle it would eventuallu cut out and stall. Kicked it over and it started right back up... the only way to keep it running was to rev it up a little so when it would cut out the higher RPMs pushed it through and it would keep going. So it cuts out every 10 seconds or so... drops the idle adn then picks back up again. No funny noises or banging, ticking... it revs free and feels strong when it isnt cutting out??

So I drained all the oil, filled it with 1600ml and it still does the exact same thing?

Whats the deal? Did I bend a valve or is one sticking. I popped the top cover and kicked it through, it seems to be a little sticky or harder to kick than usual.

Any info is appreciated. I just want to have some idea before I go to the dealer for a beating! Thanks.

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At first glance I'd say the oil overfill was just a coincidence. The first simple thing I'd check is the fuel supply to the carb. It sounds like you may not be getting enough fuel to the carb and you're running out of gas. Open the drain screw on your float bowl and let the fuel drain free with the tank petcock on. If it stops or slows after a minute you may have a clog somewhere. Check your vent on your gas tank cap. my sled did the same thing and the cause was a plugged tank vent.

With a full float bowl the bike will run normally until the level drops low. A second place to look that requires a bit more effort is to check your float and level.

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What about the hard kicking? It seems to bind even when I have the decomp lever pulled and it gets hard to kick through... doesnt that sound like a bearing or something?

Ill check the fuel and start there for now.

Thanks!

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I agree that it's probably just coincidence. These are dry sump motors so I doubt that overfilling the tank will cause any serious issues. It will definitely not cause a bent valve. Also a bent valve will cause you to have no compression. My guess is that you most likely have a clogged pilot jet. Fairly common problem especially if fuel sat in the float bowl a long time. I would pull the carb and take a look there before going any further into the engine.

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Do these carbs have icing issues?

I ride in extreme cold and never had a carb icing problem, but my air filter would occasionally get wet and then freeze.

Steade, binding with the decomp lever in is a problem. The first thing that pops into mind with that is the slide plate in the carb. Have you ever replaced yours? They are a fairly common problem on older WR's and mine went 2 years ago on my 99. It's possible that a piece of the slide got sucked into the cylinder and is causing the drag. Of course there are a lot of other things that can cause the same thing, but since you have an older WR, carb trouble and engine drag it might be the slide plate.

A bearing going bad wouldn't cause the engine to stall the way you're describing. When you're riding does the engine quit like you shut off the kill switch or does it feel like the engine is dragging and seizing?

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So its hard to kick and it pops and runs bad on the bottom end? If so it sounds like it jumped time. Have you ever replaced the timing chain?

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Warm weather here boys, no icing issues!

I have never messed with the carb or replaced any parts on it. It does sound like it may be a fuel issue. When it shuts off, its more of a feeling like I have hit the kill switch...not like the engine is siezing. As soon as it picks up again it revs freely and seems normal power wise. Then it cuts out again?

Well this is a start, I will check the carb as soon as I get home!

I have not checked the timing or done a valve adjustment either so I think its time to do that as well!

Any more comments are more than welcome as Im feeling a little better about the situation at hand...

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If you've never replaced the timing chain or the throttle slide plate these would good items to check even if they're not the cause of the original problem. The slide plate may have hairline cracks that are hard to see without removing it and inspecting with a magnifying glass. If a chunk got sucked into the cylinder it'll be obvious.

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Noob to TT but not new to MX....

Having done this before :thumbsup: I know what you're talking about.

First thing before tearing into your carb is to open the airbox and check for oil inside. I'm betting your air filter has engine oil on it also. Clean the airfilter and reoil. Clean the airbox out and check the drain. It's most likely filled with oil too.

What happens when you overfill is the extra oil is blown out the crankcase breather that attaches to the airbox and soaks the filter. Any extra gets 'saved' in a little tube at the bottom. As you ride the oil gets sucked into the airfilter and makes the bike run rich causing it to bog and die at idle.

You may also have fouled the plug, so you should take a look at that also.

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I just cleaned the airbox and filter before I overfilled it with oil so ya maybe it is all saturated in oil from the overfill. I will also toss a fresh plug in there jsut to make sure... any suggestions on the best plug to use? I think I was using NGK previously. Ill check with the dealership.

Crossing my fingers, i hope its just what you guys are saying and it doesnt end up costing me a small fortune or being a nightmare.

Thanks again.

Oh ya, should I pick up the shims from Hot ___whatever or just take it to the dealer?

Word.

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Noob to TT but not new to MX....

Having done this before :thumbsup: I know what you're talking about.

First thing before tearing into your carb is to open the airbox and check for oil inside. I'm betting your air filter has engine oil on it also. Clean the airfilter and reoil. Clean the airbox out and check the drain. It's most likely filled with oil too.

What happens when you overfill is the extra oil is blown out the crankcase breather that attaches to the airbox and soaks the filter. Any extra gets 'saved' in a little tube at the bottom. As you ride the oil gets sucked into the airfilter and makes the bike run rich causing it to bog and die at idle.

You may also have fouled the plug, so you should take a look at that also.

Good call noobie :thumbsup: welcome to TT.

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Noob to TT but not new to MX....

First thing before tearing into your carb is to open the airbox and check for oil inside. I'm betting your air filter has engine oil on it also. Clean the airfilter and reoil. Clean the airbox out and check the drain. It's most likely filled with oil too.

What happens when you overfill is the extra oil is blown out the crankcase breather that attaches to the airbox and soaks the filter. Any extra gets 'saved' in a little tube at the bottom. As you ride the oil gets sucked into the airfilter and makes the bike run rich causing it to bog and die at idle.

Except a 98 WR400 breather doesn't connect to the airbox. It vents directly to air via a hose that goes down the left side of the engine.

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Oh ya, should I pick up the shims from Hot ___whatever or just take it to the dealer?

Word.

3rd vote for cleaning your air filter an replaceing the plug first.

If you do need to adjust your shims, file your exsisting ones down with a diamond honing file and measure them with a dial caliper until there at the right spec.

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Except a 98 WR400 breather doesn't connect to the airbox. It vents directly to air via a hose that goes down the left side of the engine.

True, true PBDBlue, but Steade may have done the airbox mod. The noob is looking at all the possibilities - thinking outside the -or should I say - inside the box. :thumbsup:

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.

If you do need to adjust your shims, file your exsisting ones down with a diamond honing file and measure them with a dial caliper until there at the right spec.

I wouldn't recommend that.

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Alrighty boys, heres the deal...

1) Cleaned the air filter. Didnt look too dirty/oily, recently cleaned and re-oiled it.

2) Pulled the plg, didnt look bad, no oil on it, cleaned it and put it back in.

3) Checked the tank and valves to make sure there was fuel lowing correctly... everything looked good.

4) Re-assembled items and dry kicked with de-comp pulled... seemed normal through kick cycle.

5) started engine... ran for apprx. 20 seconds and stalled.

6) Kicked with de-comp pulled and it seemed a little tougher through first 1/2 of kick down but then got easier/normal.

7) Started engine... ran for 5 seconds and stalled.

8) Kicked normal and started engine... ran for 10-15 seconds and died.

9) Tried to kick with de-comp lever in and it was almost rock solid... stood on it very hard and eventually gor it to rotate.

10) Started engine... stalled after 10 seconds.

11) Tried to kick with de-comp pulled and its stuck... I mean stuck at the very top. I weigh 220 and it wont move with all my weight on the kick starter.

Conclusion: I have no idea, but its never been that hard to get it to rotate with the decomp lever in. Feels like the de-comp is not engaging when I try to turn it over? Doesnt seem normal to be able to put that much weight on it and it wont budge... theres definately a problems deeper than the carb?

Any input is appreciated. Thanks! :thumbsup:

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So its hard to kick and it pops and runs bad on the bottom end? If so it sounds like it jumped time. Have you ever replaced the timing chain?

Here is my original post.

Engines don't like to rotate when the piston is hitting a valve. :thumbsup: Check your timing before you do anything else.

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Alright, Ill check that timing asap!! Let ya know what the deal is. THanks.

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