'98 WR400 fouling plugs after new parts

Was the cam chain ever replaced before?

Well it ran fine with the old chain with the cams not lining up perfectly. Now with the new chain they are still not lining up perfectly and it does not run fine. This is the first time I have replaced the cam chain. Before me the bike was maintained regularly by an "AMA mechanic" which is the biggest crock of crap I've ever heard, so who knows what they did to the motor. I will be back at the bike in a week and be able to tell if my most recent cam adjustment cleared things up.'

EDIT: William also said it common to have the outside punch marks level, and the inners point up a bit.

So the bike has been in the shop or a week and a half with no verdict. I did have to replace a dead battery though which is understandable considering it hasn't been attended to in a long time.

Here is my newest question as I sit waiting for the shop to attempt to diagnose it. If the stator got messed up some how by the cam chain, would I still be getting proper voltage? With my multimeter I appear to be getting the correct amount.

So the bike has now been there just shy of 2 weeks (tomorrow marks that day), a week at least of which I believe they have actually been working on the bike.

I know I'm impatient but I just got off the phone with them as I'm getting antsy watching my roommate ride everyday in the best riding weather of the year so far.

Anyways, the shop said they have still not been able to figure out what is wrong with the bike yet, but they are fairly certain that it is not the stator, and not the CDI. They did say that they are leaning towards valves being the issue. I have "recently" replaced the entire valve train so I'm hoping it's not the issue.

Anybody have any insight on this? I'm getting pretty desperate.


EDIT: They also said not timing or jetting to state the obvious.

Any more ideas at all? Getting pretty bummed about this whole situation. On the verge of picking the bike up and messing with it on my own time just to know something is getting done, or parting it out. Maybe picking up a different motor as this one has been nothing but trouble from, quite literally, day one.


Still no luck with this. I'm not getting many hits, and I hate being the only one posting in here. Maybe this is better suited in the jetting/fueling? Mods?

This Friday will mark the 5th full week it's been at the shop.

You have it at a shop, what better place to have it fixed? You're missing something big, and I'm positive it's in the top end which we all mentioned in the beginning. But you said it was new so not sure what else to tell you. Crack in the casting?

Not much else to add, sorry. If they can't fix it, I'd take it somewhere else.


Thanks for the post. The shop said the top end looks good. They had "a feeling" that it was something with the valves but they have yet to find anything wrong. I just don't know what would be wrong that could cause this. They said timing and jetting was good, valves in spec.

Would an intake or exhaust leak cause anything like this?

I just guessed that the people in this forum would be more knowledgeable about these bikes than the average shop and would be able to help me track this problem down quickly.


Also, I don't know why it ran great for an hour +, but now it won't run for more than 5-10 minutes. I'm still wondering if some of the RTV silicone sealant on the carb worked its way farther into the carb and is clogging something up.

Did you ever figure out the problem? I have had similar problems with a wr426. And went through the same hassles with the timing cams. Let me know.

I know this is an old post, but I'm still trying to figure out this forum and how to make it send me notifications....think I finally got it.. :cry:

I'm thinking the issue was a worn cylinder/piston. Either way I'm waiting on the last few bolts then it's fingers crossed...

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