HEADS UP!!!

Site upgrade in progress... Core site functions are working, but some non-critical features/functions will be temporarily unavailable while we work to restore them over the next couple of weeks.

Please post any bugs you encounter, but before you do, check to see if it's already listed.

Thanks for your patience while we work to improve the community.

Sign in to follow this  
Followers 0
trickwarrior

Blowin Smoke

6 posts in this topic

What are some of the possible reasons my motor would be smoking upon start up??? Just wondering where to start to get her back up to speed. 1999 wr400

Share this post


Link to post
Share on other sites

Time to spend the money and freshen up the top end. Rings and valve guide seals can cause smoke problems. But due to the age of your bike in may get real spendy to fix. Wear parts will need replacing, piston, valves etc. Price the parts and labor vs a newer bike. It sounds bad like this but you can find a newer better bike for less money than parts and labor. Unless you have friends with aweome tools.

Share this post


Link to post
Share on other sites

+1 to what desracer said.

Look at it this way, you got about 8 years and god knows how many miles out of the bike. That is amazing from an all out race engine...

If you have a knack for all things mechanical and a decent assortment of hand tools, you could probably do the piston, rings, timing chain, and gaskets and save some money that way with the help of a manual. You'd have to take the head into the shop unless you had a valve seat cutter, valve spring compressor, media blaster cabinet (to clean the head) and some other things I might be forgetting.

BTW the head work is assuming your valves are shot...there is a very good chance the valves and the valve seats are fine and that just your valve seals need replacing. Trouble with that is since you're taking the damn thing apart you might as well put fresh parts in it.

Share this post


Link to post
Share on other sites
What are some of the possible reasons my motor would be smoking upon start up??? Just wondering where to start to get her back up to speed. 1999 wr400

How much smoke are we talking about? Some smoke is expected on an older bike, especially if it's been sitting for awhile. I wouldn't worry about that too much. Chronic bluish thick smoke on every start maybe a sign of worn out guides (not rings-when rings are warn out it smokes all the time-not just on start up). Either way, not a terribly expensive fix especially if you do the disassembly/assembly yourself and just send out the heads.

Share this post


Link to post
Share on other sites

you will have to look at the top end of the engine. it is most likely that your valve guide oil seals are bad.

Share this post


Link to post
Share on other sites

The 400 is by far the most durable engine of the 400 - 450 line.  They will run forever with simple maintance.  It's just not that difficult to do a top end on one.  More info on the smoke problem could probably nail down the problem a little better.  The 400 motor does not use TI valves so even valve replacement is not that bad.  I would say that if you like the bike either live with the smoke or do the top end.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0