Rebuilt, Broke-In, Still burning oil???

[scott7556]

My 2001 400 was starting to smoke not under full throttle, but during engine breaking from high rpms and as the engine "revved-down" from high rpms while stationary. I then had it bored .020 over and installed a Wiseco 10.5/1 piston. I broke it in by riding very carefully for the first 6 hours I logged, never riding all out, varying my rpms, no loading down the motor and so on. Doing all the work and break-in by the book I thought I was spot on, but now my problem is back, at about 10 hours on the motor. It does not puff blue smoke at startup, as I replaced the valve seals, and it does not puff until I really run it through the revs pretty good, riding near all out. It has to be pretty warm too, if I shut it off and let it cool for 5 minutes, then start it back up and rev it pretty high it doesn't smoke until I ride it pretty hard consistently again. My plug looks great, no backfiring, and it is pretty stock other than a K&N and Pro Circuit pipe. Any ideas fellas? I hate to think I didn't break it in right!

[alex10]

Is it using oil?

[scott7556]

It's not hardly noticible on the dipstick,atleast I can't tell that it has went through any oil. It's not like it burns constantly, just puffs when coming down off high rpms. I wish I could describe it better, but that's all it does. I just can't believe my rebuild didn't tighten things up more!

[Honda#4]

Maybe a ring didnt seat good?

[witech]

What did u set the ring gaps to? Did you use regular motor oil for the first hour? What was the piston to cylinder clearance? Were the valve guides worn? New valve seals?
As far as Wiseco pistons go if they are the short skirt forged pistons a little oil burning can be expected after 10 to 20 hours.
As far as breakin the rings should be seated after the first gallon of fuel . Do a couple of heat cycles at ten minutes intervals. Dont overload it and ride wide open for 2 miles but dont putt putt around babying it either. Generally just ride like you were on an easy trail ride.
Smoking should stop after 10 to 20 minutes if it smokes at all.
On my race engines this is the usual drill . I dont use many Wiseco's anymore due to the skirt wear but they do make good power on the dyno. We have had great results with CP and ASSO pistons for long term wear resistance.

[X400EX]

I have the same problem. But the smoke started after the 1st hour of break in I think... Sometimes it does not smokes, sometimes it does as the engine "revved-down" from high rpm... It has to be hot too, may be very hot.

I just went 416 with 12:1. I haven't seen any other problem than this occasionaly blue smoke. The power is great and I can't see a difference on the dipstick.

[alex10]

A lot of quads do that don't worry about it.

[scott7556]

In response to Witech's post:
I ama machinist by trade,so I am very familiar with tolerances, tools and the like. I checked all clearances closely and although I cannot remember the exact numbers, I did make sure that they were within Wiseco's specs. I did the same with the head components and did replace valve seals. I did use my standard issue Honda GN4 oil like I always do to break it in. I assume my motor has 15+ hours on it at this point. It runs great, starts great and everything, just like it always has, but once again this weekend, it started blowing a blue smoke cloud when I really let it rev and then let off. Also noticable during high rpm engine braking into a tight turn or the like. I just don't want to see the thing blow up or something for no good reason. I just can't believe that I rebuilt the motor because it was starting to smoke like this and then I'm right back where I started.

[whc]

my 400ex has used oil since new we also have 2 300exs one use 1/2 a quart in a 2 hour race the other never uses any, my opinion is that honda does not make them like they used to. but I still ride em cause they still keep running. Mild Bill