So after 4 months of no riding Honda finally completes my 420.
New crank, piston, bored 0.50 over , oil pump, and everything that goes with a full rebuild.

I put about 26 miles ,and 4 hours on it last sunday ,and it smoked under hard acceleration ,but it was just a little bit so I assumed or hoped it was the oil left in the muffler from the last engine failure.

The new motor after 26 miles fouled the plug to the point where it would not start.
What do yall think went wrong in the build?

My 1st guess is the bore got messed up.
Any ideas?
how would yall handle this?

Since I ruined my last motor im checking everything before every ride, and the breather hose got a good tear in it ,and they reinstalled it onto the motor!!!
Had I not noticed that I would have destroyed another motor!

Im guessing they will have to tear into the motor again.
They have had it for 5 days and have not touched it.
I just spent $1700 bucks for this work.

Im conteplating trading it in ,but only if they will give me another for next to nothing ,and just keep the money for the work they did.
I cant go another 4 months without riding!!

It only has 50 hours and 360 miles.
Any feedback would be great. Thanks.

 

Dude, I think you may have a bad ECM

Shoot me a PM, I may have some interseting advice

I will reply to you later tonight or tomorrow afternoon

thanks

----- Gimpster -----

 

Isn't the 420 under warranty? How old is the machine? If I were in this situation, I would not expect to have to pay anything.

How many miles was on the machine before the first motor failure?

 

I did purchase the extended warranty ,but it was my fault the 1st motor messed up.
I rode on ,and off for 2 weeks through creeks ,and mud ,and all that stuff with the crankcase breather off!!

Got water, mud, and sand in motor.

 

Oh okay, I didn't know that.

I have no idea what the problem could be. I will leave that up to the experts like Gimpster.

 

Well Honda has the engine out ,and torn down again.
They said everything looks good ,and they dont know exactly whats wrong.

They think the cylinder is worn out so they are putting a factory fresh cylinder ,and piston in.

 

make sure to use cheap dyno oil for the first 2 tanks of fuel, break-in is huge- Uppon first startup allow it to come up to temp then run it hard for a few seconds then treat it easy for a minute or two then run it full throttle again threw the gears then allow it to cool for 20 min shut down, start it up then run it hard again for a short period to set the rings good this time. The trick is to create alot of pressure to seat the rings by running it at full throttle but not long enough to heat the engine up to much, this the cooling off periods. check this link out:
http://www.mototuneusa.com/break_in_secrets.htm

 

just thinking, make sure all your crankcase breathers are working perfectly, a plugged one can cause oil myst to enter the airbox

 

If you just paid to have the engine rebuilt, and it started smoking after the first ride, I'd HIGHLY suggest not touching a thing and taking it back to the dealer.

If there's a problem, you don't want to have messed with anything.

One possible source of the problem: Does the 420 have an oil cooler? When dirt and grit get into the oil cooler, you can try rinsing it out with solvent, but there's no way to see that it is clean, and anything left behind could damage the rebuilt motor...

 

WOW I haven't heard of any failures on 420's so far. Honda sent out it's tech letter saying that if you put the oil filter in backwards it will fry your tranny.
You won't have the problem if you use oem honda filters, cause you cann't put them in backwards.

Gimpster send me a PM on what you have on this, thanks buddy