Hi,
I bought a 99 Scrambler 400 4x4 a few months ago, and I have a question. When I first crank it up and few the first few minutes of riding, it seems a little groggy when you try to rev it up. You can also smell some extra gas/oil in the exhaust. I have driven these 400 2 strokes before and I don't think it's normal. However, after a while it drives pretty good. I've changed the spark plug already but it didn't make much difference. Do ya'll think it could be a problem with the fuel/air mixture or what? And can you adjust the mixture on the oil injection system?

 

how long does it run groogy? two strokes like being warmed up good b4 having the pi$$ run out of them

 

It doesn't matter how long I let it sit there idling, I always have to ride it around and rev it up for a minute or two before it will quit being groggy... letting it warm up idling doesn't really help that much. When I take it out and ride all day though, it can sit for a while and still run good when I crank it back up as long as the engine stays warm.

 

its perfectly normal. ive owned two 400's and theres about 5 more in my neighborhood and they all do it. until you get the motor warmed up its going to sound groogy. warming up a 2 storke is very important. you should always warmup two to three minutes b4 cutting her loose. i recommend just riding the bike around easy for a couple of minutes until the hesitation goes away.

whatever you do dont let that motor just idle. carbon will build up causing your plug to foul. always keep the trottle moving.

 

Not sure about 2 stroke ATVs but all our 2 stroke sleds hesitate and smoke at cold start up sometimes you can barely see the machine through the dark smoke.LOL After they get warmes up they fly all day long.

 

ok thanks i was just a little worried... my throttle response on the machine also seems a little slow unless i give it a pretty good bit of gas.. is that pretty typical?

 

The stock 400 piston will grenade. Have you done a compression test?

 

i haven't had it checked but the guy i bought it from said that the motor had been rebuilt about 6 months or so before i bought it. what's the easiest way to test it? mechanic? DIY?

 

<div class="FTQUOTE"><begin quote>Originally posted by: ctownscrambler400

i haven't had it checked but the guy i bought it from said that the motor had been rebuilt about 6 months or so before i bought it. what's the easiest way to test it? mechanic? DIY?</end quote></div>

With this



It screws in where the spark plug goes and you pull over the engine a few time. anything over 120 psi is usually good.

 

ok thanks for the help... my mechanic has one so i will test it this weekend.