i was told to come here and ask for you......i have a 94 400L two stroke that i bought....i am not a atv mechanic but i work on small engines and cars...it only runs for a few seconds and quits...usually starts again on first pull...with or with out choke...i had someone look at it and say needs carb kit...so i had that put in....then was told low compression...so i had it honed and rings put in...has 120 psi...the only way it runs is to crank the idle screw all the way in...then it sputters for 10 seconds and dies...rubbers are good...i set the long brass jet from 3 to 4 to 5 then 6 at top...runs same. i cked veins...one looked like it had space..i turned it around..and cleaned...plenty of fuel flow...has spark im at a loss...someone also said put had over carb...see if it sucks in good...so i did that...pulls my hand on hard and will pull gas from float bowl....new spark plug...someone did put a toggle switch on i think its the cdi box? black wire i think but it makes no difference if its on or off...runs same..

 

Not a fan of just honing a cylinder and putting just new rings in myself,no matter what the compression reading is.One thing most people over look is crank seals that may be leaking also. If they are leaking it can't compress the mixture fine enough into a mist that can easily move up the transfer ports for ignition. Usually plugs end up wet and fouled or it can't get enough fuel for it to stay running. As far as the toggle on the black wire,probably a shorted out cdi kill circuit in the cdi itself that they toggled past it. Plus if the black wire from the reverse limiter is still hooked up,pull it as it can cause problems on running.

 

ya think i should do the lower seals first...i did a wet test this morning and have 140 psi compression...i moved the needle clip to the 1st setting and it started to flood...so i took out plug and said what the heck...ck compression again...you know where the wire is you want me to unplug? and should i just go ahead and have it bored and new piston and rings?

 

Don't try to bombard yourself with several things at a time. You can have good top end compression,but if you don't have a good seal on the bottom end,it still won't crank. You can either do a leak down test to see if other areas might be leaking also or simply order the cheap crank seals.The main seal to have problems is usually the one behind the front clutch. You have to have the clutch puller on this. Have to pull the flywheel and stator on the other crank seal. You can get them here,plus item #41 is the limiter with the black wire that you can pull.It plugs into the terminal board #34 on the parts break down.Dirt Cheap Yamaha, Honda, Arctic Cat & Polaris OEM Parts & Accessories – Cycle Parts Warehouse
Plus a good manual can help you on problems with the trouble shooting guides.http://gh-ftp.com/ORV%20Manuals/Pola...e%20Manual.pdf

 

ill order the seals and do them up first...thanks for the help...ill let you know how that turned out and if i need to go farther...thanks again for the info/help.

 

ive never done a leak down test on a two stroke...if you have the time...could you discribe it to me...i do it on 4 strokes but id guess you have to move piston up and down to do the right ports???

 

Easier just to replace the seals as you would have to spray soapy water around them while under about 7 pounds of pressure. You have to remove the clutch,flywheel to be able to do this,so you might as well replace the seals since you're there.Leak down test may help on other areas as well such as leaking base gaskets,head gaskets,the crank case itself.Several different leak down tests and tools required shown on youtube.

 

i looked at utube last light and didnt see a test...maybe i googled it wrong....i have one of those testers...and one that we used to to choke pull offs with...thanks for the info again....i ordered the clutch tool and seals last night but i havent found the flywheel removal tool yet...im still looking....thanks for the info again...

 

You can rent a good steering wheel puller at most auto stores or buy one.

 

thats an old harmonic bal puller...i have one of those....my steering wheel puller is just straight across.....thanks....for the info AGAIN...you ROCK...