LT50 engine problem ? - Off-Road Forums & Discussion Groups
Go Back   Off-Road Forums & Discussion Groups > ATVs, Quads and Four-Wheelers > Youth ATV

Youth ATV For discussion of all youth ATV's 125cc and smaller.



Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 02-24-2003, 04:28 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Default LT50 engine problem ?

My son's LT50 stalled and upon trying to restart the engine I noticed the starter "puller" was very stiff. I left it a while and it has freed up. The same thing happened today and I am concerned the engine is going to seize. Its got plenty of 2 stroke oil which seems to be flowing OK (although the engine doesn't seem to use much). Is there anything I can do before I open up the head ? Any tips gratefully received.
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2  
Old 02-24-2003, 06:00 PM
tony1034
Guest
 
Posts: n/a
Default Re: LT50 engine problem ?

Is the bike new? Perhaps the engine is getting flooded, making it hard to start. Pull the plug. How does it look?

Tony P.
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #3  
Old 02-25-2003, 09:09 AM
**DONOTDELETE**
Guest
 
Posts: n/a
Default Re: LT50 engine problem ?

It sounds like it temporarily seized. After letting it sit, it cooled off & freed up. To avoid more costly repairs, I would remove the top end & inspect. You may get lucky & just have to replace the rings & do a cylinder hone. While you're at it, disconnect the oil injection pump & pre-mix Maxima 927 at 32:1.
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #4  
Old 02-25-2003, 09:57 AM
**DONOTDELETE**
Guest
 
Posts: n/a
Default Re: LT50 engine problem ?

You my also check for an air leak around the carb and intake. Even a small air leak will cause the machine to run lean and do what Master Wrench is refering to.
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #5  
Old 02-25-2003, 02:39 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Default Re: LT50 engine problem ?

Thanks Master_Wrench you were spot-on. Upon inspecting the head I think I will get away with rings and a hone. I like the idea of pre-mixing myself, to disconnect the oil injection pump do I simply disconnect the oil hose or is it a little more involved! Thanks for the help
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #6  
Old 02-26-2003, 07:52 AM
**DONOTDELETE**
Guest
 
Posts: n/a
Default Re: LT50 engine problem ?

Where the hose connects from the oil injector to the carb, you must block off that line so you are not sucking air. You will do better if you take out the oil injector drive gear & the oil injector pump, as I have seen the pumps seize up, since there is no oil lubricating it any more, yet, it is still turning. Just make sure you block off where the line goes into the carb/intake.
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #7  
Old 01-14-2004, 04:15 PM
quad_dad
Guest
 
Posts: n/a
Default Re: LT50 engine problem ?

I know this thread is a year old, but I've just found it. My kids LT50 must have temporarily seized at some point also, the pistons and rings are badly scored. The barrel is still OK, and I've got a new piston kit that I'll fit this weekend. Thing is, I'd rather make the oil feed work the way it's supposed to before I resort to pre-mix fuel. (The bike sits for long periods) Does any one know how I can get the bike to feed more oil into the fuel by itself ?
Does the LT50 work by vacuum or pump ? Can it be adjusted ?
Any advice gratefully received.
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #8  
Old 01-15-2004, 09:51 PM
MattFisher
Guest
 
Posts: n/a
Default Re: LT50 engine problem ?

The LT's oiling system is gear driven, and I don't see how it could be adjusted short of drilling out the cases and cylinder in hopes of getting more oil to the intake. If you aren't getting oil into the cylinder, it's probably blocked somewhere, as the gear driven setup it pretty stout.

Unlike most systems, the LTA50's oil is injected into the airstream after the carb, maybe 1/8" from the cylinder itself. If you pull the cylinder off, you'll see a very small hole on the top of the cases where the cylinder meets it. Oil comes out of the tank, into a banjo fitting on the right side case, down into the pump, then through a passage in the cases ending up in a small hole drilled into the bottom of the intake port, right before it enters the cylinder.

To disable the injection is ultra easy. Pull the banjo fitting out and replace it with a bolt. Optional would be to pull the case and push the pump gear away from the transmission gear. I noticed no power difference in doing so.

Check to make sure oil is making it into the banjo fitting. Most likely the oiling hole in the intake has gotten plugged from carbon buildup, or the little motor got so hot it seized even with the lube system working. These motors are well known for having carbon buildup issues, especially when they've been run in restricted mode. I have had great carbonless results with Motul 600, using it both in the injection and now in premix. Make sure you're not running a BPR4H plug, that's one really hot plug. The BR5H or even a BR6H are much better choices.

When re-assembling the motor, make sure the base gasket does not block the oiling hole. You may also want to drill a hole in the intake skirt for more power. I posted specs on miniquads.com in the post "LTA50 Mods".

[img]images/graemlins/scs.gif[/img]
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #9  
Old 01-17-2004, 07:22 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Default Re: LT50 engine problem ?

quad_dad,
MattFishers is the man,
I followed his suggestions on another forum, finished the machine work tonight and going to assemble tomorrow. I'm up in the air about the injection. A loose banjo fitting caused damage to ours. I just like pre mix better so I'll probably un do it and use a good mixture. Also if you need parts the stealership is usually high, I found ronayers to be a good source.
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Off-Road Forums & Discussion Groups forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -5. The time now is 10:45 PM.


Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO 3.2.0
Copyright 1994-2009, VerticalScope Inc. // Off Road forums & discussion groups sitemap
side by side | atv | dirtbike | snowmobile | sandsport | competition | land use | Jeep | Toyota | Ford | GM