I am not sure the best route to go but here is my situation. Recently I fixed up a Suzuki LT4WD which had mostly external issues like bad starter, bad reciul, missing timing chain tensionor, compression release lever head in place by a wire hanger and most of the CV boots tore up. Nothing wrong in the core engine but took about $300 in parts to get it working. It ran for a few months but I found myself having to constantly adjust the intake valve out to keep it running. While I was wondering why the valve would keep tightening up on its own despite the use of locktight on the locknut I found out that the valde adjustment was not actually moving down but the valve was moving out and at one point I could not adjust it any further. The adjustment screw is completely out and the valve is still pressed hard against the rocker. Now I am not master mechanic but I assume that the valve is now all the way the rough whatever valve seat or even the head itself which means I may or may not be in the market for a new head.

I have not taken the time to pull the entire head yet but since the ngine has always leaked oil between the head and valvecover at a rate of 1 qt per gallon of gas I burn, I was thinking I might be further ahead replacing the engine or maybe just the head and valve cover. At this point though I am pretty much unable to get to work so day by day I have less and less money as this ATV happens to be my one and only transportation to anywhere.

So with everything I explained above what do you guys think is my best bet? OEM Head assemblies seem to run in the ball park of $370 and up. At one point I remember seeing an entire LT185 being parted out on ebay and the engine went for $75. I was hoping that the LT4WD might go up on ebay like that but its been months of looking and I really cannot wait now that the machine is completely dead again.

So what is my best course of action? What sort of things should I be looking for when I pull the head to know if I really need to replace the head or not. Any advise would be helpful but money is my major concern right now. I am still fighting with 15-17% unemployment rates in our county over the past 2 years. When I get work I have to be there or I am sunk. I have already lost 2 jobs in August due to this problem.

 

On my suzuki I fitted a new valve and the problem went away, must be a better valve (the replacement)

 

I am in the process of pulling apart the head but just occurred to me I might need to know how to re-time it when I am done. Right now I have the head loose, came shaft removed and the cam sprocket holding the chain so I do not lose the position. Hopefully the cam will slide through the head without having to remove the chain. But should I need it what is the best way to get it back into time?

 

Actually I just came across a nice post on another forum that helps with the timing. For anyone who might come here asking the same question:

quadsport rebuilt - Page 2 - Suzuki ATV Forum
and another thread on the same topic
91 LT4WD 250- How to line up timing marks? - Suzuki ATV Forum

Now on to see how bad thing under the head. Hopefully all I need is new valves. New head is nearly $400. I only paid $500 for the machine originally so an OEM head would not be worth it for me. I do occasional work for a local machinist and he often has very creative methods for fixing things one would otherwise thing could not be fixed. So hopefully I can get this back working quickly for very little cash.

 

I now have the head off and I cleaned up the intake valve on a wire wheel and it looks brand new. I cannot see any wear on either the head or the valve but I know something has to be worn otherwise it would not seat so deep into the head.

Does anyone know where I can find the exact dimensions the valve should be. I have access to a complete machine shop so I will be able to measure the valve diameter down to the micron. then at least I will be able to tell if a new valve will fix this problem of if my entire head is needing to be replaced. As far as I can tell there is no replaceable valve seat in the head but correct me if I am wrong.

I wish I had the ability to send pictures but I have no way to do that now. What I could use is an expert opinion from a mechanic but the ones around here want to charge too much and I am very short on cash right now.

Any help or advice is appreciated. Thanks

 

I have this exact problem. If you determine the cause, I would sure like to hear. I have not removed the head on my '87 LT4WD, but I have been assuming that the valve seat insert has been moving deeper into the head casting. Does it look like that is happening on your head?
Thanks,
Jim
Alaska

 

I have been finding articles around mostly about LT-4WD and LT-F250 models which share the same engine as far as I know. And in each of them they seem to indicate the problem is always in the intake valve which goes against the normal situation of the exhaust valve being the one to stretch in length over time. So I do not know why this particular engine seems to have a problem with the intake valve or what the exact cause is. But when I know I will be posting it as well as on suzuki atv forums as well. These two forums appear to be some of the more active when it comes to the model atv I am working with.

For right now the main consensus seems to be pointing lapping the valve and slapping it back together. And some have said that buying a new valve might help but nothing seems certain. Fortunately hardly no one appears to be saying the head is worn and needs replacement.

Right now though I am a bit poor so buying lapping compound is out of the question for a while yet for me as I prefer to have food on the table. Without transportation I am often making less then $30 per week but as soon as I can manage it I will try lapping the valve and putting it back in. I already used a wire wheel to clean the valve to what I think looks factory new. And I found the valve to have no defects that my untrained eye can see nor can I find any obvious wear on the valve seats in the head either. So I guess I will just try putting it back together and see if I have any adjustment play or if its still going to be too tight.
Then if that fails I will try and get enough money for a new valve and see if that works. And if that fails I will be kicking myself for all the wasted money and likely have to junk the machine because buying new head would cost more then the whole machine cost me originally.

 

Lapping the valve involves putting some grinding paste (lapping compound) on the face of the valve and the seat, and rotating the valve against the seat to improve the seal. I don't see how this is going to help, it will just make the valve sit even lower in the seat, further reducing the clearance between the valve stem and the adjuster.

Hope it works somehow though. If I figure out mine, I will post what I found out.
Jim

 

You can always grind the end of the valve stem down a little to get the clearance for your valve lase.

 

I think the valves weaken as they get older and stretch that is why a replacement is a better deal