Quantcast
Jump to content


1990 Suzuki Quadrunner 250 LT-4WD - Mixture and Valve specs


Recommended Posts

Hey all,  I've been working on getting up enough posts to download the service manual, but in the mean time, maybe someone is interested if giving me a few deets in a reply?  If not, no worries.

 

I'm look to confirm a couple things that I've picked up from Google searches.

 

First, I've heard that the factory mixture setting on the carb for this bike is 2 full turns out.  Can people confirm?  I've also heard that it's a fuel mix valve, not air, so screw in to lean, out to richen?  Is that correct?

 

And for the valve clearances, I've heard two different specs, one is intake 0.004" and exhaust 0.006", and that other I heard from a youtuber who claimed this bike had 'very tight' valve clearances, said 0.002" intake, and 0.004" exhaust.

 

If anyone wants to comment on the above, I would be appreciative, if not though I'll keep posting until I can download that service manual :D

 

 

Link to comment
Share on other sites

Well there goes five potential posts already Bender.. haha.

Valves get dished at the top where the adjuster rubs, so using feeler gauges is not an accurate way to adjust them. If you have a dial indicator gauge (which measures movement), that could be used, but I always just set them by ear. If you have the valves closed as they should be, and lift the valves and then snap them down as hard as you can in the confined space in there, you should just be able to feel and possibly hear a tiny dull click from the inlet, and when the exhaust is right it will just make a tiny but clear click when you do it. Those will give you figures of close to 2 and 4.. Six is noisy, testing and running

So almost silent and barely feelable for inlet, and definitely feelable and hearable for exhaust.. They do have a habit, if the clearances are too great, of hammering and getting clearance again in a short time. If, after setting them, you can hear them clicking, they are too loose.

Link to comment
Share on other sites

On 8/13/2022 at 2:15 PM, BenderIsGreat said:

First, I've heard that the factory mixture setting on the carb for this bike is 2 full turns out.  Can people confirm?  I've also heard that it's a fuel mix valve, not air, so screw in to lean, out to richen?  Is that correct?

No clue about the turns, but any carb with the screw towards the front of the carb has a fuel screw (turn out to richen) and any carb with the screw at the tail has an air screw (turn in to richen).

On 8/13/2022 at 2:15 PM, BenderIsGreat said:

And for the valve clearances, I've heard two different specs, one is intake 0.004" and exhaust 0.006", and that other I heard from a youtuber who claimed this bike had 'very tight' valve clearances, said 0.002" intake, and 0.004" exhaust.

0.002" intake, and 0.004" exhaust is correct.  Those are averages.  I always set the intake to .001 which is the smallest perceptible movement.  Like Mech, I don't use feelers.

If you find that your intake valve has no clearance at all then it means the valve is wearing and you will have to regrind the seat and purchase a new valve, preferably one made in Japan.  If the engine is nearly impossible to start when cold, then it almost certainly needs a new intake valve.

Link to comment
Share on other sites

  • 2 months later...
On 8/13/2022 at 1:15 PM, BenderIsGreat said:

Hey all,  I've been working on getting up enough posts to download the service manual, but in the mean time, maybe someone is interested if giving me a few deets in a reply?  If not, no worries.

 

I'm look to confirm a couple things that I've picked up from Google searches.

 

First, I've heard that the factory mixture setting on the carb for this bike is 2 full turns out.  Can people confirm?  I've also heard that it's a fuel mix valve, not air, so screw in to lean, out to richen?  Is that correct?

 

And for the valve clearances, I've heard two different specs, one is intake 0.004" and exhaust 0.006", and that other I heard from a youtuber who claimed this bike had 'very tight' valve clearances, said 0.002" intake, and 0.004" exhaust.

 

If anyone wants to comment on the above, I would be appreciative, if not though I'll keep posting until I can download that service manual :D

 

 

I'm going to assume you've posted enough by now to get the service manual:)  With your new found knowledge, would you happen to know if this applies to a 1995 quadrunner lt-4wds?  I'm still posting my way to 10, but this nugget would be nice to have sooner than later.   Thanks in advance!

Link to comment
Share on other sites

  • 2 months later...
37 minutes ago, DwayneM said:

I'm in the same boat as he was.

 

I'm trying to get enough post to get the manual 

 

But my problem is the fly wheel came off and I need to now if I'm missing any parts. The threads on the shaft are half corroded away and the nut has none.

These posts are have been combined. Inflating post counts is not allowed.

Link to comment
Share on other sites

You can get the correct die to clean up the threads on the crank and then replace the nut iv had to do this on several occasions it works fairly well, if the threads are too far gone gone you can use a smaller die, cut some new threads and go with smaller nut, not ideal but its better than replacing the crank. Iv also used a thread file it kind of works if you have enough patience, but a die works better. As far as missing parts you should have flywheel, see if all the magnets are in place, stator, and pickup coil.

Link to comment
Share on other sites

2 hours ago, Gwbarm said:

Iv also used a thread file it kind of works if you have enough patience

I've done that a long time ago lol

I'd probably weld more metal on then heat it to remove hardness then cut new threads with a die.  Or hire a machinist to do it.

I've welded more metal on cams lobes and polished it up then did the same to the rockers.  Because weld is so hard it will last longer than stock.  I used some differential gear paint to make sure the cam was riding flat on the rocker.  I'm kinda proud of that :)

Link to comment
Share on other sites

  • 2 weeks later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Similar Forum Topics

    • By STLJ
      Gday all,
       
      Been trying a couple different ways now to download a manual. Not sure what I am doing wrong but could someone walk me thru it?
      I go to DL page and click on link
      get a pop up for a PDfixer or something
      close that and then hit download button and no go
      tells me I have reached my limit but I have never DL anything ever. 
    • By Suzukiquad
      If you had to choose one mod that you couldn't live without, or had to recommend one what would it be? 
    • By Clydaho
      2022 Sector 550, 414 miles on it and the gas gauge reads empty.  I topped off the gas and it didn't change.
      There is no fuse that I could find.  No access at the gauge cluster.
      Wiring on the top of the tank looks good, properly connected.
      Could the sending unit in the tank be stuck or broken?
      Has anybody removed the tank lid?  Any tricks?  
      Any other ideas?
      Thanks for any help,
      Clyde
    • By rgeiser
      View File 2003 Polaris Ranger 400-500 service manual
      2003 Polaris Ranger 400-500 service manual
      Submitter rgeiser Submitted 04/18/2024 Category Polaris UTV  
    • By Admin
      View File 2006-2011 Honda Rincon TRX 680 FA/FGA service manual
      2006-2011 Honda Rincon TRX 680 FA/FGA service manual
      Submitter Admin Submitted 04/09/2024 Category Honda ATV  
×
×
  • Create New...