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

[BenderIsGreat]

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

 

 

[Mech]

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.

[JustRandy]

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.

[JLoob]

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

 

 

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!

[BenderIsGreat]

Screen snip from the manual, looks so, says 1987-1998

[JLoob]

Great.  Can't wait to earn it!  lol

Enjoying the forums so far.  Only had my quadrunner for a few months and previous owners didn't appear to maintain too much, so there's a lot I plan to do with it.

 

[DwayneM]

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.

[Admin]

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.

[BenderIsGreat]

If you're just looking to see if you're missing parts, try the parts house site, it has all the part diagrams:

 

1990 Suzuki LT-4WD OEM Parts, Babbitts Suzuki Parts House

[Gwbarm]

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.

[JustRandy]

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

[DwayneM]

I ended up finding the perfect nut that was a hair smaller than the original. The shaft still had half the threads left so I just used a impact and it snuged right up