Hi guys,

I was looking for some help when I came across this site. I purchased a used AC with 4500 miles on it. It had a lot of work done before I purchased it. Right now I get several backfires after releasing the throttle from a high revving, as the quad is idling back down. It runs good, just that backfiring. Any ideas anyone? Also a more serious problem. When I first start to move my quad especially when the engine is cold, the bike will rev up and barely move along at a snail pace for several seconds before it starts to apply the power to move properly. It seems after its running for a while this problem doesn't appear to be as noticable. This problem seems to happen mainly in mid and high range. And it can happen at all gears. Is it some type of clutch problem?

 

<div class="FTQUOTE"><begin quote>Originally posted by: brooker32

Hi guys,



I was looking for some help when I came across this site. I purchased a used AC with 4500 miles on it. It had a lot of work done before I purchased it. Right now I get several backfires after releasing the throttle from a high revving, as the quad is idling back down. It runs good, just that backfiring. Any ideas anyone? Also a more serious problem. When I first start to move my quad especially when the engine is cold, the bike will rev up and barely move along at a snail pace for several seconds before it starts to apply the power to move properly. It seems after its running for a while this problem doesn't appear to be as noticable. This problem seems to happen mainly in mid and high range. And it can happen at all gears. Is it some type of clutch problem?</end quote></div>


Brooker,

It sounds to me like you could have both issues being caused by caboration OR two different issues backfiring from carboration and the high reving by a slipping clutch or transmission.

First the backfiring coming off a high rev situation usually means you are running a rich carborator. You can check you plug color. It should be tan colored. Off the top of my head I do not know the adjustment to lean it out. You could also have an obstructed air filter not allowing enough air into engine. Valve adjustments can also cause backfiring if the exhaust valve does not close completely. Valves out of adjustment can make it hard to start and seem cold blooded. So check your valve adjustments.

Second, if you machine is an auto I would be checking the belt for slippage. Auto's usually rev higher before the clutch engages and there is a chance your clutch is not engaging like it should. If you machine is a manual tranny there is an adjustment for the clutch that you can make. Adjustment procedure has been posted here someplace or look in a service manual if you have one.

From what you mention of the slipping could be in all gears I will go out on a limb and guess you have a manual tranny that your clutch needs to be adjusted or replaced.

Hope this helps.
SJ

 

I did check the plug....it is more black than tan. But its not corroded or anything. Today I drained the gas because someone said it could be some water causing the problem. There was a small amount of water in the plastic bulb that sits below the tank. I am going to get a new NGk plug. I was using a different brand.(Champion). I am also getting some fresh gas to try. Also my quad is a manual tranny. I definitely think its clutch related. I can feel a slip sometimes especially if I try to go up a steep incline when the quad is cold. Before I purchased it the guy had I believe what was called the secondary transfer gear replaced. Could this be in any way related to my current problem? Maybe there is a adjustment that needs to be made?

Also I just replaced the air filter because it was causing the quad to sputter and lose power when applying the throttle. A new filter fixed that problem.

 

I would get a service and repair maual first ,then i would give a good servicing, pull off the carb and give it a good cleaning an rebuild kit ; check out the valve clearane's ! Clean out any old gas that maybe in the fuel tanl , and give it a good going over just to make everything is working right oil change/oil filter everythig, bad fuel, dirty carb can caus alot of these systom's ; this model has the Suzuki engine and tranny in it i think ! they are very good quad's and i would give it the TLC it deserves , hope everything work out for you ; williebee!

 

Well I have changed the oil and filter and replaced it with a good quality 10w40. Not synthetic but it is made by Shell. Can anyone point out where to find the page for adjusting the clutch? I have looked around but I can't seem to find it.

I should say too that my machine has a high mid and low range setting. It seems to be perfect in low range, but it slips in middle and high range. If the clutch was damaged wouldn't it be slipping in all ranges?

Thanks

 

Any ideas guys on where to find a clutch adjustment guide for a 2000 AC 300?

 

I was finally able to get my clutch adjusted today. It wasn't anywhere near the specs though I don't think. It was pretty much an exact adjustment though. Loosen the screw to much the quad wouldn't move, tighten to much and I couldn't get it in gear. I found the right spot and what a difference. I can actually spin some gravel now....lol. Also I have stopped most of the backfire. It will still have a kind of internal backfire where it makes a air hiss type of noise but no bang. I found a hose that was disconnected below the air filter, it was on a t-join whch rean into crankcase. I think its called the check valve. So I am slowly getting this machine back in good working order. I have to replace the muffler as well. I am not looking for any performace muffler, just a replacement. What other type of regular muffler can I use besides the factory muffler ($280)? is anyone aware of the red devil muffler? I would have to be modded a little but I think it would work ok.

 

You get a backfire because your pilot jetting system is too lean.
What happens is that when you release the throttle (coming from the main jet) it goes directly to the pilot system (just as though it were idling), this causes a big vacuum and sucks a lot of air (because your rpms are still high and drawing) this mixture is too lean to burn and sends the unburned gas to the exhaust where it collects then you get an off firing which sends burning gas to the exhaust and ignites the collected gas - thus a backfire.
You need only to make your pilot air/fuel mix richer.

 

So is that a matter of simply adjusting the pilot screw? According to the parts diagram on browns leisure world its on the bottom of the carb. So could I simply just slightly turn the screw and then rev up the engine to see how it responds? Also would it be a clockwise or counterclockwise turn?

 

<div class="FTQUOTE"><begin quote>Originally posted by: brooker32

So is that a matter of simply adjusting the pilot screw? According to the parts diagram on browns leisure world its on the bottom of the carb. So could I simply just slightly turn the screw and then rev up the engine to see how it responds? Also would it be a clockwise or counterclockwise turn?</end quote></div>

I am not sure with your machine but with most the pilot screw is on the bottom of the carb.

Turn it all the way in and then back it out about 2 turns - this is your reference point and it should idle fine there. Adjust your idle screw (speed of idle).
Turn the pilot screw in until it stops to idle smoothly - make a note.
Turn it back out to the 2 turns and keep turning it until it stops to idle smoothly again - make a second note.
Split the two settings (notes) and you should be dead on. I generally will tweak mine 1/16 to 1/8 turn for richer (out with most carbs). As is with life it is better to be a little on the rich side for a buffer.