Hello all,

I have a 1996 Magnum 425 that has a bad rattle on the right side of the engine when trying to start. I've heard it could be a weak starter but the starter is new and it sounds a little lower. I did a timing adjustment and broke one of the cam sprocket bolts off. Could this cause the noise?

Now another problem, It won't start. Not that started real easy before, I've had it running maybe 2 times since I bought it a year ago. After I did the timing adjustment it started right up but it had a super high idle instantly and it started to smoke out of the valve cover. Now it rattles and won't start at all! I know it has spark, good gas, and I cleaned the carb. But maybe someone can give me a good break down of how to clean the carb really well? Not sure if this even has to do with it.

I am completely lost. When it runs, it runs extremely good. It has never started easy. Any and all help is highly appreciated!!

 

The Bendix drive behind the recoil cover on those motor are a lose rattley contraption. Every time I hit the starter button it sounds like a can of marbles.

Your Bendix drive may need replacing . I had to change my before.

 

Ratting can be a worn out bendix along with the bushings the bendix rides in. Item#9.Dirt Cheap Yamaha, Polaris, Suzuki & Kawasaki OEM Parts & Accessories – Cycle Parts Warehouse Most people over look thse brass bushings as they do wear out. Takes one in the recoil housing,one in the engine case. Both are the same. I'd also pull the cam cover and check the cam out.You're in the year model range that had exhaust cam lobe problems.Both the 425 and the 500 engines. Valve clearance set at .006 on intake and exhaust also.Here's what most of them do that are affected.Bad Cam Pic - ATVConnection.com ATV Enthusiast Community

 

Thank You. Does this cause any starting/running problems or is it just annoying and not hurting anything?

 

Thank You. I been meaning to do a valve adjustment but don't have the proper tools. Would this cause the not starting issue?

 

Could if the valves are too tight. You can check that along with the cam lobes when you pull the cam cover off. All you need is a set of cheap feeler gauges and at least a 10mm metric wrench. Just get the cam sprocket alignment pin at tdc of the head for checking/adjusting valves.

 

Bump. Can anyone help me with the high idle and smoke from the valve cover? Or how to get it running again?

 

Have you at least pulled the valve cover,checked the oil level in the tank,checked for any leaks? Smoking could be from a leaking valve cover gasket on the exhaust or could be from a low oil level in the tank,stopped up oil passages in the head,etc.Have you tried to lower the idle screw on the carb? Made sure the throttle cable isn't too tight at the thumb lever? Either of these could cause a high idle along with a leaking intake manifold,etc.A cheap service manual can help you in a lot of ways. Here's one for 5 bucks. DOWNLOAD 1996-1998 Polaris ATV Repair Manual ALL MODELS - Download ...

 

The oil is new and full. Their is a slight tear on the outer side of the gasket valve cover but the inner side is fine. Would such a tiny tear cause smoke to billow out almost smoking out the garage? Last time it started with the high idle I messed around with the idle screw and made no difference. Also last time it started I loosened and tightened the throttle cable on the thumb with no luck. How can I tell if the intake is leaking? I also got a manual when I bought it but doesn't really help much with these problems .

Thank You for the reply and help.

 

A tear could cause smoke to escape,BUT the crank case vent that runs to the air box is supposed to take care of most of that UNLESS it's stopped up.Just check that the hose leading from the engine to the air box is open. If the filters' still on,they can get stopped up over time also. Plus check the anti siphon valve on the front of the engine to make sure it's operating ok.It's to keep oil from running back into the crank case when engine is off.The "engine" section in the manual shows you this.Spray contact cleaner,wd40,etc around the intake boot while running and see if the idle changes . If so,it's an air leak there. Plus check directly under the carb clamp at the boot. Split boots can happen there and suck air and easily over looked. Again just back off the idle adjuster on the carb,check that you have only 1/8" slack at the throttle lever. The cable slack adjuster is right on the cable under a rubber boot at the throttle housing. Once you have that set see if it idles,if not turn the adjuster in. A lot of this info is in the manual,you just have to look for it. Start at the maintenance section.