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Discussion Starter · #1 ·
I bought a 1999 400 ex that hasn’t ran in a while and I got it running the other day it was running very choppy due to low idle . Valves have been adjusted but one exhaust valve was stuck making it back fire and I’m pretty sure it’s running lean . Problem is when it starts it makes a ticking sound could it be my idle and fuel mixture is a little messy or could it be my valves need a new adjustment or a change out Video of bike running if you guys have any
Tips or solutions it would be appreciated
 

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Discussion Starter · #2 ·
I bought a 1999 400 ex that hasn’t ran in a while and I got it running the other day it was running very choppy due to low idle . Valves have been adjusted but one exhaust valve was stuck making it back fire and I’m pretty sure it’s running lean . Problem is when it starts it makes a ticking sound could it be my idle and fuel mixture is a little messy or could it be my valves need a new adjustment or a change out Video of bike running if you guys have any
Tips or solutions it would be appreciated. Timing chain is good and does not blow blue smoke
 

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If it had a stuck valve it would have never started - back fire out the exhaust at low speed or during starting is usually ignition related (late or weak spark) - backfire out the intake is usually a lean condition in the fuel system. Ticking is not abnormal for the 400 or most other air cooled engines as there is no water jacket to insulate internal engine noises from being heard. A tick is usually not valve related, but more often cam chain, piston slap or spark knock. You might recheck the valves just to assure proper clearance and then ignore the tick unless it gets progressively or suddenly louder. It's an old motor and some noise is to be expected.
 

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Discussion Starter · #4 ·
If it had a stuck valve it would have never started - back fire out the exhaust at low speed or during starting is usually ignition related (late or weak spark) - backfire out the intake is usually a lean condition in the fuel system. Ticking is not abnormal for the 400 or most other air cooled engines as there is no water jacket to insulate internal engine noises from being heard. A tick is usually not valve related, but more often cam chain, piston slap or spark knock. You might recheck the valves just to assure proper clearance and then ignore the tick unless it gets progressively or suddenly louder. It's an old motor and some noise is to be expected


What would you recommend me to do
. I had the chain looked at and it is tight and good
 

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Well that tells you nothing other than it's not broken and it's a lot of work for nothing, but if you were in there for clutch work anyway, it was a good time to take a pic.

To inspect the cam chain without removing it from the engine and physically measuring it's length; take the screw (#10) out of the tensioner - loosen the bolts (#9) about 4 turns - break the tensioner case (#6) away from the cylinder so the spring in the tensioner is pushing the case away from the cylinder - continue to loosen the bolts #9 and measure how far the spring pushes the case away from the cylinder - if the distance is 3/16" inch or less, the chain and guides are worn to the point of needing replacement or the tensioner itself is not operating properly. If the spring pushes the case more than 3/16" away from the cylinder, then the chain is serviceable and the tensioner is working as designed. Follow the instructions in the service manual to retract the tensioner plunger and reinstall the tensioner.

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If the clutch cover is still off, it is a good time to check the clutch for wear (note: the clutch can rattle at low speed and cause a noise that sounds like it's in the valve train). Disassemble the clutch per the service literature and check the wear on the clutch plates especially where the clutch plates contact the fingers of the clutch basket. If the plates have worn diviots into the fingers, both the plates and clutch basket should be replaced.

NOTE: The clutch basket (#3) is no longer available - option for repair is to buy an aftermarket basket (Barnett perhaps) or to have a machine shop weld the worn fingers and mill them back to spec, or mill the fingers and cap them with stainless steel channels. It's whatever you can more easily afford.
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Also, while you are in there, check for chipped teeth on the gears and foreign material between the teeth of the gears that can make a ticking sound too. I worked on one one time that the owner had replaced the crankshaft in because "the rod was knocking", but after installing a new crank it still knocked. I found a chip of aluminum wedged between the teeth of the clutch basket gear. As the clutch gear meshed with the crank pinion gear every time the chip of aluminum contacted a tooth of the pinion gear, it made a knocking noise. I used a screwdriver to dislodge the chip and the knock was gone.

You are looking for a tick so whatever is causing it is going to be smaller and harder to find, but if you completely dismantle the engine and replace or repair every worn part, the tick will most likely be gone. It just takes patience and attention to detail. Measure every part and anything that is not in spec, replace or repair it. When you get done, you should have a motor that does not tick.
 
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