Exhaust leak

[95sportster]

I've already solved this issue but thought it may be helpful to anyone with the same problem.

I was cruising out on the river a few weeks ago (testing out the MPEM I repaired) and about 15 minutes into the trip the engine gets loud all of a sudden. I pop the hood to see whats going on and water is leaking everywhere from the exhaust manifold. All 6 manifold bolts had vibrated loose in the 16 hours that I've put on this motor. The vibrations had also ruined the gasket so even when I tightened it back up the leak still persisted.

I traced the problem to the rubber bushings that hold the exhaust cone to the manifold. They were distorted and probably allowed it to vibrate more than normal. I've replaced the gaskets and torqued the bolts to the correct specs and am waiting on the bushings in the mail. I should be back on the water in the next few days but just thought I'd share for anyone with similar issues and to remind people to check those bolts occasionally.

 

[Albysure]

That's good you found it...but I always use threadlocker on all bolts. As ling as it doesn't come in contact with gas or oil. 2strokes shake way to much...blue threadlocker will work good..

 

[Dr Honda]

Generally... the exhaust gets too hot for any kind of thread locker to be reliable.

Here's the deal. Most people over torque the bolts in the exhaust. SO... when the parts get hot... they expand. AND... that will stretch the bolts. Then... after it cools, and you re-start the engine... they are already loose, and vibrate out. SO... when you have exhaust bolt issues... you need a new gasket, new bolts, and new lock washers. Then... put it together using only 18 Lb-ft of torque. (That's less than the sparkplugs)

If you do that... they will stay in place because the bolts will still be in their "Sprinngy" range.

 

[95sportster]

Yeah the bolts were probably overtorqued originally as well. I broke out the manual and did use threadlocker as specified in the manual and torqued them to the 18 ft/lbs. Still waiting on the rubber bushings for the cone- they might not have been the direct cause but they were distorted enough to allow more vibrations.