Exhaust flange nut!

[viclioce]

Is there a secret to keeping this tight on the Ace? I have driven the bike about a total of 11 miles around the neighborhood and 2 miles round trip to my daughter's house. It's loosened up twice already. I went back this time with a screw driver and hammer to turn/tighten it. I think I got it right again, but it seems to keep coming loose.

The first time it happened, I thought the fuel mix was too rich, but it was only showing signs at higher rpm. Turned out the exhaust nut was loose. Soon as I tightened it back up, the problem went away. In just a few miles, it's loosened a second time. Do I need to put something like anti-seize on it to keep it tightly in place? Thanks in advance! ; D Victor

[hodakamax]

There's an article in the Resonator V2, #17 on exhaust nuts and tools to use. It's a problem we never had but I do like Clarence's safety idea. Nuts need to have copper washer and be really tight. Again check for a broken nut.

Max

[viclioce]

Greg said to clean the threads really well and add some blue Loctite. So that's the route I'm headed now. I'll use a wrench like that when I put it back together, good old fashioned channel locks! Probably the best tool for the job! ; D Victor

[taber hodaka]

This is the solution that served me well many years ago. First I connect and install the exhaust gasket and then I tighten it about in the position that matches the connections at the rear of the exhaust. This seats the exhaust gasket in a more uniform manner. Then I put a hose clamp on it and wire it over over to the frame. The engine cannot be run with a air leak at the exhaust. This method allowed me about 70+ wins in cross country and motocross without this failure. Back in the day.-------------Clarence

[Bill2001]

That is different. On my BMW R-bike the aluminum exhaust nut is screwed onto an aluminum spigot on the head and MUST have antiseize compound applied yearly or they will seize together. First thing I did on the Wombat (94) was loosen the exhaust nut, wire-brush it and the spigot and apply antiseize compound. Should I re-do it? There was a copper crush ring installed, and yes, it didn't look evenly crushed.

--Bill

[hodakamax]

Lotsa good input on this one. Maybe we should summarize with everyone's good ideas. The first thing (brought up by Clarence) is that the flange must be flat on the exhaust spigot which might involve loosening some exhaust pipe brackets and assembling the system where nothing is in a bind or under stress. A crush washer is needed and things need to be tight. A cracked exhaust nut could cause a rapid loosening. Usually the problem with exhaust nuts is getting them off. I have never tried any anti-seize or Loctite type stuff nor needed any. Neutral on that one but I have an open mind. Any more input on that Gang?

Max

[Bill2001]

I've been using Channel Locks to tighten and loosen the exh nut. Would a "proper wrench" like the Hodaka tool be better? Any idea of a "TLAR" torque on that? On their aluminum exh nuts BMW specs 130-160 ft lbs (WOW!!!) though I've always used a "good double grunt" at 75-100-ish ft lbs.

I can see where snugging the nut first on a loose system and then working backwards tightening things up would work best.

--Bill

[hodakamax]

Sometimes I worry about how tight the nut should be until I think of what forces it takes to get some of them off. I doubt that we are going to get it too tight with the tools at hand!

Max

PS--this reminds me of the instructions printed on a Mazda oil filter I bought from the Mazda dealer. On the box the instructions clearly read "Tighten until tight enough."

[viclioce]

..this reminds me of the instructions printed on a Mazda oil filter I bought from the Mazda dealer. On the box,the instructions clearly read "Tighten until tight enough."

OK. Now that's the best answer yet. I'm going to remove the exhaust nut, clean the inside threads and the threads on the pipe and reassemble, and hope that it's just the exhaust leak which has provided unburned fuel/oil thst was causing the nut to loosen. ; D Victor

[RichardMott]

The problem of the exhaust flange nut loosing up had been a problem on my Ace 100 B+ back in the 1970s. Being an old aircraft assembler, I had the answer straight away. Safety wire. I drilled a #40 hole in the flange (it is cast iron) Another hole in one of the Webco head fins. I used .020" safety wire. It is hard to see in this photo, but look closely. Save the photo then increase to size to 200%.

[bchappy]

The safety wire was my solution back in the day. Never failed after that.

[taber hodaka]

My use of the hose clamp held my safety wire and I didn't have to unwire it I just loosened the clamp.------------ Clarence

[viclioce]

I think I got it now. Grabbed my channel locks and the nut took another 3/4 of a turn even after the hammer and screw driver trick. Just maybe it will stay tight now. Hopefully! ; D Victor