Bike stalls after starting up and flat spot off idle

[Donkey Hotey]

No, there is no preload on these mounts. They’re purely in shear. There is no clamping at all. The deeper nuts were designed because of tolerance stackup between parts. On many bikes, tightening the nut doesn’t actually secure the mount to the frame because the male threads on the mount bottom out inside the nut before ever clamping the frame ear. The deeper nuts allow that extra thread of rotation to properly tighten them.

Do you need them? You won’t know until the nut stops turning and you find out if they’re still loose or not. So far, I think only one of my bikes needed the deeper nuts. You could also carefully grind down the length of the protruding threads on the mounts if they’re too long. Doesn’t take much.

[wytfut]

Joe....
that was me in facebook with suggestions...
Correct me Greg as needed, but I was under the understanding the design of the deeper caps/washer trick was to spread the vibration frequency at the motormounts away as it were... to cut back vibration direct to the motormounts.
You make it too simple, I didn't even think about cutting the threads  back on the mounts to accomplish the same thing. Jamie wanted the cap to seat against the back and actually pull on the mount. He found out later that if you don't clean out the deeper threads though (painted), you can't get there by simply applying wrench. You'll have to strip/sand/file off that paint to expose clean threads.  I got the early thick aluminum washers from superXparts.... seem to work well. Jamie came up with this idea, as they were running out of mounts on the shelf then. And as we all know now, Dan has had a batch of new ones made thru the same original vender.

Looking at the chrome cap, a sign of possible trouble, is rust staining bottom of cap and hole. Its possible that it not bad, but if there is rust, you may want to look.

Joe....   I don't know your X or you, but I'm hoping that someone has loosened the belt. With the original  OEM standard for tightening belt, it was MUCH too tight, and besides taking out rear wheel bearings/hub, was also pulling on the motormounts (front specific). 

If anyone decides to replace the back mounts, please note to self there is a notch in that cup for a reason. On the back side (where you cannot easily see it) on the frame is a bump that notch fits over. You don't get that mount correct, you'll have an odd new noise when riding, and possible new vibration.

[Donkey Hotey]

Bruce, I can’t comment on any voodoo effects of damping frequencies into the mounts. Definitely out of the realm of what I know about these mounts. Could you be thinking of when they were also trying different durometer mounts (trying to find a smoother ride)?

My understanding was that they simply weren’t tightening down. If somebody had already lost their caps, the deeper ones were an obvious answer.

When I was putting 1525 back together after her 15 year nap,  I noticed they didn’t snug up. In that case I measured everything, added one thread of rotation to all the clearances and made aluminum washers that thickness. They weren’t very thick. I coated the threads in blue locktite and cinched them down.

The Jennie got new mounts but they tightened up fine. That was the same year. I haven’t had issues with the other three yet so I haven’t thought about it.

[mendonjo]

My belt is definitely not tight in fact I wonder if it isn't too loose.  It doesn't squeak going down the road so I figured it was ok.  I will receck it of course once I get the new mounts in.

Joe

[wytfut]

All interesting Greg..

I can't prove any of that one way or the other... Just was told to me or I interpreted.
Retired telephone linesmen don't have much to do with that type of engineering.

With close to 40k miles now on 525, I was on my third set of fronts. And none on the shelves I was all about getting more life outta them.

I honestly can head nor hair outta harmonics/frequencies/vibrations..

[Berlin Bob]

Replace the mounts... they are gone  as per pics ...don't  cheapen things out... you will have a better ride with new mounts

[mendonjo]

Yep.  I'm callin Marty tomorrow.

[mendonjo]

Okay mounts are on order but I thought I would post something on the 1601 engine fault code since I figured out what was causing it and it had nothing to do with my stalling and flat spot issue.

In the past the ignition switch had been converted to a universal 3 position switch and the bezel was machined to make everything look right - and it does look good.  The first position is off, the second will allow the engine to run but without lights or instrumentation, and the third position is lights on and everything working.  If I start the bike in position number 3 and then switch to position number 2 (to save on battery draw for example), then the computer throws fault code 1601 Check engine lamp Open circuit/short to ground.
  So the moral of the story is just to always run with the lights on; I need the instrumentation anyway.

Joe

[Donkey Hotey]

Haha! The switch was wired wrong. It’s supposed to be for your parking lights, not for running without lights.

[mendonjo]

Wired wrong?  Shesh it only go two wires that connect to the backside.  Pretty easy swap

[Donkey Hotey]

Well, to be accurate there are three: hot from the battery, accessory and ignition. Assuming hot is where it belongs, yes the other two are the ones that need swapping.

Just for anyone in the future who stumbles across this:

B terminal is common / hot from the fuse block and should be Orange / Blue from connector pin A
G terminal is parking / accessory and should be Red / white from connector pin B
ST terminal is ignition / run and should be Red / Gray from connector pin C

[mendonjo]

The mounts arrived today. Any tricks on installing them or just take apart what look like needs takenapartin?

Joe

[wytfut]

You sound pretty self accomplished ...
Nothing to be afraid of, and self explanatory.
If you don't have a frame to engine ground... Maybe think about one now...
I've got on on the right motor mount to starter bolt.
Have at it, and good luck...

[Donkey Hotey]

The last time I did the isolators, I remember one side had a little steel roll pin to keep the mount clocked properly during tightening. That’s the easy side. For whatever reason, there was no such pin on the opposite mount and it took some holding of the steel plate (on the rubber mount) with channel locks to get the chrome nut tight without twisting the rubber. You obviously want the rubber to be relaxed at rest.

Oh, and blue loctite on the chrome caps. It’ll make them hard to remove the next time but you won’t lose one on the road. I did the Jenny with red loctite and had to wire brush it out of the threads before I could even reassemble.

[mendonjo]

I was actually replacing the mounts when you were replying Greg, the only stray off course was the use of red locktite instead of blue

Replacing the mounts was pretty easy.  I Just had to jack the engine up a bit to get things back together.  I started with the RH mount and though it had deformed somewhat but really didn't look bad.  The ringer was the LH one, it was in two pieces as the outboard metal disk had completely separated from the rubber.

I buttoned things up and fired it up (of course it started right away and didn't stall    It was clear the engine was shaking a lot less, it could really be seen in the relative steadiness of the mufflers.  Cant wait to take it for a spin.