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Sunday, March 6, 2011

2011 - Repairs! Mosrite Ventures

Hello loyal fan and or fans.
You may recall, that in the last quarter of 2010, I purchased a Mosrite Ventures electric guitar.
The neck was superb and the tone was excellent, but the vibrato was... not quite right.
It took a little while to notice it, but there was definitely something wrong with my expensive guitar.

The vibrato refused to maintain pitch.

One motivating factor in me lusting after a Mosrite (real and it's Japanese clones) was that the vibrato had a reputation for being an excellent piece of engineering. Unfortunately my guitar wasn't displaying the legendary characteristics that I had expected.

At first I thought, maybe it needed a stiffer spring. So I ordered one from Zamm inc.
But that didn't work. The strings would not maintain concert pitch while the arm was at a comfortable height.
After this I tried disassembling the tremolo and applying some lubricant. I also lubricated the string guide as was suggested on http://www.mosriteforum.com. Sadly this didn't have much of an effect.
Then I decided that it would need a professional setup and heavier strings.
But this also was not the cure all that I'd hoped.

I returned to the forum again and followed some advice that maybe I needed to find the tremolo's sweet spot.
This almost worked.

The strings would return to pitch from pressing down on the bar. It did not however, return from a pull up.
I re-lubed and tweaked some more. Again the best I could do was to manually pull it back down to the correct pitch. This is trickier than one might think. Fine in concept though.

I posted my woes on this thread and via a process of elimination I was able to identify the problem and quickly resolve it, with minimum effort.

Unlike the previous tremolos I've worked on, the Mosrite system works on a Needle Bearing pivot.
The rest have either blade or screw pivot points. Eg: Floyd Rose, Fender Synchronised and Teisco's stamped steel screw pivot tremolo.

Apparently the Moseley trem uses a "Torrington B36" needle bearing. Mine has an "Excellent" branded tremolo.
I'm not sure if the B36 will fit. In any case, it turns out that I didn't need to find a replacement. There are two types of needle bearing, Cage and Full Compliment. The bearing in my guitar is the former.

Extraction of the bearing is simple enough, just insert an appropriately sized blunt object into the inside of the bade plate of the tremolo system and the bearing slides out.  You can see that the photos showed that the pivot looked as if it was off centre. Upon closer inspection, gouges could be seen on the pivot. The gouges were inflicted by the pivot being slightly too large for the inside of the bearing.

Rolling the pivot and bearing together between my fingers, I could feel a lot of friction, which was not evident when utilising the vibrato bar. It wasn't continuous friction, more lumpy and inconsistent. One was worse than the other.

A suggestion was made to smooth it out by rolling the pivot inside the bearing with a drill. I tried this by hand an there was a marginal improvement after about 10 minutes. My daughter was sleeping so using a power tool  was out of the question. I decided to try the other suggestion, which was to sand the pivot with 600 grit paper. Luckily I had some on hand from another project.

I spent a couple of minutes sanding each and trying them out inside the bearing.
Once they felt nice and loose, but not so loose that they'd fall out, I decided to reassemble the tremolo and restring the guitar.

Even with one string on, it became obvious things had improved. I proceeded to add the rest of the strings and tune up. Once the stable tuning point was established in regard to spring tension pushing the bar back up, I tested out the upward motion of the bar. To my delight, it returned to pitch!
The rest of the day I played it, left it, came back and played again. The vibrato was fixed.
Not only that, it felt much more free than before. Nice and loose, ready for some crazy pitch wobbles.

My doubts on being able to sort out this problem were unfounded and I am happy to say, the guitar performs much better than expected.

I have it strung with 9-42 at the moment, which feels weird, but it's actually still set up for 11-52.
Which I'll probably return to at a later date.

*A reader requested some images of the the string retainer.
So here they are:





5 comments:

  1. hey, this post has really helped me out, thanks very much for the effort that's gone into it. I have a Japanese Mosrite Avenger, recently bought, & the tremolo simply isnt working correctly. I've replaced the roller bridge saddles, which were rusted up and unrepairable, and tried any number of other setup tweaks without making much difference.
    I didnt realise Mosrite trem's had bearings, mine does not, a prior owner must have replaced lost bearings with what look like spacers. What I now need to do is find replacement pins, as well as bearings (one of the pins became a casualty of my attempts to dismantle the parts).
    If you have any idea where I might find them (pins) please let me know! Cheers.

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  2. I found a few hits when googling Torrington B36 but never got around to ordering, as I managed to fix it.

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    Replies
    1. cheere mate, I found a bearings specialist locally & looks like they have the B36's. hoping to pick some up this week. Thanks again.

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  3. Good to hear, let me know how the repair goes.

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  4. Hello,

    That's a good information here : I have EXACTLY the same tuning instability issue on my Mosrite Ventures Replica. So I will check further, then...

    Would you mind posting pictures of the string holes of your trem so I can compare with mine : I suspect a possible cause there...

    Thanks !

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