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Hi Guys,

I finally had time to pull my 1965 Monza 250 out onto the lift and finish fettling it.
I had bought a few years ago supposedly "restored" but found a number of issues.....

So I have replaced the fork stanchions and rebuilt the front forks, replaced the rear hub cush drive, and replaced the camshaft bearings and reshimmed the bevel drive etc. (I have a 1929 Velocette KTT race bike which is also OHC bevel drive so not intimidated by it)

Anyway it started right up on first kick after 5 years stored away (in warm dry garage)....

I can appreciate a bevel drive is noisy but it seems quite rattly, which I appreciate is impossible to diagnose over the interweb... However are any of you clever gentleman anywhere near central NJ to be able to swing by and help me diagnose it.?
Or any other advice..?

Thanks Andrew.

6097516457

Sometimes the top bearing for the vertical shaft isn't mounted properly, causing movement and noise.

Thanks..... mine was slightly loose, had incorrect too thick gasket not allowing it to be located properly. So was replaced and shimmed so no further movement of bearing carrier..

Its possible to assemble the gears and bearings in the steel bushings (top and bottom of the shaft) and think you have got nice close shimming, only for the bushings to move and upset it all ,particularly the bottom one. I get under the bottom bevel gear and give it a tap upwards with an alloy or copper drift to see if it will move (usually due to a missing or wrong big shim above the bearing).Its also important that the shim pack at the top of the shaft leaves no clearance at the circlip. Rocker spindles are also a wearing item.

At this age, it could be many things. The last two I did had bad big ends and were very noisy indeed. Did you check rod for play while the head was off?

Thanks for the replies so far...... most appreciated.

I have been listening to lots of youtube videos (tricky as mics pick up all sorts of noises) and there seem to be a number making a similar racket but others pretty quiet.

Before I start tearing it down I was hoping someone possibly close could listen to it. I am happy to take it to have it listened to.... poor thing.

You might think about taking a cell phone video and posting it here or on YouTube with a link here as the audio track may help forum members make a better diagnosis.

Jim

Thanks Jim, i will do that

Hi Guys, managed to make a brief video of the Monza running....

https://www.youtube.com/watch?v=V_spR8bwC1A

any advice welcome..... Thanks.

Sounds like the rocker to valve gap is too great.
I had a 450 make a similar noise even after careful shim adjustment.
Turned out to be the rocker spindles were worn in the head casting and moving around
Same noise, but hard to be sure from a video