Topic: Early Sandcast Found......

[BenelliSEI]

Are you keeping it? (the Sandy)

Yep….. This winter I plan on fitting an original air box (after lots of repair) and the 4-4 pipes that came on it. Remarkably they don’t have a single dent. The lower right has a small hole where the head pipe meets the muffler, but I think I can weld in a small patch. It’s so hidden, I doubt it will ever be seen. They should clean up very well. The bike would then be +95% original!

[PeWe]

Have you looked how the diffuser/baffle look like when taken out?

[BenelliSEI]

Have you looked how the diffuser/baffle look like when taken out?

I did. They match the ones I got with my Yamiya “no number” pipes. I’ll post a picture when I get started.

[BenelliSEI]

Have you looked how the diffuser/baffle look like when taken out?

Per, I did. They look the same as the ones I got with my Yamiya “no number” pipes. I’ll post a picture when I get started.

[Don R]

 I was looking at my original sandcast airbox a few minutes ago, later I found a piece of it on the floor. I was also wondering what to do about the hard intake funnels.
 Did you ever try the 5 step adjuster to 3 step adjuster shock swap? I have a few with the 3 step adjusters only one set shows 7 coils below the cover though.

[BenelliSEI]

I was looking at my original sandcast airbox a few minutes ago, later I found a piece of it on the floor. I was also wondering what to do about the hard intake funnels.
 Did you ever try the 5 step adjuster to 3 step adjuster shock swap? I have a few with the 3 step adjusters only one set shows 7 coils below the cover though.

Don….. the intake stacks on this air box were rock solid! I used my “paint stripper” air gun and blew it through them (one at a time) until they were just shy of melting. Using a pair of thick gloves, they folded up like hot toffee and came out easily. I’m using this new (to me) JBWeld product and repairing one piece/ crack at a time and then reinforcing from the inside. Seems extraordinarily strong so “sticking with it”. Just ordered another one from Amazon.

I have the three step ring sitting on my bench and will try that swap soon. I’ll post the outcome. Measuring carefully, the old one seems like it will be tight. Might work?

[BenelliSEI]

In the final rush to get this motorcycle ready for “Cobble Beach” I discovered the new  17T drive sprocket I had in my stash didn’t fit. The 16T that was on the bike was much narrower than the new one. The 17T had the raised section in the middle, on both sides. Machined one side off and hopefully it will now have the clearance it needs and align correctly.

[BenelliSEI]

Got it in today. Turned out to be a bit tricky. My new riveted chain just had to go on the sprocket before sliding it onto the output shaft and the clearances were VERY close. Lined it all up and gave it a little tap using a brass drift. Luckily it popped in without too much cursing. One more thing back “as it should be”……

I suspect the new chain (HD, non “0” ring) is a bit beefier than in 1969. Close tolerances require a small modification to the sprocket cover. Completely eliminated the lubricator. All good.

[seanbarney41]

I always thought sandcasts had 16/46 tooth sprockets?

[newday777]

I always thought sandcasts had 16/46 tooth sprockets?

Yes 16 tooth up to engine vin 3527 (#18 in the list of differences)

https://cb750sandcastonly.com/smf_forum/index.php/topic,217.0.html

[69cb750]

The 16T that was on the bike was much narrower than the new one. The 17T had the raised section in the middle, on both sides. Machined one side off and hopefully it will now have the clearance it needs and align correctly.

During the chain, sprocket, clutch spring, real wheel damper recall all bikes got a 17t sprocket.
23801-300-315 was used on engines to #3527 (never seen one)
23801-300-010 was used on engines after #3527 (sprocket has shoulder both sides)

[BenelliSEI]

Gentlemen…… I did NOT know this. All the charts I have suggest 17T for 1969-71. I assumed someone had swapped in the 16T! Mmmm. Put it back?

[69cb750]

I would use 17 tooth, the 16 tooth was a factor in chain failures.
Post a message on the sandcast board, ask for 16t photo.

[BenelliSEI]

I would use 17 tooth, the 16 tooth was a factor in chain failures.
Post a message on the sandcast board, ask for 16t photo.

I’ll leave it. I have the 16T that was on the bike (excellent condition).
Will post a photo later. Thanks!

[MauiK3]

I broke a chain on my K0, not a sandy. It was a bummer back then.

[BenelliSEI]

I broke a chain on my K0, not a sandy. It was a bummer back then.

Steve…… I installed new chain and sprockets. The 17T creates a larger turning radius for the chain. I had to slightly modify the cover to clear it. I think I’ll put the 16T in the “original parts” bin and leave the 17T installed. Mostly because with the endless, riveted chain it is a real fiddle to get the 17T on and off! Screw it.

[lash]

17t will also reduce your cruise rpm by about 400 vs the 16t.

[BenelliSEI]

17t will also reduce your cruise rpm by about 400 vs the 16t.

Even better!

[newday777]

And probably no judge will ever know.

[BenelliSEI]

Stu….. Not without “X-Ray Vision”! Here’s the very early 16T, in excellent condition. Nicely supports the indicated 17,628 original miles.