Topic: My first complete build 72 CB750 - completed for now...

[algophobe]

then there's the brake squeal issue. I got a set of shims from Godffrey, may be can answer. I notice there's a sheen on the shims, are you supposed to peel anything off before assembling it?

[Godffery]

then there's the brake squeal issue. I got a set of shims from Godffrey, may be can answer. I notice there's a sheen on the shims, are you supposed to peel anything off before assembling it?

Those go in as is, that's just shiny, not a film.

Godffery’s Garage godfferysgarage.com

[algophobe]

Shim is on. unfortunately I can't test it. now having to deal with the broken speedo.

Originally I used a set of nonmatching speedo/tach 2.5" and 2" combo because I like the asymmetry of it. now that the speedo is broken, I decided on using matching speedo/tach's, however the tapped holes don't work anymore. to make them centered I would have to re-drill and re-tap them. but unfortunately they're slightly off set from current holes.

I've tried drilling different holes on the mounting backet to avoid the current holes, but the bracket is harden steel, haven't been able to find a way to drill a 6-8 mm hole into the damn thing. tried everything. cobalt, titanium coated, carbide tipped bits. any suggestions? 

The other option i'm working on is to see if I could patch up the hole with JB weld and re-drill and tap. I figure this would hold since it's not really a structure element on the bike. at least 80% of the new tap would be on fresh metal while 20% of the wall would be within the JB welded area. anybody has experience with this?

[Godffery]

Install 2 good quality grade aluminum bolts, into the holes you want to plug. (using red loctite) Then cut the remaining bolt off flush and file smooth. Now your ready to drill & tap new location.

[calj737]

Hardened steel? Who made the bracket, and what material did they use?

[algophobe]

Install 2 good quality grade aluminum bolts, into the holes you want to plug. (using red loctite) Then cut the remaining bolt off flush and file smooth. Now your ready to drill & tap new location.

Good trick.. I'll have to try it. Some brackets are supposed to come friday to mount the two together. If the hole line up right i may not need to.

[algophobe]

Hardened steel? Who made the bracket, and what material did they use?

It was listed as dime city originals. But I've seen other online retailer with the same gauges. I assume its some type of harden steel since I couldn't drill through it with my newest bit on a drill press. When I try to bend it the thing snapped right in half. Not much info on the packing. That little divot in the third picture is about the most I could do before my bits Bend or break

By the way does tempering the steel make it more brittle or less brittle

[calj737]

More than likely it’s technique, not material that is your plight. Use cutting fluid, a slower speed, and you should have zero problem drilling that bracket. And WD-40 isn’t cutting fluid...

There’s no rational reason why they would use “hardened steel” for such an application.

If the top clamp is ally, filing bolts off won’t provide you a stable material for drilling new holes if the new location overlaps the original holes. Drilling into a bolt will weaken it, and then tapping it will make the remainder of the bolt worthless, causing it to let go with a new bolt. Best way is to plug weld the clamp. Peen as you go, then drill and tap.

[algophobe]

More than likely it’s technique, not material that is your plight. Use cutting fluid, a slower speed, and you should have zero problem drilling that bracket. And WD-40 isn’t cutting fluid...

There’s no rational reason why they would use “hardened steel” for such an application.

If the top clamp is ally, filing bolts off won’t provide you a stable material for drilling new holes if the new location overlaps the original holes. Drilling into a bolt will weaken it, and then tapping it will make the remainder of the bolt worthless, causing it to let go with a new bolt. Best way is to plug weld the clamp. Peen as you go, then drill and tap.

I used cutting oil, 1500 on the drill press which i thought was slow enough. Tapped as well.

Wd40 is to drilling as baby oil is to sunblock for the skin

[calj737]

Drop down to 400rpms

[slikwilli420]

Drop down to 400rpms

Yup. And after a few seconds at 1500, if you arent cutting metal, you dull the sh*t out of your bit, then you might as well be drilling hardened steel.

[algophobe]

I tried it again this afternoon, cobalt drill bit, down to roughly 400 rpm, cutting oil, and with prepunched it so it wouldn't walk. barely got a divot in it.

[calj737]

You need better bits.  Start with a small diameter bit if you aren't. Then step up the hole size.

[algophobe]

I caved and bought a prefab bracket from Dime City, and fortunately the holes are away from the prior tap site. Nothing like a easy drill and tap after struggling to drill the hole in that strange alloy bracket. I gave up on it.

[algophobe]

the idea of alternate caliper's have been milling in my head. I was looking to stiffen up my sport bike's front brakes and ran into these Brembo axials... anyone tried applying them into their builds for single side disc on cb's?

[algophobe]

a member PM'd me a question, but I wasn't able to reply to him/her, as it stated they can't receive personal messages for some reason. but I'll answer here.

Hi mate I'm just wondering if your still running the cognito oil tank on your bike are you happy with it and what quantity of oil do you currently run in there?

sure, overall happy with it. i'm running standard motorcycle oil, although a little heavier weight oil since the engine runs hotter. no issues yet. only problem is that the mounting was a little challenge since i did not use their mounting brackets instead I welded on a cross bar before the test fitting the engine. this required me to create some aluminum offset brackets to make it fit better. the major challenge was hose placement. their outgoing and return spigots are angled a little low, so fitment was a little challenge but i made it work with stainless steele braided lines. if you were to use regular hosing, it may not be an issue. check out some of the pics on the build from the vantage point of the hose and you can see what I'm referring to.

[algophobe]

Anyone know the stock fork offsets and distance between forks for the triple tree for early cb750s 69-76?

when i acquired the bike originally, prior owners had replaced the triple with the above picture triple, stem and base included. i'm thinking of just getting an aftermaket top triple from cognito to replace the existing one.

what i have is 18.2 cm from fork to fork and 6 cm from stem to fork off set.

[algophobe]

so I figured that the aftermarket triple tree that came with the bike has stock specs. the lowers works well with the Cognito Moto uppers that just came in.

I tapped and mounted the new 2.5 inch speedo and tach with a 1.5 cm space to lower the bezels down closer to the deck height of the upper triple. I also installed these preload adjusters I got from 4into1 on the forks in place of regular fork caps.

the upper triple piece designs is simple and hides the normal clamping gaps which works well with the look i'm going for. it fits perfectly. problem is the CNC milling swirls running across the center on the surface really ruined the piece. especially being the center piece of the front end. these swirls weren't in the online pics from Cognito, so I spoke to their rep today. they stand by their work and will be sending a new piece out. I guess they used to vapor blast the piece prior to anodizing, but have since stepped away from that process. which is a shame.

unfortunately for me, i'll have to take it down and re-drill and tap the piece again.

[algophobe]

so i took the bike out for 16 mile ride. the bike died at the gas station on the way down. the M ride app log on the M unit noted a drop in the battery voltage few minutes prior to arriving at the gas station. I had to get the wife to bail me out. fortunately this was only 8 blocks from the house.

the battery was completely drained. it had been running fine for about 100 miles before this happened. so I bought a new AGM battery to check to start her up again and maybe check the charging system. she sound like she's running only on 2 cylinders again. if I was a betting man I would bet its cylinder 2/3 again. my upcoming plans is to inspect he plugs and see which cylinder went down and why.

my question is, does running on 2 cylinders lower the charging capability of the alternator, therefore causing premature battery failure?

[754]

Get a set of 77 /78 F Forks  will fit in your trees, much easier to adapt newer brakes to.
 Will use your axle and you can run your wire front wheel and put Duc or Yam big floaters onto the stock hub. Then mount up calipers.   You will need drill press or a milling machine.
 The pic shows a Morris wheel, a replacement for the stock wheel, using F forks.

[754]

Get a set of 77 /78 F Forks  will fit in your trees, much easier to adapt newer brakes to.
 Will use your axle and you can run your wire front wheel and put Duc or Yam big floaters onto the stock hub. Then mount up calipers.   You will need drill press or a milling machine.
 The pic shows a Morris wheel, a replacement for the stock wheel, using F forks.

[algophobe]

Get a set of 77 /78 F Forks  will fit in your trees, much easier to adapt newer brakes to.
 Will use your axle and you can run your wire front wheel and put Duc or Yam big floaters onto the stock hub. Then mount up calipers.   You will need drill press or a milling machine.
 The pic shows a Morris wheel, a replacement for the stock wheel, using F forks.

it works with stock 1972 hubs as well? same clearance issue with dual piston calipers?

[algophobe]

so I had a chance to look at the spark plugs, a little dark but not too bad. all sparks fires well. I restarted the bike and she runs normal now. now im really baffled. could it be a temporary short somewhere? the Antigravity Li battery wasn't even charging after that ride, therefore I figured it was tapped dry. but I put a volt meter on it and it red about 9 volts and is charging now.

[calj737]

my question is, does running on 2 cylinders lower the charging capability of the alternator, therefore causing premature battery failure?

Its probably the other way around. Low voltage from the battery will cause the ignition not fire all 4 cylinder equally. I'd say you have a charging issue causing the battery drain, and you may have an ignition/carb issue. You can't sort out the ignition/carb issue until you get the electrical system 100%.

Your AG battery at 9v is a strong indication of a dead soldier. AG's don't tolerate over-discharge. It may charge up, but it won't hold up. They are also susceptible to expanding and exploding due to over-charge and over-discharge. Be very careful from this point with that battery.

Your plugs look "wet" to me from the limited picture. If those are from your general ride, you need to get 4 fresh plugs, and perform an IDLE chop, then a WOT or 1/2 Throttle CHOP. Reading plugs from general all-around riding is superfluous.

[algophobe]

my question is, does running on 2 cylinders lower the charging capability of the alternator, therefore causing premature battery failure?

Its probably the other way around. Low voltage from the battery will cause the ignition not fire all 4 cylinder equally. I'd say you have a charging issue causing the battery drain, and you may have an ignition/carb issue. You can't sort out the ignition/carb issue until you get the electrical system 100%.

Your AG battery at 9v is a strong indication of a dead soldier. AG's don't tolerate over-discharge. It may charge up, but it won't hold up. They are also susceptible to expanding and exploding due to over-charge and over-discharge. Be very careful from this point with that battery.

Your plugs look "wet" to me from the limited picture. If those are from your general ride, you need to get 4 fresh plugs, and perform an IDLE chop, then a WOT or 1/2 Throttle CHOP. Reading plugs from general all-around riding is superfluous.

When you refer to the dead solder your referring to the internals of the battery, not the wiring leading up to it correct? It charged up to 14V and i left it off its trickling down to 13V after 12 hrs. I would necessarily trust that battery and I'm working with a AGM right now to sort out the electricals.

I've never done the chop maneuver but I'm assuming the idle and wot chop you're referring to is to shut off the engine abruptly and check the spark plug coloration?  So much to learn!!! Thanks in advance Cal