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

[algophobe]

i'm back and forth on what to do with the fuel petcock. the stock petcock has two outlets, i'm assuming intended to go to the two fuel inlet on the stock carbs. the bike was a mess when I got it so never really see how it fits stock, and the parts images don't necessarily say it. i'm using CR specials carbs which has one larger fuel inlet in between the 2-3 unit. should I plug one and run the other line to the CR carbs OR use both and a Y connector?

[02z06dave]

i'm back and forth on what to do with the fuel petcock. the stock petcock has two outlets, i'm assuming intended to go to the two fuel inlet on the stock carbs. the bike was a mess when I got it so never really see how it fits stock, and the parts images don't necessarily say it. i'm using CR specials carbs which has one larger fuel inlet in between the 2-3 unit. should I plug one and run the other line to the CR carbs OR use both and a Y connector?

Use a Y

[SOHC4 Cafe Racer Fan]

Nice paint inspiration.

Use a "Y" connector for your fuel output to the carburetors.

[algophobe]

Doh! The pain of mods... Anyone make lower profile petcock for stock tank for 72 cb750? Or just finish balancing the carb then plug up the holes.

[algophobe]

 I'm on the final stretch of this build. So running into these little set backs are a little frustrating. Things that remains to be done are:
1. Treating the slight rust that built up within the gas tank from a year ago at the seam between the bottom and walls of the gas tank. for some reason the por 15 did not seal off in this area. I have the tank partially filled with the non-acid rust remover currently.
2. Figure what to do with the rubbing between the petcock and nipple on the carb boot and finish fuel line
3. Finalize carbs. Probably lower the clip on needle a couple of notches.
Can't wait to see how she rides!

[algophobe]

thanks for input gents.

by the way, I just use the Metal Rescue derusting solution for all the minor areas that POR 15 didn't cover well, i'm trying to rise out that solution. since its a water base solution, I was thinking of using acetone to rinse it out and evaporate faster without damaging the POR 15 coating.. anyone know if acetone has any detrimental effects on this coating?

either that or I was thinking of using gasoline to rinse the tank out. water based fluid aren't immiscible with gasoline, but maybe with multiple cycles of rinsing it would replace the water.

[algophobe]

Rinse with diesel, not gas, and definitely not Acetone.

I known some people recommend storing unused tanks with a small amount of diesel, but why diesel? do they mix better in this case with water? I'm planning on filling the tank with gas soon to start her up anyways.

[SOHC4 Cafe Racer Fan]

Yes, acetone will simply dry without leaving any protective layer/film to prevent oxidation.  Ideally, if you could store it in an oxygen free vacuum, that would prevent any rust.  Rinsing it with diesel is a good idea.  Liberal WD-40 will suffice in a pinch.  Then, try to keep it out of the elements.

[algophobe]

Thanks for the input gents... working on the final carbs adjustments. There was this awesome guide in the tech section.. it was pinned to the top but for some reason i can't find it anymore. It list the common symptoms and what to do to correct it on the carb. Anyone know where it went?

Nm.. found it in Faq

[algophobe]

so the CR31 was built by Dime City according to the set up I'm running. K&N Pod filters with 4:1 exhausts (spitfire from Cycle X), otherwise stock motor. damn that thing is loud. Ignition advanced to +5, I played with +10 but doesn't seem to improve much. The manual states she should idle below 1000 rpm, but she seems to struggle if I back out the idle screw. I'm curious how accurate these aftermarket tachometers are, also from DCC. you can see it in the video.

the air screw adjustments were done and idle speeds seem to settle at about 1/2 turn from fully closed. I haven't worked with these older carbureted bike in a long time, but noticed that after rev'ing. it seems to be a little slow to come back to idle, but doesn't need to be "blipped" to get back to baseline.

the needle they installed were YY9's, i had to bring the clip down to the 5th notch to get what seems to be good throttle response at 1/2 and 3/4 throttle turn. when it was at the 4th notch, the engine stalls.

take a look at her running, any observations/suggestings welcome!

[algophobe]

She's finally 99.5% done, after 7 years, got married, graduated and got a job, moved, became a father, and with a boy on the way this September, many lessons learned and skills acquired....

the fuel line in. ended up plugging one of the petcock port and simplifying the line without a quick disconnect. it flows better with less transition points/connectors. plugged up the nipple that was rubbing on the petcock with an allen bolt. and she kicks over easily and sounds fantastic.

by the way, does anyone else gets this emotional with their builds? at least the first?

[slikwilli420]

With the whole thing together, the grey looks less battleship grey, and I really like it. The yellow pops nicely and the fit and finish look excellent. Enjoy the ride!!

[algophobe]

With the whole thing together, the grey looks less battleship grey, and I really like it. The yellow pops nicely and the fit and finish look excellent. Enjoy the ride!!

thanks. It was a gamble but I've seen it on some street racer cars and thought it worked. she rides pretty decent considering I went for longer rear shocks to accommodate the frame mods that I did without realizing clearance issues. that single disc, single piston front brake though.. eek. i'm so used to dual from disc with two pistons each AND a rear disc.

[SOHC4 Cafe Racer Fan]

Nice bike.  Have you thought about re-installing the rear inner fender, or replacing it with a hugger?  Otherwise, you'll be cleaning the undertail/seat of water, dirt, etc. 

[algophobe]

Nice bike.  Have you thought about re-installing the rear inner fender, or replacing it with a hugger?  Otherwise, you'll be cleaning the undertail/seat of water, dirt, etc.

yes, i tried to think of ways to modify the stock fender but it too beat up and doesn't fit right. i'll have to look into aftermarkets. heck even with a quick ride the chain lube splashed on the oil tank and under tail. maybe chain guard combo. but i was going for minimalist look, fuctionality wise isn't as practical.

[SOHC4 Cafe Racer Fan]

Nice bike.  Have you thought about re-installing the rear inner fender, or replacing it with a hugger?  Otherwise, you'll be cleaning the undertail/seat of water, dirt, etc.

yes, i tried to think of ways to modify the stock fender but it too beat up and doesn't fit right. i'll have to look into aftermarkets. heck even with a quick ride the chain lube splashed on the oil tank and under tail. maybe chain guard combo. but i was going for minimalist look, fuctionality wise isn't as practical.

I used just the stock inner fender on my 750 bike.  It's too bad someone hasn't developed a basic one using the stock mounts in thermoplastic, CF or fiberglass.

[algophobe]

Nice bike.  Have you thought about re-installing the rear inner fender, or replacing it with a hugger?  Otherwise, you'll be cleaning the undertail/seat of water, dirt, etc.

yes, i tried to think of ways to modify the stock fender but it too beat up and doesn't fit right. i'll have to look into aftermarkets. heck even with a quick ride the chain lube splashed on the oil tank and under tail. maybe chain guard combo. but i was going for minimalist look, fuctionality wise isn't as practical.

I used just the stock inner fender on my 750 bike.  It's too bad someone hasn't developed a basic one using the stock mounts in thermoplastic, CF or fiberglass.

unfortunately I shaved of the metal tabs that mounts the plastic fender as part of the frame mods. I was trying to use the chrome outter fender and rotate it but its a lot of work to set up mounting points.

[slikwilli420]

I would get moving on upgrading the caliper to something period, like Grimeca or AP Racing. They are phenomenal brakes and can be adapted to your current forks.

[SKTP]

Looks amazing...I have been waiting to see it all together

[algophobe]

I would get moving on upgrading the caliper to something period, like Grimeca or AP Racing. They are phenomenal brakes and can be adapted to your current forks.

I was think about an upgrade, but wanted to ride it a while as is. I initially wanted to keep it retro.  But I have a feeling that I would upgrade the whole front end after a while. who knows... It might end up like Café Racer Fan's 9 lives bike. no offense.

btw. I'm looking at the Grimeca, who's the vendor. can't seem to get much listings of google.

[algophobe]

Looks amazing...I have been waiting to see it all together

thanks, really appreciate it!

[slikwilli420]

I would get moving on upgrading the caliper to something period, like Grimeca or AP Racing. They are phenomenal brakes and can be adapted to your current forks.

I was think about an upgrade, but wanted to ride it a while as is. I initially wanted to keep it retro.  But I have a feeling that I would upgrade the whole front end after a while. who knows... It might end up like Café Racer Fan's 9 lives bike. no offense.

btw. I'm looking at the Grimeca, who's the vendor. can't seem to get much listings of google.

They seem hard to come by lately. Best bet us the AP racing unit. You can get them from Andover Norton in the UK. Best price I've found.

[SOHC4 Cafe Racer Fan]

I would get moving on upgrading the caliper to something period, like Grimeca or AP Racing. They are phenomenal brakes and can be adapted to your current forks.

I was think about an upgrade, but wanted to ride it a while as is. I initially wanted to keep it retro.  But I have a feeling that I would upgrade the whole front end after a while. who knows... It might end up like Café Racer Fan's 9 lives bike. no offense.

btw. I'm looking at the Grimeca, who's the vendor. can't seem to get much listings of google.

They seem hard to come by lately. Best bet us the AP racing unit. You can get them from Andover Norton in the UK. Best price I've found.

That's where I sourced a pair (Andover Norton):

Phil
genuine-norton-spares@btconnect.com
Andover Norton International Ltd
3, Old Farm Buildings
Standen Manor Estate
Hungerford
RG17 0RB
Tel.0044 (0) 1488 686816
Fax.0044 (0) 1488 686826
www.andover-norton.co.uk

Pricing when I purchased them in 2012:

APCP2696-38EO TWO-PISTON CALIPER 107.69 BP (each)
APCP3696D36-RQ3 BRAKE PADS (PAIR) 14.04 BP (each)

BP = British Pounds

[SOHC4 Cafe Racer Fan]

I would get moving on upgrading the caliper to something period, like Grimeca or AP Racing. They are phenomenal brakes and can be adapted to your current forks.

I was think about an upgrade, but wanted to ride it a while as is. I initially wanted to keep it retro.  But I have a feeling that I would upgrade the whole front end after a while. who knows... It might end up like Café Racer Fan's 9 lives bike. no offense.

btw. I'm looking at the Grimeca, who's the vendor. can't seem to get much listings of google.

No offense taken.  I think that the AP calipers might be better than the Gold Wing calipers I used on the Nine Lives bike, but on that bike I transplanted an entire Gold Wing front end.  The AP Racing calipers might give you some clearance issues to the spokes and that's why I didn't use them on my 750 (why I ended up doing the Goldwing front swap).  Another, less period correct solution is transplanting an older R6 front.  Several members have done this including (most recently) Dave Barbier; FunJimmy and Oette also did this swap.  It's a conventional (NOT upside-down) fork so it does not stick out to the eye (and his not nearly as heavy as the Goldwing front), but the brakes and forks are a huge step forward.

[algophobe]

I would get moving on upgrading the caliper to something period, like Grimeca or AP Racing. They are phenomenal brakes and can be adapted to your current forks.

I was think about an upgrade, but wanted to ride it a while as is. I initially wanted to keep it retro.  But I have a feeling that I would upgrade the whole front end after a while. who knows... It might end up like Café Racer Fan's 9 lives bike. no offense.

btw. I'm looking at the Grimeca, who's the vendor. can't seem to get much listings of google.

No offense taken.  I think that the AP calipers might be better than the Gold Wing calipers I used on the Nine Lives bike, but on that bike I transplanted an entire Gold Wing front end.  The AP Racing calipers might give you some clearance issues to the spokes and that's why I didn't use them on my 750 (why I ended up doing the Goldwing front swap).  Another, less period correct solution is transplanting an older R6 front.  Several members have done this including (most recently) Dave Barbier; FunJimmy and Oette also did this swap.  It's a conventional (NOT upside-down) fork so it does not stick out to the eye (and his not nearly as heavy as the Goldwing front), but the brakes and forks are a huge step forward.

I looked at Andover's website, doesn't seem like they carry anything except OEM Norton calipers. It has been six years since. However have you known of anyone who's swapped stock calipers for AP's and resolution for the clearance issues?