1972 R75/5 Carbs

[RPGR90s]

I'm working on a '72 R75/5 with the stock 32mm Bing's and I'm not seeing vacuum port take-offs like I had on my '73 R75/5.

Just wondering if this is normal. I was hoping to do a carb synch.

Thanks,

RPGR90s

[20774]

On my /7, the takeoffs are on the sides facing you as you look at the carbs. On other bikes, they're actually underneath. I would think if the carb had them, they would be the same as your other /5. But they're not standard it seems. Bing sells a kit to add takeoff ports...requires drilling into the carb body at some point.

You can do a carb synch without the ports. Using the shorting technique will allow you to measure performance on each cylinder and make them run the same.

[RPGR90s]

On my /7, the takeoffs are on the sides facing you as you look at the carbs. On other bikes, they're actually underneath. I would think if the carb had them, they would be the same as your other /5. But they're not standard it seems. Bing sells a kit to add takeoff ports...requires drilling into the carb body at some point.

You can do a carb synch without the ports. Using the shorting technique will allow you to measure performance on each cylinder and make them run the same.

Thanks for the reply. I can synch them without the vacuum ports, just wondered if they were supposed to be there on 72's.

[20774]

Snowbum mentions there were no take-off ports on the early /5 CV carbs. Not sure the definition of "early"...he doesn't give a date or carb number. I'm sure Bing would know. From their website: "Some early CV Carbs did not have factory VTO ports".

[2wheeljunkie]

Thanks for the reply. I can synch them without the vacuum ports, just wondered if they were supposed to be there on 72's.

I have a '72 and there are vac ports on my carbs. I also had a '72 that I bought new in the spring of '73. It was a leftover '72 at the dealer, and not a '73 model. I just blew up a picture of it, and it shows what I think is a screw where the port would be, so I believe it had ports as well. I sold that bike in '75 and got a '90S, so I never did any work on the carbs that I can remember. So I can't say for sure...it could just be a screw, or an indentation on the carb...50 year old photo, even digitally enhanced a bit still isn't 100%.