Topic: petcock interference

[cgehrke]

Hello all,

I am new to the forum and I am rebuilding a 74 CB750 K4. I recently purchased a "new" tank and after sitting it on the bike I noticed that the petcock interferes with the carbs/throttle action as seen in the pic. have any of you experienced this before? the bike did not have a tank when I got it so I don't have anythin to compare it to. I searched, but did not find anything. From what I understand the petcock is on the right side until the K5 so what is the problem? any help would be appreciated.

thanks

[nteek754]

cge I guess check the obvious first the tank rubbers up front then if they are  not missing and in place check to make sure the  carbs are mounted properly  I would think just kinda look at the bike from the side and carbs should be level  and all the way into the intake boots hope this helps oh  PS your sure the tank is  for the 750  I had a guy on ebay sell me a tank  supose to be for 72 750 but couldnt tell from pics  nope not for the  750 good luck seven fifty four ever Craig in Maine

[merc2dogs]

74 tank the petcocks supposed to be on the right side, may be the issue, I'll look at mine and see what if any difference there  is.
 
  I have a set of later carbs so I can check if there's any difference in the linkage.
 plan to install the others on my bike, so need to know anyway!

ken.

[merc2dogs]

 On mine the carbs are offset by 1/8 inch to the left. 1-1/4 on the right 1-3/8 on the left from the frame rails.
 Don't know if you can rotate the carb boots to swing carbs to the right or not.

   Possibly shave the sides of the strap on the rear of the tank, shave the right pad and put a washer behind the left pad.

 Other carbs are identical, so I think it may be your tank is for something with the later style carbs that don't have the external linkage.

Ken.

[hopterfixer]

Is the rubber that holds the back of the tank on, the proper part?  It looks like your tank is sitting low.  My '74 is close but the tank seems to sit high enough that the hose clamp on the fuel line clears by 1/4" or better. 

[merc2dogs]

 Now that you mention it, that does look low!

  Might have got myself worried about the 'new' carbs for nothing!

Ken.

[cgehrke]

Thanks for the quick response guys. The tank is properly situated on both the front and rear rubber mounts, so maybe the issue is that my carb bank is riding hig due to the intake boot angles??? Carbs look nice and level level to me though, and centered in the frame. Are the rubber intake boots interchangeable, 1 and 4 should be the same and 2 and 3??? Maybe the petcock is a replacement from another bike/year, but it looks correct to me. I will continue to investigate.

[cgehrke]

Issue has been resolved

thanks again for the help. it turns out the intake rubbers were tweaked a bit on the right side pushing the carbs up and forward enough to cause the interference. There is about 1/4" + clearance now. As you can see, she is coming along nicely now.

[hopterfixer]

Nice looking project.  It looked like the carbs would not even open the way it was configured before.