80 carbs on a 75

Gmaan · Posted: December 13, 2008, 1:09 pm Post subject: 80 carbs on a 75

I picked up a set of 80 carbs for my 75. I want to replace them for ease of maintenance. The dual pull cables are a pain in the butt, always out of sync. the 80 set-up uses a single pull cable. MY question is jetting, I know the 80 carbs are real lean, will I have to replace jets? My motor is rebuilt with all stock parts, I have pod filters, and a header pipe.

Is this a good or bad idea guys?

One more thing, I am going to rebuild the carbs, but want to paint them black, what paint do you recommend.

Retiredgentleman · Posted: December 13, 2008, 1:27 pm Post subject: Re: 80 carbs on a 75

Why not try to find some 78 carbs, they work really well. Choke is on the carbs, no cables. Single pull cable for the throttle.

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

You shouldn't have to re-jet any more than if you put pods on an '80 but yes, some minor tweaking will probably be needed. As you mentioned, the BS34s are very lean from the factory. A change of needles is something you should really consider. XS John has the custom ground ones and MikesXS sells a couple adjustable versions. The originals are fixed and non-adjustable. I recommend the ones from John as they're a proven product. I haven't seen much feedback on the ones from Mike's so it's sort of a mystery as to how well they do or don't work.

You will also need different manifolds. The BS34s won't fit in the 38 manifolds. If you've never changed your manifolds, they're probably due anyway.

Gmaan · Posted: December 13, 2008, 6:08 pm Post subject: Re: 80 carbs on a 75

thanks for the information, I will let you all know how it went.

Gmaan · Posted: January 12, 2009, 1:47 am Post subject: Re: 80 carbs on a 75

Well cleaned up the carbs, painted them and they look sweet. I put them on the bike and it runs real rich. what are the pilot screw settings you guys have set to? I have pod air filters too.

xsjohn · Posted: January 12, 2009, 5:06 am Post subject: Re: 80 carbs on a 75

Gmaan...........If those are the brass floats they need to be set at 27.25mm....not 24-25 like the rest of the carbs.....I have those carbs ...they are good ones so don't give up....and its a good idea to change the o-rings on the float seat on any BS34....when they leak the bowl will overflow... not so much when it's running but when its sitting with the gas on......you can wrap 4-5 revs of heavy thread around the edge of the o-ring in the groove ....hide the end...and champhor the hole and push them in with some oil.......permanent fix there......puffs the o-ring out a tad.......45 pilots (start at 2 or so turns) 135MJ max is a good idea after you get the rich thing fixed.....which you will...allens from a hardware store is a good idea in the bowl....then you can access the carbs on the bike with a shortened allen or allen socket and pliers.........makes life easier......

xsjohn

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