J tank petcock woes

Hi Everyone,

So after going through two sets of BS34's on my 82 KZ1000, and not being happy with the performance, I decided to switch to a set of VM carbs. Of course this led to swapping to a push/pull throttle, new intake rubbers to match the VMs, pod filters, etc, I have the bike running great off of my shop aux fuel tank.

When I went to replace my tank, behold the huge vacuum fuel petcock on the J style tank hits the top of the #1 carb. Damn!! So I order a pingle replacement unit thinking that should solve my issue. No luck, although closer it still hits the carb and I can't seat the tank.

Anybody out there run into this? I would be interested in what folks did to get around this.

Thanks,

Bill

yes, I ran into the same issue when I replaced my BS34 with Minkuni RS36's. What I did was cut off the entire vavle assembly and just used the base. I plugged the two holes where I had cut the valva off wih epoxy. I then tapped the side of the base with a 1/8" pipe tap then installed a barbed nipple. I sealed the inside with tank liner. I put the modified base back in the tank with the stock filter on it. I put on a small length of gas line and ran it to a 5/16" manual in line ball type valve. I epoxed the valva to the underside of the tank and ran my fuel line from it. Worked great and cost me about $15.00.

I like it! This is the same issue that owners run into when converting KZ1100B1 (1981 GPz1100) to carbs....the traditional fix is to use a 1982 GPz1100 tank as the petcock is situated more anteriorly than the 1981. The baldy110 fix is much more elegant...not to mention cheap.

never mind wrong fuel valve

Thanks fellas. These are some great ideas. I knew someone else had to have run into this issue. I'll let you know what I come up with.

Thanks again,

Bill

never mind - not applicable here

I am in the process of doing the same, RS34 on my 82 KZ100 LTD K2. So far, besides needing adapters to lengthen back to the Airbox Rubbers, and changing the throttle cable, and jetting. I see plenty of room around the petcock, it hits nothing. Seems to have a good 1/2" clearance to the top of the carb or the rack holding bar. This is with the stock Fuel Tank and Petcock for the LTD.
Have you installed yours and got them running? Have you done any jet changes? Seems the 17.5 is lean on mine, so I'll be ordering some different pilots, just a few different sizes to try.
Also did you go with the motion Pro Throttle set up? If so what are you doing with your OEM throttle/ switch housing? Where is your On/Off/Start switch now?

I ended up running 22.5 pilot jets and 127.5 mains but my engine has the MTC 1135cc kit and the head has been ported. I just used the stock 1 cable throttle assembly on mine. The return springs on these are very strong and have not had an issue with the throttle not returning to idle even when I am puching it hard. I really think Mikuni tells you to use the 2 throttle cable system for liability reasons. Oh, and I LOVE these carbs.

Hi Baldy110,
I see your running the open filters though, but I think the bigger pilots would be needed anyway. The 127 mains would be for the open filters. I know from messing with the BS's, which are 34, that a 120 or 122.5 main works great with the V&H 4-1 and stock Airbox. So I'm going to start with the 122.5's and see how that works.
On the stock cable, I find mine to short to use, as it has only the one adjustment at the throttle housing, no mid point cable adjustment. I may but a longer cable and do the same, use the stock throttle housing. I agree the return springs are quite heavy, and it doesn't need the return cable. Now also I see on the Cable Support Bracket on the RS's there is no cable guide, for the end of the cable housing to sit in, like the stock one. So I'll add that as well. There must be a piece that comes on the suggested cable and throttle set up.
I'm hoping the Carbs will be as good as I here. Got them used of off Feebay, $283 to the door! :woohoo:

I used a cable guide from an old throttle cable I had. I have a bunch of throttle cables from various bikes. Some of these cables had built in threaded guides. I cut the cable in half and removed the guide, then with my trusty Dremel tool I cut a slit into the guide and locking nut. I then screwed the guide into the threaded cable bracket on the RS carbs. With the slit I made to the cable guide the throttle cable slides right into the guide and I can adjust it up or down as needed.