Petcock question

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Ok, this is a real newbie question but I can't find it anywhere, and I wasn't paying attention when they came apart ...

Which sides are the main/reserve petcocks on .... :roll: .. does it really make a difference?

Good Morning Dana,

On my '72 the reserve is on the right. Do you have a parts manual for your '75. Look at the gas tanks and see what side they have the "reserve" sticker on.

I'm off for the Mt Hamilton ride this morning.
Hi David,

I hope the ride was nice! Great weather for it.

I put it on the right before I saw your answer. I figured I would want to pull the clutch in if it went dead, which leaves the other hand free to reach down and do its thing.

BTW ... I installed the battery, tank, petcocks, fuel line, yata yata, and gave the beastie a few good swift kicks. I was quite surprised when I actually got a few pops and sputters (no pipes).

After a premature celebration, I put on one of my Dunstalls (cleaned up very nicely on my wire wheel). Tomorrow I install the other.

Oh yes, I forgot to mention ... I left a gallon of fuel on my concrete driveway (it evaporated quickly in the 95 degree sun). I don't think I have the Mikuni's lines and other settings right. Any ideas where I can find a good site for the carbeuretically challenged ... I've been to th Sudco site, but I need more than a blowup ... the fuel was pouring out of the (overflow?) at the bottom :oops: Next time ... I take more pictures :oops:

... getting close!

You seem to have already found my biggest gripe with Mikuni's. Let fuel stand in the float bowl for a couple weeks and the float will stick. If you are lucky, a sharp rap on the side of the bowl will stop it. Then ride it enough to let the fresh fuel flush the needle and rods the floats ride on.

If not, you will have to take apart the float bowl and thoroughly clean the needle and seat and the rods the double floats ride on. It seems that with today's fuels, the rods get gummy very easily.

I have a few bikes in the garage and seem to have less time than ever to ride. This is not good for the bikes or me! Those that ride with the Mikuni's on a regular basis don't seem to have as much problem.

As far as which side is reserve, it doesn't matter. The factory manuals seem to show reserve on the right. However, I have seen at least one showing it on the left, and at least a couple bikes which were set up at the dealer on the left.

Ron L

Hi Dana,

The ride had perfect weather, 22 Nortons showed up and no roadside repairs or crashes. As you said the temperatures were in the 90s. Gar took me to a ranch just off Mines Road where an acquaintence has several older Brit machines including a '59 Velocette with 200cc flat opposed engine (like a BMW). He said there were very few made. I know I haven't seen or heard of this model before. I'm going to have to do a search.

I mentioned your "which side for reserve" to Phil Radford. He said he like reserve on the left so that you can stay on the gas whil reaching to flip on the reserve. Makes sense to me and I know when I run out I end up trying to turn the right side petcock on with my left hand.
On both of my Nortons reserve was on the right. I think I'll swap the petcocks around though. Would be much more convenient to have reserve on the left. As David pointed out, when it runs out you need to keep your hand on the throttle. Reaching over to the right petcock with your left hand while riding is very hard to do!

Regarding the gushing Mikuni carb - I had that happen on my old suzuki recently. I was shocked to see how fast the gas was pouring out! In this case rapping the float bowl didn't stop it but shutting the engine off and flushing the carb by draining the bowl did. I had to do it several times.

That also happened on my Norton recently. Those amals don't have overflow tubes so it just filled the cylinder full of gas. Had to kick it over with the plugs out to flush out the gas. It shot out like a geyser. Funny thing was the bike would still idle though it didn't run above idle. I guess they all need to be ridden regularly...

Thanks folks,

I think I know the fuel problem without even looking. I recall someone (no names ... but not on this list) was helping me set it up and told me to make sure the tab was horizontal.

That seemed strange because I had to bend the tab a bunch (and no ... I didn't stop to think about the tab and float's functions ... I just followed blindly). I believe he really meant to say the floats should be horizontal.

Well, I'm guessing I need to re-bend the tab back up so the jet shuts off the flow as it should ... :oops: :oops: D'uh!

BTW ... everything inside my Mikuni is either brand spankin new, or cleaned and shiny. That includes all the jets, needle, etc. (even that durned hard-to-get-at air jet --- boy was that ever fun to remove after 20 years of being gunked up).

Stay tuned folks ... pipes going on this week.
It's funny but on my 68 commando the reserve is on the left; I just thought it was 'British backward' just like the shifter and brake.
I just remember "left for leftover gas" "right for run".

My float has been sticking lately also; dripping gas all over my points cover. I hope a little spark from my points doesn't make things too exciting.
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