Last minute Jet questions before ordering

[bgrubb7]

Getting ready to order some carb parts, and want to double check everything before placing the order

81 H stock mains are 115s (1&4) 120s (2&3), Stock pilots 42.5

Everything stock but will be going to individual filters.

According to the tech tip - up 3 sizes then - 1 would leave me at 120s on 1&4 carbs and 125s on 2&3.

Since I'm only going up 2 main sizes, I don;t need bigger pilots, right?

My plan is to get a new pair of 125's for carbs 2&3, move the 120s I've already got to the outside carbs, and leave the stock pilot size alone.

Oh ya one more thing, I had to use an extractor on one of my pilots. Will I be alright just replacing 1 pilot with one from MikesXS? or will I have to replace all 4.

[John]

Going up two main sizes is right at borderline where the pilots are concerned. The pilot circuit supplies most of the fuel until the rpms near 4000. It also keeps supplying fuel after the main circuit comes in. An extra turn out on the pilot screws may be needed, but with three main sizes, you may want to go up to the next size of pilot jet. You still have stock pipes right? On my bike, I have done an 1179 cc big bore, with 78E carbs and ignition governor on a big valve 80SG engine. I have a UNI foam filter in the stock airbox, and a set of Jardine spaghetti pipes, I have only increased the main jet one size, and left the pilot jets alone, only I have them adjusted out about 2.5-3 turns. Don't know exactly, as I have balanced them recently, and some of the settings got changed.
If you can get all of the pilot jets out, go ahead and replace them all. Cheap insurance, if you get the correct ones. A real headache if you don't.

[bgrubb7]

To avoid any possible variations between Jet manufacturers. I'm going to just spring the extra $12 to get all new jets instead of just replacing half of them.

So my next question would be if I'm going to go ahead and get all new pilot jets anyways, shouldn't I just go up one size just to be safe? Or is it better to stay with the original size and turn out the mixture screws?

[John]

If you can afford it, buy both sizes, and if the need should arise to change from the bigger size to the stock size, or vice-versa, then you will have the parts in hand. You could probably sell off the ones you don't need. Beats waiting for a second parts order to arrive.

[pggg]

BG, I'd change all main jets to the same size in all 4 carbs. Gets all settings in the carbs identical. Also CV carbs prefer an airbox rather than indy filters. If using indy filters you're gonna want a decent exhaust system at least. Going up more than 2 sizes on the main jets will get too rich. Dunno if your carbs have a linked pilot/main but chances are a 45 pilot jet will suit the indy filters for a stronger low to midrange and one size increase on the main jets will likely be plenty.

[bgrubb7]

If going to the same in all 4, should I rejet from the smaller size of the larger size?

120s or 125s in all 4?

[pggg]

bg, what about 122.5's all round? These things are pretty much a guess until the bikes' running with those new filters, but going up in small steps on the jet size is preferable, especially if the bikes running well as is.