Hi,
I've got the 1990 Sportster above.

I'm either dumb or senile but I had my tank and pipes replaced and carb rejeted in 1991and now she's been in a coma since 2008 (accident then bad gas problem) and I'm trying to revive her but can't trust these dealers! It appears the tank/pipes installer added two in line fuel filter, a K&N air filter and mut havr circumvented/eliminated the vacuum system?
It don't look like the replacement parts or the shop manual pictures of them?
It appears the vacuum lines to the carb and petcock was removed and no hose in the air cleaner manifold/stock air filter roasting pot housing?

Did yours have a VERY significant power increase and mileage gain?
Have you any problems or people saying "you can't do that", or "It won't run that way"?
But it did/does?

Harley wants me to take her to the nearest authorized Harley Davidson Stealer, for the "CURE"?
She's been sleeping, dusted and a little corroded and rusted bug I don't believes she needs a "CURE" just a cleaning fresh gas and some TLC (I was in an cage accident 2009 and want to give her a chance, before I go? She deserves it.)
I definitely don't want those sniffling pipes and sucking tank? The new (was new) long range tank with a : ON OFF RESERE PRI (prime) petcock and the extra horses in the barn was a dream come through! Nothing like today's space ships , but good.

Lemme know how'd it go with yours, and if mine runs once before the snows, I'll do likewise and let chu know!
Eric...

 

It's not a Harley!
If your gonna ride on;: get more than one. Anybody else make go fast after market: but no body will make the EPA stuff until there's no parts left any where, except to steal them?

 

The vacuum cut off on the tank is a safety item since most people forget to cutoff the petcock on carb bikes and Harley put it on to protect people. I would want it but as long as the port pipe were the vacuum hose is capped, it will run fine. With out it and the needle and seat in carb leak and you do not cut fuel, you might find your oil loaded with fuel or worst case a huge fire. Be sure the cap is a good one. Some cheap Autozone vacuum caps will only last a few months with the heat there.

The crankcase vent to the air box is an EPA violation. Harley says it affect the poppet valves making them flutter. Back when they were metal, they would break from being bent. Most are rubber now. Around here, our state inspectors will not allow it. People do run them that way. Most in ignorance or think they are above the law. Take your choice.