deathstar80 Posted March 23, 2015 Report Share Posted March 23, 2015 I took all the unnecessary vaccuum lines off my stock Hitachi carb on my 1980 720. Every thing runs well but I was wondering if I need to reject the carb. I would like to get better gas mileage if possible. Quote Link to comment
MicroMachinery Posted March 23, 2015 Report Share Posted March 23, 2015 Rejection is the worst thing for a carb :( 1 Quote Link to comment
ggzilla Posted March 23, 2015 Report Share Posted March 23, 2015 Why reject it? It gets better mileage than the smaller Weber 32/36 carburetor. Quote Link to comment
deathstar80 Posted March 23, 2015 Author Report Share Posted March 23, 2015 I am only getting 17-19 mpg. I have seen threads about webers that are getting 25 mpg. Since I removed the vac lines the mpg has dropped a little. Quote Link to comment
ggzilla Posted March 23, 2015 Report Share Posted March 23, 2015 Yes, some of the 720 vacuum lines increase fuel economy. Quote Link to comment
ggzilla Posted March 23, 2015 Report Share Posted March 23, 2015 4x4 720s don't get 25 MPG. Fitting 15" tires reduce indicated fuel economy Quote Link to comment
deathstar80 Posted March 23, 2015 Author Report Share Posted March 23, 2015 So is 19 mpg the best I am going to get? Quote Link to comment
Doctor510 Posted March 23, 2015 Report Share Posted March 23, 2015 NOT reject : REJET Quote Link to comment
datzenmike Posted March 24, 2015 Report Share Posted March 24, 2015 I took all the unnecessary vaccuum lines off my stock Hitachi carb on my 1980 720. Every thing runs well but I was wondering if I need to reject the carb. I would like to get better gas mileage if possible. None of them are 'unnecessary'. The 720 gives the best mileage if left alone. Did you know that there is a fuel shut off device when decelerating that shuts of the idle fuel that would normally be sucked out the exhaust and wasted??? That there is another sensor that adjusts the carb mixture to prevent an over rich idle when under hood temps get too hot? Time to do some research before ripping stuff off. At least keep the vacuum advance hose for the distributor. Quote Link to comment
ggzilla Posted March 24, 2015 Report Share Posted March 24, 2015 vacuum advance is not necessary. All it does is give better fuel economy and more part-throttle power. If you live above 4000 ft elevation, capping the vacuum lines make the 720 burn more fuel. Quote Link to comment
datzenmike Posted March 24, 2015 Report Share Posted March 24, 2015 vacuum advance is not necessary. All it does is give better fuel economy and more part-throttle power. Which is what he's after in the first post. No one would run without vacuum advance by choice just so they can get poorer mileage. I took all the unnecessary vaccuum lines off my stock Hitachi carb on my 1980 720. Every thing runs well but I was wondering if I need to reject the carb. I would like to get better gas mileage if possible. Quote Link to comment
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