750 Fuel tank size

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Freddy
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Joined: 06 Sep 2017, 11:06
Location: Sydney Australia

750 Fuel tank size

Post by Freddy »

Lots of sources list the 750 tank capacity as 17 liters. Does anyone know what is the tank capacity is before reserve?

Put another way, how many liters is reserve?

I know I use about 11.5 liters before the fuel gauge hits the red bar, but really have no idea how far this is away from actually running out if not switched to reserve.

I'm trying to figure out tank range without reserve (that for emergencies only in my way of thinking) at various fuel consumption rates with different main jets.
Freddy
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Location: Sydney Australia

Re: 750 Fuel tank size

Post by Freddy »

Found an online owners manual .... It says reserve is 3 liters.
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ZR468
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Joined: 04 Sep 2017, 13:51
Location: Vancouver, BC, Canada

Re: 750 Fuel tank size

Post by ZR468 »

I second that 3 litre reserve. I think to get the other 14 litre of gas into the tank, you'll have to put the bike on its centre stand. Not sure how much capacity you lose when the bike is on its side stand, I always filled up before reaching the reserve.
Kenny
David Richard
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Joined: 04 Sep 2017, 20:21

Re: 750 Fuel tank size

Post by David Richard »

its very strange how quick the petrol gauge moves off from the full mark even after 20 miles ,it leaves me thinking where is the next filling ston ,I too think its about 4 litres if your brave enough to go that long just while I'm here did you fit your 16 teeth sprocket as yet ,david
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ZR468
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Location: Vancouver, BC, Canada

Re: 750 Fuel tank size

Post by ZR468 »

David, I am still waiting for the 16T front sprocket. I bought it on Ebay, shipped from UK, seller is telling me to wait for a couple of more weeks. That is Ebay for you, some stuff comes a head of time and some stuff keeps you waiting. I should have bought from a US source, I would have it installed by now. Sorry to highjack the OP thread.
Kenny
Freddy
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Joined: 06 Sep 2017, 11:06
Location: Sydney Australia

Re: 750 Fuel tank size

Post by Freddy »

ZR468 wrote:Sorry to highjack the OP thread.
Kenny
No problem I'm probably the worst offender.

Actually in all of this perhaps I was misguided thinking how many kilometers I was getting from a tank (filled to the bottom of the filler neck on the center stand till it empties to the red section on the gauge) on a spirited ride with the stock jetting. I never did record it, but keying into Google maps a ride that I've done a zillion times and know I arrive consistently at a certain location to refuel with the fuel gauge pretty well down on the red, the distance is 162 kilometers. That is mostly open highway and two sections of about 40 kilometers of tight twisties where everyone goes like the clappers.

So perhaps getting 180 kilometers using the same procedure in a 50:50 mix of heavy city traffic to get to the 'public motorcycle raceway' in the local National Park to test the various jet sizes isn't so bad after all.

Decent long fast ride tomorrow with my regular Meetup ride group, so be interesting to monitor consumption accurately over a few tanks. Mistake was not accurately recording it with stock jetting prior to this experiment. Live and learn.
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ZR468
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Location: Vancouver, BC, Canada

Re: 750 Fuel tank size

Post by ZR468 »

Fred, can you feel the difference in the throttle with different jets? Does it change the power band much?
Kenny
Freddy
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Re: 750 Fuel tank size

Post by Freddy »

ZR468 wrote:Fred, can you feel the difference in the throttle with different jets? Does it change the power band much?
Kenny
I can only speak for a D1 (which has different jetting to the C models), and for the conditions I've tested under (sea level, moderate to hot temperatures, mid range humidity). Under this conditions the difference is HUGE.

Previously the bike would accelerate consistently when you gave it full throttle, with a decent enough kick around the 6,000 rpm where the cam etc are tuned around. Now when you fully open the throttle and let the revs climb a little (I'm assume this delay is the building of vacuum to pull the needle clear of the needle jet, so the main jets then come into play) it feels like an afterburner has just kicked in. OK, I've never flow in a jet with an afterburner, but its what I image its like.

As I have deliberately only changed the main jets, the change is primarily all in the upper rev range using the second half of the throttle e.g pulling hard up long hills, quick overtakes, etc. I believe I could get some more grunt out of the mid-range by shimming the needles. I've even bought the shims. However I'm happy with the stock mid range grunt and don't want to adversely affect cruising fuel economy. Tank range is important for primarily how I use the bike (remote country roads). Not to hard to guess why we travel some distance to these relatively remote back roads.

Basically all the extra grunt is at the top (where the main jets come into play), and that's to be expected because that's the only area I focused on.
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ZR468
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Re: 750 Fuel tank size

Post by ZR468 »

Fred, I was at the belief that the main jet would affect the whole range of operation except for the idle jet. Could the delay before the G-force performance caused by the fuel mix being too rich? I am no expert, just that I had a similar experience with a fuel injected bike after installing a fuel enriching chip.
Kenny
Freddy
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Re: 750 Fuel tank size

Post by Freddy »

ZR468 wrote:Fred, I was at the belief that the main jet would affect the whole range of operation except for the idle jet. Could the delay before the G-force performance caused by the fuel mix being too rich? I am no expert, just that I had a similar experience with a fuel injected bike after installing a fuel enriching chip.
Kenny
Most seemingly reputable sources of CV carburetor operation and tuning use a graphic similar to the one below to indicate what each part does and where. Pull one apart and the graphic seems to align with what you can visibly see.

Image

In this graphic the influence of the main jet is shown to come in earlier than others I've seen. I suppose it depends totally on the needle profile. To my simplistic way of thinking, the main jet should start to kick at the point where the needle has lifted out of the needle jet sufficiently enough to be larger than the main jet size.

Anyhow that's theory, and certainly the performance of the engine seems stronger across a wider range than the above graphic represents. But that may be imagination. But the top end increase is certainly not.

CV carbies will always have a slight delay when you crack open the throttle as the slide has to rise under vacuum. That's why race bikes never run them, they want the instant 'hit' that only direct pull with an accelerator pump type carby can give. If you've ever observed how much pure gas an accelerator type carby just dumps into the intake of an engine, its hard to imagine ever being to rich just at that point when the air rushes in.

P.S. And another think I've become aware off (having never given it much thought), and the reason I've haven't shimmed the needles with pretty solid mid range grunt already, is that needle jets wear and increase in size over time. The needle is relatively hard stainless steel so it doesn't wear that much. But the needle jet being softer brass does over time wear from the harder needle flopping around inside it. So the mid-range is getting slowly richer over time all by itself.
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