400 bandit petcock fuel flow rate

[Gouraami]

Hi Guys

Has anyone measured the flow rate from the petcock? It will be less once the tank starts reaching reserve, but I would like to know +- what the design flow rate is.

Thanks

[ventYl]

I don't know exact value, but it took me some 10 - 15 minutes to fill 5 litre bottle when draining the tank with petcock switched at PRI position.

[Gouraami]

Thank you ventYl, that gives me a benchmark to work with

[Chris H]

I'm unsure if you would even get that sort of flow when using the vacuum, no idea if it simply opens the flow or flows faster as the vacuum speed increases with the engines revs.

[Gouraami]

At 10 minutes it works out to 8.3ml a second which is fast, 15 minutes it works out to 5.55ml per second.

I am also unsure, but PRI should then be the maximum value.

The reason I have asked is due to me buying a manual one for a 600 Bandit, I want to check if its flow is within spec. The outlet is much smaller than the original, this is why I will need to compare the flow rates.

[ventYl]

with the B6 manual petcock you can get to situation when petcock butterfly will end up behind the frame (B6 petcock is physically higher than B4 petcock). Get DR 350 or DR-Z400 petcock which should be same cheapo but will fit mostly perfectly (except the fuel hose is connected from "rear", the place where vacuum is fed into normal petcock IIRC). someone here already tried that. here or at 400greybike

[Thief400]

Buddy you are over thinking shit! If the petcock can support a 600 it will work on a 400 period!!! Vacuum has got nothing to do with how much fuel flows. It's only purpose is to shut off the fuel when the bike is parked so the engine doesn't floor if someone forget to turn off the fuel. Or for the squid who forgets to turn it back on fly into traffic them gets run over when the bike losses power and dies 

[Gouraami]

The problem is I ordered a cheapo to see if it is going to fit in the space provided. It turns out the quality of the cheapo isn't bad, it is just the outlet that has a very reduced diameter to the original.

ventYL -  it said it is compatible with the DRZ400 as well, it was thanks to this forum that I came across that info. Initially that is what I was looking for.

Thief400 - It may state it is for a 600, but the diameter has me worried. Worried enough for me to create this post.  I rather want to check it before I end up with a fuel starvation issue.

[ventYl]

well maybe it is the same.

but some easy math will show you that there is no need to concern about this. let's say that the bike has consumption of 4.7/100 km. if you'll be traveling at 130km/h constant you travel the distance of 100 km in 46 minutes (and burn about 4.7 liters of fuel). so if the petcock is able to pass 6 liters per hour it is sufficient for most of cases.

[Gouraami]

The concern is at at full throttle. You will be surprised how much fuel is used under full acceleration conditions. That is why you won't be able to calculate it like that. Using my car as an example I can easily multiply the average figure figure by four to get instantaneous when I floor it (it has an instantaneous fuel read out).

But as you guys say, I am probably over analyzing this.

[ventYl]

i am aware of that. but most probably you won't be accelerating at full throttle for infinite time so if the flow is at least little bit higher (which most probably is) it will refill the carbs shortly after you begin to cruise.

[Gouraami]

You are right, I am definitely over thinking this.

If I do run into issues and  suspect it could be fuel flow related I can I can swap it out for something else to test.