Fuel Filter/ carb issue

[Howie]

The rectangle pump produces less fuel volume.  This should not be a problem on a stock bike, particularly since it runs koko's modified machine.

[koko64]

How much less howie?  Athough mine isnt leaning out at 9000rpm, Im interested.

[Howie]

How much less howie?  Athough mine isnt leaning out at 9000rpm, Im interested.

http://www.mikuni.com/c-fuel_pumps.html

The pentagon pump shown is two outlets, I assume ours is similar.  Seems to me 65 liters/hour should run a large V8.

[koko64]

Thanks for the info, Howie.

He Man, how's it goin'?

[He Man]

Just getting to the garage today. I  am going to redo do the vacuum lines (1.19cents a foot on mcmaster, im pretty sure NAPA will have some silicone hoses i can use as well) this is to ensure a good vacuum so i can relocate some things away from heat.

What size should the vacuum tubing be? what about the fuel lines? Im not sure how much those run, but i think those are pricey.

Now what color?
http://www.mcmaster.com/#tubing/=ekpn5g

I am looking for a  100% guaranteed genuine Mikuni Pentagon rebuild kit if anyone knows where i can find one.

This is the diaphragm for the fuel pump. looks sad. im pretty sure its NOT suppose to look like this and should be taught.

[Howie]

http://www.sudco.com/CatalogJPG/507.jpg  for the rebuild kit.

5/16 or 8mm fuel hose, I'm going to take a guess at 3/16 for the vacuum hose.

[He Man]

i was o nthat page but im pretty sure that the double outlet pentagon is bigger than the one on our bikes at 65L/hr it almost has to be bigger!

[MongoReturns]

I got my Mikuni rebuild kit from bikebandit, pretty sure it's this one http://www.bikebandit.com/mikuni-fuel-pump-rebuild-kit-for-pentagon-pumps

The pic is obviously not correct, but the parts were.  And my old Mikuni diaphrams looked like yours.  I replaced the little valves too, mostly because they came with the kit.  The old ones looked fine.

[He Man]

what brand was it?

[MongoReturns]

what brand was it?

Mikuni.  I made double-sure of that before I got it.

[Howie]

i was o nthat page but im pretty sure that the double outlet pentagon is bigger than the one on our bikes at 65L/hr it almost has to be bigger!

I believe the only difference is the amount of outlets, since I haven't bought one I can't say for sure.  Why not give them a call?

[He Man]

I believe the only difference is the amount of outlets, since I haven't bought one I can't say for sure.  Why not give them a call?

thats always the answer isnt it? lol


i actuallyed called bike bandit yesterday and they couldnt identify the brand because they dont actually have it in stock through customer care only  but at the warehouse.. but the brand says mikuni and if mongo also verified it, i will go with that.

[He Man]

okay, why is this so cheap?

http://www.bikebandit.com/motion-pro-clear-vinyl-fuel-line

the tygon ones are much more expensive....

[MongoReturns]

I forgot the package came with a weird '70's looking sticker huh.  Yes I keep empty packages for Ducati parts.  At least I don't horde cats or actual ducks (yet).



And be careful putting the pump back together, I figured it would only go one way but was off by a side or two of the pentagon, then wondered why it wouldn't fit back in the bike.

[He Man]

so as long as  it works!

i just had this thought... bike only has 16,000 miles, but the pump is over 12 years old so im not sure what to say about it failing or if it is even the culprit.


hopefully this clears the issue, as i see it, all the lines are clear, all the vacuum lines are in good standing condition, the vacuum petcock works great, the carbs are clean. brand new fuel filter and the bike had always fired up on the first go.

failure happens when the bike has been on for a while. if you let the bike sit down and lift the tank for it to cool down, the bike works again. so perhaps the heat is causing the already frail pump diaphragm to stop working (though its relatively far from heat sources). so im kinda at a lost if it isnt the pump because i cant question anything else except for electrical issues as DP pointed out, the color of the spark aint quite blue. but that wouldnt explain why the bowls were so low.