couple questions about fuel delivery

[wjw11teen]

first what sort of fuel milage is considered typical?

i discovered that my bike wont run with petcocks set on reserve. my petcocks leak a little when sitting on the bench..could i just need to re build them??

where can i find rebuild kits for both the petcocks and the octopus?

i ordered some of the round rubber 4 hole thingys from ebay and they where way to big...anyone show me a link or some part numbers?? thanks!

[motoman]

first what sort of fuel milage is considered typical?

i discovered that my bike wont run with petcocks set on reserve. my petcocks leak a little when sitting on the bench..could i just need to re build them??

where can i find rebuild kits for both the petcocks and the octopus?

i ordered some of the round rubber 4 hole thingys from ebay and they where way to big...anyone show me a link or some part numbers?? thanks!

Well, from your statement, I'm gonna presume you were just guessing that was the issue getting the wrong pieces. Unless the old rubber pieces are damaged, never had an issue with just taking apart, cleaning everthing up, polishing the pivot where it rubs up against that piece, and re-assemble with a film of dielectic grease on gasket contact surfaces.

Not fitting properly would not surprise me if it was K&L kits.

[wjw11teen]

nevermind about the fuel milage..i found the answer with a little more searching

can the octopus cause any issues as far as the bike seeming to be a little bit lean? i only noticed it a tiny bit and only a couple times in the last 140 miles.

i noticed it after steady throttle cruising about 65-70mph then try to open it up and it seemed like it needed more throttle and a little more time to reach 85mph.

after a good ripon the throttle it seemed fine...kinda strange..mabey im over thinking it?

[TopCatGr58]

Well,

Let's see who responds to this the fastest!!

Find eBay seller GeorgeFix and you can find petcock and octy repair/rebuild kits, they run about $30 or so, but yes, will be enough to rebuild both petcocks and the Octy.

Mileage is on average 30 mpg, but some get mid and even upper 30's and lower 40's depending on how heavy handed they are, how lean they have their bikes tuned, the average speed that they ride....the slower...ie. less than 70 the better the mileage....pushing these things against the wind really gets tough to fight above 65 or so!

T.C.

[TopCatGr58]

Okay, just posted my reply and see Brant and yourself have already posted and replied. I have had the 4 holed rubber valve disengrate and such in mine, so replacing with new parts was necessary. It's possible that the Octy wasn't flowing enough and the carbs were able to run LOW, then with various throttle motions and rpms, more vacuum got applied to the Octy and it then flowed more fuel to refill the bowls?? One way to test this is to just bypass the OCTY by running on PRIME. IF it still behaves the same way, then you've ruled out the Octy as a possible culprit.

The 81 has the advanced programmed TCI with the cent. adv. curves built into it. IT still uses the vac. adv. and when cruising the bike will usually attain a fairly high level of vac. and vac. adv. timing to take advantage of the leaner fuel rates for better mileage. But crank the throttle and the vac. drops, releasing the vac. adv. which retards the timing back to the MORE POWERFUL level of ignition timing around 35 degrees max, vs. the 52 degrees max of the vac. adv.! And the 81's were tuned a bit leaner to begin with due to the EPA standards!

As has been stated here time and time again, many carb/throttle issues are actually ignition problems....ie sticking vac. adv. timing plate. The 81 is less likely to experience the pick up coil wire problem with only the vac. adv. plate rotating vs. the early models with the cent adv. as well as the vac. adv. action.

T.C.

[jetmechmarty]

I used the GeorgeFix kit.

XJ1100 XS1100 SPECIAL PETCOCK KIT


Here's the help you need, with, or without a kit:
Rebuilding the Yamaha Vacuum Fuel Valve w/pics

[GLoweVA]

The 81 is less likely to experience the pick up coil wire problem with only the vac. adv. plate rotating vs. the early models with the cent adv. as well as the vac. adv. action.

T.C.

The mechanical advance only moves the pointer/trigger not the plate.