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Post by wilmo on Nov 13, 2023 20:54:03 GMT 10
There is still a mod around for the Yamaha XT660 single called the 'Kev Mod' (you can buy one from the man on Ebay). It takes the temp signal from the temp sensor in the airbox on that bike, and lets you alter the signal to fool the ecu into thinking you are operating in a colder air temp (more dense air), therefore the ecu will richen the mixture in open loop running. This might work if it could be adapted, but firstly do the 2022+ urals have a temp sensor in the airbox?
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Post by Uralee on Nov 14, 2023 4:56:28 GMT 10
3rd uphill with light throttle and pinging ?…. BUT what speed ?
Given your load and reported fuel economy, it screams “revs too low”.
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Post by twomotokiwis on Nov 14, 2023 7:16:35 GMT 10
I think we are getting good mileage from not going fast but 3rd up hill at about 70 then change down at about 50-60 depending as pinging starts.
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Post by wilmo on Nov 14, 2023 8:54:45 GMT 10
I emailed Kev the guy that makes the fuel mod - he's in Queensland, if the Ural has a temp sensor in the airbox he would be happy to look at it. Anyone with a late model care to confirm?
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Post by twomotokiwis on Nov 14, 2023 9:41:25 GMT 10
Interesting, we are in Myrtleford right now and raining but can have a look later on if it stops, very keen to do something as it isn't ideal at present, one bonus is having to be ginger on the throttle means using way less fuel 😂😂
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Post by wilmo on Nov 14, 2023 11:38:37 GMT 10
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Post by miker on Nov 14, 2023 13:05:45 GMT 10
I think we are getting good mileage from not going fast but 3rd up hill at about 70 then change down at about 50-60 depending as pinging starts. If you're easing the throttle on to go up the hill, and not taking a run at it, that may be the problem. Whilst not having a mixture graph to look at, I think to me mine feels like it's at it's leanest in the mid rev range. From my experience, if I get pinging and I think the revs are OK, I'll accelerate. The extra acceleration adds more fuel, cools the burn and the ping goes away. It does with mine, but now mine's pretty well run in at 17,000km, the pinging is a lot less. It really only happens when it gets really hot and has to work hard. You shouldn't need an octane boost running 98, but you should use it if you have to use anything lower.
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Post by wilmo on Nov 14, 2023 13:56:30 GMT 10
I think we are getting good mileage from not going fast but 3rd up hill at about 70 then change down at about 50-60 depending as pinging starts. If you're easing the throttle on to go up the hill, and not taking a run at it, that may be the problem. Whilst not having a mixture graph to look at, I think to me mine feels like it's at it's leanest in the mid rev range. From my experience, if I get pinging and I think the revs are OK, I'll accelerate. The extra acceleration adds more fuel, cools the burn and the ping goes away. It does with mine, but now mine's pretty well run in at 17,000km, the pinging is a lot less. It really only happens when it gets really hot and has to work hard. You shouldn't need an octane boost running 98, but you should use it if you have to use anything lower. Good point, opening the throttle wide will default to the 'open loop' map programmed into the ecu, whereas at part throttle the 'closed loop' map (uses the 02 sensors in the exhaust to maintain optimum fuel ratio) is probably in use. Usually manufacturers will err on the side of caution with full throttle applications and richen them up accordingly.
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Post by twomotokiwis on Nov 14, 2023 15:45:32 GMT 10
Good point, opening the throttle wide will default to the 'open loop' map programmed into the ecu, whereas at part throttle the 'closed loop' map (uses the 02 sensors in the exhaust to maintain optimum fuel ratio) is probably in use. Usually manufacturers will err on the side of caution with full throttle applications and richen them up accordingly.
Good advice, tomorrow we bail to Bright and Mt Beauty etc so will try this approach, my Levis dyno say the middle too so will get it a bit more to see if this works.
Looked at the air box and there are no sensors or wiring to it.
Wonder about a plug in line on each of the o2 sensors?
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Post by Uralee on Nov 14, 2023 16:34:28 GMT 10
Only temp sensor in r/h head. Don’t go below 70 uphill in 3rd Power on uphill will richen mixture ………your engine is not run in yet. It will improve.
A/F mixture determined from base fuel map, engine temp, throttle position and O2 sensors.
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