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#16 |
Join Date: May 2021
Posts: 355
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ProDigit, two questions, I see from above what tire pressure you’ve been running, what is the maximum pressure stated on the side of your tire? That’s question 1 because my Hawk 250 DLX manual calls for 40 psi on the rear tire and the tire itself says 32 psi max. I do believe the manual may be incorrect. Second, your post above you use 0.04-0.05” I’m sure you meant.004-.005” right? If you changed the intake to .002” it would be quieter and cooler, I agree. Was looking at your thread and sounds like your having fun with the bike. My thoughts
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#17 | |
Join Date: Aug 2013
Posts: 297
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Quote:
I was thinking in mm, writing in inch. The outside tire of my Lifan Xpect stated 40psi. I'm running roughly 35psi cold, and 38psi hot,both front and rear, 1psi tolerance. The bike can actually run fine at 10psi, but really needs a good 28-30psi minimum, to roll efficiently. |
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#18 |
Join Date: Aug 2013
Posts: 297
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The Xpect runs way too lean in hot climates.
I was thinking of install an oil cooler, but recently I've discovered a sine generator that can be plugged in instead of the O2 sensor, called a dummy plug O2 sensor. I bought it off eBay and will do tests with it. The O2 sensor will basically be unplugged, and instead the dummy plug will be plugged in. The device contains a +12v, ground, and data (0.1-0.9V) wire. It generates a 0.9v pulse, I'm guessing the adjustment dial adjusts the width of the pulse, causing a higher or lower overall voltage (depending on how it's set) than ideal (0.45V). The average voltage is the average of the peaks (0.9V) and troths (0.1V). The stoichiometric value is 0.45V average. When the fuel injection system reads this value, it will determine that the current mapping is too rich, and will try to lean out the mixture more. Without actual wideband O2 sensor data, I can presume it wants to lower from 14.7:1 to more like 15:1 or 16:1, so it will be expecting an o2 sensor value of closer to 0.5V (estimated) or higher. I'm just not sure if the EFI system on the Xpect will continue to try getting that signal from the dummy O2 sensor, until it runs so lean the bike will stall, or if there are limits to it's adjustment curve. Considering that the signal is a pulse, I can presume the EFI will variate only a a bit off of the dummy plug signal, and that increasing or decreasing the mean voltage value will result in a small offset from the ECU. Anyway, I'm presuming setting the value above 0.45V, but below 0.9V will make the bike run richer, and in theory trick the bike into believing the exhaust is running lean, when it's actually running stoic. Issues I can forsee is that the bike may run better at certain rpm ranges than others, like better idle or low rpm response, but worse in the mid-rpm range; or some similar deviation. From what I read, the EFI system will go off it's closed loop system, and run stoic from 75-100% throttle. In other words, the system won't look at the O2 sensor values above this point. This makes me believe that the stoic values of 75-100% throttle will become lean values when an open (more freeflow) exhaust is installed, which can be dangerous when riding longer at higher speeds. |
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#19 |
Join Date: Aug 2013
Posts: 297
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I'm thinking of replacing the 36t sprocket with a 37t, for slightly higher top speed, before selling the bike to the new owner.
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#20 |
Join Date: Sep 2024
Location: Washington, USA
Posts: 11
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I'm really glad I ran into your thread, just read all of it. Lots of good information. I have been using my xpect for bdr type rides, with two track and rocky, muddy offroad back roads. Sometimes they're steep, but with my 17/46 sprocket setup my bike can still climb them in 2nd or 3rd no problem. This tells me I can probably safely gear the bike up and still have enough torque for that kind of terrain. Anyway, I was wondering if you would recommend a 17/40 sprocket setup for someone like me, who does some mild to medium offroading but still wants to be able to cruise at 65-70 on the two lane highways and occasionally the interstate. Any thoughts on the subject would be greatly appreciated. Right now I can hit 60mph, but that's at RPM and it just feels mean to the little 200cc engine to leave it hitting that high of revs for any kind of extended riding.
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2020 Lifan Xpect - JT 17 Tooth Front Sprocket 2022 Honda Navi 2016 Honda CB500x ? Honda CRF100F ? Honda CRF70 Honda/Suzuki 50cc Kids Bikes |
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#21 |
Join Date: Aug 2013
Posts: 297
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I wouldn't recommend this bike if you want 60+ mph out of it.
It can do it, but not reliably. I hit 75mph GPS today with a tail wind, and the death wobble started happening from about 72-74mph. I had to put more weight on the front wheel,and squeeze the tank with my legs to stabilize. Another reason for me to get a 37t instead of a 36t as an absolute minimum rear size sprocket, which will again improve start from stop by 3% (less feathering the clutch), and maintain higher top speeds on level ground, or with a headwind, but will drop mpg by roughly 2.5 mpg. As far as trail riding, I can't tell. But on average each gear is 20-25% spaced from one another. That means, if you go down 20% on the rear sprocket (46 *0.8 = 37), your 2nd and 3rd gear riding will be similar to 1st and 2nd gear riding. The only reason why I wouldn't recommend a 40t or below, is because this bike tends to stall with a too high gear ratio, and no fine clutch control, especially in rocky or rough terrain. But a 17/40 should ease up the rpms on the highway. |
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#22 | |
Join Date: Sep 2021
Location: De Soto, MO
Posts: 1,945
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Quote:
The X-pect is not a good bike for over 60 mph. Forget about highways on this thing. Too little power and too unstable. Don't get me wrong, the X-pect is a good bike, but was never designed for American highways.
__________________
2021 Lifan Xpect--sold 2022 Lifan KPX 1972 Honda CT90--The Carrot 1969 Honda CT90--The Tomahto Cheesy is the WDK (workplace drama king). Now retired. Nope, back in the saddle. Nope, finally retired. Climate: The Movie https://www.youtube.com/watch?v=A24fWmNA6lM How our government really works https://www.youtube.com/watch?v=QjadCd0VRBw Question all authority.....think for yourself |
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#23 |
Join Date: Aug 2013
Posts: 297
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Talking about highways, I couldn't for the life of me, find my 37t sprocket. I've ordered one and received it together with the 38t, and when I went looking for it the 37 was gone.
So how does a 38t compares to a 36t with a 17t front sprocket? Well, for one, the bike starts easily from a stop. The 36t required a bit of feathering, for it not to stall. But if you properly engage and disengage the clutch, those little hesitations are not an issue anymore. The bike feels a bit slower IMHO, in acceleration, but 5th gear got more power, and is more fun. Instead of 82-84mpg, I should now be getting 78-80 mpg. In terms of top speed, I lost between 2-4mph compared to the 36t. So the ideal street gearing will be 17/37t. This bike was perfect for me, but I'm looking forward to swapping out my Vader's 150cc engine for a CG250, and experimenting with it. This bike will replace the Lifan, and the CFMoto 450nk will be my new highway capable bike. |
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