04-24-2019, 11:53 PM | #1 |
Join Date: Dec 2018
Location: Oregon
Posts: 81
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Max. RPMs
two questions to chime in on, I want engine longevity kept in mind. Motor that will likely run 20,000 miles +
At what rpm's would you consider max. for sustained time periods? My thought based on no real data other than what CSC has posted on their posts regarding running the bikes on adventure trips. They have said many times they have run their bikes a few 100 rpm's below max. tt250 max. hp is at 7,000 rpms. They run them at 6,800 for hours on end? For short bursts, I am guessing 7-8,000 rpms is ok? |
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04-25-2019, 01:11 AM | #2 | |
Join Date: Apr 2017
Location: Omaha, NE
Posts: 8,100
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Quote:
The crucial thing is that your fueling is dialed in, because you will start tapping into the main jet when trying to sustain highway speeds. Being lean with the throttle cranked at high rpm for long periods of time can be unfriendly to engines.
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Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 2024 Royal Enfield Shotgun 650 https://chinariders.net/showthread.php?t=34124 |
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04-25-2019, 02:07 AM | #3 |
Join Date: Aug 2018
Posts: 158
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Before I tuned my hawk, it was running pretty lean where I'm at. It would run fine, but it would get HOTTTT if ran at max for like 20 minutes or so(stock sprockets too).
However after I put the new exhaust and new carb and tuned it, It'd run max for a long time before I would worry, Definitely lots of vibrations at that rpm though. I drove like 38 miles on the highway to visit a friend when it was my only vehicle. It kept it maxed the whole way there, once I got off my legs and arms were like jelly. Took some rest to drive it back lol. I wouldnt see any reason it shouldn't be fine. If you do lots of highway, it might be smart to get an oil cooler and just gear it high for so you're not redlining at top speed. The bike reallly loves 6-7k and honestly i think would run rabid like that all day |
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04-25-2019, 07:57 AM | #4 |
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Join Date: Oct 2016
Location: Houma, La.
Posts: 11,707
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Like Dan said, these engine are in there happy place between the 6000-7000 rpm range. I change the front sprocket depending on what type of riding I'm doing. With a 17 tooth on from I can cruise 60-70 mph and not have the throttle pegged. An oil cooler would be a good idea if you plan on making long trips at high speeds.
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2024 Linhai 300 ATV 4x4 2023 Lifan Lycan 250 Chopper 2023 Venom Evader 2022 Lifan KPX250 2020 Kawasaki Vulcan S (Sold) 2004 Honda ST 1300 2016 Black Hawk 250 (sold) Keihin PE30 carb,125 main,38 slow.Pod filter,ported & decked head 10:1 CR,Direct Ignition Coil,15/40Sprockets,NGK DPR8EIX-9,De-Cat,Dual Oil Cooler,Digital Cluster 2016 Cazador180 XL 2014 Coolster150 JerryHawk250.com My YouTube Channel |
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04-25-2019, 08:27 AM | #5 |
Join Date: May 2017
Location: Michigan
Posts: 107
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mabye im crazy but after 3000 miles on the engine with no hick ups i frequent 8k rpms for extended duration's kinda have it in my head that any rpms under 9k the bike handles just fine so far. i wonder how long its gonna hold up tho so basically im trying to blow it up and it hasnt yet and shows no sign of slowing down. i never broke 7k rpms tho for the first 1000 miles. i have been playing with the idea of going to a different rear sprocket again mabye a 42 or somthing just so at max speed its closer to the 7k mark but im worried ill loose the offroad grunt
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04 flywing 150 05 flywing 150 07 gasgas ec200 18 csc tt250 / foam filter mod, amazon exhaust, mikunki carb, 47tooth sprocket, o ring chain, stereo system, amsoil oil, honda 10w fork oil, tusk bars and brush guards.... more to come |
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04-25-2019, 08:42 AM | #6 | |
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Join Date: Oct 2016
Location: Houma, La.
Posts: 11,707
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Quote:
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2024 Linhai 300 ATV 4x4 2023 Lifan Lycan 250 Chopper 2023 Venom Evader 2022 Lifan KPX250 2020 Kawasaki Vulcan S (Sold) 2004 Honda ST 1300 2016 Black Hawk 250 (sold) Keihin PE30 carb,125 main,38 slow.Pod filter,ported & decked head 10:1 CR,Direct Ignition Coil,15/40Sprockets,NGK DPR8EIX-9,De-Cat,Dual Oil Cooler,Digital Cluster 2016 Cazador180 XL 2014 Coolster150 JerryHawk250.com My YouTube Channel |
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04-25-2019, 11:48 AM | #7 | |
Join Date: Apr 2017
Location: Omaha, NE
Posts: 8,100
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Quote:
I really enjoyed my 43 rear sprocket, but it does give up a bit of grunt for off road riding, and it does require lots of clutch use in slow speed crawling. As Jerry mentioned, I got into the habit of swapping over to a 15 tooth front if I planned on using it more strictly off road. It takes 10 minutes to swap, and you can even toss the extra sprocket in a bag, pocket, or burrito tube.
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Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 2024 Royal Enfield Shotgun 650 https://chinariders.net/showthread.php?t=34124 |
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04-25-2019, 11:27 PM | #8 |
Join Date: Dec 2018
Location: Oregon
Posts: 81
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I am basically geared for off road use, but will sometimes hit a paved road in a rural area where I can putter along at 35mph or so and let cars go faster if they catch up. Traffic volume will be very minimal. Hit a paved road run 2-3 miles then take to the off road adventure.
With my gearing 14/56 I am going to be running about 6,500 @ 35 mph and was wondering just how much I could push it in the rpm's to get 40 maybe 45 for topend speed. Geared like this I won't be full throttle, just running high rpms under essentially only a moderate load. Sounds like running 7,000 is no issue. |
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