Gearing for 200mph

[FastNinja]

So theoretically speaking a 19f + 40r would enable the bike to achieve 200mph as long as it’s got enough power.

If you ran a 19front sprocket would a 44 rear mimic current standard gearing.

I wrote 40 rear sprocket in my last message. But it's my mistake, i wanted tell 42 (-2) rear sprocket. The gearings 19/42 sprockets give 202 mph @ 12 250 real rpm. and 200 mph @ 12 150 real rpm.

This gearing can reach 200 mph. But it's barely.

Now, you know the gearings for reach the 200 mph, but the stock H2 SX/SE have the power to reach 200 mph ?

The answer is sadly not. Reach 200 mph is more difficult we think. My prediction whp to need for the H2 SX/SE for to reach 200 mph is around 210-220 whp and maybe more, it's depend of the drag of the bike. The average power of the stock H2 SX/SE is ±170 whp.

[Switch18]

Thank you FastNinga. My bike stock is 184rwhp so not too far to go.

[cOoTeR]

viewtopic.php?f=2&t=840&p=7571#p7571

I tried a top speed run today with a +500rpm rev limit and stock gearing. I hit 191mph on the GPS app on my phone. But I ran out of room before I could hit the rev limiter. My bike is flashed and full exhaust. From 185mph up it took awhile to gain speed. Not sure how taller gearing will affect this.

[FastNinja]

Hi Cooter,

I read your thread. Nice power, with the flashed and tuned with full line. It's would be interessting to see how many whp and what gears need the H2 SX for to reach real 200 mph speed. Your bike have +500 RPM and with +2 rear (42T), i think you can reach 200 mph.

I'm glad to know how the tach is off on the H2 SX. It' the same of the H2. It's will be easy to change the rear sprocket for the 42T and do the test. Let me know your result ? It's will be interesting to know what distance you need for to reach 200 mph ?

Yes, after 185 mph you need a lot of power to reach each mph until 200 mph.

Good luck !

[cOoTeR]

Hi Cooter,

I read your thread. Nice power, with the flashed and tuned with full line. It's would be interessting to see how many whp and what gears need the H2 SX for to reach real 200 mph speed. Your bike have +500 RPM and with +2 rear (42T), i think you can reach 200 mph.

I'm glad to know how the tach is off on the H2 SX. It' the same of the H2. It's will be easy to change the rear sprocket for the 42T and do the test. Let me know your result ? It's will be interesting to know what distance you need for to reach 200 mph ?

Yes, after 185 mph you need a lot of power to reach each mph until 200 mph.

Good luck !

I want to try to get that last 500 rpms out of the bike on a longer stretch before changing the gearing. The boost temps were getting into the 185° F range so that was a little worrisome. But no issues that I noticed from it.

[Kwee]

Hi Cooter,

I read your thread. Nice power, with the flashed and tuned with full line. It's would be interessting to see how many whp and what gears need the H2 SX for to reach real 200 mph speed. Your bike have +500 RPM and with +2 rear (42T), i think you can reach 200 mph.

I'm glad to know how the tach is off on the H2 SX. It' the same of the H2. It's will be easy to change the rear sprocket for the 42T and do the test. Let me know your result ? It's will be interesting to know what distance you need for to reach 200 mph ?

Yes, after 185 mph you need a lot of power to reach each mph until 200 mph.

Good luck !

I want to try to get that last 500 rpms out of the bike on a longer stretch before changing the gearing. The boost temps were getting into the 185° F range so that was a little worrisome. But no issues that I noticed from it.

Under 100°C(212°F) you should be fine.

[cOoTeR]

Hi Cooter,

I read your thread. Nice power, with the flashed and tuned with full line. It's would be interessting to see how many whp and what gears need the H2 SX for to reach real 200 mph speed. Your bike have +500 RPM and with +2 rear (42T), i think you can reach 200 mph.

I'm glad to know how the tach is off on the H2 SX. It' the same of the H2. It's will be easy to change the rear sprocket for the 42T and do the test. Let me know your result ? It's will be interesting to know what distance you need for to reach 200 mph ?

Yes, after 185 mph you need a lot of power to reach each mph until 200 mph.

Good luck !

I want to try to get that last 500 rpms out of the bike on a longer stretch before changing the gearing. The boost temps were getting into the 185° F range so that was a little worrisome. But no issues that I noticed from it.

Under 100°C(212°F) you should be fine.

For Boost Temperature? If my boost temps get that high I'm going to start worrying about detonation and all kinds of possible issues. Are you thinking of coolant temperatures?

[Kwee]

Hi Cooter,

I read your thread. Nice power, with the flashed and tuned with full line. It's would be interessting to see how many whp and what gears need the H2 SX for to reach real 200 mph speed. Your bike have +500 RPM and with +2 rear (42T), i think you can reach 200 mph.

I'm glad to know how the tach is off on the H2 SX. It' the same of the H2. It's will be easy to change the rear sprocket for the 42T and do the test. Let me know your result ? It's will be interesting to know what distance you need for to reach 200 mph ?

Yes, after 185 mph you need a lot of power to reach each mph until 200 mph.

Good luck !

I want to try to get that last 500 rpms out of the bike on a longer stretch before changing the gearing. The boost temps were getting into the 185° F range so that was a little worrisome. But no issues that I noticed from it.

Under 100°C(212°F) you should be fine.

For Boost Temperature? If my boost temps get that high I'm going to start worrying about detonation and all kinds of possible issues. Are you thinking of coolant temperatures?

Intake temperature become really critical at 140°C(284°F), less than that is okay. At 110°C(230°F), you're start to loss power. For sure less is better but you're not going to drill a hole in your piston with only 85°C(185°F).