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[Bullet Whisperer]

This machine is soon to be fitted with some of Hitchcocks tuning parts, including valves, guides, cams and carb kit. I may also do a few of my own things as well, but in the first place, I needed to get some idea of the performance in very near standard trim, to use as a yardstick. Here is the first test run ... https://www.youtube.com/watch?v=wtEn5o47gOI

[Chris Tindal]

It will be an interesting before and after, keep us posted. Not sure why the factory didn't make them with modern performance, my old
1987 Yamaha SRX600 had around 40 horses standard, as did the contemporary Honda XBR500.

[Bullet Whisperer]

It is now running again, with all the go faster goodies from Hitchcocks fitted, plus I shortened the cylinder barrel for better squish and increased compression. ... https://youtu.be/d4RRMA-r3wY

[25Tom]

Looks good. Like the exhaust wrap!

[Bullet Whisperer]

That exhaust wrap is NOTHING to do with me !!!

[jefrs]

Paul, we discussed cam timing on you video. I have been digging around online and can find absolutely nothing on what the EFI valve timing is supposed to be except perhaps this https://forum.classicmotorworks.com/ind ... pic=6024.0 which is from 2007 anyway. You came up with some strange numbers for the stock cams, I'm wondering if the hydraulic tappets (dry) would give you a false reading? The numbers are not in the service manual, does RE not publish what valve timing they use? What are the stock valve/cam timing numbers - anyone?

[jefrs]

Chris Tindall - to slightly answer your question the XBR500 (nice) makes 44bhp up at 7000rpm and 42.7Nm at 6000 - the latter is very much on par with the EFI's 41.2Nm down at 4000. The much lauded Goldstar made over 40bhp as the DBD34 but only 34bhp as the DB34, as did the Velo Venom, it seems to be a sort of limit with any push rod 500 if you want them to stay reliable - the EFI is quite easy to tweak to around 34bhp with bolt-on goodies but what is more noticeable is the torque shoots up, casual estimate 54Nm is possible. Given the way we ride Bullets it is possibly beneficial to tune for more torque lower down than for more bhp higher up.

[Bullet Whisperer]

Here is a test ride on the modified machine. jefrs, I recorded the valve timing with the valves 0.3mm [0.012"] off their seats, as I would do with the older types. Even if I shouldn't have done it like that, the cams, their lift and timings were dismal. Regards, Paul. ... https://youtu.be/iO00SldM1J4