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Discussion Starter · #1 ·
Hi Guys

I have been considering breathing a little on my 08 efi Bonni Black.
After reading a lot on this forum, and a little extra research I have been in contact with Bob Farnham in view to him doing the work.

As it stands so far I have a couple of options to give me about 70 brake, but as I want to try and keep the TORs the list is

904 conversion
Raised compression
Head work / gas flow
Cams (I think)

I know some of you have used or considered using Bob in the past, any comments ?

And for the UK crowd: did you have any problems with insurance, and what sort of premium rise should I expect?

Thanks for the help

Barry
 

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You might be the first person to do the big bore on an EFI bike - I'm not totally sure, but I don't recall hearing anyone else do it yet, you trailblazer you! :D Cooool!
 

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The 904 would be a good kit to use. You probably would only have to slightly modify your tune for fuel.

I would send an email to Triumph Performance USA since they do alot of bore kits to see if they have a map ready made.
 

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wiseco makes high compression replacement pistons for the 865 motor.
Sweat...does it make more sense to forgo the BB kit and opt for the high comp. pistons since one only gains 39cc's with the BB kit?

Perhaps do just the pistons with a bit of massage work to the head?
Do you know the $ tag on Wiseco's high comp. pistons?
Thanks,
George
 

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my only concern with the high comp 865cc pistons is breaking in new rings on used nicasil bores. I guess it works though, nicasil is some hardcore stuff and is not easily honed, but it doesn't really wear either.

I think if those pistons had been available when I did my motor I would have gone that route vs 904.

The pistons are listed on their website, but I don't have a link handy.

I put bigger valves into my head, but I think anyone that takes off the head should at least clean up the intake/exhaust ports with a mild port/polish etc and also port match the intake manifolds to the head.
 

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You could probably achieve 70hp with the pipe and remap. Some guys are praising that EFI . If you go 904 you might want to go carbs and rip out the EFI ( if possible) .
 

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my only concern with the high comp 865cc pistons is breaking in new rings on used nicasil bores. I guess it works though, nicasil is some hardcore stuff and is not easily honed, but it doesn't really wear either.

I think if those pistons had been available when I did my motor I would have gone that route vs 904.

The pistons are listed on their website, but I don't have a link handy.

I put bigger valves into my head, but I think anyone that takes off the head should at least clean up the intake/exhaust ports with a mild port/polish etc and also port match the intake manifolds to the head.
Thank you bro. Makes sense.
Ride safe,
George
 

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You could probably achieve 70hp with the pipe and remap. Some guys are praising that EFI . If you go 904 you might want to go carbs and rip out the EFI ( if possible) .
no way man. First off, no how is an FI bike going to make 70hp with stock throttle bodies, stock internals, etc. Maybe mid 60s on a generous dyno, but no way 70 real hp. Second, imagine the wiring mess it would take to get rid of the FI for carbs...

If someone wanted to go hog wild, find some larger throttle bodies off a GSXR or something, make 'em work on the bonnie, go 904 or bigger, cams, pipes, etc and now you're talking.
 

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The 865 wiesco pistons are around 179 usa but i dont know if that comes with rings and pins.You would have to have a near new set of bores for them to work good.I would guess the hp between the 865 and the 904 would be with in 5 hp of each other.70 hp on a efi I think might be doable with head work pipes air box and cams If you had a custom made map .
 

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This is what you can get with airbox gone, pipes and remap:

http://www.triumphrat.net/twins-technical-talk/97729-twins-dyno-results-thread.html#post1149525

Not bad, but not 70 HP.
there is another dyno run with an efi thruxton with pipes and airbox removal, it made 65hp. Seems to be about the norm for a FI bike sans airbox and with pipes.

I bet bigger throttle bodies could be sourced cheap from ebay, and a good tuner could make them work and pick up 5-10hp especially on top.
 

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It looks like 70RWHP is easily within reach for the EFI bikes without delving into the engine internals. Airbox removal, pipes, remap and cams should do it. Does Pieman do his ignitors for EFI bikes?

Fiddling with larger throttle bodies on the EFI sounds expensive to me as it would be pioneering work, not saying it wouldn't produce results but cams and/or ignitor looks like the better route to me for just the additional 5Hp required to make it to 70RWHP.

If you were prepared to delve into the engine internals Wiseco 10.5 to 1 pistons and a little head work combined with the above mods should net close to 80RWHP I would guess.
 

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Discussion Starter · #18 ·
You could probably achieve 70hp with the pipe and remap. Some guys are praising that EFI . If you go 904 you might want to go carbs and rip out the EFI ( if possible) .
Doesn't seem to make much sense ripping out all that expensive electronics, Whatever I do it will stay with the efi it got to be the way forward.

Barry
 

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Discussion Starter · #19 ·
is it underpowered? dunno why anyone would bother spending heaps of time and money for a small power gain on a relatively new bike
No its not underpowered, but I do most of my riding 2 up and I would like more mid range for touring. I considered buying another bike like a R1150RS to do this. But I prefer riding the Bonnie.
The Bike has done just over 3500 miles and seems to be getting better every time I ride it, Especially the gear box.


Barry
 
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