hello to all I just parked my first Bonnie in the shed and she's a beaut, 904cc Norman Hyde conversion Sai removal stubby exhaust and a bellmouth. I had a dyno readout from the previous owner and I have to say a little disappointed at only 62 Hp @ 7000 rpm Could anyone advise if this is what I should expect and how to go about getting more The airbox is stock with a bellmouth & KN filter should I go for a eliminator kit? It would be great to get your insight
Hi AK, it seems to me like the first thing you should do is to take out the bellmouth and filter and then take it for a ride. It should feel like revs more freely. In my opinion 62bhp dyno result seems to disappoint but bare in mind that the dyno result shows power at the back wheel whereas the manufacturers power figures are always given 'at the crank'. Just to show the difference : an 865cc fi engine has a mfrs power figure 67bhp (from memory) whereas it will have a dyno 'at the wheel' of perhaps 58 bhp. Transmission losses account for the difference, in broad terms. The other thing to consider is that if you take the same bike and put it on 3 different dyno's you will get 3 different max. bhp figures - due to the differing dyno configurations. Dyno runs are not really there for providing single figure outputs - they are there to provide 'before and after' numbers, to show the effects of engine modifications.
Big bore conversions tend to only give you more torque and thats no bad thing on a bike, to get the most from it you would have to fit a better cam and up the compression ratio.
Thanks for the initial comments, to clarify 2006 790cc bike 904cc kit Gas flow and cylinder skim K&N filter Bellmouth snorkel replacement Sai removed 2-1 stubby exhaust system (can not see o2 sensors) 18t sprocket This is everything I either have a receipt for or can see What Hp should I expect? What would you do beyond the list above to make more? Don't drink or smoke so have a little saved to improve the Bonnie
Bought the air box eliminator kit to install today so hopefully that will help the bike breath easier and increase Hp, no makers mark on the stubby exhaust so I'm not entirely sure. Does sound fab though
You'll definitely need to check your carburation if you remove the airbox as there will be loads more air going into the motor.
Me thinks I need proffesional help I was confident with the airbox removal and semi confident in changing the jets but I have no idea how to adjust the carburettor (is there an idiots guide to Bonnies somewhere)
The Jenks Bolts guide to tuning Bonnevilles may help you: http://www.bonneville.se/nedladdning/Hur man jettar.pdf
Not sure why folks get so hung up on horsepower numbers. Is the bike fun to ride? Guys who want "just a little bit more" tend to never be satisfied. (Bikes & life!)
Valid point Bob though I always like to tinker and think it's all part of bike ownership (a forum would be a dull place if we all discussed our stock (exactly the same) bikes. I was only originally enquiring because the lady owner spent a small fortune having the 904 conversion done for (on paper) little increase in power . The bike is fantastic fun and I got of a 140hp RSV Mille for my Bonnie so i no longer require break neck speed and power, like most men I just want a little more
Don't blame you there. I've modded every bike I've owned, mostly cosmetic, lights, & functional items. The only engine mods I've ever really felt necessary were things to improve breathing & get a bit more noise/MPG. If I upped the HP in the course of it , all the better!
