Bonneville America Forums Forums Technical Forums Performance Mods The Long Awaited Much Anticipated...

I think you need to look back at the dyno sheet. Hp and Tq are higher everywhere, from start to finish,not even being fine tuned. Freddy

Just to recap (this is a really long thread), could you list the exact mods made to the motor being dyno'd? And is the stock motor being compared actually bone stock? Not even a jetting change? I'm just trying to interpret what I'm really looking at in the comparison.

Ok, when I did my first dyno, pre-904, I made 53.8rwhp and 44ftlbs of torque. That was with airbox removed, Scepter pipes re-jetted to 45/145.
The second run I did is above in red, 904 with ported/polished head and +1mm oversized valves re-jetted to 45/155 with 2 shims under the needles and made 69.8rwhp and 53.2ftlbs of torque.
The third run is above in black, and it has the 38mm bored out stock carbs with stock intake manifolds, same jet setup as before.
My next run on Tuesday will have the new billet intake manifolds and a 45/157.5 jet set up with 2 shims under the needles, carbs perfectly synced and balanced. Then I should be able to fine tune again it after I see my air fuel mix, right now it's as close as I can get it without a readout.

Anything else?
or

Were all the runs made on a superflo dyno.

the first one was on a WINPEP7 DynoJet, that machine broke and I have used the same Superflow machine since

THX, the reason I was asking is because your first numbers are virtually stock 790 numbers with airbox in place and stock exhaust. Just seemed a little low for the setup you were running.

Right, I know they seem low, but I've seen other actual stock motor dyno numbers from people posting them here and they weren't much different than mine. I think that maybe factory specs are a little generous, and I think those may be power ratings at the crank instead of the rear wheel.

The factory specs are NOT at the rear wheel and dyno results will be lower than published specs. BUT, your results still seem low to me.

And you're talking about my first run, yes? Truth be told, it may have been the machine since it ended up broken anyway.

Factory numbers are at the crank (61hp) and most stock 790's dyno at about 54hp.

Just to sum up guys , All dynos will read a little different. Some more than most,but If you are using as a tool on the same dyno the #s should be the same. All we look for is before and after on the same dyno, not just peak #s. Most guys give peak #s from different dynos that will not give you a accurate gain from one # to the next.The way Roadworthy is doing this is the rightway. Thanks Freddy. Just a note when I dynoed 865s bonnies and thruxtons on our dyno in GA stock were 40s TQ and 48-51 hp on 08 bikes.

This morning I went and had my final dyno run for this experiment. This time the high flow billet intakes were installed. The numbers were even better now than with just the bored out carbs. My peak number isn't as high because the rev limiter kept kicking in. I even did a pull with it disconnected, and it still hit early. Just for a bit of extra info, there was no difference anywhere in the numbers from TPS connected or not. Red line is 904, blue line is with bored out carbs, black line is with high flow billet intakes. When you look at it from red to black, it's a good jump in power and torque for only adding carbs and intakes. If I had a higher rpm limit, no doubt I would reach 80hp+. It also appears that the only way I'm going to get the dip out of the middle is to change my needles to one with a fatter taper. I think it's pretty well proven here that these motors like more air flow when they run the 904.

That's a sweet jump in torque you've got there Dave, almost 5 ft/lbs over the basic 904 and enough to really grab my interest in more than just a 904 kit.

You will probably see similar improvements (maybe not quite as high) on a stock motor. It's definitely worth what Fred charges for them when you look at other carb prices.

Why was your rev limiter kicking in early on this last dyno run and not the other runs.

I don't know, I hope the ignitor isn't going to fail.

is it possible for a rev limiter to get progressively "worse" or kick in more often? I swear mines kicking in more often than before.

Fred told me that when he worked at Atlanta Triumph/Ducati, that was something owners would say was happening before it crapped out completely. I hope it's not what's going on here. I know that in the wintertime, I seem to hit it very fast, and a lot more than in warmer weather.

one more worry to add to the bin of paranoia...ahah Its probably all in my head cause ive been racing my buddy on his 1200 sporty and getting slapped in the face by the limiter at the worst times.

Today Fred told me that he is now able to get 12 more cfm's out of the stock carbs, which put them right there with the 39mm FCR's in flow output. He also told me there may be a price increase, but people throw money at the FCR's and the 35mm CVK's, so it seems logical to increase the price for a comparable setup.
From the results I have posted, has anyone else seen a better bang for the buck?

See, that's what Fred wants everyone to know. You can get a big gain from these, and you don't have to throw down 1100 bucks to get it.

Do you know if I can use my modified airbox with his intakes and carbs? My modified airbox consists of just opened up bottom and snorkels removed with UNI or K&N filter. I am not running the freak or ghetto freak. I am getting very close to pulling the trigger on Fred's carbs and intakes.

Ron

I don't see a reason why you couldn't, but I don't know if the gain will be the same. Maybe Freddy can answer this.

D@mned!

If Freddy had his shop in Sweden my carbs would have been there already..

The shipping cost, import taxes and the bad exchange rate just dont make it worth it.


Dave,

Been fun to follow your progress on this, keep up the good work!

I will offer a stage 3 carb set up with the new higher flow #s and i will still sell the carbs as they are will be $360.00 US and stage 3 $550.00 US. Guys It does not matter on exchange rates and shipping this will still be the best bang for your dollar .Even if these only made you 5 hp this is still better.

Ok in the end,it's all done I take it.Have you ran a few tanks of fuel through it? What kind of fuel mileage are you now getting.I know I should not care,but it is hard to ignore this question with gas going back up every day or two a nickle or a dime.Sounds like a great way to go for more power.It would be really nice if the mpg went up also,then it would actually pay for itself.A good excuse to tell the wife why your doing the carbs now.

Heck no!
He'll have premature chain stretch and sprocket wear due to the increase in torque, He'll wear out brake pads, wheel bearings, tires quicker. His fuel mileage will drop, extra traffic tickets, Higher octane, higher insurance, shorter durations between tune ups, Better gear, More accessories, The costs will SKYROCKET now!
If you want a economical motorcycle, LEAVE IT ALONE!

premature chain stretch and sprocket wear due to the increase in torque. : I have a new sprocket and chain kit on a shelf right now waiting for an install. 19k on original chain.
wear out brake pads, wheel bearings, tires quicker. :I'm gonna do that anyway.
fuel mileage will drop : nothing noticeable yet, but I haven't paid too much attention.
extra traffic tickets :still haven't gotten one on the bike, believe it or not!
Higher octane :been running premium since the day I got it, no difference there
higher insurance :why would I tell those fools what I have?
shorter durations between tune ups :still no tune up since BB install, only oil changes
Better gear : umm... the best gear
more accessories :seriously? do you not know me?
If you want a economical motorcycle, LEAVE IT ALONE! :+1!! I have an economy car that gets near 50mpg, my bike is for fun!!

i get anywhere from 40 to 45 with my 42 mikunis

What a great thread. I've just read it from go to whoa and really impressed with your numbers Dave. This stuff is so addictive

you think the numbers look good, you should feel it!

Thats what she said!

Ya bast@rd, I'm jealous as Dave. Hopefully I'll be able to do this with my own steed when I get a chance and then I'll know what you are talking about. In fact I can just feel the excitment each time you write an email. Great stuff man.

You know, you would have to think Triumph would monitor these sites for goof R & D that's virtually free wouldn't you? I mean all the work's been done for them including dynos as verification. They'd be mad not to look at what the back yardies and various workshops are doing, and considering now they will be offering the kit for boring out the new Thunderbird, makes me think they do

I think the engineers at Triumph have long known what we have learned. They have contraints we don't, mostly price points and government regs. Point in case, I doubt Triumph could get a factory installed T-Bird big bore into the country (USA). Plus it's easier to sell a $12500 Triumphs than a $15000 ones. Besides you can install the 100cc kit any time during ownership. For about $1500 plus 8 hours labor you get a 100 cubic inch T-Bird. I think it include air box mod, remap, pipes, and a 100 cubic inch clutch cover Triumph will only sell you if you've done the kit.

8 hours of labor?

I talked with Fred this weekend and he told me that he can now put an air bleed in the stock carbs, which will cure any mid range rich spots and dips in the power. He's really dedicated to making the best possible product for an affordable price for our bikes. As it is, he is already the only manufacturer of high flow billet intake manifolds for the America/Speedmaster. I'm hoping that he gets enough business and income to keep coming up with ideas for getting the most out of the motors on a limited budget. It seems the sky is the limit for our bikes with the knowledge he's got .

Been following the posts quietly. I'm definitely in the market for this to upgrade my 2008 stock BA. For the price vs. options, very reasonable.

Taking baby steps. Just put on long TORs yesterday (need to adjust mains yet - advice was I could keep stock but back out 3 or so turns). Will do airbox removal (probably use kit for nice replacement and tool box compartment, etc...) without butchering airbox (in case ever need to go back to stock).

Thanks to Freddy for the dedication and Dave for the sharing and work on this, blazing the trail.

Just came back from Cambria rally, canyon bombing with nimbler Bonnevilles/Thruxtons with upgrades has me lusting some more jump - but held my own with complete stock BA '08. But tougher passing on Hwy 1.

Thanks!
CHUCKLES