Triumphrat

InkSlinger

Has anybody tried the Thunderbike cams in their 865cc Triumphs? They claim to give you

more horsepower while retaining the low end torque and mid-range of the stock cam. My

Thruxton currently has 40 pilots, 130 mains, 3 turns, NH bellmouth, and Predators. The bike

runs a hell of alot better than stock, but I want more without tearing my motor down. I'm

going to get rid of the airbox next and I was thinking these cams would help alot. Maybe if

funds allow a set of Mikuni 42's and head work in the future. Oh yeah , what about

changes to the ignition timing and rev limiter?

Hated by ALL

Look here for cams

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...Hated By ALL

sweatmachine

another source for cams is http://www.fastfredsheadworks.com/

email Fred, he knows his stuff about the bonnies. He's made several custom grinds and dyno tests them all.

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"If you will it Dude, it is no dream"

904cc Custom Bonnie Cafe Fighter!

mikeinva

There are better cams out there then Thunderbike cams check out the ones hated and sweet posted

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Why do I feel young on my bike

InkSlinger

Thanks for the info. I've never seen a stock cam that was ground for optimum performance.

I know there are gains to be made by changing cams but is the horsepower to dollar ratio

worth it in a stock motor?

mikeinva

getting rid of the air box will give you more for less.

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Why do I feel young on my bike

beemerrich

I've looked closely at cams for my thruxton and, until someone in the aftermarket steps up with direct comparison data to state otherwise, the best option out there appears to be the original, 242-degee duration 790 cam from the 2001 model machines.

When I enquired with thunderbike regarding performance improvements their cam provided over the 790-242 cam, they responded with:

"We have not produced a camshaft suitable for use in the 790cc motors I'm afraid, despite several attempts nothing producing significant benefits has been found."

So, in a word, you won't realize any significant difference using their rather pricy thunderbike cam over the 790-242 cam in your 865. I can't speak to the other aftermarket grinds since no one publishes direct cam swap dyno data or cam specs for that matter...

As far as where to go w/ bolt-on mods, you can make about 70 rwhp by losing the airbox, adding the 790-242 cams, and getting the ignitor reprogrammed to match the more aggressive cam. That's where I'm hoping to be by the end of winter too...

Cheers,

--Rich

sweatmachine

the 70hp mark with stock internals and stock carbs is a little out of reach, that is unless your dyno guy is blowing smoke.

__________________
"If you will it Dude, it is no dream"

904cc Custom Bonnie Cafe Fighter!

beemerrich

The dyno run I saw hitting near 70 rwhp wasn't my bike (unfortunately)...though I'm at a hair over 62 rwhp without the 790-242 cam or enhanced ignitor.

The ignitor tweaking is *supposed* to be good for about 1-2 hp and the cam adds about 4 hp up top...so that'll theoretically put me at about 68 rwhp. Here in Michigan, we round up... :^)

I've selected 70 rwhp as my goal and I'm sticking to it! I'll ditch the CV carbs should I fall short...

Cheers,

--Rich

mikeinva

no air box 790 good ing box and 42mm carbs= 65rwh on a stock motor.I think the guys showing 70hp with stock carbs/motor better look close at there dyno guy and see what there sae c/f is .You might get one now and then as high as 62hp but most are in the high 50s.A bone stock bike should be around 50hp +or- 1 or 2 hp.

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Why do I feel young on my bike