Bonneville America Forums Forums Technical Forums Performance Mods big bore kits

ok I know that I have ask this question before. but I really would appreciate any info that I can get on the british customs 994 billet cylinder.also has anyone had any dealings with british customs are they a good company. do they produce good products. any info greatly appreciated.

I have just fitted the 904cc Big Bore Kit and I can't believe the difference. I run a K&N re-useable air filter and open pipes. HP increase from 55 stock to 70HP!

Best money I have spent on my BA

Wizza
Australia

I wanna say with the 994 you need to do alot more work that with the 904. Cams, cranks reground etc. (let me go find a link for you)
Don't mind the 998cc in this post, they just mistyped the size, it's a 994 they are reffering to.
http://www.bonnevilleamerica.com/forums/...p;page=4#136300

British Customs is a reputable place to go but Remember, Brent (newspeedmaster.com) is a supporter of the site and always is a good place to go shopping.

thanks reido113, but the kit that you are talking about from brent is a 988 stroker kit. the 994 bb from BC is a billet cylinder no sleeves.I do know that you have to cut the case for the bigger cylinder bore on the 994, but no crank work is needed.

i imagine if you keep your oil changed the sleeves will last quit a long time, and i would much rather have a forged piston like the weisco kit, if bc offered there kit with a forged piston i would take a harder look at it

Frank

Ahhh.. I see.
Sorry if I slid confusion through the door.

I too have done the 904cc wiseco kit, and support this option 100%.

My horsepower hasn'nt been dyno'd yet but I expect mid-70's due to the headport job etc performed aswell. I wouldn't bother doing anything else to this bike, it just wouldn't be worth it.....

I just fitted the BA 904cc kit to my America and it is the best and cheapest way to gain a HP and Torque increase. The bike suprises a lot of Harleys now!

As a side note w/r/t Harleys -- I did a 500-mile run with a buddy on his Night Train this past weekend. Now, while it was pretty close, that HD did very, very well. We swapped bikes and I have some observations:

As Hunter Thompson put it "Can you handle this BOTTOMLESS PIT OF TORQUE"? The 1,400+cc engine has some real advantages, and in terms of just raw power, it wins. The Speedy 790 is more "civilized" and agile, but for raw acceleration, the HD wins.

The HD absolutely crushed me off the line, every time. No contest. The only way I could get him was if there was at least a mile where I could wind the engine up... and at 120+ the Trumpet is more stable and has better power delivery. Over 100mph the Trumpet wins across the board. The Speedy is also WAY more comfortable on all counts, particularly regarding the saddle.

The fact that I could pace my buddy's Night Train while using only about half the displacement is kind've funny, but... still. For all the smack we talk here about the Harleys, I have a new appreciation for 'em. I wouldn't trade, to be sure, but I think the reason we embarrass of lot of HDs is that many HD pilots are deficient.

This episode also taught me that I need to do the FREAK/pods and bigbore mods. Tee hee hee.

--Jaeger

I hear what you're saying, and for the most part I agree. Those big V-twins have TONS of low end torque, for sure. I'm not saying I beat all Harleys off the line (just some ). But I often run with the "big boys", and I have no shame, and no trouble keeping up. I get comments like "That little Triumph sure keeps up OK", and "What size is that Triumph...1200, right?" It's just such a super machine...I can hardly wait until I get the big bore in w/ ported/polished heads and stage 1 cams...

Oh, there's no shame, believe me -- the fact that we can more than "keep up" with a 50% handicap is pretty f'ing impressive, no question about it. I'm just impressed at what the HDs can do with an experienced and aggressive rider who knows what they're doing! Too often I see them ridden buy RUBs who are afraid to peg the throttle.

And no, his Harley isn't stock either, which helps him quite a bit. I'm just slightly less cocky about thumbing my nose at the HDs... until I get the FREAK and big bore, that is.

--Jaeger

i never raced one from a stop, but on the highway a guy wanted to run and after 100 i was pulling away at a pretty good pace

Frank

Actually -- forgive my ignorance here for not asking sooner -- what's the diff between the Wiseco 904 Kit ($500) and the BC 904 kit ($1,200)?

That's an AWFULLY big difference in price... what's teh deal?

--Jaeger

Wiseco's kit requires you to bore it out and install cylinder liners.

If I read BC's website correctly - they supply the actual cylinders - their cylinders are bored out and replated- no liners.

Ok, that makes some sense... but is there an advantage to doing this? From what I can tell, having the Wiseco kit professionally installed isn't THAT expensive -- is it? Hell, some of the more experienced wrenchers on here have done it themselves (e.g., Dinqua) so presumably it doesn't require a whole lot of heavy machinery... right?

From all I hear, the Wiseco kits are very good -- I just don't grok spending more than twice as much. Explainations?

--Jaeger

Send your cylinders to any good cycle machine shop.
they press out the stock sleeves, bore for the wiseco
oversize sleeves and press them in.
That's pretty much it for the cylinder machine work.

I am doing a 904 big bore this spring before the GA Rally. I'm tired of Pat outrunning me!

I've done a cursory look at both offerings and I believe I will get mine from Brent and have the machine work done locally. The reasons behind my decision:

1. The cylinders need to be bored, period. I am not sure what BC means by 're-plating the factory cylinders' but sleeves are included with Brent's and I have resleeved cylinders with long lasting success before. I would love to see the BC jugs though.

2. Other than offering the plated cylinders, the kits are the same although I do see BC includes new locating dowels. Not sure why.

3. I plan on doing the teardown and buildup. Having the knowledge, this should save a few $$

So.....

I figure the cylinder machine work might cost me around $200 (boring, pressing) and the head work might be another couple hundred. So for about $900, I have the motor where I want it. If Pat would get off his arse and get those new carbs dialed in, well...... (kidding buddy, please don't charge me double!!)

Now I just have to convince Janet that 'we' need to spend about $1200-1400 all told. I am planning on a decent tax return.

Heheh, ok. That's sort've what I figured. Still for $1.2k and a rebuilt motor, that ain't bad!!

Is the FREAK manditory for the big bore? What about upgrading the carbs? (not rejet but the whole carb)

--Jaeger

Also I believe the Weisco has FORGED pistons, whereas maybe not with the BC. Forged is good! Worth some extra cash.

I would imagine you don't NEED the freak, but if you're going as far as a big bore... Do the freak or some equivilant. I hear tell they are working on a budget freak. Or do a chopped air box like priveteer. If you want power enough to spend for the big bore, do it justice and let it live up to its full potential.

yes weisco does have forged pistons, and i emailed bc about what theres is and they never got back to me

Frank

Where did you get your big bore kit in Australia mate?