Triumphrat

robnobrakes · 11-22-2007

Quote:

Originally Posted by BeastInBlack

My bonnie had the same treatment as yours, minus the carbs and big bore kit, I think it was the bob farnham package (gasflow/skimmed headwork) which pushed it up to 70 rwhp.

What do you have at the rear wheel now? Also, how long is your average journey? I have found that makes a big difference, shorter journeys reduce my overall range by about 20 miles. I have the 19t and usually get to between 100 - 110 miles before reserve.

One more thing how much were those carbs? Are they any more/less user friendly than the stock ones?

about 84 rwhp on the dyno.

Short rides/long rides, it makes very little difference. I managed 54 mpg on a trim to the Ace Cafe and back to Essex.

The carbs and fitting kit currently cost £699.00 from http://brspecialtuning.co.uk/Keihin.htm They are brilliant carbs, although cold starting requires priming the carbs by snapping open the throttle a couple of times before starting because there is no choke.

ggRAT · 11-22-2007

Rob,
Is this arithmetic correct?
1 UK Gallon = 1.2 US Gallons
1 US Gallon = .80 UK Gallons
therefore
50 MPG (UK) => 50 x .8 => 40 MPG (US).

I'm getting about 40 MPG (US) with my 904cc BBK.

Old Scratcher · 11-22-2007

Thanks for the input everyone. It sure is good to get the "good oil" from those who've gone before me. I know that tyre wear is directly related to my throttle hand. But that's also directly related to how many herbs that hand has to play with. i.e. If it's there, I'll use it. That's the point of hotting up an engine in the first place. So there probably will be a slight increase in tyre wear, for me. But it sounds like it will be negligable, & it won't put me off modding the motor.
To answer some questions. I've done 30,000klms (20,000mls) in 11 mths, & intend to do even more klms next year. I've spent over $2000 on tyres alone, in that time. So you can see why tyre wear is an issue for me. I'm very happy with the power that my TB kit gives me, & I've no intention of doing any more engine mods until this one starts to feel a lot more tired. I'm just gathering info now, so I can spend some time investigating & planning my next move. & for the record; my favourite option so far is BiB's suggestion to stick an 1100 kit in it. & stuff the tyre wear! But I'll probably moderate that position as I get closer to the rebuild.
Thanks again guys. You came through with yet another excellent response. Well done.

amanger · 11-22-2007

Keep the Scrambled Egg for potering around on and buy a KTM950/990 for serious klm s and bush work.
Its only money,the bank just gives it to you.

SCCTrim · 11-22-2007

Also, you have an 865 cc motor... the 904 kit isn't going to add a whole lot... Especially if the rest of the intake/exhaust side of things are pretty much stock...

This is a buncha crap.....do not buy into the above comment.

sweatmachine · 11-22-2007

Quote:

Originally Posted by SCbonneville

Also, you have an 865 cc motor... the 904 kit isn't going to add a whole lot... Especially if the rest of the intake/exhaust side of things are pretty much stock...

airbox elimination kit, port/polish the heads, open exhaust, cams... that will make the most performance difference...

Like SCCTrim already said, this is incorrect. My bike was an 865 before I installed the Wiseco 904 kit and it made a dramatic difference. The bike never pulled wheelies in 1st and 2nd gear before the big bore install. Now it lifts the front end in those gears, and will spin the tire in 3rd.

Old Scratcher · 11-23-2007

Quote:

Originally Posted by sweatmachine

Like SCCTrim already said, this is incorrect. My bike was an 865 before I installed the Wiseco 904 kit and it made a dramatic difference. The bike never pulled wheelies in 1st and 2nd gear before the big bore install. Now it lifts the front end in those gears, and will spin the tire in 3rd.

Hmm I like the sound of that. Tell me more. Do you have to upgrade the bottom end, clutch & gearbox as well? Is the 904 kit just a re-sleeve? & does an 1150 kit require new barrels? What needs to be done to the head? Just a port & polish, or is there more involved? Would my TB cams & pipes be compatible, or does the kit come with new cams? Is there a choice of compression ratio's? Which would you recomend? & finally what's the best jugs to feed a big mill like that?
Sorry for the "third degree" Sweat, but your tales of 1'st & 2'nd gear wheelies have intrigued me. & I might not be waiting until this motor's cactus, before I bomb it up, after all.
Thanks
Scratch

sweatmachine · 11-23-2007

the kit includes the pistons and liners for the cylinders, and a base gasket and head gasket, the wrist pins and circlips, and maybe a couple of other small gaskets or something.

Your cylinders/barrels must be bored out and the liners from the kit are press-fit into your barrels. The going rate around here for the machine work is $200-300 USD. It is only a top-end rebuild, in that you do not have to mess with the bottom end. No headwork is required, but since you have the head off of the motor and the parts at a machinist it makes good sense to have the intake/exhaust runners cleaned up a bit. The compression ratio is 10.5-1, but you could mill the barrels down a bit to raise it if you wish. I would think 11-1 would be safe as well. Stronger clutch springs are required, but the stock plates are ok with the stronger motor. I have stock plates and stronger springs and the clutch holds just fine and the lever action is not much firmer than stock.

I had larger valves fitted, and also the intake manifolds port-matched to the newly ported/polished head, so I had a lot of stuff done at once. Your cams would be compatible with this mod.

The 1100 kit is just an overbore (like the 904) but it requires bored/split cases, along with a billet barrel, and pistons, and liners....

the 989 and 1200 kits require all of the above PLUS a stroked crank $$$

BTW, what kind of a difference did you notice with the cams?

Old Scratcher · 11-23-2007

BTW, what kind of a difference did you notice with the cams?[/quote]

It's hard to say how much of a part the cams played in the kit's performance improvement, 'cause it didn't really work that smoothly until I got the K&N filter (It was on back order for 3wks). But it's got a lot more mid-range acceleration & torque. & the idle is a lot lumpier than it was, which must be the cams. For the money, I'm very happy with the improvement it made. I no longer crave a bit more speed from my bike (but I wouldn't say no, if some became available).
BTW Thanks for all that info Sweat. You are the go-to-guy for that kind of thing. & I for one, am very glad that you're willing to share your wealth of knowledge with the rest of us. It makes it a lot easier to find out what can & can't be done with these bikes. & hopefully we'll all end up with better bikes because of it. So good onya. & thanks again
Scratch

SCbonneville · 11-23-2007

Quote:

Originally Posted by sweatmachine

Like SCCTrim already said, this is incorrect. My bike was an 865 before I installed the Wiseco 904 kit and it made a dramatic difference. The bike never pulled wheelies in 1st and 2nd gear before the big bore install. Now it lifts the front end in those gears, and will spin the tire in 3rd.

39cc's alone gave you enough extra power to pull wheelies in 1st and 2nd gear!!????

Why do I find that ... um... interesting???

My point, and I have ridden a couple of 904 bikes... was that a bigger boost to power will be accomplished by working on improving the intake and exhaust sides rather than adding just 39cc's... I stand by that assertion...

>I had larger valves fitted, and also the intake manifolds port-matched to the newly ported/polished head, so I had a lot of stuff done at once. Your cams would be compatible with this mod.<

Just saw the above quoted statement about head work... That is intake/exhaust work... It seems you did a lot more than just bolt on a 904 kit... Now... did you do a dyno test to see what gave you the largest hp increase.... the cc's or the improvement in breathing....