Triumphrat

Gary_spain

Ok, so today I got on with fitting my Breathe which Mike sent over to me a couple of weeks ago.

I combined the job with taking the internal baffle (restrictor plate) out and fitting 135 Main jets. While I was at it I took the shims (1x) out from under the needles (looking to improve MPG) and drilled the slider air-hole out to 3.0mm.

Once everything was done I started her up and she sounded good - however as she quickly warmed up things started to go a little awry and the engine started to sound lumpy and uneven, this got worse the hotter she got.

Took her for a quick blast around the block and the bike doesn't pull untill up around 2,500-2,800 rpm - there she really takes off! but below this rev range the engine is lumpy, and rough.

I've tried adjusting the air-screws from 2.5 to 3.5 turns out (in 1/2 turn steps) but no improvement is noticed.

Any ideas? Should I put the shim's back in? Maybe try more turns out on the air-screw?

Any advice would be much appreciated - Cheers guys!

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07 Thruxton: TEC 2 into 1, K&N, TTP Breathe Bellmouth, 135 mains, 40 pilots, std. needles, 1 shim (0.65mm). All baffles removed. Bitubo Fork Cartridges. Bitubo Rear Shocks. TEC Steering Damper. 3 Pot Nissin (Honda) brake caliper.

mikeinva

Why did you drill the slides and take the shims out? was bike running good before you did? I would not drill the slides myself have seen to many do that and have troubles.changeing springs is better to me that way if its not needed you can go back to stock.

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Why do I feel young on my bike

Gary_spain

Hi Mike, er, well, at least what I've read here on the forum (plus the Jenks Tuning guide) the drilling seems to be recommended - I used a 2.9mm bit. The shim I took out as I also read here that this wasn't so important and really just upped the gas consumption.

The bike was running great before with the setup which you can see below in my signature.

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07 Thruxton: TEC 2 into 1, K&N, TTP Breathe Bellmouth, 135 mains, 40 pilots, std. needles, 1 shim (0.65mm). All baffles removed. Bitubo Fork Cartridges. Bitubo Rear Shocks. TEC Steering Damper. 3 Pot Nissin (Honda) brake caliper.

Gary_spain

I've checked the carb balance with my Twinmax and it's spot on. Also I've checked for air leaks around the carbs and everything looks fine, all caps are on the vacuum hose connections. Problem persists...

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07 Thruxton: TEC 2 into 1, K&N, TTP Breathe Bellmouth, 135 mains, 40 pilots, std. needles, 1 shim (0.65mm). All baffles removed. Bitubo Fork Cartridges. Bitubo Rear Shocks. TEC Steering Damper. 3 Pot Nissin (Honda) brake caliper.

PieMan

Gary, put the shims back in and see if it helps. The Breathe allows more air to be sucked in than the Polaris mod. The mains take care of the upper throttle opening, but at smaller openings the shims do make a difference.

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Mike (UK)

04 Bonnie Black Special

http://www.triumphtwinpower.com

Gary_spain

Thanks for your replies guys! Ok, I'll try putting the shims back, I'll give it a shot with 1 and with two shims under each needle. I won't be able to get anything done 'til Thursday though.

Should I set the air screws to 2.5 turns out? That should be the setting right?

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07 Thruxton: TEC 2 into 1, K&N, TTP Breathe Bellmouth, 135 mains, 40 pilots, std. needles, 1 shim (0.65mm). All baffles removed. Bitubo Fork Cartridges. Bitubo Rear Shocks. TEC Steering Damper. 3 Pot Nissin (Honda) brake caliper.

Baltobonneville

Yes, I'd put the shims back in.

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Marty
2005 Bonneville Blue 790cc, AI removed, Staintunes RC, Uni filter, no snorkel, 118/40/NBZT "Thruxton" needles/1 shim/3 turns, tachometer, Ikon 7610s, Ricor Intiminators, Dunlop GT501s, D9 gauge panel.

PAAS

The baseline setting for the pilot screws is 2.5 turns out but you may well need to adjust them from there to get the best low speed running for your particular bike. They control fuel rather than air, so more turns out equals more fuel and vice versa. Don't turn them out much more than 3.5 turns or you'll risk the screws dropping out. Don't worry if you get some crackling on the over-run with the screws set correctly - that's fairly normal on these bikes with a free flowing exhaust on them. You can tune it out to an extent with the pilot screws but you may end up with an off idle stumble if you do as you'll be running too rich.

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Paul.

Herts. UK
Aubergine & White 05 T100 (865cc) with numerous mods.
(Previously Ducati Monster S4 and several UJMs)

Gary_spain

Hi, after a few days laid-up with back trouble I was finally adjusted the air-screws to 2.5 turns out and put the shim's back in.

My Bike is now running just fine - at least in the garage (at operating temperature) as I haven't had the chance to take her out on the road yet.

Thanks all for the great advice!

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07 Thruxton: TEC 2 into 1, K&N, TTP Breathe Bellmouth, 135 mains, 40 pilots, std. needles, 1 shim (0.65mm). All baffles removed. Bitubo Fork Cartridges. Bitubo Rear Shocks. TEC Steering Damper. 3 Pot Nissin (Honda) brake caliper.

LukiSevenAce

It's possible there's more than 387% better "CFM" being delivered by the mod.

Try stuffing a sock in the throats, but use wool ones and not the synthetic type.

The wool sock will have a thread count on the package.
Look for a number between 250 & 350, but not higher than that; any higher thread count will cause the carbs to choke down more than you want.

You can turn the balled up sock (called 'indexing') 90° to adjust the idle too.
Turning it 45° will alter the tone of the exhaust note. (Look for a high C)

Good luck with it.
*I like the part where you know it's running 'just fine' without taking it out on the road.