Amal UFO and spray tube notch on '69 Bonnie

MIki mouse UFO kit here
http://thunderproducts.com/u_f_o.htm

My Cdo bud Wesley has UFO single Miki mouse carb kit on his '71 and pulls like a Combat with easy starts and nice idle. He used JBW to mimic similar in dual Amals on his 650 Turnip clunker that prior was depressing to ride with him as barely could power to 65 mph and lagged below that climbing the small Mt's here. Yesterday he was able to run to 80 mph so nice I had to get into Combat 2S cam to hang with him and take some care working to stabize THE Hinge following his turn speeds too. He'd also notched back side of spray tubes and drilled small hole in front side going by what he'd seen in Miki options. Only issue is a slightly fast idle that needs almost closing pilot air screw to enrichen enough to tame the fire to idle in 1000 rpm zone, which does tend to soot up plugs, but cleared righ up on the hotted up road use. As he'd changed two things at once we don't know what is doing what, so told him to put in spare intact flat top spray tubes to see what that does. But end result so far is distinctly better power that upped my opinion of the famous Triumph 120 model. We don't know if he's cut air flow volume by closer fitting slide bottom that didn't change the cut out exposure so needs less pilot opening to draw fuel up, or if the air flow speed increased to point of too much air flow for the pilot to compensate for.

My plain Combat could out power him but required WOT and right gear to do so. I've notched Trixie's spray tubes 1/16" for distinctly better off idle hits, so next will try the UFO mod on the open bottom slides to see what that does. Hope others try some of these mods on 750's and report back.

Re: Anal UFO and spray tube notch on '69 Bonnie

UFO anal probes? are you sure JBW is indicated for a mod/repair in that region? Sticky/puckered/jet efflux?L.O.L.

Re: Anal UFO and spray tube notch on '69 Bonnie

Called Wes at 6pm to hear that he'd tried replacing the spray tubes with normal ones and that didn't do a thing for the too fast and plug fouling idle. So put in normal slides and got back the normal idle. Wes is too far off pavement for just a quick hi speed test ride, but right now he'd back to stock, so tonight will put in the notched-drilled spray tubes to see if that was what atomized mixture better on hi throttle. I've done my Amals with just notched spray tube and think I'm happy with it. UFO works for Mikuni but has more air path I think than Wes provided when slide down and surrounding the spray tube.

I ain't worried about no alien abduction, had contact with em long ago and they rejected me - the dam aloft jerks. Can't feel no acceleration on those flashy saucer things so what the use anyway.

Steam punk dont need no stinkin` anti-grav, he`s gotsta feel the G...
Well, that & the exquisite flow dimensions of the arcane analog amal instruments.
[Good stuff, let us know the results, ta.].

Maybe the significance escapes you or just don't care but by golly Wes wimpy Trunip Bonnie sure got better go power so will see what else he comes up with to adapt to my own, as long as don't involve jumping fence out of Norton garden patch.

Is he running some Big D Texas Jack light-weight internals in that mill, or a Routt 800cc kit, or an old TT Triumph factory set-up with triple springed square lobed cams, open inch &3/4 TT pipes & flame grooves in the 11:1 hi-comp pistons?

Naw, that'd be more like my first Norton the P!! i miss so so much. Nothing dramatic as that expected nor could little ole 32 Amals supply what that level Triumph could burn. Trixie's Amals, actually hand me down Peel's have fuel slot cut and Anodized #3 slides and this month also my file notched spray tubes so likely is what Wes will end up with too, stock slides and nicked up spray tubes. Wes seems to think the spray tubes atomized better. I think it may also pull more fuel too with less vacuum as needed in some 850's and 2 strokes. From my point of view it changed a slightly depressed mood on seeing his Triumph brought out to alrighty batten down and lets fly around fast as we care too. Trixie is not my hot rod any way measured by world or by me, but eager optimal factory performance is a sweet thing to seek. Round slide Mikuni is so similar to Amals [but for small enricher carb, and UFO's help them, so why not Amals? Trixie is good enough I have to watch speed and not go by acceleration sense as that just increases up to I don't care to find out how fast. Fact is where the Bonnie was topping out about 80 for pull Trixie is just getting into power band. If I wanted to hot up Trixie I'd throw on the standard small port head, single mIki and 2-into 1 long dong megaphone but she couldn't handle it nor could I.

Ok, so do his exhaust fumes smell 'exotic'? Is he tipping a bottle of 25% nitro-methane model fuel into his tank? Or is it just a light weight ,quick steering, snappy riding & low gearing synergy?

Re flow smoothing [UFO type]Concentric slides; it does seem a worthwhile mod, given the factory attention paid to the exotic racing Amal instruments of the GP/TT ilk.
With Mikuni VMs the pilot jet size requirement [on 2Ts in my experience] is reduced [improving cruise economy], as is the part throttle/opening throttle [reversion?] over-rich stumble/bog.
Do you link your inlet tracks with a balance pipe like BSA/Triumph/Yamaha twin carb set-ups?

Aw man JAW you are talking whole other hi orbital power modifications that might apply to Ms Peel, so interesting, but have no relation to Wes's Bonnie or my Trixie '72. Wes's Amal experiments are interesting to me for what it reveals in which items are affecting idle or hi end power character. I've had a few world class hot rods and know I can't resist tapping it often as I can but also know that level of power needs all the bells and whistles to stand the power hits and handle the hi power turns and similar braking. i think the Bonnie and my Trixie are real stinkers when it comes to serious riding. Wes offered up how much he was working though from my view point he looked like relaxing prince on flying carpet. I don't think I had to work as hard in the turns but definitely was to point of caution entering, even though half again faster than speed signs suggested...

Wes wondered about his Mikuni having a bigger pilot jet to handle the UFO idle but I don't think Mikuni single came with special pilot and UFO kit don't supply one yet they idle just fine both of us have found. I don't want to run Miki carb again, sold one off and still have spare, just in case. We want sweet sounds top to bottom but not anything special w/o going too far afield. I"ve not really studied the UFO configuration in Miki's carbs so don't know how to mimic it correctly in Amals. I'd like a bit more 4th gear spunk for passing from 60 to 80 zone, but after that Trixie gets on cam and can keep up with best sports bikes passing in tights out here going from 80-115. No she can't out run them or out accelerated them, just can keep up with as much as they are brave enough to apply out here, which is too thrilling for me on plain jane Combat but too dam boring to tag along long on Ms Peel, my real road orgasm giver.

Wes needs a smaller pilot jet in his Mikuni [down to ~1/2 size using the UFO] these guys have them for $3.75ea. http://hvccycle.com/carburetor-parts.html

Wes needs a smaller pilot jet in his Mikuni [down to ~1/2 size using the UFO] these guys have them for $3.75ea. http://hvccycle.com/carburetor-parts.html

Click to expand...

Huh? Wes's Miki + UFO on his '71 ex-HyRyder works a spunky treat no need to alter pilot in his case. But advice might apply to his Amals with the epoxied slides. Wes put in the notched drilled spray tubes last pm and said Bonnie now idles as expected and desired. But He's off to Colorado later in week so can't test the new combo on pavement, ie: stock slides with leaking spray tube, which is combo I've been pleased with on Trixie's dual Amals. Trixie seems a richer idle but quite adequate slow and stable as I care to show off or feel myself.

I can use back up advice on what pilot to put in Miki 34 that was fine for a Combat 750 but put on 920 instead. IIRC a #43 size was advised here prior.

Ex Hi-rider? Wha...ya mean someone didn`t want a `70s classic peanut tank/ape-hanger/banana seat combo?L.O.L.

Who Sir Me Sir, I've got HyRyder bars on hand for some of Ms Peel/s costumes, so that's who, who'd else.

From K.Cameron re carbs;
"When the intake suction pulse from the engine reaches the carb at part-throttle, fuel cannot flow until the pulse partially evacuates the region under the slide, above the needle jet.If that volume is large, the process takes longer & fuel delivery is delayed & reduced. The Mikuni VM, by using a solid slide, greatly reduced this volume. [& the UFO, more-so] If some airflow was lost to the 'hole in the roof' into which the slide rose on full throttle, the gain from superior response more than made up for it. In later developments, the flat-slide, TMX, & Keihin PJ, have further reduced under-slide volume. Such designs can deliver good mixtures when the engines suction 'signal' is weak - as when operating at the edge of the powerband...because they make better use of engine signal they can be used in larger sizes..."