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Rigger

Hey ned what are you like at tuning bikes

a. boozer

nedwalk

sorry mate unless their humming the blues i can,t play along, maybe frankie has some answers. but i,ll pose the questions to some mates

friscofrankie

Not me. Not much for mikuni carbs. But the mid rang 'cough' could be down to "reversion." there's plenty of literature on it on the internet with pipes (im thinkin straight pipes?) like those in the photo you may have reversion problems at certain RPM. I'm not sure I'd blame timing but it certainly should be checked. Reversion typically shows up as a mid-range flat spot that can cause that 'cough'

If your engine is diseling after you shut off the ignition you definitely have excessive heat build up in the combustion chamber. retarded timing can put a lot of heat into a motor, so can lean mixture aor even a hot spot on in the chamber. if it was timing you would expect problems throughout the rpm range. Are teh two related? maybe, maybe not. I had an old dual point ignition on a panhead once. never could get the rear barrel to time right. never had a mid-range flat spot though. At night you could see my rear exhaust pipe glow red. was kinda cool lookin and nice source of warmth up in the Sierras at night but probably not real good for the life of the old stroker. Changed the distributor for a shovelhead auto advance no more red pipe.

if you have an electronic ignition with mappable advance curves there could be a midrange flat spot or the curve is just not aggressive enough. I'm not sure about these new mikuni flat slide carbueretors, but the needle/jet set up is tuneable does the mikuni have different needle profiles? Many of those slide type carbs have a needle with varying profile to control mixture at different throttle openings. Some things to look at and investigate sorry I can't be specific.

Sometime you gotta live what you got but with the tuneablity of today's new systems I would not run a carb unless I was forced to. You could always dump more money into the thing. Three letters: EFI. Plenty of programmable kits out there with pre-compiled fuel maps available and you don;t really need a comp or dyno to workout what works for you.

Same goes for ignition; I just got my new JP cycle catalog, they got pages of programmable ignition systems from Crane, S&S Accel, Dyna, etc.

I've been ramblig again. Ignore all the above. Thing is, it's a guessing game until a guy can get his hands on the machine and start the process of elimination; ticking off causes. retarded timng will put heat into a motor (deiseling) but usually will not cause a mid range flat. if the bike runs good at low and hi rpm then you might have fuel problems (not saying 100% it's NOT timing or 100% it is fuel, just probablities) Reversion will cause fuel (mixture) problems. If you are runing straight pipes you might look at putting some small baffles in there. or see if the mikuni has a stepped needle you can swap for better mid-range. I really have no idea on the layout of different fuel circuits in the new mikunis. I have heard they are quite tuneable so you probably have options there.

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Rigger

Thanks for the reply frankie I dont beleive it is the pipes as it hasnt always done it, I also run torq cones where the pipes bolt onto the head. I have ordered this DAYTONA TWIN TEC 1005 IGNITION KIT HARLEY SHOVELHEAD:eBay Motors (item 120292760808 end time Jun-05-09 07:26:59 PDT)
and hope it might solve the problem.


Timing is set at 98% full advance, set by a Harley dealer and ran great with this setting for a while. Then it started a small mid range cough and now has turned into full on miss firing anything in the upper rev range.

Going to take the buell on a long ride when I get back so I bought a springer seat set up Harley Chopper Bobber 16" LaRosa Leather Solo Seat:eBay Motors (item 190312354475 end time Jun-10-09 2251 PDT). Last time I did just a 200klm ride I had calases right at the top of me ass crack

also ordered all different types of mounting hard ware as I am not really sure how its going to fit. I think it will make it look more like a bobber style.

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Work to ride & ride to work.

friscofrankie

I rode rigid exclusively well into my thirties and am still tempted to build another. I do like the way they handle. I always ran a bates or bates type seat with 3" springs and they help ALOT.

Sounds like something's changed, no? if you haven't changed anything in that time, then something has worn or loosened or... Did you check for intake leaks? just a thought. Would make it run hot as well. again, just guessing but from what I am reading here I still suspect air/fuel.

I've never liked mikunis mainly because of thet hose & clamp mounting system they have.

I was reading up on that Twin tec 1005, looks like a good thing. Actually was the first ignition system in the new catalog that caught my eye.

what's the hit like on new parts you order from the US anyway? I've been told it's 30% of invoice. true?

Oh forgot here's some interesting readng at the mikuni website:
http://http://www.mikuni.com/fs-tuning_guide.html

Sounds like you got setup alright though just something got knocked outta whack, still worth a read.

Spin

Rigger, I would swap out the ignition leads for known good ones, they can cause the missing and hesitation in the mid range when the motor is under load.

Marmite the Dog

I'm going to get some new leads as well as mine are starting to crack. What are an easily available, reasonably priced, decent make? And how much roughly for a set?

Norton

Would expect you can buy enough cable from any auto supply shop and have them cut and fitted to the MC as I have done for cars. Shouldn't be expensive at all. Surely much cheaper than buying a factory set.

Rigger

You might have got it there, as I put new leads on about the time it started. But they were propper Buell hi porformance leads, Well lucky the new ignition comes with leads so I will change them out again
Cheers



The intake seals are all good and new, Mine doesnt have the clamp mount its just a push in rubber seal job and is good tight fit

Rigger

It deppends on the wind as alot I pay none or very little. But have noticed that electrical motorcycle parts the sting you about 30%. As long as I receive it I am happy,

mrsquirrel

Just use metal coat hangers wrapped in electrical tape

Marmite the Dog

I don't ride a Hardley.

Airportwo

Plugs and leads not a lot of money, worth getting a decent set, go into a car tuning place that the Thai kids go for there car go faster goodies and get them to make you a set up.

Rigger

Does anyone know what this pet cock came off ?

Eliminator

Don't know Rigger but I hear good words on the Pingle petcock, supposed to do a great job but you have to shut it off whenever you stop. I have a vacuum system for fuel on the Eliminatorl and the Pingle is a great replacement from what I've heard. I'm trying to stick with stock though.

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Eliminator
1986 Kawasaki 900

nedwalk

fuck me, that thing looks as old as BG, where did you get it?

Marmite the Dog

The US.

Rigger

Yeh it looks pretty old and I am scared it will fuk up one day on the road, I have no idea what it came off. But the cnut welded a fitting over the standard HD 22mm thread, I want to order a new one but not sure of the thread. I think it was 16 or 14 mm thread.

I just order a brand new helmet still in the box made in 1970 open face but has had the inside re fitted,

Bung

Hope it's not a Davida, I bpught one here in TH second hand after wanting one for years. Size large, ok 58-60 cm, ok should fit. Well fok me it is too tight even for the mrs! fits my 8 yo boy...just. Unreal, what person would a small fit? B700 down the drain...Teach me for buying a lid without trying then.

At least my new Bell Moto 8 fits like a glove.

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