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 my 175... mikuni..

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nigel breeze

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Number of posts : 341
Registration date : 2007-12-23

PostSubject: my 175... mikuni..   Sun Feb 12, 2017 9:17 am

https://youtu.be/1z-gkglGxqE afr metering thing lol! had some bits for trying this out for a while, oxygen sensor and gauge. i had hoped to make it for probing inside the exhaust but the sensors bulbous size stopped me . so i cobbled this together to See if it would work,, well the gauge showed something!!.. now maybe i should tidy it up get it all in a box so it looks less rough lol! from a static point of view and if the gauge is correct i think im somewhere near to whats needed but under load this could be very different. which brings me back to that frustrating situation of having nowhere to test it in real terms. Sad
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nigel breeze

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Number of posts : 341
Registration date : 2007-12-23

PostSubject: Re: my 175... mikuni..   Sun Feb 12, 2017 9:42 am

https://youtu.be/SjtD5wPK5t8 † this is what the 34mm flatslide gave me after sorting out the pilot circuit.. no transition from idle to 1/8 †1/4 †throttle.. i did move the carb needle up and a small shim to see if it changed the situation along with advancing the ignition quite a bit. it then was able to a least rev out. cheers cheers
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Jimmie



Number of posts : 132
Registration date : 2011-07-25

PostSubject: Re: my 175... mikuni..   Sun Feb 12, 2017 11:15 pm

Hi Nigel

When I clicked on the links I got a request to sign in. Guidance please. Even if I don't understand the instructions I may feel better. What a stupid machine I have!
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nigel breeze

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Number of posts : 341
Registration date : 2007-12-23

PostSubject: Re: my 175... mikuni..   Mon Feb 13, 2017 4:32 am

ok, sorry looks like i hadnít ticked a box on the you tube account. it even asked me to log in . should be ok now. i have decided to get hold of a temp gauge as well to see if i can measure the exhaust gas temp . study
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Jimmie



Number of posts : 132
Registration date : 2011-07-25

PostSubject: Re: my 175... mikuni..   Mon Feb 13, 2017 6:59 am

Many thanks.
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nigel breeze

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Number of posts : 341
Registration date : 2007-12-23

PostSubject: Re: my 175... mikuni..   Sun Feb 19, 2017 9:00 am

oh dear, looks like i need a new conrod and big end bearing..affraid . ill post some pictures of damage....could have been worse. i had a t&g conrod but its design wasnt up to the job for this application.. aah well .. i did show the conrod to derek some time back and he felt that the lack of a slot in the big end of the conrod would cause poor lubrication for the bearing.. seems he was right.. study
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johnSbantam

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Number of posts : 254
Localisation : New Zealand
Registration date : 2006-12-01

PostSubject: T & G rod   Sun Feb 19, 2017 3:07 pm

Sad but interesting news Nigel.

My T & G rod in 186 has done some 20hrs hard work without worry.
But it has a slot in big end eye.
Will put micrometer on pin and rod when it comes apart this winter
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nigel breeze

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Number of posts : 341
Registration date : 2007-12-23

PostSubject: Re: my 175... mikuni..   Mon Feb 20, 2017 2:10 am






as you can see.... affraid and also this t&g rod has no bigend slot to help with lubrication. still never mind,, got a couple of conrods, just need to get the crank to accept 22mm crank pin ect ... gives me a chance also to incorporate a couple of new ideas to the mix:study: . i did mange to wire up the exhaust temp guage but didnt video, seemed to work.
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Trevor Amos



Number of posts : 860
Registration date : 2010-08-13

PostSubject: Re: my 175... mikuni..   Tue Feb 21, 2017 2:22 am

Nigel,
Been enjoying your video clips and what you have been trying to do, have a load of questions to ask but will wait until a bit later in your experimenting. Can`t imagine what goes on in the design department of some of these rod manufacturers, to omit the proven benefit of slots in a big end eye is absurd. Not only does cooling lubrication get at the cage and pin but heat gets centrifuged out, an easy win, win. Sorry about your travails but hey that`s the learning curve, but one we could all do without. Top work as always Nigel!

Cheers, Trevor
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john bass

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Number of posts : 1719
Age : 88
Localisation : Bensberg, Germany
Registration date : 2006-12-06

PostSubject: Might it be the cage   Tue Feb 21, 2017 5:27 am

The only big-end trouble I ever expereinced with both Icarus-1 & Icarus-2 was with the bearing cage centrifuging itself to rub on the big end eye in Icarus-1. Just five minutes on the lathe skimming the cage and our problem was solved.... We assumed that with the cage rubbing on the brig-end eye it expanded sufficient to lock the rollers.

Maybe it is notthe case with your problem Nigel....?

Of course neither Bantams ever revved to 12,000 rpm but Icar-2 got to †>11,000 but only suffered piston destructions...
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nigel breeze

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Registration date : 2007-12-23

PostSubject: Re: my 175... mikuni..   Wed Feb 22, 2017 6:28 am

yes John, i anticipated a piston seizure, with it being a cast barrel... (4 transfers and a little boost port....Shocked ) but i had been pre warned the conrod would not be up to the job. Embarassed
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