Honda MG & MF 750

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Greg Watters
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Joined: Mon Sep 27, 2004 8:57 pm

Re: Honda MG & MF 750

Post by Greg Watters »

bottom of the cyls cut just below the bottom ring so under piston air from 1 coming down easily passes to 2 going up
same with 4 and 3
one of my earlier ones, do it much easier now with an anglegrinder making a v then rounding it and recutting
Image

Your a few mm smaller than the later 750, expected so but never hurts to ask
Johno Senior
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Joined: Mon May 21, 2012 12:17 am
Location: Berri Sth Oz

Re: Honda MG & MF 750

Post by Johno Senior »

Some serious work there Greg.
So reducing the pumping loss mod, is that a hypothetical or have you seen some numbers for the bike ?
I remember reading about a concerted effort by an old Chevy man David Vizzard who had a US university do lots of testing different ways to come up with some numbers, its in a couple of his performance books.
Speaking of old chevy men I tried the ol Grumpy Jenkins mod of exhaust vacuming the crankcase on a drag bike once, bought the bits from the local speed shop, exh nozzle , oneway valve and tubing etc but on my bike set up it made no difference to the ET on or off, figured the weight wasnt worth it. I didnt pursue it as the engine was not at the elite level of output and me taking a dump before the run made more difference. :D

I find the pumping redution interesting, I guess your looking at something for nothing , a bit of labour. Is this a common mod on the US bikes ?

cheers johno
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Greg Watters
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Re: Honda MG & MF 750

Post by Greg Watters »

Results will vary with the bottom end design, the busa and gsxr 750 have a similar shape in the cases where the cyls drop on, looks like they planned it but never finished
later bikes like gen 2 busa have it standard, and i have seen other brands with holes in the bottom of the cyls, even with the one piece case/cyls that is just about universal now , they vaugely resemble a 2 stroke with the exhaust where the transfers should be
i have no before and after , as after i pull them apart they all look like that, just one of those costs nothing , no negative, maybe positive things
Johno Senior
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Joined: Mon May 21, 2012 12:17 am
Location: Berri Sth Oz

Re: Honda MG & MF 750

Post by Johno Senior »

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just setting up to checka few clearances and deck height etc
Johno Senior
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Joined: Mon May 21, 2012 12:17 am
Location: Berri Sth Oz

Re: Honda MG & MF 750

Post by Johno Senior »

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.008 thou deck height, .048 head to piston clearance, hell I like my play doh....makes me feel young
Johno Senior
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Joined: Mon May 21, 2012 12:17 am
Location: Berri Sth Oz

Re: Honda MG & MF 750

Post by Johno Senior »

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weather was too hot, 45 in shed still 39 at 10 pm tonight
drove to adelaide to buy the fuel, sunneco supreme, $355. for two 20 lire drums,
then new bridgestone tyres, skinny suckers all mounted balanced rarin too go, HMMM just need a bike now. getting a bit ahead of myself.
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gennyshovel
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Location: Broken Hill

Re: Honda MG & MF 750

Post by gennyshovel »

Hey Johno, you should do a candle smoke job on your YELLOW paint job mate.
I'm not sure if I will notice it on the salt without something BRIGHT
Good job with the build btw.
Tiny DLRA# 484
Postiebike Racing , created & funded by TwoBob Engineering
Johno Senior
Posts: 260
Joined: Mon May 21, 2012 12:17 am
Location: Berri Sth Oz

Re: Honda MG & MF 750

Post by Johno Senior »

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While I was waiting for the new set of rings I done the clearance checks,
The larger inlet valve was just nicking the edge of the valve cutaway, depending on the rock of the piston at TDC, I had the head off 4 times before I realised what was going on. I just ground the lip back about 1.5mm for valve clearance , but in doing so I ground through the ceramic coating. Time for poor mans ceramic coating, VHT exhaust paint. Before the ceramic thing came on the market I used to do all my piston tops in this paint as an insulator....worked well.
so just like the old days
Johno Senior
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Joined: Mon May 21, 2012 12:17 am
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Re: Honda MG & MF 750

Post by Johno Senior »

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The rear sprockets arrived today, 43 and 41 teeth, 520 alloy. From Titmans racing , two gold o ring chains and 20 joiners should do the rest.
I was going to run none o ring chain for more ponies at rear wheel but after reading a few yarns on this forum about chains wearing dramatic II thought O ring and lots of lube :D
Johno Senior
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Re: Honda MG & MF 750

Post by Johno Senior »

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this is why I am running webers ! here is another set of carbies for approx $200, these are a 32mm combo venturis and jets , the set up I have in my carbs to start is 31mm venturies, I'll try both on the dyno and see which size gets the nod
Johno Senior
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Joined: Mon May 21, 2012 12:17 am
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Re: Honda MG & MF 750

Post by Johno Senior »

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Bought this italiano fork brace off ebay cheap, the guy bought the wrong model, my good luck 8) 8) 8)
harky
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Joined: Fri Feb 09, 2007 9:03 am
Location: Adelaide

Re: Honda MG & MF 750

Post by harky »

keep @ it Johno
like a man I worked for years ago said ---------- at 5'0 clock just think you have started a NEW shift , ------ I did it for a few days and then got REALLY tired
the thing about race cars / bikes time disappears ---- I known not where it goes
harky
harky
DLRA #643
so far 120mph for$2000---imagine how fast I can go for $20,000
Johno Senior
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Re: Honda MG & MF 750

Post by Johno Senior »

Hi Harky , thanks for the encouraging words.......you read my mind....tired

Are you heading up this year ? if I know you your totally organised.

I suppose this heat wave will end late Feb....fingers crossed and beautifull autumn weather to greet us on the salt, if I'm not suffering heat exhaustion by then
cheers johno
harky
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Re: Honda MG & MF 750

Post by harky »

pm sent
the real pain is in the past I m the one who needed the "pickup " trailer
made one so I don't need to use it ---------- might work
seeyasoon@thelake
harky
ps dyno s are evil things ---------- or is it just me !!!???
harky
DLRA #643
so far 120mph for$2000---imagine how fast I can go for $20,000
Stayt`ie
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Joined: Fri May 13, 2005 11:47 pm
Location: Mackay

Re: Honda MG & MF 750

Post by Stayt`ie »

harky wrote:ps dyno s are evil things ---------- or is it just me !!!???
ive been going in and out of dyno rooms for years now, its always a relief to walk out of 'em, even when your motors broken, :)
First Australian to ride a motorcycle over 200mph at Bonneville,,,
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