Author Topic: Another vintage project from Great Britain, target Speed Week 2011  (Read 133756 times)

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Offline panic

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Re: Another vintage project from Great Britain, target Speed Week 2011
« Reply #30 on: October 17, 2010, 01:41:59 PM »
Re: 90° transition from transfer tube (parallel to wheelbase) to manifold entrance.
A big radius here is a tight fit, but helps keep fuel suspended by keeping the wall lengths closer (inner vs. outer).
If you can't do anything else, a 3-dimensional shape with a much larger radius allows more efficient flow (and more internal volume) by shifting the bulk of the curve outside the envelope. From the transfer tube, the curve goes up (or down) 90°, and left 270° to align with the manifold CL. Think of 2 donuts at right angles.
The disadvantage is that it adds substantial width alongside the engine.

Offline thefrenchowl

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Re: Another vintage project from Great Britain, target Speed Week 2011
« Reply #31 on: November 13, 2010, 12:31:01 PM »
Hi all,

Got a few bits done recently, slow progress!!!

Ordered the screens for the fairing, looks good so far, still not quite happy with the top bracket to the tripple tree, we'll see...









Methanol tap is also done...







I've started dismantling the 1954 KHK engine today, more on that later...

All the best from Patrick
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Offline thefrenchowl

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Re: Another vintage project from Great Britain, target Speed Week 2011
« Reply #32 on: November 16, 2010, 03:34:41 PM »
Hi All,

So I've started work the engine... Which really mean I just dismantled it to check it, it's got about 4000 miles since last rebuilt...
Cylinders, heads and pistons, no signs of distress anywhere, weird shapped carbon deposits in the squish area!!!













Small traces of combustion passing the compression rings, so just a little deglaze and new rings at this stage...

Patrick
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Offline wobblywalrus

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Re: Another vintage project from Great Britain, target Speed Week 2011
« Reply #33 on: November 16, 2010, 11:14:45 PM »
Patric, that one piston with the shiny spot above the first ring...  Do the other wear marks on the skirt indicate the piston might be cocked in the bore? 

Offline thefrenchowl

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Re: Another vintage project from Great Britain, target Speed Week 2011
« Reply #34 on: November 17, 2010, 02:12:04 AM »
Hi, wobblywalrus,

No, that's "normal" on these K/KH engines, that's the face of the pistons that is exposed in the combustion chamber due to piston pop up and the deeper flow channels that I cut in the cylinders, racing KR style. So that part is facing the combustion front full on, never gets deposits there...

That pic shows the front piston at TDC:



Patrick
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Offline wobblywalrus

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Re: Another vintage project from Great Britain, target Speed Week 2011
« Reply #35 on: November 17, 2010, 11:28:27 PM »
Thanks for showing this.  An interesting project, for sure.

Offline oz

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Re: Another vintage project from Great Britain, target Speed Week 2011
« Reply #36 on: November 19, 2010, 03:39:38 PM »
Lookinh good Patrick!
Newcastle born and bred a City built on Coal and Steel and a people built of stronger stuff

Offline thefrenchowl

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Re: Another vintage project from Great Britain, target Speed Week 2011
« Reply #37 on: November 21, 2010, 07:02:29 AM »
Hi Everybody,

the KHK engine is now in bits...

Today some of the mods I did to it over the 25 years I've owned it, mainly mods to reduce drag in there, these sidevalve are OK on power, but everything you can save on friction is a bonus!!!

Standard crank main drive bearing is a massive double Timken taper roller arrangement:



Moded the cases to fit single lip single row roller, plus a few spacers to suit:





Standard crank timing side bearing is caged rollers and a steel bush in the case:



Same thing but slightly smaller roller bearing cause the cam bearings are in the way...



See you,

Patrick

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Offline thefrenchowl

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Re: Another vintage project from Great Britain, target Speed Week 2011
« Reply #38 on: November 21, 2010, 07:11:24 AM »
Hi Everybody,

Timing chest, this is a 4 cammer, plenty of scope...

Standard K and KH are all brass bushes in there:



So, plenty of Torrington needle bearings on the timing cover, plus an XR750 lip seal in the bore for the timing shaft, makes sure oil goes to the crank rollers and don't overflow back in the chest:



And ball bearings on the other side:



In the gear box, the mainshaft/sprocket runs on loose rollers, fitted the same roller bearing as on the crank drive side, makes it as well a lot easier to assemble:



See you,

Patrick

« Last Edit: November 21, 2010, 07:13:41 AM by thefrenchowl »
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Offline thefrenchowl

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Re: Another vintage project from Great Britain, target Speed Week 2011
« Reply #39 on: November 21, 2010, 07:24:52 AM »
Hi Everybody,

That's the carburettor I'm planning on using on this built, good old S&S MGAL 1"7/8 from the early 70s, already moded some time ago for methanol for one of me OHV Sportsters...

S&S told me it couldn't be done but hey, if you don't try, you don't get anywhere... I had to relocate the whole iddle/intermediary circuit on the outside, Tillotson needle for the iddle plus fitting of a Mikuni adjustable extra main jet...





NOS air filter came free from a friend in Scotland, Nick, I think it's from a big Holley type carb for a car!!!

See you,

Patrick
« Last Edit: November 21, 2010, 07:27:08 AM by thefrenchowl »
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Offline panic

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Re: Another vintage project from Great Britain, target Speed Week 2011
« Reply #40 on: November 21, 2010, 10:12:05 AM »
No personal experience with KR lower ends, so merely observations (not advice)?
single lip single row roller: IIRC this is where Norton used a Superblend to prevent edge contact due to crank flex (H-D used a ball bearing).
slightly smaller roller bearing: for those not familiar, this requires the smaller R shaft (not easily visible).
Torrington needle bearings: I see the #2 is full-complement, while the smaller ones are cage-separated (1958-* XL used full-complement). Any capacity problems with the lower roller count?
S&S told me it couldn't be done: I've found that this sometimes means "We can't do it, therefore you can't do it".
fitting of a Mikuni adjustable extra main jet: do you mean the power jet, or is there a 2nd main? If PJ, are you using 75/25, or something else? I understand that the height of the discharge tip is a tuning point, is yours adjustable?

Love the Tillotson wheel! (for non-believers: this was the cause of more cursing, swollen knees, fires, and short sales than any other 1966-70 Sportster part including the magneto).

Offline thefrenchowl

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Re: Another vintage project from Great Britain, target Speed Week 2011
« Reply #41 on: November 21, 2010, 10:51:55 AM »
Hi panic,

Quote
single lip single row roller: IIRC this is where Norton used a Superblend to prevent edge contact due to crank flex (H-D used a ball bearing).

There's less than 3"1/2 between the crank bearings centers, I can assure you these K/KH/Sporty cranks are not FlexiFlyers!!!

XR750 did go for superblend bearings after 1980, more due to ever higher rpms and brinneling than flexi cranks. They were happy till then with the old KR ball bearings. My roller bearings are the same dimms as the KR ball bearings, drive side 25 x 52 x 15, timing side 25 x 47 x 12. Just went for rollers cause I used the bike on the street, a bit more longevity!!! Also makes for quicker setting of end play and assembly...

Quote
Torrington needle bearings: I see the #2 is full-complement, while the smaller ones are cage-separated (1958-* XL used full-complement). Any capacity problems with the lower roller count?

Did not notice any problems with the cage needles. Plenty of oil feed through the cast in oil collectors on the back of the bearing bores. If I remember right, I've done that probably 15 years ago, these where INA needle bearings since I could't get Torringtons at the time. The full complement one is a Torrington.

Quote
fitting of a Mikuni adjustable extra main jet: do you mean the power jet, or is there a 2nd main?

There's a fixed main jet inside the bowl at the std location. The OHV was running quite lean even with a 3mm (.120...) diameter main jet... Rather than the hit and miss to increase it bigger, I fitted the Mikuni needle on the outside, makes for quicker setting... It is level with the fixed one in the chamber just below the emulsion tube.

The clear pipe you see on the side of the carb is actually the outside iddle/transition circuit, with transition jet as a 3mm diameter lenght of copper bar with a suitable hole in it and trapped by safety wires!!!

Quote
Love the Tillotson wheel

I quite like the whole Tillotson meself!!! Bit of an acquired taste, but once you get the idea, it works and it's got the most wicked response of all Sporty carbs!!!

Patrick

« Last Edit: November 21, 2010, 11:11:09 AM by thefrenchowl »
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Offline k.h.

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Re: Another vintage project from Great Britain, target Speed Week 2011
« Reply #42 on: November 21, 2010, 01:23:47 PM »
Great stuff.  Takes me back to my sordid early days of adapting superblends into an XLR and a KHRM for the crank, single row on the timing side.  Worked fine and lasted a long time.  I'm with panic on the crank flex, it was a problem and I had some cracked cases as evidence.  The fix for the "new" 1972 XR750 was the double row Superblend bearings first done by Johnny Goad, held in by retaining hardware inside the crankcase.  H-D borrowed his engine and made changes in the casting to use the double rows from then on.  I used to own one of his 1972 engines.
In theory, there is no difference between theory and practice.  But in practice, there is.--Jan L. A. Van de Snepscheut

Offline thefrenchowl

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Re: Another vintage project from Great Britain, target Speed Week 2011
« Reply #43 on: November 21, 2010, 04:40:26 PM »
Hi K.H.,

Thanks for the info...

Reading the parts books, there's a change in crank bearings in 1988. I always assume they were just single row rollers up to that date and superblend after that... Since there's no illustrations, it's hard sometimes to see what the changes are if you don't own an actual XR engine!!!

Still, went to have another look at my cases, nothing seems untowards at this stage, just maybe my roller bearing on the timing side showing a bit of play... Mind you, I had it geared very long for street use, about 4500rpm for 95mph.

See you,

Patrick
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Offline thefrenchowl

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Re: Another vintage project from Great Britain, target Speed Week 2011
« Reply #44 on: January 15, 2011, 10:21:19 AM »
Hi everybody, happy new year to you all...

Finally received the AMR500 supercharger this week, a month and 1/2 from Australia, air mail, it takes some beating, even accounting for busy Christmas period!!! So not much done on the bike except loads of preliminary drawings for the drive and other bits...

Just had a quick look at the AMR this afternoon, looks nice, no wear on the lobes...







The main problem, I'll have to fit the pulley on the other rotor, seems like inlet and exhaust are not swappable as such while it will turn backwards. As it is, the pumping occurs clockwise while I need to drive it counter-clockwise from the engine sproket on the engine's left hand side...

Looks like it's all symetrical, so it's probably just a question to fit the bottom lobe on the top and the top one on the bottom... Had a go at it but it will take a better press than I have here in the garage to split the body!!!





I'll go back in the garage tomorrow to fit empty engine in the frame and look at the general layout for the drive.

All the best from Patrick
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