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SpacedMarine's D14
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SpacedMarine
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December 17, 2018 - 4:23 pm
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Ta sponge 👍🏼

As far as I understand it a longer inlet improves low end torque at the expense of high end power and vice versa (hence variable length intakes etc.) I'm not sure the bantam revs high enough for a really short inlet to be any advantage unless you're building a racer I guess.That was kind of the reasoning behind me wanting to put the tube on as on the pancake thing the airflow has to do an immediate right angle before it's even started! 

After a ride it does seem a little more flexible at the bottom end and not as deafening.

What's 7/16 in mm again?

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nickjaxe
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December 17, 2018 - 8:01 pm
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Interesting comparison.

My Bantam video              https://www.you.....jpOFmzRZRI

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mike p5xbx
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January 1, 2019 - 4:41 pm
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mike p5xbx said

well
if you accept the thought that Bsa would not have fitted them and had 3 engineering attempts at stopping the Bl&^dy things falling off if they served no purpose what are you left with
they do to some extent increase crankcase compression ?
they reduce turbulence in the crankcase because of the smooth face unlike the bare crank with a big weight at the bottom which can be spinning at upto 100 times a second
which may make getting the mixture up the transfer ports more efficient ?
  

thought I would re-visit this as I found this photo advert from BSA
if you cant read the text at the bottom it says
“the robust flywheel assembly with Faced flywheels to ensure minimum air friction and maximum induction transfer efficiency”

bantam-flywheeln.jpg

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D? - D10- D14 Bantams 350 AJS -500 Triumph http://bsanotru.....lfire.com/

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SpacedMarine
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January 1, 2019 - 5:37 pm
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mike p5xbx said

thought I would re-visit this as I found this photo advert from BSA
if you cant read the text at the bottom it says
“the robust flywheel assembly with Faced flywheels to ensure minimum air friction and maximum induction transfer efficiency”

bantam-flywheeln.jpg  

There you go then 🤪 so next time the subject comes up we have a definitive answer 👍🏼good job.

What's 7/16 in mm again?

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two-stroke
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January 1, 2019 - 8:58 pm
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why not used on D7 then?

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mike p5xbx
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January 1, 2019 - 11:22 pm
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guessing again...
they were on the early bikes but kept falling off
so not fitted on D7 (were they fitted on the D5 cant remember? )
come D10/14 and trying to squeezes a few more BHP out of them someone had the great idea of fitting the plates with rivets so they would not fall off
but now the rivets fell out and made a *&*^ real mess of the crankcase
B175 finally cracked it and only took 22 years of engine development

D? - D10- D14 Bantams 350 AJS -500 Triumph http://bsanotru.....lfire.com/

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cocorico
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January 2, 2019 - 8:23 am
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mike p5xbx said
...B175 finally cracked it and only took 22 years of engine development  

So they stopped development and left the market to the Japanese...old

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SpacedMarine
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January 5, 2019 - 6:28 pm
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IMG_20190105_183111.jpgIMG_20190105_183037.jpgDecided to pull the engine to see if i can sort this 4th gear issue.Seems to be a little oil passing the seals on the points side of the engine and the gearbox oil looks a bit mucky to me.I think some fuel mix is getting in somehow as I was expecting it too be pretty clean especially as it's not done so many miles am I correct?

Also primary chain (which was supposed to be new)seems really slack and is wearing a couple of grooves inside the case.wasnt paying too much attention when I rebuilt it as just wanted to get it going.Whats the free play spec?Found plenty of threads on tensioners but not how much play there should be.(after a bit of rooting 3/8 is standard 3/4 means replace.oh well add that to the shopping basket)

I'll do it right this time,I'll even make sure the switches are on the right way round 😂

The shopping list is mounting up clutch plates, Conrod kit, primary chain and that's before the gearbox.Im hoping its the clearance between top gear and the output bearing im thinking of making some kind of shim if it is that.Who knows??

What's 7/16 in mm again?

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nickjaxe
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January 5, 2019 - 8:36 pm
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I had the same marks from the chain on my B175...looked fresh...the chain was new...but didn't seem slack enough to contact the case.

Seem to remember some ali filings in there as well.

Nick.

My Bantam video              https://www.you.....jpOFmzRZRI

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SpacedMarine
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January 5, 2019 - 8:48 pm
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nickjaxe said
I had the same marks from the chain on my B175...looked fresh...the chain was new...but didn't seem slack enough to contact the case.
Seem to remember some ali filings in there as well.
Nick.  

The clutch and primary sprocket are still attached so I'll put the chain back on and measure it before I get another.It does seem pretty slack .At least 1/2 inch maybe more.Pretty sure I could hear the odd rattle on the overrun.

I was gonna go for a ride the other day and it was really unhappy so I turned around and thought this is just the excuse I need to sort the gearbox,so here we are 😂😂😂

Think I'm more interested in seeing how the crank plates are faring.

What's 7/16 in mm again?

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johnsullivan
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January 5, 2019 - 9:58 pm
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Please stuff something in the crankcase mouth to stop the rod hitting it.

67 D10. and a D7    2007 Honda Hornet FA. Suzuki 89  DR 250S, Sinnis SC 125. 78 Honda 90  75 Montesa Cota 247 an electric scooter of famous make.

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mike p5xbx
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January 5, 2019 - 11:49 pm
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SpacedMarine said

Also primary chain (which was supposed to be new)seems really slack and is wearing a couple of grooves inside the case   

there was not much clearance between the chain and crankcase even when new
if you have fitted a new chain and can make it touch the casing screw holes as in your photo top or bottom its the clutch chain wheel and or the front sprocket teeth that have worn
could try a new front sprocket or fit a chain tensioner as a last resort

D? - D10- D14 Bantams 350 AJS -500 Triumph http://bsanotru.....lfire.com/

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SpacedMarine
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January 6, 2019 - 9:36 am
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mike p5xbx said

there was not much clearance between the chain and crankcase even when new
if you have fitted a new chain and can make it touch the casing screw holes as in your photo top or bottom its the clutch chain wheel and or the front sprocket teeth that have worn
could try a new front sprocket or fit a chain tensioner as a last resort  

I was thinking that but assuming the bikes mileage is correct it's only done 8000 miles.Would be interesting to see the state of a new sprocket compared to the one currently on it.Im thinking changing the clutch sprocket would be a bit of a pig?

What's 7/16 in mm again?

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SpacedMarine
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January 12, 2019 - 9:43 pm
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Ok so some progress on the 4th gear issue.Had a chat with a knowledgeable bloke who said that some of the sleeve gears had a large chamfer where the dogs engage and lo and behold.IMG_20190112_213725.jpg

Just so happened to have one on the shelf!Along with a brand new sliding gear.IMG_20190112_213936.jpg

Quite a difference.Just wondering if someone had a mill they'd be able to take the chamfer off and make use of it but could end up being a sloppy fit?

I'm tempted to stick it in the pillar drill and see if I can just drill it out a bit as looking at the machining marks looks like it's just two slightly offset drill holes anyway.Just need to find some way of refacing it without a lathe.

Anyway hopefully that cures it.Just got to press the bush out of the old one and see if I can reuse it as the bush seems fine and is a very nice fit on the shaft.

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What's 7/16 in mm again?

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SpacedMarine
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January 17, 2019 - 8:52 pm
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10mm diddy 1/4 long socket and tiny extension did the job nicely.12 ton press was overkill though 😂.IMG_20190117_201936.jpgIMG_20190117_201905.jpgIMG_20190117_201845.jpg

Should do the job 👍🏼

Was looking how I might clean the other one up going to have to find some way of clamping it really tight and use a really short drill bit as I think if I use a normal one it'll just deflect and bounce around and make it worse.

Been trying to make a good case to the other half to get myself a lathe 😂

What's 7/16 in mm again?

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SpacedMarine
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January 31, 2019 - 9:03 pm
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I appear to have come into possession of a D14(I believe) crank with decent shafts(rivets an all) plus a few fancy bits and bobs from Rex caunt.I now have a conundrum.Rebuild the engine with an original crank or keep pursuing the one I rebuilt.I reckon Im not far off having two engines worth of stuff now so i may end up doing that yet. 😂😂😂 Old motorcycles, eh.

I'm thinking possibly rebuild the original crank cases with the new crank and continue the experimental build with another set of I can get hold of some 🤔🤔🤔🤔

IMG_20190131_205534.jpg

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What's 7/16 in mm again?

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SpacedMarine
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February 6, 2019 - 9:15 am
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So I've gone and done it.Cue angels singing in harmony 😍😍😍IMG_20190206_091300.jpg

If you're wondering if it's worth it.IMG_20190206_091014.jpgIMG_20190206_090857.jpg

What's 7/16 in mm again?

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SpacedMarine
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February 6, 2019 - 9:34 am
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Can't get the pictures of the rod uploaded for some reason but between the new piston and rod we've lost about 65 grams(2 and a bit ounces in old money) of mass flying up and down thousands of times per minute which should make things a little smoother and sprightlier.😃

What's 7/16 in mm again?

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nickjaxe
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February 6, 2019 - 1:06 pm
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Seem to remember when my big end was fitted...not quite the same as the old one....could not just press till it stopped.

Bit trickier....be interested in your views on pressing it after you have done it.

Nick.

My Bantam video              https://www.you.....jpOFmzRZRI

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SpacedMarine
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February 6, 2019 - 1:27 pm
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Yeah sent the big end back to him with the old one .It has a little radius where it meets the crank and it's slightly different to mine  was scratching my head for a bit hopefully be sorted one way or another in a couple of days.cant use the old pin either as the new bearings are . different size.

What's 7/16 in mm again?

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