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Is it worth buying the rex caunt 64mm Piston kit for 45Quid?
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nickjaxe
Runcorn Cheshire UK
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December 5, 2018 - 12:49 pm
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Nice to see they have a good name Ed...I wonder could they put a liner in the likes of a Bantam barrel that doesn't one at present have one i.e. solid cast iron.

I know some of the more modern bikes from new have a pressed in liner.

Nick.

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

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richard hyatt
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December 5, 2018 - 5:38 pm
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thanks all for your ideas - the D14 is coming together now - Rex 's standard piston and rings are a good fit in the bore - deglazed fine and uniform end gap.(.010" at various places up and down the bore) and skirt clearance (.003" to .004")

interesting fact though reference head gaskets, I'm aware that they should be .050"(as per BSA manual)  but when I have ordered them from my normally very good supplier he's sent (under the correct D14 part number) 1 x alloy gasket of .025"  - not 050

apparently that's what he gets when he places orders - so I shall use 2 x of these to achieve the correct total.

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JulianS
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December 5, 2018 - 7:20 pm
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An aside on D14 head gaskets from parts service bulletin G48 from January 1968, see first photo. My D14 partsbook was printed in November 1967 and obviously does not show the revised part number for the thicker one.

 

Ignore what it says about the spark plug, they changed back to N4, see second photo, parts bulletin 52 from August 1968.

 

G48-January-1968-General-information-D14-head-gasket-RM213.jpgG52-August-1968-General-information-Spit-Mk4-head6.jpg

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richard hyatt
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December 5, 2018 - 7:55 pm
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Perfect , just confirmed to me that I need 2 x .025 or 1 x .050 gasket

If it's good for bsa then that's it.

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podman
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December 5, 2018 - 8:13 pm
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Just out of interest, what sort of increase in BHP/torque does this piston kit conversion give?

 

I can also vouch for PJMEs work and reputation, again regards my Yamaha LC.

1967 D7

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nickjaxe
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December 5, 2018 - 8:21 pm
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Sent PJM an email yesterday as I'm on +60 so a bit twitchy if I have a problem.

I wasn't sure if the can fit a liner to a barrel that didn't already have one.

Got a reply today...yes they can but it will cost..£165 +vat...need a piston to match to the new std size bore....so its a option.

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

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richard hyatt
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December 5, 2018 - 10:04 pm
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Certainly , when I opened the box from Rec Caunt with the new standard piston I was impressed.

Beautiful quality casting and lovely texture on surface,  gudgeon pin lovely fit , checked skirt and end gaps , all correct.

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wildun
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December 6, 2018 - 10:57 pm
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Richard, Rex Caunt sells aluminium head gaskets at 1mm and 1.5 mm thicknesses. I use the 1.5mm in my B175 which is already slightly lower compression than the D14, but I am after reliability, not power. My engine, fitted with a Rex Caunt piston, has not been apart for three years now, maybe 4000 miles, so I am well pleased. Enjoy your Bantam.

1951 Bantam D1 125, 1970 Bantam B175, 1954 off road Bantam bitsa, 1995 Yamaha Diversion 900 and 2016 Honda Integra 750 scooter. Horses for courses, all very different to each other, but a bike for every occasion.

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nickjaxe
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December 6, 2018 - 11:05 pm
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Put 3000 miles on a +60 piston from Rex...around 3 years ago...B175...still very peppy.

Look good to me.

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

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richard hyatt
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December 7, 2018 - 7:36 pm
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thank you for these thoughts - the D 14 is back together now with Rex's standard 61.5 piston in it - also 2 x 0.025" head gaskets - spent a while getting the timing to as near as I could to 16.5 degrees(allowing for the back and forth at tdc) and seems to start well and run up the road fine.

just got to take it steady now and let it settle down - certainly seems snappy on the throttle - just checking the carb settings as well while I'm in this far - I reckon it should be 160 main , 105 needle jet , 3 slide and position 3rd notch

 

trouble is I have seen another D14 bsa book that says 150 main , 105 needle , 2nd position on the needle and 3 slide

 

I know it all relies on plug colour etc and load - so if it stops raining , I can take it out and check plug colour - I was even thinking about an N3 to keep the plug temperature down ??

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bantammad
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February 12, 2019 - 1:51 pm
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Hi can i have two penuth. it be of use. Well my bike is a well  sorted  d5 with  D14 crankcases but has d5 outer cases. has 186cc capacity engine  the piston is 64 .5  from Rex Caunt nice guy that Rex MZ conrod  modified  B175 crank  machined crank case Pete Savage another nice guy with his modern generator and ignition mainly for trials comp bikes. the cylinder head has a twin plug head oh two plugs both sparking. Carb is a 626 amal 150 main jet 106 needle a 25 pilot jet . engine timing set at 16deg , fuel mix 30cc per ltre of petrol  ,the bike has been together for 7years done many many miles.Runs like Black Mountain trials, the Levis .Saunders Foot, vmcc runs also to name but a few.Now how do we stop the thing, well I welded two brake drums back to back you get the idea thats another story, I have never had any seizure  or major problems I do ride my bike hard, My mate he has a d5 same sort of set up but not the same spec  he says why does your bike go so well, with a grin I reply i spend money on mine thats the reason mind you he s a farmer with sown up pockets, any way enough from me  regards                                                                                                               les   Bantammad

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