A A A
Avatar

Please consider registering
Guest

Search

— Forum Scope —






— Match —





— Forum Options —





Minimum search word length is 3 characters - maximum search word length is 84 characters

Register Lost password?
sp_Feed sp_PrintTopic sp_TopicIcon
D14 piston travel
Avatar
SpacedMarine
Up north
Top Gear User
Site Member
Forum Posts: 525
Member Since:
July 1, 2018
sp_UserOfflineSmall Offline
21
November 8, 2019 - 1:07 am
sp_Permalink sp_Print

mike p5xbx said

the Key words were if everything is as it should be
incidentally I have 150psi on the D14  

Damn I can only get mine to read 125.Its only on +020 and not been rebored,just had a light hone when I rebuilt it.Still knocks and pinks a bit at that.Tempted to add 1mm to the stroke if I ever get my new crank finished and get a 64mm piston just for kicks🤣 by my reckoning that would be a 192cc👍🏼

What's 7/16 in mm again?

Avatar
Bee175
Felixstowe, Suffolk
Top Gear User
Club Member
Forum Posts: 461
Member Since:
April 26, 2014
sp_UserOfflineSmall Offline
22
November 8, 2019 - 8:56 am
sp_Permalink sp_Print

SpacedMarine said

mike p5xbx said

the Key words were if everything is as it should be
incidentally I have 150psi on the D14  

Damn I can only get mine to read 125.Its only on +020 and not been rebored,just had a light hone when I rebuilt it.Still knocks and pinks a bit at that.Tempted to add 1mm to the stroke if I ever get my new crank finished and get a 64mm piston just for kicks🤣 by my reckoning that would be a 192cc👍🏼  

Out of interest, how would you add 1mm to the stroke? 

If yours is coming up short on the stroke, then it could be long on the down stroke and potentially making contact with the crank. This could be the knocking you said you were getting. This is exactly what happened to my friends B175.

Isn't the 64mm piston the one where you need to get a barrel from a Suzuki? A TS185 jumps to mind.

If 64mm is possible on a Bantam barrel, it would rule out any further rebores. Yours has already had one rebore but has 2 more to go on the standard barrel if you went the normal route of +40 and +60.

Gary.

BSA Bantam B175 1971 and BSA C15 1966

Avatar
SpacedMarine
Up north
Top Gear User
Site Member
Forum Posts: 525
Member Since:
July 1, 2018
sp_UserOfflineSmall Offline
23
November 8, 2019 - 9:02 am
sp_Permalink sp_Print

The piston is Suzuki you just need to shave a bit off the skirt or buy one off rex caunt that's already been done.

I'd just move the big end 1mm out from the centre.Its all theoretical at the minute and would add 2mm total.Im just hoping the rings wouldn't fall out the intake the only way is to try it though  🤣

Bit off topic here though!

What's 7/16 in mm again?

Avatar
Bee175
Felixstowe, Suffolk
Top Gear User
Club Member
Forum Posts: 461
Member Since:
April 26, 2014
sp_UserOfflineSmall Offline
24
November 8, 2019 - 9:25 am
sp_Permalink sp_Print

Good luck with your project👍

BSA Bantam B175 1971 and BSA C15 1966

Avatar
nickjaxe
Runcorn Cheshire UK
Top Gear User
Club Member
Forum Posts: 1940
Member Since:
February 24, 2015
sp_UserOfflineSmall Offline
25
November 8, 2019 - 10:56 am
sp_Permalink sp_Print

SpacedMarine said
The piston is Suzuki you just need to shave a bit off the skirt or buy one off rex caunt that's already been done.

I'd just move the big end 1mm out from the centre.Its all theoretical at the minute and would add 2mm total.Im just hoping the rings wouldn't fall out the intake the only way is to try it though  🤣

Bit off topic here though!  

James moving the big end 1mm...would that be to give in more or less throw.

So you would need to machine 2 new crank outers?

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

Avatar
SpacedMarine
Up north
Top Gear User
Site Member
Forum Posts: 525
Member Since:
July 1, 2018
sp_UserOfflineSmall Offline
26
November 8, 2019 - 12:23 pm
sp_Permalink sp_Print

nickjaxe said

SpacedMarine said
The piston is Suzuki you just need to shave a bit off the skirt or buy one off rex caunt that's already been done.

I'd just move the big end 1mm out from the centre.Its all theoretical at the minute and would add 2mm total.Im just hoping the rings wouldn't fall out the intake the only way is to try it though  🤣

Bit off topic here though!  

James moving the big end 1mm...would that be to give in more or less throw.

So you would need to machine 2 new crank outers?  

Depends which way you move it.Move it out from the centre you get a longer stroke closer you get shorter.

What's 7/16 in mm again?

Avatar
mike p5xbx
E-Sussex
Top Gear User
Site Member
Forum Posts: 1604
Member Since:
June 15, 2012
sp_UserOfflineSmall Offline
27
November 8, 2019 - 4:19 pm
sp_Permalink sp_Print

SpacedMarine said
Damn I can only get mine to read 125.Its only on +020 and not been rebored,just had a light hone when I rebuilt it. 

did you check piston clearance and ring gap when you had the engine apart
my D14 is a relatively new re-bore and Hepolite piston with factory spec minimal clearances
looking again at your photo is that with the piston at TDC?
Looks a good bit short

PSItest.jpg

sp_PlupAttachments Attachments

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

Avatar
SpacedMarine
Up north
Top Gear User
Site Member
Forum Posts: 525
Member Since:
July 1, 2018
sp_UserOfflineSmall Offline
28
November 8, 2019 - 4:55 pm
sp_Permalink sp_Print

I did Mike they all seemed to be within tolerance.To be honest I'm not sure that is at tdc. I checked the squish with some solder and the head on and it was about 1.5mm without the head gasket from memory.

I might give it another go with the tester and give it a couple more kicks.Starts and runs fine though.

I bought a new piston and rings as I was struggling to find rings at the time and the end gap on the old rings was enormous!

I therefore have a spare 020 piston 😆

What's 7/16 in mm again?

Forum Timezone: Europe/London

Most Users Ever Online: 223

Currently Online:
14 Guest(s)

Currently Browsing this Page:
1 Guest(s)

Top Posters:

Cornish Rooster: 3314

Anderzander: 3208

bart: 3135

cocorico: 3125

Sprung Chicken: 2651

Mags 1: 2612

David Dale: 2485

Munchkin: 2231

Blue Heeler: 2138

Katj: 2138

Newest Members:

_2223

Forum Stats:

Groups: 9

Forums: 46

Topics: 12106

Posts: 104197

 

Member Stats:

Guest Posters: 518

Members: 3726

Moderators: 3

Admins: 3

Administrators: Piquet, JMD, Rusty Floater

Moderators: xcgb, Mick W, Stoo63