BritBike Forum logo
BritBike Sponsor BritBike Sponsor BritBike Sponsor
BritBike Sponsor

BritBike Sponsor

BritBike Sponsor
BritBike Sponsor BritBike Sponsor BritBike Sponsor
The Bonneville Shop JRC Engineering dealers
Home | Sponsors, Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons, "OLD" BritBike Forum | DVD- Manuals & Parts books | BritBike Stickers & Decals
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
Member Spotlight
ludwig
ludwig
belgium
Posts: 558
Joined: September 2002
Show All Member Profiles 
Shout Box
Search eBay for motorcycle parts in following countries
Australia, Canada, France, Holland, Italy, United Kingdom, USA
Random Gallery photo
Who's Online Now
18 registered members (Alan_nc), 183 guests, and 406 spiders.
Key: Admin, Global Mod, Mod
Newest Members
Mums, MyrtleBeezer, Crockermc, mpotter78, Frezz
10485 Registered Users
Top Posters(30 Days)
NickL 97
franko 89
Triless 65
Popular Topics(Views)
752,359 mail-order LSR
Forum Statistics
Forums34
Topics68,895
Posts671,100
Members10,485
Most Online3,995
Feb 13th, 2017
Like BritBike.com on Facebook

Previous Thread
Next Thread
Print Thread
Rate Thread
DBD rod side play #728120
03/09/18 5:54 pm
03/09/18 5:54 pm
Joined: Sep 2014
Posts: 53
Pacific NW
9
998John Offline OP

BritBike Forum member
998John  Offline OP

BritBike Forum member
9

Joined: Sep 2014
Posts: 53
Pacific NW
I have a customers DBD engine where build that was started several years ago. It has a new Alpha pin and Carrillo rod installed.
Not comfortable the side play of the rod, the crank was disassembled.
There is excessive side play between the rod and thrust washers. I can not get a feeler gauge between the pin shoulder and the crank.
The rod width is .873 and the distance between the thrust washers is .915 The outside shoulder to shoulder of the Alpha pin is 1.000.
Am I correct in thinking that the thrust washers are extremely warn? I don't know how thick a new thrust washer is.
John


Support your #1 BSA Forum and our favorite sponsors

Check out BSA on e-bay: BSA Parts in UK, BSA Motorcycles in UK, BSA Parts in North America, BSA Motorcycles in North America

 
Re: DBD rod side play [Re: 998John] #728156
03/09/18 10:35 pm
03/09/18 10:35 pm
Joined: Aug 2015
Posts: 1,301
Bolton Lancs UK
A
Andy Higham Offline
BritBike Forum member
Andy Higham  Offline
BritBike Forum member
A

Joined: Aug 2015
Posts: 1,301
Bolton Lancs UK
The pin shoulders are supposed to butt up to the crank as the taper seats. Chances of that happening with a new crank and pin=almost nil, Chances of that happening with a 60 year old crank=about the same as the pope getting pregnant


BSA B31 500cc "Stargazer"
Greeves 200cc "Blue Meanie"
Greeves 350
Greeves 360 Challenger
Suzuki GSX1100 EFE "Sorcerers Apprentice"
GM500cc sprint/LSR bike "Deofol"
Jawa 500cc "Llareggub"
2003 Aprilia RSV Mille "Lo Stregone"
'35 OK Supreme
'36 OK Supreme
Re: DBD rod side play [Re: 998John] #728158
03/09/18 10:37 pm
03/09/18 10:37 pm
Joined: Sep 2016
Posts: 178
County Durham
D
ducati2242 Offline
BritBike Forum member
ducati2242  Offline
BritBike Forum member
D

Joined: Sep 2016
Posts: 178
County Durham
The only crank i have available to check is a used one that i discarded for use myself . There is no play on the up and down movement but there's at least 1 mm of side to side movement . Could be worn but I never checked my new crank for side to side so dont know the as new tolerance your looking for . Someone will come along with the correct answer im sure .

Re: DBD rod side play [Re: 998John] #728164
03/09/18 11:29 pm
03/09/18 11:29 pm
Joined: Sep 2014
Posts: 53
Pacific NW
9
998John Offline OP

BritBike Forum member
998John  Offline OP

BritBike Forum member
9

Joined: Sep 2014
Posts: 53
Pacific NW
This crank has .042 rod side play (.915 - .873) The BMS book quotes .010 to .012 side clearance. This still leaves .030 too much side play.
I would like to find what the thickness of new thrust washer are to compare with those on this crank.

Re: DBD rod side play [Re: 998John] #728240
03/10/18 9:39 pm
03/10/18 9:39 pm
Joined: Aug 2001
Posts: 1,897
Elko, Nevada USA
dave - NV Offline

BritBike Forum member
dave - NV  Offline

BritBike Forum member

Joined: Aug 2001
Posts: 1,897
Elko, Nevada USA
John .. FWIW .. Several years ago I was fitting a new OEM crank pin into a used spare set of DBD flywheels. This was following a crank pin failure at moderate RPM that ruined a flywheel. The pin failed across the oil hole on the timing side as has happened to others. aargh. As Andy has mentioned the engineering 'dream' of the flanges bottoming simultaneous with the tapers is near impossible.

I had noticed the 'classic' fretting marks in the wheel tapers due to the wheels movement 'breathing' on the pin. I decided to lap in the pin to the wheels. My local machinist friend attempted to spin the pin in his mill with poor results, so I resigned myself to laboriously lap the pin in by hand using valve lapping compound. This took many hours of work and when finished I found the side clearance of the rod to be nil. I then had my local auto machine shop grind and narrow the rod side faces for 15 thou clearance that worked OK.

BTW, shortly after this exercise I ordered up my first Phil Pearson crank, rebuilt the engine and rode off with a big smile. BomBom Barroom. "Let The Goldie Sing" heh.
Speaking of Phil's cranks.. I've recently received one of his pressed up '5 main bearing' cranks in modified cases for my current Clubman project. A shame to hide them away, Jewelry!

Last edited by dave - NV; 03/10/18 9:47 pm.

Dave - NV
Re: DBD rod side play [Re: 998John] #728248
03/11/18 12:30 am
03/11/18 12:30 am
Joined: Aug 2015
Posts: 1,301
Bolton Lancs UK
A
Andy Higham Offline
BritBike Forum member
Andy Higham  Offline
BritBike Forum member
A

Joined: Aug 2015
Posts: 1,301
Bolton Lancs UK
The rigidity of the Pearson crank makes for a very smooth engine. 80 mph cruising would be effortless and pleasant on my B31


BSA B31 500cc "Stargazer"
Greeves 200cc "Blue Meanie"
Greeves 350
Greeves 360 Challenger
Suzuki GSX1100 EFE "Sorcerers Apprentice"
GM500cc sprint/LSR bike "Deofol"
Jawa 500cc "Llareggub"
2003 Aprilia RSV Mille "Lo Stregone"
'35 OK Supreme
'36 OK Supreme
Re: DBD rod side play [Re: 998John] #728254
03/11/18 3:05 am
03/11/18 3:05 am
Joined: Sep 2014
Posts: 53
Pacific NW
9
998John Offline OP

BritBike Forum member
998John  Offline OP

BritBike Forum member
9

Joined: Sep 2014
Posts: 53
Pacific NW
I will install new thrust washers and rivets, then see what the side play is. Grinding the shoulders on the pin will be the last option.
Lapping the taper may require a skim off the flywheels. I just don't want to box myself into a corner.

Last edited by 998John; 03/11/18 3:10 am. Reason: spelling
Re: DBD rod side play [Re: 998John] #728277
03/11/18 11:18 am
03/11/18 11:18 am
Joined: Feb 2012
Posts: 1,273
Middle East,
Kerry W Offline
BritBike Forum member
Kerry W  Offline
BritBike Forum member

Joined: Feb 2012
Posts: 1,273
Middle East,
As an enthusiast, rather than a professional engineer, I see the 'jiggery-pokery' of adjusting flywheels and pin to gain an acceptable fit as a short-term solution while one saves for a good crank! How many OEM pins actually fitted tapers in cranks that resulted in the shoulder being pulled up against the wheel when the nuts were done up tight? Not so many, I suspect...

I did have a very good (possibly never rebuilt) set of B33 flywheels (so probably never overstressed repeatedly either) and a brand new BSA-made (GS) pin...it went straight to the shoulder without much torque on the nuts...that said, it did get revved mercilessly for several seasons as a road-racer and never failed or produced high vibrations, excessive side-play, etc...it then sat, though was run regularly, for the next 10+ years before going to a new home, where I believe it has still to be rebuilt and is used regularly..

Peace of mind rests in a new cranks though, especially if it's in original (and number-matched) cases and used as they were intended...


No generalisation is wholly true, not even this one.
Oliver Wendell Holmes
Re: DBD rod side play [Re: 998John] #728297
03/11/18 4:52 pm
03/11/18 4:52 pm
Joined: Aug 2015
Posts: 1,301
Bolton Lancs UK
A
Andy Higham Offline
BritBike Forum member
Andy Higham  Offline
BritBike Forum member
A

Joined: Aug 2015
Posts: 1,301
Bolton Lancs UK
I cannot stress enough, when rebuilding a crank place the rod in a suitable bin and BUY A NEW ROD.
Using an 60 year old rod is a sure way to make the "matching numbers" bike into a "non matching numbers" bike. A couple of hundred quid spent on a Carrillo (or similar) rod is cheaper than a scrapped engine. A leg out of bed will probably take out everything below the head gasket


BSA B31 500cc "Stargazer"
Greeves 200cc "Blue Meanie"
Greeves 350
Greeves 360 Challenger
Suzuki GSX1100 EFE "Sorcerers Apprentice"
GM500cc sprint/LSR bike "Deofol"
Jawa 500cc "Llareggub"
2003 Aprilia RSV Mille "Lo Stregone"
'35 OK Supreme
'36 OK Supreme
Re: DBD rod side play [Re: 998John] #728299
03/11/18 4:55 pm
03/11/18 4:55 pm
Joined: Jun 2005
Posts: 97
montreal
J
johnnie690 Offline
BritBike Forum member
johnnie690  Offline
BritBike Forum member
J

Joined: Jun 2005
Posts: 97
montreal
I measured 2 sets of NOS connecting rod side thrust shims and they are .120 to .122 just to give you an idea what they started out as .

Re: DBD rod side play [Re: johnnie690] #728357
03/12/18 1:56 am
03/12/18 1:56 am
Joined: Sep 2014
Posts: 53
Pacific NW
9
998John Offline OP

BritBike Forum member
998John  Offline OP

BritBike Forum member
9

Joined: Sep 2014
Posts: 53
Pacific NW
johnnie690, Thanks for the info on new thrust washers. That will help determine what to do next. As I said before, I have a new Alpha pin and a new Carrillo rod so the customer wants to try and save the crank.
When I get to my Catalina, it will get a Pearson crank for sure.


Re: DBD rod side play [Re: 998John] #728364
03/12/18 2:36 am
03/12/18 2:36 am
Joined: Jun 2005
Posts: 97
montreal
J
johnnie690 Offline
BritBike Forum member
johnnie690  Offline
BritBike Forum member
J

Joined: Jun 2005
Posts: 97
montreal
998John, the Carrillo rod is the same width at the big end as is an original rod and the 1" shoulder to shoulder measurement of the pin is also the same as original parts.So that said it could very well be the thickness of the thrust washers.

Re: DBD rod side play [Re: 998John] #728555
03/14/18 10:51 am
03/14/18 10:51 am
Joined: Sep 2014
Posts: 53
Pacific NW
9
998John Offline OP

BritBike Forum member
998John  Offline OP

BritBike Forum member
9

Joined: Sep 2014
Posts: 53
Pacific NW
The thrust washer thickness checks out ok. Next plan will be putting a shim behind them. Won't know that thickness until the taper is lapped. Then making sure the shoulder on the pin is home at the same time the torque limit is reached. Fun Fun

Re: DBD rod side play [Re: 998John] #728570
03/14/18 2:24 pm
03/14/18 2:24 pm
Joined: Apr 2012
Posts: 45
city island ny
H
hunter h Offline
BritBike Forum member
hunter h  Offline
BritBike Forum member
H

Joined: Apr 2012
Posts: 45
city island ny
cheers I had crank with a Alpha pin and a Carrillo rod that needed work so it was sent back to Alpha and was made right . you could send the crank to them for the right fix. the can make a new over size crankpin if needed they did a great job. by the way i have two of Phil,s cranks .The stock parts could be sold to help cover costs of new. hunter

Re: DBD rod side play [Re: 998John] #728581
03/14/18 4:29 pm
03/14/18 4:29 pm
Joined: Sep 2014
Posts: 53
Pacific NW
9
998John Offline OP

BritBike Forum member
998John  Offline OP

BritBike Forum member
9

Joined: Sep 2014
Posts: 53
Pacific NW
Thanks Hunter, a bit over budget for this project so will mover forward in house. I have full machine shop capabilities including surface and od grinding.
It will be a learning experience to say the least.

Last edited by 998John; 03/14/18 4:30 pm. Reason: format

Moderated by  Rich B 


Home | Sponsors | Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons | "OLD" BritBike Forum | DVD- Manuals & Parts books | BritBike Stickers & Decals
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
Powered by UBB.threads™ PHP Forum Software 7.6.2