BritBike Forum logo
BritBike Sponsor BritBike Sponsor BritBike Sponsor
BritBike Sponsor

BritBike Sponsor

BritBike Sponsor
BritBike Sponsor BritBike Sponsor BritBike Sponsor
  JWood Auction  
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
Photo posting tutorial

Member Spotlight
DeejayP999
DeejayP999
London, England
Posts: 26
Joined: April 2003
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
202 registered members (57nortonmodel77), 1,704 guests, and 529 spiders.
Key: Admin, Global Mod, Mod
Newest Members
Brian Ellery, Jon Andrews, Berni Ernst, johnguppy, michael morgan
9955 Registered Users
Top Posters(30 Days)
btour 185
koan58 98
Stuart 87
NickL 59
Popular Topics(Views)
435,973 mail-order LSR
Forum Statistics
Forums33
Topics65,261
Posts631,968
Members9,955
Most Online3,995
Feb 13th, 2017
Like BritBike.com on Facebook

Previous Thread
Next Thread
Print Thread
Rate This Thread
#689499 - 03/26/17 9:09 pm B50SS question  
Joined: Jul 2016
Posts: 36
kj61 Offline
BritBike Forum member
kj61  Offline
BritBike Forum member

Joined: Jul 2016
Posts: 36
Owego, NY
hello
71 B50 ss
New piston and bored out to 40 over. Doing static timing and noticed that the "INFAMOUS compression is not there. The bike has compression, yes! but I can kick it over without using the decomp lever.
I disconnected the decomp to make sure it want an issue because the spring on "new' cable dosent hold decomp lever all the way back tight. it is loose between lever and bracket.
Oh bu the by this bike hasn't been started since rebuild.
Sound normal?
Q1:- Not enough compression?. All new to the B50 and have heard that you should be able to stand on kickstarter with out turning motor over on compression stroke?? true?
Q2:- should spring on decomp cable always contact bracket and decomp lever when not activated< valve closed??
and valves set at 8 and 6

Cheers Knobs

Last edited by kj61; 03/26/17 9:10 pm. Reason: additional info

KJ
Support Your #1 BritBike Forum!
Membership Type! Free
Member
Premium
Member
Premium Life
Member
Vendor
Member
Site
Sponsor
Recognition No Premium Member Premium Life member (5 years) Vendor Member Site Sponsor Membership
Post commercial threads No No No Yes Yes
Custom title No Yes Yes Yes Yes
Upload avatar & photos No Yes Yes Yes Yes
Link avatar & photos Yes Yes Yes Yes Yes
Private Message Storage: 10 100 100 100 100
Length of signatures 255 600 600 600 600
Removes this very advert island between post 1&2 No Yes Yes Yes Yes
Price Free $12.90/year $105.00 No End
$55.00/5 years
$210.00/year
($17.50/month)
Email
Click on button >>
  Premium Member Premium Life member Vendor Member Site Sponsor Membership
#689514 - 03/26/17 10:38 pm Re: B50SS question [Re: kj61]  
Joined: Oct 2008
Posts: 1,654
LarryLebel Offline
BritBike Forum member
LarryLebel  Offline
BritBike Forum member

Joined: Oct 2008
Posts: 1,654
Canada
Valve clearances should be in 008 and ex 010 but that won't cause your issue. I'm not sure whether having the push rods reversed would make any difference. Gaps in the rings not staggered?

My B44 Instruction manual says there should be an adequate gap between the lobe on the exhaust rocker arm and the lifter spindle. This gap is controlled by the adjuster on the cable bracket on the top of the engine. The handle bar lever also needs to be loose. On my B44, I can depress the handle bar lever by more than half its travel before the lifter engages.

Last edited by LarryLebel; 03/27/17 12:09 am.
#689535 - 03/27/17 2:03 am Re: B50SS question [Re: kj61]  
Joined: Jun 2002
Posts: 906
Peter Quick Online content
Sponsor
Peter Quick  Online Content

Sponsor

Joined: Jun 2002
Posts: 906
Jaffrey, NH, USA
One can kick over a B50 motor without using the valve lifter. Just it is nicer on all the parts of the kick quad, kick ratchet and mainshaft if you ease past TDC with the valve lifter to start the motor. That way you are not jumping on the mechanism and beating up all the parts. Can you kick the bike over with little effort?

It would be easier to comment on your valve lifter lever position if you could post a picture of it.

Peter


check out: www.bsaunitsingles.com
2500 BSA part numbers with inventory in stock just for the unit singles!
#689576 - 03/27/17 8:53 am Re: B50SS question [Re: Peter Quick]  
Joined: May 2004
Posts: 3,546
BSA_WM20 Online content
BritBike Forum member
BSA_WM20  Online Content
BritBike Forum member

Joined: May 2004
Posts: 3,546
Sydney Australia
Originally Posted by Peter Quick
One can kick over a B50 motor without using the valve lifter. Just it is nicer on all the parts of the kick quad, kick ratchet and mainshaft if you ease past TDC with the valve lifter to start the motor. That way you are not jumping on the mechanism and beating up all the parts. Can you kick the bike over with little effort?

It would be easier to comment on your valve lifter lever position if you could post a picture of it.

Peter


You never "Jump" on a kick starter, you kick them. particularly on a B50 where the kickback can be very savage.
MY B50 would lock up the rear wheel if it misfired just once so you sound like you have a problem.
Do a wet & dry compression test.
B 50's and B44's had a funny habbit of grabbing the rings from time to time causing a loss of compressin as the piston cooled and dragged the rings off the bore.


Bike Beesa
Trevor
#689581 - 03/27/17 11:06 am Re: B50SS question [Re: Peter Quick]  
Joined: Jul 2016
Posts: 36
kj61 Offline
BritBike Forum member
kj61  Offline
BritBike Forum member

Joined: Jul 2016
Posts: 36
Owego, NY
thank you for reply's.
Rings were staggered when placing barrel
it takes some effort to kick engine over, but i was expecting this total "lock up" from the compression.
I realized that on the B50.org site there are starting instructions, But after re-reading i realized that the author is starting a bored out CCM, not a stock B50

Should I open Valve gap? to 8 and 10 from 6 and 8?
getting the push rods backwards, how could I check that?
Kj


KJ
#689582 - 03/27/17 11:15 am Re: B50SS question [Re: LarryLebel]  
Joined: Jul 2016
Posts: 36
kj61 Offline
BritBike Forum member
kj61  Offline
BritBike Forum member

Joined: Jul 2016
Posts: 36
Owego, NY
At rest, exhaust valve closed, does the spring on the cable float loose between back of bracket and lifter lever or is it in contact all the time. My spring fite loose and only comes into contact, Presasure when lever is pullet 1/3 way in


KJ
#689583 - 03/27/17 11:19 am Re: B50SS question [Re: kj61]  
Joined: Dec 2004
Posts: 8,882
kommando Online content
kommando  Online Content


Joined: Dec 2004
Posts: 8,882
Scotland
Quote
getting the push rods backwards, how could I check that?


Using the manual

http://www.bsaunitsingles.com/Archi...71%20Workshop%20Manual%2000-4188%20x.pdf

There is a diagram in there showing the pushrod location, remove the cover on the side of the rockerbox to see the pushrods.

If the engine has been rebored but not started then the rings are not bedded in, until they are you should be able to feel compression but also not be able to stand on the lever without it slowly moving as the air leaks past the rings.

#689604 - 03/27/17 3:36 pm Re: B50SS question [Re: kommando]  
Joined: Jul 2016
Posts: 36
kj61 Offline
BritBike Forum member
kj61  Offline
BritBike Forum member

Joined: Jul 2016
Posts: 36
Owego, NY
Originally Posted by kommando
Quote
getting the push rods backwards, how could I check that?


Using the manual

http://www.bsaunitsingles.com/Archi...71%20Workshop%20Manual%2000-4188%20x.pdf

There is a diagram in there showing the pushrod location, remove the cover on the side of the rockerbox to see the pushrods.

If the engine has been rebored but not started then the rings are not bedded in, until they are you should be able to feel compression but also not be able to stand on the lever without it slowly moving as the air leaks past the rings.


ok thank you for help
Will check pushrods tonight
Looks like Outer rod goes back to intake valve


KJ
#689615 - 03/27/17 5:17 pm Re: B50SS question [Re: kj61]  
Joined: Sep 2008
Posts: 530
Stein Roger Online content
BritBike Forum member
Stein Roger  Online Content
BritBike Forum member

Joined: Sep 2008
Posts: 530
Skudeneshavn Norway
I'm following this with great interest, as a friend has the same bike with the same problem and I've promised to fix it for him!
It does run but is a bit gutless so I'm thinking lost valve clearance, or something with the decompression system. Or the rings may be stuck due to a partial seizure or something, as already mentioned.
And I agree, it's very easy to mix up the push rods on these engines, did it myself once on a B50, and didn't catch on to it before I noticed the carb exhausting... a true "hey, wait a minute..." moment!
It won't run then of course but compression will be good, so I don't think that's the issue in your case.

But please forget "staggered rings", old wives tale and utter BS. I never stagger rings because I find it easier to insert the pistons in the cylinders if the gaps are situated in roughly the same place, be it singles, twins or triples. I don't use ring clamps. The rings will rotate, sometimes quite fast and at different speeds, so even if it mattered say to the tune of 1/10 of a percent, after ten seconds of running at idle (some 150 revolutions) they'd be all over the place anyway. The gaps, that is.
Long after I decided not to give a damn about ol' Stagger Lee anymore, I came upon this article:

http://www.diagnosticengineers.org/journal_%20articles/Ring%20Gaps%20vs%20Knowledge%20Gaps.php

Food for thought.

Hth
SR

#689659 - 03/27/17 10:32 pm Re: B50SS question [Re: Stein Roger]  
Joined: Jul 2016
Posts: 36
kj61 Offline
BritBike Forum member
kj61  Offline
BritBike Forum member

Joined: Jul 2016
Posts: 36
Owego, NY
"Carb exhausting!!!"
Interesting
When I turn the engine over I get a pusssssht out of the carb.
Damn did I get them backwards?

How to tell without dimanteling
pull tappet covers and watch to see which one is opening the intake?
KJ


KJ
#689682 - 03/28/17 4:38 am Re: B50SS question [Re: kj61]  
Joined: Sep 2014
Posts: 150
Andrew Dunham Offline
BritBike Forum member
Andrew Dunham  Offline
BritBike Forum member

Joined: Sep 2014
Posts: 150
Ohio
Hi KJ61,

I actually just did this on my B44 a few hours ago. You were correct earlier in the thread about the INNER pushrod going to the EXHAUST side and OUTER rod going to the INTAKE.

I don't think you'll be able to check without removing the rocker cover and looking down the pushrod tube. I did this a few times tonight to make sure I had mine correct. There has been a lot of chat about pushrods with red tips on them. I believe the conclusion is that the only purpose was to help you remember which pushrod was which during install.

I don't know about the B50's, but on the B44 you can lift the rocker box up as far as you can (at this point there should only be one bolt still in the hole on the cover), rotate it clockwise about that bolt, then remove it once you have the clearance to lift up further.

Last edited by Andrew Dunham; 03/28/17 4:40 am.

1968 BSA A50
1969 BSA 441 VS
1970 BSA Thunderbolt
#689687 - 03/28/17 7:48 am Re: B50SS question [Re: Andrew Dunham]  
Joined: Dec 2004
Posts: 8,882
kommando Online content
kommando  Online Content


Joined: Dec 2004
Posts: 8,882
Scotland
You do not need to lift the rockerbox to check the pushrods, there is an inspection cover on the timing side of the rockerbox.

#689748 - 03/28/17 6:44 pm Re: B50SS question [Re: kj61]  
Joined: Jul 2016
Posts: 36
kj61 Offline
BritBike Forum member
kj61  Offline
BritBike Forum member

Joined: Jul 2016
Posts: 36
Owego, NY
Yes there is an inspection hole, but it only shows top 1/4 inch of push rods, so I cant tell which one is in front of the other, Intake in front of exhaust


KJ
#689749 - 03/28/17 6:52 pm Re: B50SS question [Re: kj61]  
Joined: Jan 2004
Posts: 3,512
DMadigan Online content
BritBike Forum member
DMadigan  Online Content
BritBike Forum member

Joined: Jan 2004
Posts: 3,512
ca, us
It does not matter. Look through the inspection hole whilst turning over the engine. After compression the exhaust should lift first then the intake as the exhaust is closing.

#689843 - 03/29/17 1:16 pm Re: B50SS question [Re: DMadigan]  
Joined: Jul 2016
Posts: 36
kj61 Offline
BritBike Forum member
kj61  Offline
BritBike Forum member

Joined: Jul 2016
Posts: 36
Owego, NY
Thank you very much.
Will have a look
Kj


KJ

Moderated by  Allan Gill, Jon W. Whitley 


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
UBB.threads™ PHP Forum Software 7.6.0
Page Time: 0.598s Queries: 15 (0.083s) Memory: 0.9038 MB (Peak: 1.1477 MB) Zlib disabled. Server Time: 2017-11-19 21:49:56 UTC