BSA Owners' Club Forum

The BSA Workshop => Twins => Topic started by: A10 JWO on 17 November, 2020, 16:35:10

Title: Popping on over-run.
Post by: A10 JWO on 17 November, 2020, 16:35:10
Since taking off my Siamese pipes and fitting twin side pipes and silencers I have a popping on over-run. Tend to blame the joints on the H Joint. I want to take it off and apply sealant to the joints. The compound's I have go off like concrete which I don't want. Is there a product that will seal but not fully harden. Thank you.
Title: Re: Popping on over-run.
Post by: Greybeard on 17 November, 2020, 16:59:08
This worked for me on a worn 1949 Matchless exhaust spigot - it should be fine on lesser machines too  ;)

https://www.henkel-adhesives.com/uk/en/product/loctite_si_5990.html

Steve

Title: Re: Popping on over-run.
Post by: DAVE BRADY on 17 November, 2020, 17:13:41
Hi,

Wurth do some silicon exhaust sealant.

Dave.
Title: Re: Popping on over-run.
Post by: chaz on 17 November, 2020, 17:48:15
always useful to remember...Cement goes hard and solid, Silicon stays soft and flexible.
car systems have multiple fixing points so tend to use gaskets and cement and have various rubber suspension points, bikes vibrate and have fixed fittings.
Title: Re: Popping on over-run.
Post by: A10 JWO on 17 November, 2020, 18:07:28
Thanks lads. Loctite so expensive !!
Title: Re: Popping on over-run.
Post by: idie on 17 November, 2020, 18:16:32
Bath sealer works for me.
Title: Re: Popping on over-run.
Post by: Greybeard on 17 November, 2020, 18:30:14
Thanks lads. Loctite so expensive !!

Perhaps you're right. Six quid is a lot to spend on a BSA  ;)

Steve
Title: Re: Popping on over-run.
Post by: A10 JWO on 18 November, 2020, 09:34:19
Steve there is a tube of Loctitie SI 5990 ( large ) 125 !! ob Ebay another 75 !!
Title: Re: Popping on over-run.
Post by: Greybeard on 18 November, 2020, 10:08:54

??? 6.80 at CPC and 6 quid at Halfords too. I'd post the links but they end up occupying 4 or 5 lines each

Steve

https://www.google.com/search?q=loctite+copper+silicone&oq=&aqs=chrome.2.69i59i450l5.-1j0j8&client=tablet-android-lenovo-rev2&sourceid=chrome-mobile&ie=UTF-8#scso=_VvC0X8jQMN2i1fAP4vi6yAk14:0
Title: Re: Popping on over-run.
Post by: Mike40M on 18 November, 2020, 12:36:01
I've used a high temperature silicone for head to downpipe on a B40WD and a RG250, worked ok. Also used it on downpipe to silencer joint on a Manx, a Vincent and a Ninja.
Title: Re: Popping on over-run.
Post by: A10 JWO on 18 November, 2020, 18:08:51
I removed the exhaust today and did all the joints with bathroom silicone. Will leave it overnight to harden and fire up tomorrow. Thanks everyone.
Title: Re: Popping on over-run.
Post by: Nanonevol on 19 November, 2020, 14:06:25
May need to retune the carb with your new pipes and silencers.
Your symptom suggests leanness.
Title: Re: Popping on over-run.
Post by: B Murphy on 19 November, 2020, 17:53:59
I quite liked the popping on my Triumph, the B31 has a backfire bang on the over-run which turns heads lol.
Title: Re: Popping on over-run.
Post by: A10 JWO on 19 November, 2020, 18:33:38
Fired up today and no popping, despite a very clean carb it is asking for choke to run at low down revs. Sounds weak from the primary circuit which is clean as a whistle. ? Thanks so far. 
Title: Re: Popping on over-run.
Post by: Nanonevol on 19 November, 2020, 21:35:24
May need to adjust your pilot air screw.  Turning in is richer.
Title: Re: Popping on over-run.
Post by: A10 JWO on 20 November, 2020, 16:29:09
Thanks for replies.