The BSA A7-A10 Forum

Technical => Amal, Carburation => Topic started by: Wrinks on 10.10. 2020 15:31

Title: Slide position at full throttle
Post by: Wrinks on 10.10. 2020 15:31
My A7SS has  all the correct carb and slide according to the BSA parts list but with the twist grip fully open the bottom of the slide (not cut away side) still shows in the bore.
Any comments gentlemen and/or ladies
Title: Re: Slide position at full throttle
Post by: RDfella on 10.10. 2020 17:27
If you can manually push the slide higher, then either the cable is too long or the twistgrip isn't providing enough travel.
If it won't push higher, you need to take the carb top off the find what's stopping it.
Title: Re: Slide position at full throttle
Post by: JulianS on 10.10. 2020 19:11
If the slide return spring is not seating properly on the slide it will prevent it opening fully.
Title: Re: Slide position at full throttle
Post by: Greybeard on 11.10. 2020 09:24
If you can manually push the slide higher, then either the cable is too long...
In case you haven't played with cables: if the inner cable is too long, (and there is enough slack in the cable assembly) you may prefer to shorten the outer to achieve the same result. Cut through the spirals with a saw or Dremel.

Update: Sorry, this is how to lengthen the amount of inner available, so would achieve the opposite effect!
Title: Re: Slide position at full throttle
Post by: morris on 11.10. 2020 10:03
If you can manually push the slide higher, then either the cable is too long...
In case you haven't played with cables: if the inner cable is too long, (and there is enough slack in the cable assembly) you may prefer to shorten the outer to achieve the same result. Cut through the spirals with a saw or Dremel.
Sorry to have to correct you on this GB, but shortening the outer cable will lengthen the inner hence worsening the problem. If the adjuster can’t pick up the slack there’s only one solution and that’s to shorten the inner cable.
Title: Re: Slide position at full throttle
Post by: Greybeard on 11.10. 2020 13:26
If you can manually push the slide higher, then either the cable is too long...
In case you haven't played with cables: if the inner cable is too long, (and there is enough slack in the cable assembly) you may prefer to shorten the outer to achieve the same result. Cut through the spirals with a saw or Dremel.
Sorry to have to correct you on this GB, but shortening the outer cable will lengthen the inner hence worsening the problem. If the adjuster can’t pick up the slack there’s only one solution and that’s to shorten the inner cable.

Yes, of course. What a duffer I am!  *red*

Maybe a split collet for the outer would do the job then.
Title: Re: Slide position at full throttle
Post by: Wrinks on 11.10. 2020 14:47
Thank you all. On further  investigation the slide will go right  up without the return spring but with spring in  protrudes about1/8 inch. No matter how much I try to ensure the spring is seated correctly.
The spring does not compress fully into the recess in the carb top by about 1/8 in. Short or removing a couple of coils from spring any other  ideas?
Title: Re: Slide position at full throttle
Post by: Black Sheep on 11.10. 2020 15:05
Try a different spring? Could it be that the spring is from the wrong model of carb? They do vary between 376 and 389 monoblocs and again between concentrics. 
Title: Re: Slide position at full throttle
Post by: Wrinks on 11.10. 2020 15:13
Good thinking Black Sheep. I didn't know that. Now to find the right spring.
Title: Re: Slide position at full throttle
Post by: metalflake11 on 11.10. 2020 19:23
Why would anybody want their slide that far up anyway! *eek*

Last time I did that is was on a moped in 1976! *smile*
Title: Re: Slide position at full throttle
Post by: Wrinks on 18.10. 2020 11:46
Problem solved.(Hopefully) 2 coils cut off spring. Still  slams shut when twistgrip is released so all should be well.
Title: Re: Slide position at full throttle
Post by: Greybeard on 18.10. 2020 13:47
Problem solved.(Hopefully) 2 coils cut off spring. Still  slams shut when twistgrip is released so all should be well.
I have friction on my twist grip so the throttle does not slam shut when the twistgrip is released. How else could I do right hand signals?  *smile*

I know, I know, you have indicators!  *smile*
Title: Re: Slide position at full throttle
Post by: Wrinks on 18.10. 2020 14:29
Grey beard I I too have the friction adjustment  but just undid it to check the shortened spring was still  strong enough.  It was😄
Title: Re: Slide position at full throttle
Post by: Kickaha on 18.10. 2020 19:32
but just undid it to check the shortened spring was still  strong enough.  It was😄

Shortening the spring will increase the spring rate so if anything it will get stiffer
Title: Re: Slide position at full throttle
Post by: RDfella on 18.10. 2020 20:02
Not necessarily. Other factors involved come into play.