So tonight I decided to strip and check the carbs to see if I can find my running issues with a view to fitting some new jets and needle valves. Jets are main 80’s and pilot #25. Not blocked but whilst apart I’m tempted to replace them. I was going to get the parts from discount bike spares but it seems they have closed down... Any recommendations and whether I should go with original or pattern? Plus do I stay with the 80’s?
Thanks
Dave Bailey
GT380 Carbs...
- Harrymail
- Posts: 639
- Joined: Thu Jul 07, 2016 8:35 pm
- Location: East Yorkshire
Re: GT380 Carbs...
Mikuni genuine jets can be bought from Motocarb. Very quick to post out and not expensive.
Currently without a GT, but looking
2003 Yamaha Fazer 600 Blue
2020 Triumph Street Twin Red
1968 BSA Bantam Sports Red
2003 Yamaha Fazer 600 Blue
2020 Triumph Street Twin Red
1968 BSA Bantam Sports Red
-
- Posts: 3120
- Joined: Wed Sep 26, 2012 7:33 pm
- Location: Prestatyn.Wales
Re: GT380 Carbs...
IMHO don't mess about with aftermarket jets. Buy genuine Mikuni. It's the only way to eliminate doubt if you are tackling running issues. As Harry says http://www.motocarb.com/mikuni-main-jets.html is in Liverpool.
NO SMOKE .......NO POKE
-
- Posts: 80
- Joined: Tue May 22, 2018 8:37 pm
- Location: Portsmouth UK
Re: GT380 Carbs...
Thanks guys..
Dave Bailey
Dave Bailey
-
- Posts: 80
- Joined: Tue May 22, 2018 8:37 pm
- Location: Portsmouth UK
Re: GT380 Carbs...
Gary.. yes apologies only logged on tonight..
I'll get things sorted over the weekend...
Thanks
Dave Bailey
I'll get things sorted over the weekend...
Thanks
Dave Bailey
- Alan H
- Posts: 12110
- Joined: Fri Aug 05, 2011 6:38 am
- Location: Wombwell, Republic of South Yorkshire
Re: GT380 Carbs...
If the bike was running reasonably well and the jets areb't worn, why mend summat wot int broke?
Proof that four strokes are over complicated
-
- Posts: 80
- Joined: Tue May 22, 2018 8:37 pm
- Location: Portsmouth UK
Re: GT380 Carbs...
Ok so update from today’s efforts....
It seems that the pilot jet adjustment has no influence on the idle speed... My running issues are almost certainly down to carbs...
I have a flow meter and balanced the carbs at both 3000 rpm and 1500 rpm.
Adjusting the idle screw at 1000 rpm has no rpm change. I screwed both the right and left idle screws right in and it still ran with no rpm increase...
Dave B
It seems that the pilot jet adjustment has no influence on the idle speed... My running issues are almost certainly down to carbs...
I have a flow meter and balanced the carbs at both 3000 rpm and 1500 rpm.
Adjusting the idle screw at 1000 rpm has no rpm change. I screwed both the right and left idle screws right in and it still ran with no rpm increase...
Dave B
- Alan H
- Posts: 12110
- Joined: Fri Aug 05, 2011 6:38 am
- Location: Wombwell, Republic of South Yorkshire
Re: GT380 Carbs...
Running stationary and running on load (real life) are 2 different things. Get out on it and ride it. 70s carburation was approximate at best.
Proof that four strokes are over complicated