Backfire on Start Up
- Thread starter LamboV12
- Start date
It's the round annular tube in the venturi of the carb like the one inside the Triple X carb. There are a couple companies selling the things.
If you scroll down on this page you can see it on the right.
http://www.masclassics.com/vtwin/2007/964.pdf
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LamboV12
Active Member
Thnx Ray and your right. In my case they reduced the jet size (back to stock) and added the Sifton. Did not stop the afterfire problem I'm having. Also - noticed decrease in performance (due to smaller jet) - but I guess my mileage will go up 
I think the Sifton may have performance merrits when used with larger jets.
The afterfire seems to be an unresolvable problem - unless I change my igntion, carb, etc etc at my own expense and that would void my warranty.
I've officially initiated arbitration with BDM to resolve - so I don't think it would be wise for me to comment any further....
I think the Sifton may have performance merrits when used with larger jets.
The afterfire seems to be an unresolvable problem - unless I change my igntion, carb, etc etc at my own expense and that would void my warranty.
I've officially initiated arbitration with BDM to resolve - so I don't think it would be wise for me to comment any further....
jgwingman
New Member
Relating to questions about backfire on startup. My K-9 was also giving me problems. Does not do it cold because you are choked. The low idle jet needs to be increased. If you have big radius pipes, the dealer should have corrected the problem. Stock jet is .040. I went to .046 and am still having a slight problem. Probably need to go to .055 or even .060. Find out what jet is in your carb and if you have slightest know-how, you can drill them out yourself, providing you have the small drill bits. My rule of thumb is, I dont even let dealers touch my shit. It dont get done right if you dont do it yourself. Party on dudes!!
First off Welcome to the forum jgwingman, How about doing an intro in that section and tell us where you are from.
Secondly, what do you mean by "doesn't do it cold because you are choked"? Our carbs don't have a choke unless you put on a Mikuni.
And the stock jet is only a 28.9 or maybe a 31. Don't know where you are getting the .040, .046 and .055 unless you are talking about the air bleed cause that's the only sized jets in this range. And the Big Radius come with a 31/76 kit if I'm not wrong.
But, welcome to the site again and party on!!!
LamboV12
Active Member
We requested to change the Ignition under warranty to fix the problem and BDM denied the warranty claim
Ray you are correct - If you run Big Radius the jet kit is:
076 main and 031 intermediate and it comes as a BDM Part # 103-000032-00
Been there done that
island chop
Member
My bike used to backfire on warm startups after I turned it off using the ignition key. Then I read the owners manual where it tells you to turn the bike off using the kill switch first (off button on right side handlebar). Never backfired again.
scubaman15
Well-Known Member
Mine still does it now and then? I think compression releases ? Sometimes does it sometimes not ....It seems better when 1 turning fuel off before shut down 2 No extra fuel while cranking ... seems better also after rejetting carb in Jan ..
Throttle Jockey
Don't Look at my Member!
I had my jets done with new mean muther pipes etc. I started having that pop on warm startup.
What i did that eleiminated it was when I go to warm start I hold my throttle SHUT all the way. That stopped it. If you hold your throttle shut it wont pop. You should try this before making any major adjustments.
Throttle Jockey
What i did that eleiminated it was when I go to warm start I hold my throttle SHUT all the way. That stopped it. If you hold your throttle shut it wont pop. You should try this before making any major adjustments.
Throttle Jockey
