Backfiring

[Terrence]

Hi

Our 88 Vmax hasnt been run for probably over 5 years. We have completely overhauled it. It is now just about done. I am trying to tune and sync the carbs but i just cant get it to run smooth. I have gotten the vacuum's very close but still it dosnt sound right and it back fires like crazy when the idle is below 1200rpm. So pretty much when revs are above 1200 i can get them close and no backfiring, (still dosnt sound quite right tho mind you)

To give everyone bit of an idea of what could or could not be effecting this, i have fully cleaned and adjusted the carbs, new spark plugs, and one thing i am worried about is i have done the COP conversion, with resistors and a made up wiring loom from another Yamaha. Oh and def four sparks and firing.

Please any help will be appreciated, the neighbours must be sick of me trying to tune it haha.

 

[alorio1]

You could have the front cop connections crossed, it was an oversight for me when I installed my cops.

 

[tugla]

Was it running like this before the cop mod??? Also any mods to the carbs.....u set dry and wet float levels......have the air box on correctly.....

U can check the sync roughly by setting them by eye then with carb tune or such once running decent on bike...

Sometimes still dirt caught in the tubes and jets....emulsion tubes have little holes,make sure those all cleared out.....

 

[Terrence]

You could have the front cop connections crossed, it was an oversight for me when I installed my cops.

Of course there on the right way, im not that stupid (runs to shed to check)

So that possibly might have been the problem... Slightly embarrassed, Little more careful tinkering with the sync's and its sounds perfect. Thanx a heap, i had a feeling it was going be something like that. I have done thousands of sync, links, and tunes before so tho im not an expert I'm def no beginner either.

 

[tugla]

Glad to hear you got her running right......

 

[DMAN999]

Nice, glad you got it figured out.

 

[Redbone]

You could have the front cop connections crossed, it was an oversight for me when I installed my cops.

I was sure I had them going to opposite side like they should be but when I went to start her she wouldn't run properly. After much checking I lastly just swapped them and the bike fired right up.
I'm glad it's running fine now Terrance!:clapping:

 

[95spfldmax]

You could have the front cop connections crossed, it was an oversight for me when I installed my cops.

"X" GETS THE SQUARE!! Nice call Alorio!!

 

[dannymax]

Absolutely....nice call Joe!!

Terrence....if it ran but 'didn't sound quite right' with the front coil wires crossed....that baby is gonna be downright nasty now!! :clapping:

Albany NY or Albany GA?

 

[alorio1]

Thanks, its a good feeling to be able to help another member with problems. The members on this forum are the best trouble shooters and problem solvers on the net...........

 

[Terrence]

Albany Western Australia DannyMax. This forum is GREAT. Have used it a lot during this build, wealth of information! alorio1 I and my neighbours thank you!

 

[alorio1]

Come again, the forum is open 24/7........

 

[sdt354]

Of course there on the right way, im not that stupid (runs to shed to check)

So that possibly might have been the problem... Slightly embarrassed, Little more careful tinkering with the sync's and its sounds perfect. Thanx a heap, i had a feeling it was going be something like that. I have done thousands of sync, links, and tunes before so tho im not an expert I'm def no beginner either.

\

Good to hear it's all straightened out now. Don't feel bad, that's a common mistake, made by many. I have a friend....
Steve-o

 

[Terrence]

Was great to be able to take it for a spin, it's running sweet. Now have a charging problems that is caused by a faulty stator. Oh well at least I got to take it for a ride!