I did a search and read several threads on backfiring but mine seems to be acting different than those that I read about. I just aquired another Viper the guy I bought it from just had a new top end installed by a Yamaha mechainc. He let it sit for 8 months after he had the work done, before he rode it. when he did, he said it was very low on power and seemed very restricted. I figured the carbs were gunked from sitting. I pullerd them yesterday and gave them a through cleaning, reinstalled them. It fired right up sounded great for a minute idled fine. when I gave it some gas it reved right up then it seemed to hit a wall right before a huge backfire that blew the expansion chamber off the silercer.
The TORS was unpluged when I got it. I reconnected it when I put the clean carbs back in. Plugs are wet and dark blackish, plenty of white smoke coming from the exhaust, so it doesn't seem to be running lean.
I removed the plugs after the backfire and there was a very light, thin, misty, (kind of looked like smoke, but wasn't) floating out of the #1 plug hole.
Do you engine experts have any idea whats going on or adivce on what the check?
Thanks
The TORS was unpluged when I got it. I reconnected it when I put the clean carbs back in. Plugs are wet and dark blackish, plenty of white smoke coming from the exhaust, so it doesn't seem to be running lean.
I removed the plugs after the backfire and there was a very light, thin, misty, (kind of looked like smoke, but wasn't) floating out of the #1 plug hole.
Do you engine experts have any idea whats going on or adivce on what the check?
Thanks
super1c
Super Moderator
Sounds like it could be the torrs acting up. For testing disconnect the torrs again and plug back into eachother. Then try. If problem gone it the torrs. 99% of the time the torrs acts up because the throttle cable it to tight. That thing needs more play in it then you think. Post #6 will give you proper way to adjust torrs. Not for viper but all the specs are the same on yamaha sleds. http://www.totallyamaha.net/forums/showthread.php?t=73210&highlight=torrs+adjust
I put more slack in the throttle cable and tried disconnection the TORS. it runs better and has eliminated the giant explosive backfiring but still experiencing small backfires, any other advice. I haven't tried adjusting the TORS yet, do you think it still might help?
YAMMIEGOD3:16
Active member
get a set of new spark plugs, gap them to spec. 3:16 (yammie tony)
roudyroy1
Active member
powervalves?[edit] oh yeahh, check the float height, very important and overlooked by many.
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are there any threads on adjusting the float height?
YAMMIEGOD3:16 said:
X2 - cheap and easy to eliminate as a cause.
Pull the fuel pump and thoroughly examine for any bad diaphrams
I got new plugs haven't put them in yet, the current ones are sparking enough to launch the space shuttle. I will pull the fuel pump this weekend if I can find time and try the new plugs after cleaning the screens in the carbs
roudyroy1
Active member
do the floats!!!! there is a write up in the tech section