Hey everybody- Nubie from New Zealand here. I have been reading all the posts on Carb farts and I am also suffering a similar problem. My VTR will backfire either at idle or low revs through the carbs. Somehow the result is that it blows the gasket on the top of the motor and oil runs out all over exhaust and back tyre- not nice! So.........

1/ I need to figure out what is causing the carb farts and 2/ why the heck does it blow out the seals and gaskets when it happens.

I run a dynojet kit in carbs, K&N filter and currently have Danmoto carbon GP mufflers. The issue also occurred with previous Kerker mufflers and has even happened with the stock exhausts. Oh and restrictors have also been removed from inlet manifold. I welcome any discussion and tips.

 

Greetings

Are you saying the cam cover gasket blows oil?

 

If the cam cover/cylinder head cover gasket is not seated properly or sealant has not been used on the half moon cutouts in the cylinder head before the cam cover/cylinder head cover was installed, copious amounts of oil will blow out. The problem is most likely to occur after a valve clearance inspection. Don't ask me how I know.

 

+1 lol! Those rubber things can shift when putting the covers on .

Easy to fix, don't need extra parts or anything (unless the gasket is torn or something). Probably a 30 min job. If it's on the rear, slight chance the oil could be coming from the CCT too. Most likely it is not related at all to your carb farts.

 

I have had the Cam covers off and replaced the seals/ gasket. Made sure they were well goooooed up. It is definitely related to the engine cough....EG leaving gas station, first gear pulling out into traffic. Big engine cough- nearly kills the motor completely. Couple of km down road I notice the oil spewing out the rear cam cover gasket. It has done it 3 times, Twice it blew the rubber bungs at the side and once the gasket. Always after the big motor cough....sounds like a big chuffffff. Lucky it dosent happen every ride and I can normally manage to fix it enough roadside to get home.

 

Something odd going on here.
The airbox cough is where the incoming charge ignites in the carb throat and airbox.
This can't really pressurize the engine; although the engine breathers exit into the airbox, the airbox is also open to atmosphere and so won't pressurize.

Certainly not enough to blow seals.
One way or another the crankcase pressure is too high in your motor.

Have you got the PAIR emissions control pipework still connected to the top of each cam box?

 

I will have to pull her apart again and check those things- from memory when we fitteted the dynojet kit to carbs we did some drilling of the airbox but I think this was just for better air flow. Did not remove any of the breathers etc. As for Pair emission control I dont think the NZ model came with this? I could be wrong...

 

While it may work on IL4s, making similar mods to the airbox on the VTR has a detrimental effect on performance. Did you dyno the bike for optimum changes before and after?

https://www.superhawkforum.com/forum...my-bike-18742/

 

Check your alternator output. Mine started shorting out and ignited the oil vapor and blew the head cover gasket out made one hell of a bang then lots of smoke.