Rotary valve blow back ?????

[erectordale]

I just looking for some thoughts on a rotary valve 2 stroke the tiger will start and run just loading up severly. with the air filter off you can see the gas blowing out of the carb. this thing will soak anything in it's way tires legs etc... I know with a reed type engine that the reeds would be leaking and need replaced has anyone dealt with these rotary valves and would the rotary valve be bad ???:wondering

[blue27]

Don't know much about them(yet!) but I would start with the rotary timing.

[daputz]

I agree, check the valve timing.

If the valve timing is spot, on the the valve has way to much slop (front to back), or the burn is severly inefficient.

If you can't find the trouble your self, a good pwc tech should be familiar with your set up.

[erectordale]

I'm on a learning curve myself right now I will solve this one by trikefest I have another engine really close to being ready and may just switch them out for the fest

[erectordale]

Is it possible that its just getting way too much fuel as it won't idle just full throttle. If you shut off the fuel it will run more normal as it is about out of fuel in the carb Remmeber I don't know where too start at jetting these and they seem too be larger jets

[daputz]

pm me with the engine #'s, I'll search the archives at work and see if I can find a rotary valve that is comparable.

Edit..............float height? is the carb overflowing while stopped?

is it possible the needle length is too long? shutting off flow at anything below wot?

[erectordale]

ok will do I need too get too the grocery but will pm you as soon as I'm back Thanks

[erectordale]

! thing I thought of I have a can am 250 carb here its a bing 84 off a air cooled may be that's a good place too start

[daputz]

reply tag:lol: ........your it:w00t:

you type way too faast for me to keep up:lol:



Edit....................the can am carb would probably be close, not ideal but a good base line, the jawa specs are also in the ball park compared to the can am. I have no clue as to what the tigers were set from the factory.

[MTS]

reply tag:lol: ........your it:w00t:

you type way too faast for me to keep up:lol:



Edit....................the can am carb would probably be close, not ideal but a good base line, the jawa specs are also in the ball park compared to the can am. I have no clue as to what the tigers were set from the factory.
Same carb, Is the tiger have a BING carb? they are notorious for having bad seals in the Choke-assembly, causing them to run real rich ect....but it sounds like your roatary valve timing is off....my friend had the same problem with his Cam-am 250...i can see if he know's how to set it right (dont know if he ever did)...and will let you know..

[blue27]

I checked my Tiger 200 manual and Rotary Valve timing disc opens at BTDC 142 degrees and closes ATDC 85 degrees + or -3 degrees. Don't know if its the same or not, no carb info. Thats all I got. Good Luck.

[erectordale]

I found a manual for the air cooled 250's and according too Tony murphy rotax it's really close but the carbs they talk about are the bing carb's

[erectordale]

THe rotary timing is close I have a gage that was made too set these this engine will get checked again tommorrow I know 1 tooth off and it will run like crap