Honda Spree and Elite 50 Forums

I am fixing a 1997 yamaha razz. It didn't have an air filter so i got a uni air filter. It will only run with half or full choke at no more than half throttle. If you go over half throttle, it bogs down and it seems like it misses where the motor will run and then quit. I didn't do an actual plug chop as I can't get it at full throttle, but after I rode it around a little bit, the plug seemed to of only browned a little bit. Also, I don't know if this could be doing it but, the exhaust pipe has about 10-15 holes drilled in it. There are 2 holes the size of the original exhaust outlet, there are about 6 holes on the back on either sides of the welds of the pipe that are about 1/4 inch and there are 3 holes drilled along side of the pipe that are about 1/4 inch. Also, I have cleaned the carb twice already and it is pretty clean. The main jet is an 82 if that makes a difference. I bought an 87.5, but it is the wrong thread size so i have to go exchange it, if that is the problem.

Yes the yamaha is being a stubborn lady right now. In my experience with yamaha's. Idle could be to low turn idle high enough till the wheel barely turns. Adjust the air screw in all the way. But a new plug gap about .26-.28" also make sure if has it has a fuel filter the flow is correct way. Make sure there is no leak in the manifold to reed. This should get you started wish bike was here in tn i could fix it for you in less than an hour or your money back

the parts place can't get a bigger jet. i moved the needle clip down 2 positions and gas started pouring out of the carb and the air filter got soaked with gas. i drained all the gas out and it would still run so i took it around the block and it would run with half choke but i could ride it at full throttle now. I did also notice that one of the bolts for the exhaust where it bolts to the motor is missing and a little bit of exhaust pressure is coming out. I am going to get a new bolt tomorrow. I moved the air screw all the way in, and the idle is set so the wheel turns just a little bit. If i turn the choke off, I can't give it more than half throttle otherwise it will bog out. There is a new exhaust pipe on craigslist for $25. Should i get it since the current pipe has tons of holes drilled in it?

Sounds like the float bowl bushing is bad this bushing when the float bowl is full it rises and pushes this bushing in the carb and stops gas flow. If this is not sealing the carb will be flooded with gas. I think this could be your problem but atleast it idles now

Limp1144 wrote:Sounds like the float bowl bushing is bad this bushing when the float bowl is full it rises and pushes this bushing in the carb and stops gas flow. If this is not sealing the carb will be flooded with gas. I think this could be your problem but atleast it idles now

this set up sounds more like the razz is running lean than rich. Yes, get the exhaust pipe.

But elite guy he said gas is pouring into the airfilter carb is flooding out thats why it only runs with choke= high rpm

I feel like a dummy haha. You need to move the needle clip up to lean it out. Moving it down 2 clips is flooding it with gas.

Limp1144 wrote:But elite guy he said gas is pouring into the airfilter carb is flooding out thats why it only runs with choke= high rpm

the excess fuel is from the float issue you mentioned earlier. but the pressure is not at all right with this razz...open intake (hence the choke, needs to restrict airflow the way the Yamaha engineered air box did), the lack of a secure headpipe(poor scavaging) and holes all over the muffler(backpressure). That is why he was able to acheive full throttle only AFTER the needle was lifted 2 notches (making for a richer mixture). the motor was not able to get 'energy' (fuel) at full throttle before because it was too free flowing with air so there was no suction in the carb to draw out the gas....And to adress the post about choke=high rpm, what??? a choke and hot start have the same affect on stoichiometric ratios (richer) but it is the volume of the charge entering the cylinder that is different. the choke is simple a mechanism that restricts the air intake flow and causes more suction through the bowl, generating a richer mixture while increasing charge velocity at half choke.

eliteguy50 wrote:

Limp1144 wrote:But elite guy he said gas is pouring into the airfilter carb is flooding out thats why it only runs with choke= high rpm

the excess fuel is from the float issue you mentioned earlier. but the pressure is not at all right with this razz...open intake (hence the choke, needs to restrict airflow the way the Yamaha engineered air box did), the lack of a secure headpipe(poor scavaging) and holes all over the muffler(backpressure). That is why he was able to acheive full throttle only AFTER the needle was lifted 2 notches (making for a richer mixture). the motor was not able to get 'energy' (fuel) at full throttle before because it was too free flowing with air so there was no suction in the carb to draw out the gas....And to adress the post about choke=high rpm, what??? a choke and hot start have the same affect on stoichiometric ratios (richer) but it is the volume of the charge entering the cylinder that is different. the choke is simple a mechanism that restricts the air intake flow and causes more suction through the bowl, generating a richer mixture while increasing charge velocity at half choke.

Good post

I got a new gasket for the exhaust so there is no leak there. I was unable to get the used exhaust pipe as it was already sold, so I patched all the holes on the exhaust with small pieces of metal and some jb weld. This thing is soooo much quieter now. I have moved the needle clip back into the stock position in the center, as there are 5 positions for the clip. It still won't run without the choke on and it won't run at more than half throttle. The weird thing is though, at half throttle, this thing gets going 27 mph, and at full throttle I am thinking this thing will move pretty good. I also tried running it with the needle clip in the fourth position down, raising the needle 1 position from stock. It did not help it or hurt it and it was the same as when the needle was in the stock position. I can't raise the needle all the way otherwise gas will start coming out of the overflow and it will soak the air filter when the bike is not running. The bike will idle when it is semi-cold without the choke on and it doesn't like to idle when it is warmed up with the choke on or off. Also, how many turns out should the air screw be? It is about 1/2 to 3/4 of a turn out from all the way in.

might just have to bite the bullet and buy a new carb.I had a yamaha ca50 and it did the same thing but i bought a new carb for 40.00 and it ran great

hondadirtracer wrote:Also, how many turns out should the air screw be? It is about 1/2 to 3/4 of a turn out from all the way in.

call your yammi dealer, they can tell you for sure but it is usually more than that.
82 main jet and 46 pilot jet should be fine with a stock setup.

Get rid of that Uni and put a stock airbox and filter on it. Or restrict that Uni somehow so it is not running so lean.

ALOW1 wrote:Get rid of that Uni and put a stock airbox and filter on it. Or restrict that Uni somehow so it is not running so lean.

A new airbox assembly from the dealer is close to $100. How would I be able to restrict the uni?

build a box for it and spend hours tuning it is the best way but I have seen people put tape on the outside or a restrictor plate on the carb's intake itself.