TOPIC:

Does anyone know if this is right. I have a set of Mikuni 29's for my 78 1000. I went to check the jets and both the 1 and 4 carb have a 117.5 main. Then the 2 and 3 carbs have 120's. This doesn't seem right to me but with these carbs being aftermarket, ya never know. I've been struggling with these carbs for a while now and I just want to get them working right. I appreciate any input.

Some folks will jet 2&3 a size richer on the theory that 2&3 are warmer and the richer mixture cools off those cylinders. I don't think it is needed.

Look at your slides. There is a number on the slides that represents the slide cut outs size. What is that number... it is on the top of the slide and will be 1.5 or 2.0 or 2.5 or something along those lines. The slide size makes a big difference in rejetting those things on the bottom end.

As far as the top end, you didn't mention which airbox type or pipes you have or engine mods. You might want to mention this... if your bike is stock (stock airbox and pipes) #117 mains are a decent starting point. The 5DL31 jet needles seldom need much adjustment for mid-range flat spot and are typically OK in their middle (3) position.

George, thanks for the reply. I checked out the slides, they are marked with 1.5 on top. As far as I know the motor has had some valve work done. Right now I have a V&H sidewinder pipe. I am not running an airbox, I have Emgo individual pod filters. At this point I can't really tell how the jets are working. I had a major issue with the fuel not stopping. It was coming out the breather and out the intake for the jet needle. I replaced the float needles and seats, that stopped the flow from the breather. Now its steady pumps out the jet needle intake hole on the intake side of the carb. My main question about the jets was due to this. Does the needle have to seat down in the jet itself or does it hover just above. On my old 2 stroke ATV I know it sets all the way down. Is this the same on four stroke, at this point the needle doesn't seem even close.

There is no overflow on the smoothbores so when gas doesn't stop flowing inside the bowl, it comes out the needle jet hole... There isn't any great way to set the smoothbores wet because of the big main jet plug in the bottom of the bowl so turn them upside down and set the float levels. I think they should be set to 23mm; that is, from the gasket mating surface (no gasket in place) to the top of the float. You do have brass floats? I have seen folks try and use regular floats but they just don't work by setting the float level. Anyway, make sure you have small screens on the bottom of the float seats. If you don't crud will get between the needle and seat and gas will just flow. The jetting has no effect on this problem

As far as jetting for your set up... #120 mains, #17.5 pilots with the air screws out 1/2 turn only and 5DL31-3 (that is, leave the jet needle clipped to #3 slot).

Make sure the vents are not plugged/kinked. This WILL cause float problems. See the link on my web page for VM carb connections.

Hey George, thanks for the input. I do have regular floats. I will look into changing them, if I can fix the next problem I have. I pulled the tops to check the needle postion. When I did this I found that 3 of the 4 have link levers that have broken at the ring that slides over the lever pull, and one broken lever pull. I have checked around and it seems I won't be able to find replacements directly for the 29's. Would I be able to replace them from a different carb, say a 26 or a 28. If not I guess I will have parts to sell. In turn what carbs would you recommend for my 1000. It is for drag only. I have almost had it with these things and think that they will make a good fishing weight. Now that the end of the season is here its not a pressing issue, money races are over this weekend locally. So I'm going to have some time to get it right, but I'm so close I can taste it. Thanks for the time, and for listening to me whine.

thanks to george for me also. i have been having trouble with my 29's too. i'll try out the advice i read here.

Yeah, George is the resident PHD of carbs. If he can't give me an alternate solution to my problem, I might have some good 29 parts for sale. The jetblocks are solid, as well as everthing else that I didn't mention in my last post. If something is needed, contact me. I usually check the site once a day.