What jetting would you say I would need on my DS to get more low end? Also, are there any needle adjustments needed? I will be running stock air filter and box. Thanks.

 

I tried experimenting with the pilot jet. I tried lowering it from a #40 to a #25 and a #30. I couldn't maintain a stable idle with these two sizes so I gave up and went back to the #40. I didn't have any pilot jets larger than a #40 to try. That carb seems tricky. I probably will only adjust the needle position and possibly the main jet to be sure I'm running peak. I believe the way the carb is designed/setup, there is a weakness from zero to 1/4 throttle, if the RPMs are low. If you take that carb out and look at it, it is unusual. The throttle valve is keep open at least 1/4 at idle. The throttle valve does not raise directly from the thumb throttle cable - airflow and vacuums have something to do with it. I have heard that if you let the RPMs drop and start to bog, you can recover by giving the motor more gas beyond 1/4 opening. I haven't tried it yet. I have heard rumors about different jetting between early and late DS650s but have not beeen able to confirm this or get the new jetting changes if they exist. Is your DS a 2nd production run model?

 

Yes this is a second production run bike. It runs very strong, but after warmed up it will bog when launching out of the hole in a drag race. My service department is great, he is going to try to find out where the bog is. He said that the support from the manufacturer is not there at all. If he calls them with a problem all they have are suggestions. He said he has seen no service bulletins for either production run. He is having problems with the Traxter as well, wanting to hesitate. He fixed that by a hotter plug. Maybe that is the key, is the plugs the further south you get. Have you tried chaning to a warmer plug on your bike like a 7 or even a 6??

 

Dynojet shows a jet kit available for the DS650 for $57. I don't know the details. www.dynojet.com

 

I am experiencing more off idle hesitation than I think is normal. I didn't have this when the DS was new. I'm wondering if it is a maintenance issue - dirty air filter, clogged vent hose, clogged crankcase vent, dirt in carburetor, etc.

 

I think I am going to take my stage I DS to an authorized Dynojet center to get my ds in peak operating condition. I will let you guys know the results. Scooby where did you get the #2 adjusting screw for the accelorator pump. The one that stops it, that's all I need to get mine running. Sudco doesn't have it.

 

LUBA, Yeah I have thought about doing that too. I will see how good I can get the DS running this weekend with the RW carb, accel pump, rev box and stock exhaust and air filter. If I still have trouble, I'll have to get air/fuel data either from my own sensor or at the dynojet center. I plan on pulling the plugs from running the stock carb and saving them as a reference. This should help me out since I am not a veteran plug reader. As long as I have enough time and energy I think I can get the jetting near peak.

Sudco does have the #2 accelerator pump screw (pump stop screw), although it is not listed for the HSR45 carb. I bought a screw from the local hardware store in the mean time. I ordered the correct screw from sudco. It is sudco part number 007-168 for $2.82. It is the screw listed on pages 46-47 for the RS40 carb (item #65 in the drawing, TM36/48A screw). I received it earlier this week and it looks fine. I also ordered gaskets, needle clips, bowl screws, O-rings, etc. since the stuff was wearing out from all the messing around with the carb that I have been doing.

 

It is my understanding that there are some badly adjusted floats coming from the factory, other than that I think every DS is jetted for sea level to make sure nobody burns one down. I have jetted mine on just the main and the result was very little hesitation out of the hole and very strong power from there on up. There are alot of variables involved in jetting such as elevation, humidity, temperature and I'm sure I'm leaving a few other things out. I live in S.E. Idaho and the air is dry and temps are now somewhat normal and elevation is 4400 ft above sea level. The dealer suggested jetting is two sizes leaner on the pilot (35) and low speed (30) and two or three sizes leaner on the main (160 or 157.5) and going up one notch on the needle which would drop the needle lower and lean this part of the carb also, I'm told that if I change all these that it eliminates the low end hesatation. The reason I have not went ahead and purchased the the other jets is I plan on piping my DS and I would probably have to jet back up again when my big gun gets here ( I'm getting tired of waiting for them to send it by the way! ). Hope this helps, this is jetting only for my situation and the variables above will change the jetting for your situation, it is always better to be rich on your jetting.

 

I called DynoJet and the DS650 jet kit isn't available yet. Also, I found this web site with a dyno chart on the DS650: www.quadstore.com/sys-tmpl/dynoruns/

 

Here is the jetting I have from the dealer. 45 pilot, stock main jet, needle up one position, floats leaned 1/16th of an inch. 7 series plugs and they are medium tan at 3/4 throttle and a tan at full throttle. There is no hesitation off of the start other than the horsepower not being there. Sitting on the back of the seat and launching, the bike comes straight up. On the front of the seat in grass, four gears still spinning. Middle of the seat great traction but some rolling of the throttle to control spin. All I have to say is practice, this is a new bike with alot of horsepower. Get it to the ground and you will be tough to beat.