Mid Range Power

pup55

pup55

New member
Joined
Mar 21, 2007
Messages
285
Age
64
Location
Boylston Ma.
96 Vmax 600XT stock. Hi guys. I had a thread earlier on my poor gas mileage. I took the sled out today and went 70 miles and got 7 mpg. I had a problem with mid range power. At idle and low speeds up to 4000 rpms it was ok. From 6000 rpms and up it was ok but between 4000 and 6000 rpms the sled seem to run poorly. It sounded like the engine would break done and not run smoothly. It has great throttle response but at mid range it sounds like it skips. Could all this be part of my poor gas mileage? I will be pulling the sled in the garage this weekend to take a look at the carbs.
 
You are going to have to play around with your carbs.

1.) Make sure they are clean
2.) Adjust air/fuel screws, make sure they are set properly (you can find specs in your manual)
3.) Try dropping your needles 1/2 -1 position (this really helped my mid range)
4.) Check your jet sizes and make sure they are the proper jets for your elevation.
5.) Make sure your float heights are correct and your carbs are synched.

Hope you get it straightened out. I used to have mileage and mid-range power problems until I got my carbs figured out. Now I see a minimum of about 11mpg and as high as 14mpg and my mid range power is good. Also, realize the mid range on these sleds is inherently not going to be stellar, its the way the engine was designed, but you can make adjustments to get it better than what you are experiencing now.
 
Chris when you say drop the needle do you mean raise the clip 1 postion so the needle will drop?
 
hold it at 4,000 to 6,000(your problem zone) for a wile then kill the motor
and check plugs..

or at that rpm put choke on, does it run better or worse??
 
I will try that, but what will that tell me? Could you guys give me a little help on the needle postion. I am going to check the needle postion and set it to the #2 postion. My service manual shows the clip on top and the two shims on the bottom of the clip. Does that sound right? Thanks for the help.
 
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pulling the plugs @ that r's will show ya how it's burning(to rich to lean)

same with the choke(runs better with it's lean)
 
Remember though, Just by dropping the needles ISN"T going to give you better fuel economy, it will just make the sled run crappy and possibly burn down a motor. ONLY if it is needed(basically fouling plugs at trail speeds) is THE ONLY time to drop the needles. Tracy
 
pup55 said:
Chris when you say drop the needle do you mean raise the clip 1 postion so the needle will drop?
Click to expand...

Yes, raise the clip to drop the needle. This should help clean up your mid-range. I would first do as Daman suggests though, run your sled at those r's and do a plug read, that will tell the story of if you are rich vs. lean. I'd bet that you're running rich which is why you'd need to drop your needles, but incase it turns out you're running lean it probably means you have a clogged jet somewhere. Good luck.
 
Thanks again for the help. I will take the carbs apart this week and clean them. Next weekend I will take it out and see how it runs. If it still runs poorly I will shut it down and check plugs.
 
Make sure you blow all the jets and passages out good with shop air, you
want to see light through the jets when done, good luck!!

if she's stock check tech for setting's and spec, for your app.
 
It is stock and I have all the spec's. Will go threw carbs and let you guys know what I find out. Thanks
 
I have a parts sled with the sams carbs. I just took them apart so I can see how it will go when I remove them from my sled. I have 1 question for you guys. You talk about raising and lowering the needle. On my needle I only have 3 notches. Both carbs that were on my parts sled the clip was in the middle notch. Also you talk about putting the shim on top or bottom but I have no shims on my carbs.
 
i don't beleve '96 vm carbs had the spacers,just a C clip and three slots, the middle slot is the stock "standard" position..
 
I was just looking threw the service manual and that what it shows. I just took the top covers of my carbs from my running sled. I don't know how to put this but I will try. The rod that goes to both carbs to control throttle. If you are sitting on the seat the carb to the right with the spring on it seems to be leaking a small amount fo grease into it. Could this cause a problem with the running of the sled. Pull the plugs and one plug was black but not wet from oil. The other plug was black but the tip was a tan or dark brown.
 
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