Installed the HMF late this afternoon (8/9). The stock carb was pulled (first time I've ever done something like this). Yes, the screws at both the bottom and top are a bi$%h to get off. We had to grind slots to get a flathead screwdriver on them enough to break free. I'll be purchasing the hex stainless screws for the top and bottom. Anyway, we jetted from 165 to 170 main. So, all is good there.

Now, for the question. The needle clip is on position 4 (I think). I've read where I should set to position 5 with the HMF and 170 main. Where does the position start from, the butt end of the needle, counting towards the needle point? If so, I should move from position 4 to 5?

TIA

 

Okay, I did a search, I should have started there but I still have a question.

Should I leave the needle at postion 4 or go for 5 (richer)? After taking the carb off, I'd prefer not to do it again soon. I'm not one to test the plug, check at idle, check at throttle, then loop through the process again. If someone has a comment at riding about 500 - 1000ft above sea level with the clip in positions four or five, I'd appreciate it.

 

it's funny a few years ago jetting was around 180 for most , but i've always been happy around 170 .

 

Trial and error......175 Main was a bit fat for me. I run 170 main, needle in the fifth position.

 

Coyote..not to ask a dumb question, but how could you tell that the 175 main was alittle fat? How did it run and what symptoms does a fat main give?

 

Dingo,

Try a 175, then go climb a steep hill or two (if thats convenient) and if she coughs/hesitates then your a little heavy on the jetting. Next size down is a 172.5. Try that and see how it feels. I would just keep changing them until I get it running the way I want.

 

I am in pretty much the same situation as Oz. I put on a Mr. HP end cap (believe it flows similarly to the HMF) a few weeks ago and ran my bike at Pismo (sea level-zero elevation). My jetting was: 172.5 Mikuni main jet, needle on richest position, four loops cut from carb spring, K&N filter with outerwear, air snorkels just like stock. Set up like this, I did not like how it ran at all. At low RPMs in both second and third gear, a "pop-pop-pop" sound would come out of the pipe and it would start to bog down until I downshifted and got the RPM's back up. Overall, it just seemed sluggish. I looked at the outside plug, and it was really black and sooty. I assumed that it was rich, but I really am not sure how you go about reading the spark plug. So, I adjusted the needle one notch leaner, and that seemed to help some, but the popping would come back at low RPM's in second and third gear. I was talking to some guy at the drags with a DS, and he told me my problem was probably the outerwear, so I took it off, and that did not make a bit of difference. So, my conclusion was that I was jetted too rich, even with just a 172.5 main jet.

Last week, I put in a 170 Mikuni main jet, put the needle back to the richest position (because I am afraid of being too lean), and put back in a stock length carb spring (I read somewhere that a shortened spring can cause a rich condition). It seemed to run better, and after running wide open (and really irritating my neighbors) I checked the plug, and it was sort of a whitish tannish color, which I guess is good. I am hoping I have it dialed in now, but I won't really know until I go on another dune trip in a few months. Oz, I hope that this post, which I would call "One Idiot's Jetting Experiences" is of some use to you.

 

Jusrlax,

I wouldn't call it "One Idiots Jetting Experiences", so don't be so hard on yourself man. The only way to get your bike dialed-in for your riding elevation is trial and error. The jetting advice that everone is handing out is what works for them and will get you in the ballpark. The rest is trial and error and good part about that is, no matter where you plan to ride, that trial and error you have experienced will help you determine which jet to put in to make it run best.

 

This information is excellent. I think I'll start with the 170 main jet and keep the spring at the stock length. From there, I'll play with larger jets based on feedback from riding. I'll then experiment with a second "shorter" spring.

Here's where I'll start:

MainJet = 170
Spring = Stock Length
Needle Clip = 5th Position

Based on engine feedback (isn't running as good as I expect/want), I'll play with each setting to dial the carb in to my desired engine performance. I'll have the carb back on the DS tomorrow night (Thursday). After a few rides over the weekend, I'll post the configuration I like best.

 

FYI,

On the needle, I tried the 5th clip position and had to go all the way down to #3 to get it right. It is best to only make once change at a time, then you'll know what the change did. I know it takes longer but it does work.

Oz,

Excellent starting point. And having both lengths of springs is also a good idea. The spring cut does seem to richen things up a bit, funny thing I could only notice it on one of my two DSs which were both stock at the time.

jusrlax,

You have a good starting point as well, but try to only change one item at a time or you'll just loose your mind. I have a feeling you may need to be in the #4 or #3 position on the needle to get it to run correctly, so don't be suprised about that.