[slo100]

Hi all,

I recently installed a V&H Pro Pipe HS, rejetted my CV40, and set the mixture screw. I have no access to dyno tuners so I am going seat of the pants.

2001 Night Train, K&N A/C, Dynojet kit, Pro Pipe standard baffle. 185/45 jets in the CV with 3.5 turns out on the mix. Bike is otherwise stock.

This plug pic was taken today immediately after a one hour highway speed ride. According to the shop manual this is a healthy reading but I always like to get the general population's commentary.

Thanks in advance,
Bret

 

[HIPPO]

Heat range OK. Rich.

 

[HIPPO]

Probably didn't chop it right after the high speed run, as it shouldn't be rich with that jetting, ie if you ride it home and then check the plugs, it's not really valid.

 

[slo100]

Thanks, Hippo. Can you help me with your second reply? Chop what?

I didn't get the gist of that last one.

Thanks,
Bret

 

[LittleBear]

Here is some info that may help.
http://www.dragstuff.com/techarticles/how-to-read-plugs.html

 

[pa-glazier]

Thanks, Hippo. Can you help me with your second reply? Chop what?

I didn't get the gist of that last one.

Thanks,
Bret

I think he meant that you have to shut it off as soon as you have done the high speed run and check the plug. If you ride home at a normal pace after the run it can change your plug reading.

 

[HIPPO]

Yup.

Other thing that comes into play is where you live, around here they use emissions fuel (as they do in some other cities) and even with correct AFR the plugs will show very little color, ie with correct AFR they will be chalky off white.

The link posted above is a good reference, but I suspect that they are talking racing gas, or at least pure pump gasoline and not this oxygenated or whatever gas.

 

[HDWRENCH]

Looks like you use Mobil fuel by color on plug

 

[slo100]

Are you just showing off, now?

I was hoping to learn something about the tuning of my bike but I am back to square 1.

 

[captainlee]

Are you just showing off, now?

I was hoping to learn something about the tuning of my bike but I am back to square 1.

is he right?

 

[slo100]

Exxon. One in the same, I suppose.

It would be great if I could actually learn something here other than this being a "guess the gas station" exercise.

Other than that sidebar tangent I appreciate the other responses. I will try the plug reading again as suggested above.

So what am I looking for once I re-do this test and pull the plugs on the side of the road? I am trying to make sure I am in spitting distance of a decent tune without the expense or headaches of dyno tuning.

I live in Northern Virginia BTW and am sure if emission control gas is available...the DC area uses it.

 

[captainlee]

well since you ask soooo nicely.

Adjusting Intermediate Circuit(s)
Adjusting High Speed Circuit(s)

Adjusting the main jetting requires a long stretch of open road with no traffic. You must be in fourth or fifth gear and running at 3500-4000-4500 RPM. then open the throttle all the way to the stop, noting the feel of the bike. Immediately let off about 1/8 turn and note the feel of the bike. If the engine just slows a little, the jetting is very close. If it seems to accelerate some when you let off the 1/8, your main jet is too lean. If it hesitates or the top speed is poor (i.e. less than 80 MPH) you are too rich. Adjust the main jetting accordingly. Use your common sense and seat of the pants feel and you will get close enough to do plug reads.

Plug reading is as much an art as a science for most people. Lots of experience is needed to REALLY do it up right. For most street riders, making sure your plugs are a nice tan color is usually good enough. Don't bother reading the plugs until you have done preliminary fine tuning. You will need several sets of new plugs, gapped and ready to use. After your bike is properly warmed up, after installing a fresh set of plugs, you will need to do a full throttle acceleration test, making sure the bike gets to full RPMs in 4th gear. (The Motorcycle Performance Guide staff recommends you take the bike your local drag strip for this testing. Your local sheriff usually has no sense of humor about a motorcycle running down his roads in excess on 90 MPH). At the peak RPMs, you will need to shut down the engine before you let off the throttle, and coast to a stop. Remove the plugs and look at the general color of the porcelain. If the porcelain is black, the engine is running rich, requiring the installation of a smaller jet. If the porcelain is bone white or a very light tan the engine is running lean, requiring the installation of a larger jet. If the porcelain is tan to light brown, the jetting is close. If additional tuning runs are required to adjust the carburetor, make sure you install a fresh set of plugs before each run. You can not read the condition of the plugs unless the plug is fresh.

If you are in doubt as to the jetting, make sure you jet on the rich side (tan>brown>black). Because of potential engine damage, you are better off slightly rich rather than lean. A lean engine can detonate, causing permanent damage.

http://www.nightrider.com/biketech/carbadjust.htm

and if you are really "smart" GET IT DYNO'D

 

[HDWRENCH]

WELL sorry for stating " fue' TO read the plug you really need a plug magnifiying glass, . Second you need to understand "chop" Two stroke guys do more plug reading than any, as there are many additives in pump gas that can make it hard to read. IMOP use a a/f/r moniter as if will be more accurate and offer better results. If you are concerned about damage make sure the plug has some color. As you siad you do not have a tuner you could also get a K&N weggo unit as they work nicely and will be of much help. As plug color will get you inthe area but there are easy ways and better if you are running pump gas. Race fuel is another story.


I can tell you that at 3.5 turns out on the fuel screw you are open to far, the sweet spot is 1.5 to 2 out any more than 2.5 and you are not doing anything as you have lost control of the circuit. It looks like you are a bit rich and that maybe you allow the bike to idle a bit too long or run with the choke a bit too much.

Get some fresh plugs gap them, and take a plug wrench or socket with you and make a hard 4th gr pull shutting of at end and then pulling the plugs and go from there. ANd captin got the cruise portion listed nicley. Again that is going to get you in the "area" . Hope I was of some help this time

 

[slo100]

Thanks so much for the detailed responses, guys. HDWRENCH I was just giving you a hard time. I've seen you give such great responses to others I wanted one, too!

When I bought my Pro Pipe Vance & Hines tech support gave me the jet sizes and screw setting to use. I questioned them about the 3.5 turns and they were pretty adamant about it based on my bike's setup (stock other than a K&N S/E AC).

I may try new plugs and start from scratch. I bought the bike used and changed the pipes and carb jets/adjustment to what I listed above. I suppose it would do me good to start with fresh plugs and go from there.

I don't let the bike idle and if anything, use the choke less than more. The max I've ever pulled it out cold starting is halfway. I can't speak to the original owner's habits, unfortunately.

If anyone has a trustworthy dyno man/woman in Northern Virginia I would be willing to give it a shot but all I have heard of so far have been local HD dealers none of which have received glowing reviews.

The thing is the bike runs so well with crisp throttle response, no spitting, no detonation (that I can detect), starts right up, and is in the 40+MPG range. Am I over-analyzing? If it runs good, perceptively to me, do I need to drop coin, time, and effort getting a dyno being that I am not one to care about HP/TQ numbers?

Again, I thank you for the detailed response. Still learning here....

 

[HDWRENCH]

That plugs does not look what I would call bad if the bike is running good and no problems being abit rich is not a bad thing. Leave it and ride the wheels off it.

 

[dcfatboy]

If anyone has a trustworthy dyno man/woman in Northern Virginia I would be willing to give it a shot but all I have heard of so far have been local HD dealers none of which have received glowing reviews.

Some of us around here have had our bikes tuned at HD of Frederick, MD. Try to get Rob to do it if you can.

 

[slo100]

I have heard that from a few sources and they are great and the only ones I would consider at this point. They are very easy to get to from my house. Do you know if they take appointments for dyno tunings? I would have to ride it and wait...trailering not an option. Patriot, for example, won't even discuss such a thing...they told me I would HAVE to drop it and they'd call me whenever it got done. That is not in the cards for me getting rides, dropping off/picking up and so on.

If I can get it done efficiently in one stop I might go for a dyno but the whole point of this thread was to get input if my home-tune is close enough for rock n' roll thereby saving me time, effort, and expense.

What do they charge?

Thanks for the tip on Rob and the reference for Frederick HD!
Bret

 

[Ozzie In Arabia]

What Hippo started and HDWrench finished.........................in the leaded fuel days you "tuned" you bike, went for ride taking your plug spanner and screwdriver with you and usually in a fourth gear hard run........, clutch in and at the same time shut the motor off (chop it as Hippo says) and then coast to a stop, pull BOTH plugs and have a look.

You were aiming for tan color and grey in the exhaust pipes............this got you pretty close to optimum for your open or main fuel circuit........obviously if the plugs were dark then you pulled the main jet and went down a size and did it all over until the plugs went tan in color............

As HDWrench stated, mostly 2.25 to 2.5 gets most carbs sorted out for idle circuit......................got to turn the idle screw in/out to aim for highest rpm, then adjust throttle stop and re check idle rpm, then turn idle screw in/out again to see if rpm increase again and do this again until rpm is set..........usually 2-3 times is enough.

Acceleration circuit does take some time to get right because now you are experimenting with needle depth/height, then needle thickness, etc. aiming for highest acceleration without stutter or bogging down, both of which indicate too rich........

AFR...........14:1, approx best fuel mileage
................13.5:1 good power with good fuel mileage
................12.5:1 excellent power but mileage suffers somewhat.

Merry xmas to you and Hippo and HDWrench and all the other guys who chimed in on this one......., Ozzie

 

[HIPPO]

Ozzie, merry Christmas and a happy New Year.

Same to all.

 

[dcfatboy]

I have heard that from a few sources and they are great and the only ones I would consider at this point. They are very easy to get to from my house. Do you know if they take appointments for dyno tunings?

Bret,
Yes you can make an appointment. They charge $175. (At least as of Mar 2005.)