Hey RFF

Big Bear hasa done mods so his bike isn't stock.


The 1700's come with a 182.5 main which I consider rich but others might not.

Roadie

Stock 1600's came with a stock 165.00 main
stock 1700's come with a 182.5 main BUT the needle is fatter to compensate

Most aftermarket jet kits have smaller jets but skinny needles which allow for finer tuning

in other words a 182.5 main wasnt just put in with the old needle .....THAT would make the carb very rich

I was always under the belief that to meet federal emmisions bikes came from the factory lean and I was worried that changing out the exhaust would make things leaner

But the biggest effect comes with an air intake mod
Exhaust changes effect back pressure and MAYBE slightly air /fuel mixture
Why the change to a larger jet AND needle on the 1700 ??? maybe makes slightly
richer setting and with AIS still meets emission standards?????

And I too would like to know which is it????Rich or lean from the factory????<br><br>Post edited by: Pop Rivet, at: 2006/11/03 06:30

Good job on the respones guys. OK, this morning , before I read you all's advice, I let it warm up for probably the longest I ever have. Temp this morning out my way was 31 degrees (doc's summer temps ). Left the choke on for about 1 1/2 mins. then 1/2 choke for about a min then just idle for a minute or two. And I'm pleased to say that she did not do her recent &quot;cold morning dance&quot; with me! .
Now lets cover the second &quot;new&quot; thing she is doing. Doc has used a phrase that best descibes the problem, and that is at random in the last couple of gears she feels like she is bogging. It does not have a routine for doing this, no backfiring, it just feels like nothing is happening in the power dept. and you can here what sounds like the engine bogging. This occured after the hole were drilled,but it was still plenty warm here in Ga. when I performed that mod. I will admit this too if it is relievent(?).I also adjusted the the accelorator pump screw down on the same day I drilled the holes just to see what the difference would be like, did not like the power results,so I put it back in the original location (3 1/2 turns from the bottom with the nut still on top is what I counted ,so thats where I put it back to).
Alright , I'm finished confessing so....................... Bear

Big Bear, how about putting some tape over the holes you drilled in the stock airbox just to see if it changes anything?

DJ175 main , DJ needle 4th groove , stock spacers in the stock location, stock pilot, pms 3 turns out.

I suspect that you need to go up one size on the main (DJ 180) but consider this ....

If you try and accelerate quickly and the bike bogs when it's still cold then go up one size on the main. If it runs better when cold and worse when warm then go down one size on the main.

Warm means full operating temp. (about 15 of driving).

Doc

Pop Rivet wrote:
And I too would like to know which is it????Rich or lean from the factory????

I think we all seem to have parts of the pie.

You're right, the bike has to be jetted to meet Federal emission standards. These standards set the amount of carbon monoxide, nitrous oxides, particulate matter and volatile hydrocarbons. In the EU they will be probably be regulating the amount of carbon dioxide in the near future.

To meet federally and locally mandated standards the engine must be 'tuned' to minimize these regulated emissions.

So ..... would a stock bike running on the rich side pass? I believe so.

How rich or lean the carb is tuned only partially affects emission values. One must remember that the stock bike has the Air Injection System. The AIS is effective at reducing the amount of hydrocarbon and carbon monixide emitted, effectivley allowing it to pass emission standards.

So I believe the stock bike is jetted slightly rich (which may be reflected in the stuck valve syndrome).

Once you start 'fiddling' with the stock carb then all bets are off. As Pop has indicated, the various different jet and needle combinations can cause all kinds of headaches.

Which reminds me, it's time for a morning pause.

Doc

Just a possible thought to be included in this cold stuttering problem that you have had. You could be getting carbon build up on the rings or in the cylinder walls as well causing your ride to be a bit sluggish in the early part of the ride. A little ring free might help to solve this matter as well. I have heard that some try some Mystery Oil to help out with this.

Just an idea.

clifdog wrote:
Just a possible thought to be included in this cold stuttering problem that you have had. You could be getting carbon build up on the rings or in the cylinder walls as well causing your ride to be a bit sluggish in the early part of the ride. A little ring free might help to solve this matter as well. I have heard that some try some Mystery Oil to help out with this.

Just an idea.




..... and a good idea it is.

Thanks,

Doc

Big Bear,
I kinda wonder if your temporary stuttering problem might be carb icing. Though the carb is heated, It may be that the cold air cools the carb internals, cooling the carb faster than the electric heater can compensate.
-Your bike will run when cold with the choke on (crappy atomization of fuel, but still rich enough to burn)
-Then the choke is turned off when the carb is heated a bit enough to atomize the fuel.
-You embark on your journey, the bike is sucking in lots of cold air, cooling th carb resulting in icing. Fuel and air mixtures are upset. The bike farts and complains, a couple of backfires clear out the ice from the carb.
- By now, there is enough heat generated by the engine to help in heating the carb enough for everything to be again as it should be.
(I know that my old Honda car would not run well in the winter. It would act the way you describe you bike is acting. I eventually modified the stupid wimpy stock air intake so intake air would be well heated by the exhaust manifold before entering the carb. A little isopropyl aclcohol in th gas helped out too. But DON'T use METHYL alcohol in your bike! IT eats metal, hates aluminum, and damages rubber parts.

The bogging issue actually started before the weather got cold,and it does it on its own time schedule, never know when it's gonna &quot;do it&quot;. Jetting is probably suspect since the holes were drilled. Just seems odd, cause I'm sure I'm not pulling in as much air as the BAK, thunder man. crowd. But then again who knows. Didn't get to ride at all this weekend, as I also am a died in the wool 4x4 nut , and was working on my scout II all weekend. We will be getting some good weather here on thurs-fri so I'll play with it then. I also have come the conclusion that seafoam/MMO is a good regular thing to do as maintenance for these rides, so I used the seafoam I had and added it about a week ago to ward off carbon. I'll keep you posted and if you guys have anymore ideas, well , just let it fly. Thanks ,Bear.