I would really appreciate if you can give me advise on the following.

I own a 2005 Roadstar Silverado 1700. I have put 1200 miles on it. The modifications made are:

- HK 3" straights
- KN Filter in stock airbox
- AIS Plugged
- Stock needle
- Stock main 182.5
- PMS out 2 turns

Before this setup I had the dynojet needle on the 4th groove and the PMS out 3 turns and the bike was too rich.

I typically run in mountain roads, lots of curves, hills and descents, low speed, normally riding between 2nd and 3rd gear. I'm seeing only from 25 to 30 mpg.

The bike starts with the choke but after 10-20 seconds I can push it in and bike idles without problems.

Yesterday I was going down some hills, with the bike just idling in 2nd gear. When I reach the bottom of the downhill I opened the throttle and the engine died. This happened twice. Also on several ocassions, under the same scenario, the engine misfired (similar to when you are starting to run out of gas) and then caught up after quickly moving the throttle back an forth several times.

Any ideas? I would like to get better milleage, what would be your jetting recommendation.

Another question. I'm planning to change my oil to synthetic. With only 1200 miles, is it the right milleage or I should wait?

Thanks in advance for your help. I normally ride in 85 to 95 degrees F outside.

Roadstars are set quite rich from the factory,and my guess is that you are still too rich. To start I would try dropping the needle to the 3rd clip. If that doesn't help, I suggest you get an aftermarket jet kit or even better a Barons BAK which comes with jet kit included.You will see a huge improvement in performance and mileage. The K&N filter you have right now won't breath much better because it is still in a very restrictive stock box. If you decide to go with the BAK most guys would suggest 170 Main, 4th clip on the needle and somewhere between 2- 2.5 PMS. With regard to synthentic oil, I believe most of your break has already occured and you should be OK.
Be careful not to overfill the crankcase. Half way between the hash marks on the dipstick is more than sufficient.<br><br>Post edited by: Topher, at: 2006/09/18 11:03

It seems you may be lean on the bottom end and high on the top end but it sounds like you may have more than one thing going on at a time and your style of riding (mountains - up and down) makes it hard to make recommendations for your current setup.

Remember that the stock needle is somewhat restrictive in its operating range so its hard to do much real tuning and you've added pipes, less restrictive filter and you're at altitude.

You could try dropping the main jet down to 180 and then 175 to see what happens but I'm only speculating on what you'll get for an improvement in performance.

Topher's suggestion to buy a jet kit is a good idea just so that you can get a tuneable needle.

Doc

Thanks for the quick answer Doc and Topher.

I have a Dynojet kit and when I installed the pipes I put in the supplied needle with the clip on the 4th groove. The milleage was very bad (~20 - 25mpg) and I thought that was the cause and I removed it and installed the stock one. The only thing I still have installed from the dinojet kit is the pilot jet, I think its a 40. (The instructions in the kit ask for the installation of the needle, the pilot jet and the 190 main jet for stage I).

Even though I mentioned I ride in the mountains, it is probably 40% of my riding. It is in Puerto Rico where the highest elevation is approximately 4000 feet.

One question, If I'm too lean on the bottom side, would I expect backfiring when I close the throttle? I have not experienced backfiring with my bike and that leads me to think that I might not be lean there.

Another question, what is the rev limit for these bikes? I tried to make the wot test but either the bike started misfiring or I hit the limiter.

Another piece of information. This weekend I pulled the plugs and they were very black covered with sooth.

Thanks again. This is an excellent information source.

The only thing I still have installed from the dinojet kit
is the pilot jet, I think its a 40.

If you went back to stock on everything else I would go back with that too. One thing you could try for the stalling is adjusting the accel duration screw in a half turn at a time. Maybe it is getting too much of a squirt and it is flooding it out. Or maybe it isn't getting enough of a squirt and you need to go out a half turn at a time. Just something to try anywho.

CAPR06 wrote:
I have a Dynojet kit and when I installed the pipes I put in the supplied needle with the clip on the 4th groove. The milleage was very bad (~20 - 25mpg) and I thought that was the cause and I removed it and installed the stock one. The only thing I still have installed from the dinojet kit is the pilot jet, I think its a 40. (The instructions in the kit ask for the installation of the needle, the pilot jet and the 190 main jet for stage I).

The #40 is much too big and that may be your main problem. Go back to the stock #35.

Even though I mentioned I ride in the mountains, it is probably 40% of my riding. It is in Puerto Rico where the highest elevation is approximately 4000 feet.

To go from sea level to 4000 ft means your bike will run rich 40% of the time. You're going to have to move to the midwest. For example, if you were to run a 170 at sea level, you would need a 162.5 at 4000 ft to compensate for the less oxygen at higher altitudes.

One question, If I'm too lean on the bottom side, would I expect backfiring when I close the throttle? I have not experienced backfiring with my bike and that leads me to think that I might not be lean there.

You have a mix of carb settings so its difficult to know what's what. For the HK 3&quot; straights and K&amp;N Filter in stock airbox I'd recommend that you start with ...

- DJ 190 (have a 185 and 180 on hand to try out)
- stock #30 pilot
- DJ needle on 4th clip
- PMS at 3 out

Do the WOT test to tune in the main and then you can do the needle.

Another question, what is the rev limit for these bikes? I tried to make the wot test but either the bike started misfiring or I hit the limiter.


When you hit the limiter it feels like bikt is missing so I don't know. To do the WOT test, don't let the bike run out to the limiter. Put it in third or fourth, crack the throttle about 3/4 and when she's almost wound out, back off the throttle slightly. You shouldn't hit the limiter this way.

Don't forget to read this article http://roadstarclinic.com/content/view/94/96/

Doc

Thanks for the advise guys. I will open the carb tonight and make the changes. I will try your settings Doc. I had a feeling that the pilot jet was screwing up the gas milleage will start with that. I will take it for a short spin tomorrow and see how it behaves.

Thanks again and I'll let you know the results.

Wow, how time flies by!. Now I realize that it has been almost one month from the last post I made and it was yesterday when I tried the modifications recomended by Doc.

When I opened the carburator I found that the pilot jet was actually loose. I could remove it by hand without a screwdriver. I believe that part of my problem was that the fuel was bypassing the metering hole in the jet through the threads.

I reinstalled the original #35 pilot jet. Also installed the DJ190 main and DJ needle with the clip in the 4th position and set the PMS at 3 turns.

I did the WOT and experience no change at all when closing the throttle i/8 of a turn. Does this means the main jet is OK? I still see high fuel consumption, around 25 -30 mpg. I was planning to change the needle clip to the 3rd position or even reduce the main jet size. Which could be a better alternative.

I still see black sooth in the pipes, although less than before the changes. I'm planning to remove the plugs to see how they look.

Any comments will be greatly appreciated.

You need to fine tune the main first.

I know it's pain but put the DJ185 in and repeat the WOT test. If necessary repeat until you find the ideal main.

You'd doing good, it usually takes me a year to get to things. Actually it's been 5 and my kitchen cabinet doors are not yet finished.

Doc

Thanks Doc. I'm getting very proficient removing the carburator and changing the jets. The best thing I've done in my bike is changing those weak factory screws that hold the carburator bowl in place with hex screws. I think I could probably change the main jet without having to remove the carburator from the bike.

Another question: Should I leave the needle on the 4th slot?

Thanks again for your help.

On the kitchen cabinet doors, use a small cloth curtain in the meantime. I will buy you time to keep riding........ and you can change the pattern depending the season.......