|
Post by kschlotz on Jun 21, 2004 11:06:40 GMT -5
Just got done with opening up the air box. Opened the stock opening bigger so it can not be noticed by looking at it. After trying many different combonations of shims under the needle and main jets, arrived at one shim under the needle and a #85 main jet and cutting the slide spring about 3/8". I did this for my son. He needed better take off speed and was not concerned so much about speed,,,, yet! He says it is great and seems to be happy. The #85 seems like it may be just a little rich yet, so I may open the box some more. He has taken some pride in his Ruckus and installed the bicycle pegs, I likem too. Oh and the sound, well it sounds a little serious now, "Like a real motorcycle" is one comment we have gotten. More to follow, of course, I'm a tinkerer and I also remember the Express that I grew up on and I want better for him.
|
|
|
Post by Tigermon on Jun 21, 2004 16:52:15 GMT -5
great info! I'm wondering what might be a good starting point if running a K&N style cone filter.
|
|
|
Post by Dandy Dan on Jul 6, 2004 17:45:49 GMT -5
It seems to my uneducated mind that your mods would slow your ruckus down. Wouldn't opening up the airbox have almost no effect on the amount of air getting into the engine since the camshaft is the real bottleneck and then by increasing the jet size you made the mix too rich which would slow you down? Maybe i'm way off cuz i don't know much about engines. According to some other posts people found the stock jet to be faster than i higher one so unless opening up the airbox really does have a big effect you'd just be wasting gas and losing speed. Also how did you get it to sound 'like a real motorcycle" ....surly opening up the airbox wouldn't do that? Anyways, all of you can now correct me.... - Dan
|
|
|
Post by kschlotz on Jul 6, 2004 18:30:07 GMT -5
The Ruckus now goes to 30 faster than it went to 20 before. However the 85 main jet is still not enough, I have a 90 and a 95 to be here Thursday for the finishing touch. The main is still lean, in fact we taped part of the whole shut to get by until the new ones get here. It will now do 40 on a slight downhill and 37 on the flat. I and my youngest son rode it and both of us had HUGE eyeballs when we took off on it, real big surprise, Jr. is now doing burnouts in sand in the alley. We stuck a drill in the exhaust the second day we had it also. ;D
|
|
|
Post by Tigermon on Jul 6, 2004 22:20:39 GMT -5
The change in sound is a result of opening the airbox. Bigger jets are needed to get the air/fuel correct when using a less restrictive intake path. To get an idea of what it sounds like, remove the outer cover off the airbox a rev your engine for a few seconds.
|
|
|
Post by Dandy Dan on Jul 10, 2004 0:03:00 GMT -5
Well I stand corrected! I opened my airbox up yesterday and you were right. It does have a lot more growl to the sound and it definately lets in a bunch more air. I took a PVC plumbing pipe and cut it in half and used that to replaced the existing tube in the inside of the box (I used a glue gun to attach the tube). On the outside of the box i used a jig saw to cut out the existing tube and widened the hole. I'm guessing the intake is about twice the size. When i got it back together i was sure pleased until i took it for a ride. Once i reached about 5km/hr the engine sputtered and produced no power due to way too much air getting in. For now i've got the intake 3/4 taped over with duct tape until i can get some bigger jets from the battlescooter store. Hopefully i can figure out how to properly install a new jet. I have no idea what i'm doing. I also purchased a 'feeler gauge' yesterday to check my valves which i'm gonna attempt tomorrow.
Oh and for the person wondering about running the K&N filter: you're gonna get a heck of lot more air just by opening up the box. I doubt you'll need the K&N but hey if you really get 'er souped up then maybe.
Thanks for setting me straight, Dan
|
|
|
Post by Tigermon on Jul 10, 2004 1:11:43 GMT -5
Well, running the K&N would be for aesthetics and the sound. I really don't like the look of the airbox. Also digging around my spare parts I found a 24mm carb that was previously on a souped up Elite 50. It fits the rubber sleeve on the Ruckus intake manifold perfectly. Wonder what size jets would make it work.
|
|
|
Post by abe on Jul 10, 2004 17:39:16 GMT -5
I have been adding to the tech on battlescooter. One of the additions is jetting ;D
I'll post another thread for gauze and foam filters.
|
|
|
Post by Tigermon on Jul 12, 2004 13:05:44 GMT -5
Very good writeup on jetting! I do have a question though, as a general trend, will jet size go up when when using a less restrictive air path? For example, when running an open filter. I've tried to reason through as to why this might be the case but cannot come to any conclusion. As I understand, carbs use the Venturi (or Bernouli, can't remember which Italian it was!) principle of drawing up a fliud when a stream of air is drawn across an orifice, i.e. the jet. Should'nt the carb automatically compensate for the increased supply of air? To rephrase, is the amount of fuel drawn up through the jet constant or is it proportional to the air velocity traveling over it? I assume it was propotional but I don't really know, hence the question.
|
|
|
Post by Dandy Dan on Jul 13, 2004 17:33:28 GMT -5
Hey kschlotz, I was thinking about the performance increase you noticed when you opened up the box and changed the jetting. I am wondering how is it possible that your ruckus now accelerates to 30 faster than it did to 20 before yet the top speed is basically unchanged. My ruckus does 37mph on flat just like you're souped one does. One would think with that kind of power boost you'd notice an improvement in top speed. Perhaps its because of the gearing. Have you tried shortening the variator spacer? I realize you wrote that you're not that concerned with top speed so maybe your carb mods are responsible. Anyways... i was just curious what the deal was. - Dan
|
|
|
Post by kschlotz on Jul 13, 2004 19:26:19 GMT -5
The electronic restriction is the problem now. It takes off very good and bumps the limiter. We are looking to get rollers and the electronic bypass pass out of the battlescooter store when the funds are availible.
|
|
|
Post by abe on Jul 14, 2004 18:11:19 GMT -5
Very good writeup on jetting! I do have a question though, as a general trend, will jet size go up when when using a less restrictive air path? For example, when running an open filter. I've tried to reason through as to why this might be the case but cannot come to any conclusion. As I understand, carbs use the Venturi (or Bernouli, can't remember which Italian it was!) principle of drawing up a fliud when a stream of air is drawn across an orifice, i.e. the jet. Should'nt the carb automatically compensate for the increased supply of air? To rephrase, is the amount of fuel drawn up through the jet constant or is it proportional to the air velocity traveling over it? I assume it was propotional but I don't really know, hence the question. I guess if the carb was small enough. It's not quite proportional. If it's easier for the fuel to stay in the float bowl it will A CV type carb is sort of self adjusting but not to that degree. If you increase the vaccuum and the airflow at the same time jetting would not be needed, but that's crazy talk.
|
|
|
Post by Dandy Dan on Aug 13, 2004 12:57:24 GMT -5
Umm...On the air intake tube that goes from the airbox to the carb there is another branch off of it that is a few inches long and ends in a slighly mushroom shaped dead end. I was looking at this yesterday and i noticed that the end of this tube is cracked. It is a small crack that's not visable unless you bend the rubber a bit to open it up. Basically i'm wondering what the purpose of this dead end branch is and if it's bad that mine is cracked? Replacing it would be a pain so i threw some electrical tape on it for now. Any help would be grand. - Dan
P.S. I'm taking my ruckus in tomorrow to a shop to get the jetting done. I have the jet kit from the store so all i have to pay is labour. Hopefully i'll be setting some speed records soon.
|
|
|
Post by abe on Aug 13, 2004 14:58:15 GMT -5
Umm...On the air intake tube that goes from the airbox to the carb there is another branch off of it that is a few inches long and ends in a slighly mushroom shaped dead end. I was looking at this yesterday and i noticed that the end of this tube is cracked. It is a small crack that's not visable unless you bend the rubber a bit to open it up. Basically i'm wondering what the purpose of this dead end branch is and if it's bad that mine is cracked? Replacing it would be a pain so i threw some electrical tape on it for now. Any help would be grand. - Dan P.S. I'm taking my ruckus in tomorrow to a shop to get the jetting done. I have the jet kit from the store so all i have to pay is labour. Hopefully i'll be setting some speed records soon. That little branch is for volume. It keeps the motor from knowing that intake tube is so small. I would make sure it's all sealed up tight to keep the dirt out You can use bellows adhesive from the marine store to seal it for good! It's the same type of glue Honda used to seal between the airbox and that tube.
|
|
|
Post by Dandy Dan on Aug 15, 2004 16:37:31 GMT -5
Well instead of taking my ruckus into the shop i asked my bro to help me out and together we managed to swap the main jet. First i put in the 90 and it ran mediocre. I don't know how to tell if it's lean or rich so i figured trial and error was the way to go. Next i swapped in the 85. That was definately too lean. I had to tape up 1/2 of the opening to get it running. Next i tried the 95 and it was great off the line but rain poorly above 40km/hr. Now i know that i need to be somewhere between 85 - 95. Currently i swaped the 85 back in and taped it up cuz i'm still playing with the size of my airbox hole. When i originally opened up the airbox i put in a short semicircle piece of PVC tubing to replace the tube in the stock box that ran the air to the middle of the filter. Do you guys think this is necessary or can i just ditch the tube? If i ditch it i can make the opening even bigger. Also has anyone checked out the briggs&stratton filter and the honda mower filter to see how the flow compares to the stocker? My last question is how do i fine tune the air/fuel mix? I don't wanna run around with tape on it forever. Do i have to shorten the spring? I don't really wanna do that cuz i don't really know what i'm doing so i'd probably wreck it. And tips would be super...Maybe i'll have to make the shop visit after all...
|
|
|
Post by kschlotz on Aug 15, 2004 22:55:50 GMT -5
We have settled on the #90 main jet and have the hole in the air box opened at much a possible with it showing on the outside. The tube is also gone, ground it out a drill and a metal cutting carbide bit. Happy for now, electronic restriction will be the next mod.
|
|
|
Post by Dandy Dan on Aug 27, 2004 6:05:30 GMT -5
With my high flow air filter and a airbox that's opened to the max i've settled on a #95 jet and no tape. My scoot is running better than ever. In another thread i posted that it was running a bit rich with the 95 but it turned out that i didn't tighten the jet in tight enough and it was vibrating loose. Good thing i opened the carb up when i did or i could have been stranded.
One other questions: Do you think modifying the airbox intake shaft into something that catches the wind for a bit of a 'ram air' effect would make a difference? I was thinking about cutting off the front side of it and bending (heat gun?) the other sides to form a bit of an air catcher. I realize that at 40mph the air pressure wouldn't be much. Someones should try it.... To order a new airbox cover off of ronayers.com is only 11$ so if it gets too shmucked it can easily be replaced.
|
|
|
Post by Dandy Dan on Sept 13, 2004 14:11:39 GMT -5
Someone wrote that if you make your engine run too lean that you could possibly melt the piston. If i adjust my carb so that my scoot is running as fast as posible am i in danger of this happening? Or do you need to be running extremely lean as in it hardly runs lean in order for this to happen. Any insight would be great.
|
|
|
Post by abe on Sept 15, 2004 6:48:54 GMT -5
If you went down from too rich to get the jet you chose you should be OK. Does this make sense alway start to rich, then go down to what seems to be the correct jet. Ride it at night in cool air. If it doesn't lean out you should be OK You don't want to be able to tell the difference between how it runs in the day or at night. If it's faster at night you may still be a little rich.
|
|
|
Post by nuscootr on Nov 4, 2004 13:52:45 GMT -5
Hiya.
I am about to open up my stock air box and I have tried to find bellows adhesive at a local marine store - they don't know what I am talking about and they are pretty big - 8 branches in this city.
The mechanic at the Honda dealer uses a black silicone called Sili Gasket. Has anyone else used it? Maybe I can use something else?
Thanks for your time.
|
|