| Author | Message | ||
     Puls4521 |
So I'm still trying to get the jetting dialed in on my '98 S1W. It has a force exhaust and forcewinder intake. Currently I have a 46 (cv-performance jet) and 200 main. It has an unknown brand adjustable needle in it from the PO. The needle is currently set at the second richest clip. It runs great in the afternoons when the air temp is around 80 degrees. But in the morning when the temp is down in the low 60's it runs awful. In fact, on the freeway on my way into work (3500-4000 rpm) I have to pull off because the bike will start hanging, and wont pull rpm. All of this leads me to believe that it is definitely lean. My question is: should I order a 205 main, which seems really rich, and work my way from the top down? Or am I completely missing something else? Any advice is welcome! Thanks! | ||
| Phelan |
Are you sure you're not running through the rev range with highest reversion? You will definitely have reversion between 2500-3500 RPMs with that pipe, maybe slightly higher rev range. It's an inherent issue with open 2-1 designs. Take the air cleaner off, start the bike, and rev the gas up through this rpm range. If you see gas shoot out of the carb like mist, it's reversion. Sometimes when riding it's more noticeable than others. | ||
| Phelan |
If it is reversion, jetting won't change it. Changing exhaust or cams can minimize it though. There's a lot more to it, but that's the jist of it. | ||
| Puls4521 |
Phelan, at the expense of sounding like a complete idiot, would you mind explaining, or pointing me in the direction to learn what reversion is? I have been around engines (mostly 2 stroke snowmobiles before this) my whole life, but haven't really every heard of reversion. It may just be because I never had an issue with it! | ||
| Dannybuell |
reversion as I understand it is when the pressure in the exhaust starts working its way back up the system. I don't think that it is reversion, I have a D&D megaphone, correct me if I am wrong isn't a Force sort of a modified megaphone? Reversion suggests timing issues to me. I have a 96 s1 w/ 103K miles. I tuned and tweaked a Keihin over the years. Eventually I broke down and bought a Mikuni HSR42. Big surprise they are better than a Keihin right out of the box. Bigger surprise they are better than ever after dyno tuning! It revs almost as sharply as my injected 1125cr! For a good running engine, timing and the proper amount of fuel is everything. | ||
| Puls4521 |
Danny, yup force is a megaphone. I really should just buy a mikuni, but man they are pricey! The bit about the timing makes me wonder though, I had the cam cover off during my rebuild, I marked the timing, where it was and set it exactly back, but I wonder if the timing needs to be adjusted... | ||
| Puls4521 |
What makes me think it is just lean is the fact that it runs night an day better when the air temp is higher, thus less dense and evening out the ratio. | ||
| Phelan |
I notice the reversion in my bike less in warmer temps. Here's a good read on reversion. http://ds650.org/community/index.php?topic=61.0 A force pipe is an open megaphone. I have two megaphones on my 2-1-2, though baffled, but they are open through the center. Any 2-1 with an open baffle on a Harley, especially with high lift cams (like SE .497s, which are stock in an S1W, or N4s, which are pretty similar, or anything higher than that) will have reversion, even in perfect time. My bike is in perfect timing and dyno tuned, yet it still has reversion because of the cams and pipe design. You can try baffling the pipe to offset the effect some (Force makes a lollipop to put in the end, which will help a little), or you can change the pipe. This is one reason the stock mufflers are so popular, is because they are designed to resonate in such a way that minimizes the reversion in the bike. | ||
| Puls4521 |
That's all really great info. Thanks for that. I'll have to wait for my lunch to read that article on reversion. I have a stock x1 exhaust, to bad that it wouldn't fit. It would be nice to throw it on and see if that cures it. | ||
| Phelan |
No prob. I'm not ruling out a jetting change, but a 200 main sounds right on to me. | ||
| Jayvee |
Could be something tangential, like Intake Seal? | ||
| Puls4521 |
Could be, but those were new at the beginning of the season. | ||
| Trojan |
I think you will find that the more answers yo get the more different they will become, for two reasons........... 1. CV carbs are notoriously poorly made and tolerances are nowhere near as close as something like an HSR Mikuni. What this means is that what works on one bike doesn't necessarily work on another, even with the same exhaust etc fitted. 2. You bike will be affected by temperature, pressure ect where you ride, which of course will be different than other peoples bikes. The bottom line is.....go to a decent dyno centre and get your bike set up properly by taking the guess work out  .............................Or fit a Mikuni HSR42 and be done with it  | ||
| Phelan |
I have a Mik 42 on my bike and dyno tuned. It's sweet and extremely responsive. That said, made no difference to my reversion issue. I'm planning a redesign of my custom exhaust to try to alleviate it a bit. | ||
| Lakes |
I know what reversion is & have always had best results with the simple duel pipe that does not have a baffle & just tapered end like cycle shack make. But with my m2 have never really checked I goes strong or I thought so, with the stock 2" collector header & a baffled sport muffler made here in Australia . But I just fitted the D&D 2.5" collector & seems to have made a good gain in performance .but will wait till I get it to the track. I don't know why people think the D&D overly loud I've always owned Harley's & an old Panhead would make more noise . Also would like to point out I noticed the D&D has like an anti reversion built in like looks like stock diameter as pipe comes from port then a larger diam pipe goes over that so ex gas goes into larger pipe & smaller pipe at exh port helps to cut down reversion also the vacume slide would help some as this is not a straight butterfly carb like s&s more like an su | ||
| Hootowl |
The D&D header has smaller diameter exhaust tubes for the first few inches of the pipes. If I recall, they said it was to maintain exhaust gas velocity in the exhaust ports of the heads to help with scavenging. Their dyno testing showed that their pipe and exhaust made more power across the entire rev range than the Buell race exhaust, and completely eliminated the stock hole in the midrange, or the 'reversion' you're talking about. Made in Texas too  | ||
| Phelan |
Glad the D&D is working for ya John! It is indeed a sweet pipe, wish it woulda fit my bike! | ||
| Lakes |
Thanks Ross, I have been slow to get it on, it has been at my friends work shop in Sydney. I had a 5 hour ride to get there, we fitted the pipe same night then next day took it for a ride too much traffic but could feel a good gain. Am still in Sydney & bike has been waiting for me at friends work shop, will catch bus & train over there in morning then ride 5 hours home let u know what I notice. Also planning more cam as have too much cranking pressure, have the N6 will have to go higher lift, will also put bee hive springs, will have to set it up check valve to valve & valve to piston, that's why I just chose n6, works great with some vP c16 fuel added but I like to ride to the track then ride home so bit hard getting c16 on the road. So have to do this. | ||
| Lakes |
Thank's for that Hoot I enjoyed my time inTexas 14 years back, loved the slogan "don't mess with Texas" Hey the muffler very heavy but built to mount to stock brackets, built to last, just a surprise at the weight. | ||
| Hootowl |
Yeah, it's a tank. But it's built really well. I've never heard of one failing. | ||
| Phelan |
I had a D&D slipon on my last S2. Believe it or not the cap blew off on my way to Snyder, TX and blew all the baffling out, leaving just the megaphone. That was quite a loud sucker! LOL | ||
| Hootowl |
Well, now I have! | ||
| Phelan |
That said, I'm pretty sure it was just a freak accident. I'd get a D&D system in a heartbeat if they had a full system to fit my bike. | ||
| Lakes |
When you have been around Harley's as long as I have ( I'm 66 ) you know anything is possible. I think with a Buell it is important to have a strongly mounted muffler as it is under you. Still I would not change that! As the muffler might be heavy but it's mounted low & it is close to central not up high or over the side of the bike. But I have never thought Harley's were perfect but that's all I know, |
