Hello, I have been checking out some of the pictures that people have here when I saw yours with that pipe. How long is it? I have talked to a couple people and they have told me that the problem with a 500 is fitting a pipe long enough to work well. How well does yours work? Is there anything that you can tell me about it? I am trying to understand more about two strokes and aside from porting I think that the pipe really adds alot to them.

Thanks
Tom

 

TTT

 

Tom,
Mine is 53" long and 5.4" diameter [img]i/expressions/face-icon-small-happy.gif[/img]. I have it fit in the chassis for trail ridding. It fits fine. We discussed pipes a while ago and I said I would make the next one about 55". Hope this helps

 

Thanks Halfliter, is this the proper way to actually judge or compare pipes when looking at them or talking to a company, by length and diameter? I have tried a few different pipes on this in the past and I know the biggest increase in power came from the porting I had done, but my friends lt250 had almost as big an increase in torque with just a pipe. I wonder if a 500 will ever notice as drastic a change as a smaller motor will from a pipe change.

Also, do you think when build your new pipe at 55" that it will have as broad a powerband? Will everything else about it be the same except the length?

 

No this is not the way to compare pipes. You can have two totally different pipes with the same diameter and length. It's all how steep and long each section of the pipe is. Like I said on mine; I'm going to make it about 2" longer. I'll make one part longer for less rpm's and another part longer and another part shorter to reduce overrev. It will have less broad power but it already has too much broad power so I can get more peak and it will still be very drivable. I did other things to the motor for that. It's all about rider and intended use as to what pipe to use.
I have a KX 500 dirt bike and LT 500. I had an after market pipe for both. I noticed that all four pipes were very close to each other in size and shape. They are two totally different ported motors. Thats when I started wondering how good the aftermarket is. I got more power out of my stock LT pipe than the aftermarket one and the stock one is a real piece of crap. Why are the aftermarket 500 pipes about same size as a 250? They are moving alot more air. Look at how big the pipes are on a 300cc/cylinder snowmobile. I think its neat that you tried different pipes and didn't notice much of a difference. Most people can do 100mph plus when they install a pipe[img]i/expressions/face-icon-small-wink.gif[/img]

 

Thanks again Halfliter, I look forward to hearing about how the next pipe works out. When ever that may be, I know how projects go [img]i/expressions/face-icon-small-blush.gif[/img] . Mine sat for about 8 years and I'm getting it back in running condition. On a side note have you checked out macdizzy.com. They have a two stroke forum over there, geared more towards the motor work. Just one more source of information in case you have not seen it before.

 

Well, I sold the halfliter so I won't be trying my new pipe idea. I still have the cones rolled up but just not fitted. I told the guy that bought it about the over rev concerns. I told him to get a FMF fatty. I don't know what else he could get. He will probably just leave it. It works fine, just dangerous. Did you see my pics of how its fitted? The hardest part was trying to keep the head pipe as straight as possible for as long as possible. Thats important to me.
Anyway, I was checking out Macdizzy. It is a good site for learning about tuning. It seems like DrQ is the god in everyones eyes so I don't post. I don't want to get into a huge argument if I post a different opinion. It happened here once so I don't get too deep. It takes too long to type a explanation of a theory that your not even sure is right. But it is a good place to check out.
Duneaddict, where are you? This was a question for you. I feel like I'm crashing a party. I couldn't help it. It sounded like Tom might have got some bad info on pipes.

 

Sold the halfliter[img]i/expressions/face-icon-small-shocked.gif[/img] , do you plan to get another atv? I hope you plan to stick around the forums for a little while. It sounds like you have some two stroke experience and your own ideas (your heat exchange-changer and your powervalve)and it's nice to have another opinion like that.

Check your pm.

 

I'll be around. I plan on getting a DS 650 X. I was just getting bored with the LT. And dispite popular belief, I was not tired of working on it. It never gave me any of the troubles that everyone complains about. Except the main bearing case problem. I think it was an excellent quad. I'm sick of defending it to people who create their own problems. I do enjoy talking about tuning but its getting hard to find people who are not doing 100mph with a pipe and jet kit next to their buddys Yugo. [img]i/expressions/face-icon-small-wink.gif[/img]

 

Hi guys.... Sorry I've been so quiet... been out roosting sand up in Idaho for a well deserved vacation.

I'm SHOCKED Halfliter!!!! Of course, everything I have is for sale provided my price is met... But a DS??? a 4 stroke??? Are you sure you're feeling okay??? Gosh I'm worried about you J/k...
I know you will be modifying and tinkering the minute you get it... and I've seen a couple of them run pretty darn hard for a thump thump.. And by judging by the mods you performed on the LT, she'll run!

To address my experiences Tom: I am extremely pleased with my homemade pipe. To get technical on the dimensions, i'd have to run to the house and get my specs., but I remember it being nearly 5' long, and fat in the mid section (around 5"). Each section of pipe has it's own dimensions and related function. I was lazy when it came time to fit the pipe... especially since I really didn't know if I would like it's performance. Now that I am confident, I plan to build another 'in frame' to similar specs. There's a tremendous amount of time involved with building one of these.
Is it better than the aftermarket pipes out there.... I think so. The only one I haven't really played with is LRD's unit... but they are no longer available.

two stroke theory in general: It's not just porting, or just a pipe that makes a great running machine. It's the entire setup from air filter to silencer. Components/specs/etc. should be 'matched' to work together as a symphony... so to speak.

I first researched my riding style and needs. What are my intentions and goals for modifications, and what was I looking to improve. The 500 is an excellent platform for an all around performer.
Then looking at the RPM range I wanted my setup to run at...
All these being known, I then started using TSR software to analize carb size, port configurations, compression ratios, head modifications, and even pipe specs. I followed a very conservative route, because I didn't want to hurt my precious LT that has always been very reliable since new.
This winter, I plan to massage things a little further, but as an overall package, my old antique runs surprisingly well compared to a stocker.
So in summary. My ports are matched to the RPM range I'm wanting, and the pipe is also matched for that RPM range.. and it works as a very effective package.

It's really tough to get much info from the aftermarket companies... "What RPM is your pipe setup to run or make peak HP?" It's nearly impossible to tell just by looking at the pipe unless you were to accurately measure and simulate it.
I know Paul Turner has a decent pipe... but all they'll tell you is its an 'all around' pipe, which its supposed to improve performance bottom to top.
I've ran an FMF gold series, and then their 'fatty'.. big difference b/w the two, even though they look nearly identical.

I've read all of Dr. Q's info on Macdizzy's site... he seems pretty knowledgeable, but not sure I agree with all he suggests either. His port specs exceed the max % of bore diameter, which I've always thought was a no-no. In fact, I'm kinda hoping Halfliter would be willing to share some specs/tips, etc. especially since he's 'came out of the closet'... Ha!