new filter and exhaust so i need new jets.

[IanDMacDonald]

What you could do is not cut-off the "ugly" Harley pipes, and tune with them till you gain enough money for an alternative. The Harley muffs provide the back pressure the engine needs.

[skids]

There are those that somehow got straight pipes to work. Review the threads. A free-flowing set of pipes can have you chasing your tail trying to make comensating carb adjustments. Just tryng to help you save time and money...especially time. As I see it, 4 cylinder engines are different than 4 cylinders because of reflection pulses coming back to the head as the exhaust valves open - twice as often with 4 cylinders. You will be trying to overcome the laws of physics with straight pipes. Unfortunately, supplies of descent exhaust systems are limited...

[Schming]

I have a silly question: Straight pipes w/ baffles? Is that not a contradiction? Or am I a little ignorant as to what straight pipes are?

Not a silly question at all Ian, HD's run them everyday, as they also need some back pressure that Nate has stated.

There's a lot of riders that want the loud pipes, both American and Metric, but the pipes need tuned with some sort of baffle to achieve a well running engine throughout the rpm range.

[MPittma100]

Fuel/Exhaust

You will likely run into some issues with the straight pipes that you may not like as has been suggested.

Another way to make the fuel curve richer is by adjusting the needles in the sliders to a richer (notch) position. From the standard center notch there are 2 richer and 2 leaner notches. Upper notches are lean. Lower notches are rich.

By adjusting this, you may not have to change the jets at all. Don't change anything until to you read the plugs as you will need a starting point.

One bike that I was into that had a modified exhaust and air intake had the needle clip moved to the one-rich position using the OEM jet. It was getting plenty of fuel. The exhaust was a 4 into 1 header with muffler.

[D0wn5h1ft]

Don't let them get you down, man . I went on a quest with my '79 to put some dual macs on for an exhaust and could never get them to run right. Ended up taking the slip ons off and went straight pipes with a set of '80 Midnight Special carbs, stock jetting and it runs like a champ.

If you're looking for some advice on getting straight pipes to work, you might run into some resistance here. I "stumbled on" the answer just out of dumb luck. For some reason 4-2 straight pipes, those '80 carbs w/stock jets, and velocity stacks makes for a good combo (at least on my bike). For you, I would start your tuning process by leaving everything, carb wise, stock and seeing how it runs. THEN take a look at this guide: http://home.everestkc.net/malsin/Mot...theory_101.htm

It will walk you through how to do a standard carb tuning process. Everyone has their own way of doing it but I've found this guide is pretty comprehensive. But WHO KNOWS, you might get lucky like me and not have to change anything!

[Rasputin]

All I have to say about the people that don't like what I'm doing is that I'm asking for help not criticism. The bike is way beyond bringing back to anything close to stock. I'll post some pictures. And keep in mind i got the bike this way without a title.

You might want to try to get a title before you go on with very much. I would be a shame to put money and effort into something you can not ride.

[crazy steve]

The problem with straight pipes is you can tune them to run well, but only in a narrow rpm range, generally at the top of the tach. Performance will suffer badly everywhere else. Even the Harley guys have learned this lesson, what with 'torque cones' and washer fixes.

If you're trying to do this for a $1.98, sell the bike now and save yourself the aggravation. But for these bikes to run right, you have to have some sort backpressure in the exhaust and mufflers do the best job. Stock Harley mufflers are a popular choice as they can usually be gotten cheaply as take-offs and have the 'right' amount of backpressure (or at least pretty close). There's a ton of exhaust/muffler threads on here, from high $$ stainless steel to 'I found these mufflers on the side of the road, will they work?' types, pick your poison.

DOwn5h1ft, all I can say to you is you've been lucky so far. The '80 bikes were lean from the factory, with open exhaust and stacks I can't imagine how you haven't sent a piston or two out the exhaust...

[IanDMacDonald]

You might want to try to get a title before you go on with very much. I would be a shame to put money and effort into something you can not ride.

I missed that. Excellent point!

[DGXSER]

I have to agree that Downshifts bike is a freak of nature, must be more to it than meets the eye. There is just no way one of these engines is running right on stock jetting and plain open pipes.

As to tuning one with straight open pipes, I won't say it is impossible, bit it is just this side of it. Many MANY MANY have tried, and failed. Many have come on here asking for help with getting it to run correctly, had very knowledgable folks tell them they need some back pressure, and then get their panties in a bunch over folks "picking on them" or "hating on them" or criticizing. In reality, these engines just plain do not run at all well without some backpressure. Toyota Corolla we had was the same way. Pipe in front of the Catalytic rusted out, thing ran like crap. Fixed the pipe, ran like a scalded dog.

Anyway, tuning for the setup your after will be trial and error. Start out at least four sizes up on the mains, and a couple on the pilots IMHO. See how the plugs look from there. OR get a colortune to see what is going on at what RPM in there.

[IanDMacDonald]

Gabe- I'll race you one of these days, lol. Your free-flowing bike against my piddly stock exhaust

[Schming]

I'm not telling anyone to f-off. I'm just asking for help. look at the bike. I don't really have the $$ to put on a full new exhaust. I'm trying to work with what I have. So I thought it would be a good idea to just cut off the old ugly Harley muffler that someone else welded on. Now if the straight pipes don't work what could I do to solve my problem. So far most if the replies have been helpful.

I agree your bike is a little rough around the edges and a good candidate for a custom. With that said, what has been stated already, pertaining to the title, might be first on the list. I'm not familiar with the laws in your state so you would know best.

Can you get the title ?

Here's a site with some videos of their exhaust components on different bikes:

http://www.coneeng.com/product_videos.html

Not all the site is working for me as I believe they are still building the new site. It's changed since the last time I visited less than 6 months ago.
There is contact info available though if you decide to fabricate your own exhaust and need more info.

[D0wn5h1ft]

Gabe- I'll race you one of these days, lol. Your free-flowing bike against my piddly stock exhaust

Challenged accepted. I better get on that rear fender bob to cut down on weight!

If anyone remembers, I had an unnaturally rich condition in the top end with dual macs+pods+stock 80 carbs so I had two options: go down on the mains or take those cursed slip ons off and run straights. Obviously, I elected for the latter (mostly because I love straights). I'm still skeptical about this "needing backpressure" thing but if these guys say it's true then there has to be merit to it.

I will have to add, though, I HATE tuning these bikes. Hate it, hate it, hate it. It's no fun, they're finicky, the late model carbs don't have needle clips, they don't like non-stock intake or exhaust options, and did I mention it's no fun.

[skids]

I will have to add, though, I HATE tuning these bikes. Hate it, hate it, hate it. It's no fun, they're finicky, the late model carbs don't have needle clips, they don't like non-stock intake or exhaust options, and did I mention it's no fun.

I think you were ready to grenade it. It's good that you finally got it going.

[IanDMacDonald]

It could be worse Gabe, it could be like Sparkfly's "Excelssior". He ALWAYS has issues with that thing! Poor guy just wants to ride, lol.

[MPittma100]

Tuning

The problem with straight pipes is you can tune them to run well, but only in a narrow rpm range, generally at the top of the tach. Performance will suffer badly everywhere else. Even the Harley guys have learned this lesson, what with 'torque cones' and washer fixes.

If you're trying to do this for a $1.98, sell the bike now and save yourself the aggravation. But for these bikes to run right, you have to have some sort backpressure in the exhaust and mufflers do the best job. Stock Harley mufflers are a popular choice as they can usually be gotten cheaply as take-offs and have the 'right' amount of backpressure (or at least pretty close). There's a ton of exhaust/muffler threads on here, from high $$ stainless steel to 'I found these mufflers on the side of the road, will they work?' types, pick your poison.

DOwn5h1ft, all I can say to you is you've been lucky so far. The '80 bikes were lean from the factory, with open exhaust and stacks I can't imagine how you haven't sent a piston or two out the exhaust...

+1 on the narrow performance window. Open header/pipe is for one thing mostly - Drag Racing. And even then you may need a little back pressure. Been there - done that.