1977 JD300 Exhaust Ideas

[thekingofclubs]

Hi everyone!

As per my intro (http://www.jdsleds.com/community/viewto ... 38&t=17398) I've got this old jd300 that I finally got going again. Unfortunately during my test run my exhaust system snapped clean in half. Now that I've been looking at it I would venture a guess that this is someone's homemade work. I've attached pics for reference. There are several sets of welds along the system that don't look factory. Also, I don't think those flanges are supposed to be there based on what i've seen i parts manuals - can anyone confirm this? I briefly considered just welding the break back together but then I found that the muffler has several holes starting to show. It's time for something different (read: simple). The header is also loose at the connection to the exhaust outlets. Of course I can't get the cylinder cover off to see how it's currently held on there because the stupid flanges are in the way.

Here's what I'm considering:
I'll cut the header right behind the first flanges so I can at least get the cyl cover off. Depending on how the header is attached to the exhaust ports I'm interested in building a dual megaphone system for this sled. The sled is just a novelty item up at the cabin, I won't be trail riding it or anything like that. I can get mandrel bends as well as 18" pre-fabbed megaphones in town here.

My main questions are centered around what will happen to the sled if I do this? I can tell you for certain that the moment that exhaust broke I felt like I lost half the power I originally had. Is this how it will perform with the megaphones? I've read some related threads and see that a plain straight pipe is a terrible idea yet the megaphones seemed to be quite popular on the old racers. Also, what changes can I expect to make to the WDB carburetor? Just mixture screws? I'm fairly new to carb tuning and I had a heck of a time with that walbro carburetor. If I'm going to have to re-jet that might be a deal breaker.

I'm not expecting a high performance machine. Just something fun to ride around on and I really don't want to burn down the engine.

Any input would be greatly appreciated!

Thanks in advance

[Matt]

Yea, that's definitely home made. Megaphones have a science behind their design so you might want to look into that if that's really what you want. The length and bell size affect the tuning of the engine.

[JDT]

My advise would be to post in the classifieds section for a complete 300 exhuast system.

It would be a futile effort to experiment with megaphones on this machine.

When in dought keep it stock.

[JDT]

How could i forget!
Change the crankseals ASAP.

[ljm]

There should be lots of used 300 exhaust systems available. I think I have a spare one if your interested

[Livestock 109]

I've got a few that are in good shape if you want a stock exhaust. There's a few wreckers you could check with too in saskabush. Either would be better than homemade if you can help it.

[thekingofclubs]

Thanks everyone!
I was actually browsing some threads earlier today on how to change those seals. Seems like a no-brainer if I want to keep the thing going. Any good sources in Canada for the parts? Is there a good sticky on doing this procedure? I've got a good harmonic puller for the mag side, but will have to invent something for the clutch side. I've had luck using grease before.

Does anyone have a picture of what the stock exhaust is supposed to look like?

Also if you folks have an exhaust (whole or parts) for this 300 let me know what you want for it, I'm certainly interested. Will save me from having to fab my own.

Scott are you by chance in Saskatoon? Where are the salvage yards you're referring to?

Thanks again

[Livestock 109]

Yes I am actually. I made my own pullers but you might get one at rec supply with the seals I know they sell. Or newbreedparts online if that's better for you.

[croyturbo]

In Saskatchewan I found the best places to get seals and other odds and ends is rec supply in to on town or agri-sport in Regina which ever is handiest.

[thekingofclubs]

Well I got around to cutting off what's left of my exhaust this weekend. Was surprised to see that the attachment to the cylinder is a threaded connection? Should it be like this from the factory? I have a parts manual but it doesn't clearly show the exhaust tube and cylinder arrangement. Is this a part I can still get somewhere?

Thanks

[Steven Rempel]

From all the kohler 295 2ax I have worked with, the exhaust tube is a threaded piece of pipe. what I see in the pic above is what I would expect to see,

the nipple is threaded into the cylinder and the Y pipe slips over the pieces of pipe and held on with exhaust clamps.

295 full exhaust jdx4 jd 300

This is a repair I did to the y pipe where they most commonly fail I find.

hope this helps, this is assuming that you are working on a kohler 295 2ax

[thekingofclubs]

Thanks Steven, the photos help a lot, it is indeed the 295 Kohler. I'll see If i can't find a couple used tubes. If not, surely its something I can have made locally - doesn't look that complicated!

Cheers

[markzrt1]

http://www.ebay.com/itm/NOS-JOHN-DEERE- ... 1b&vxp=mtr

[Steven Rempel]

Might be easier to find a use 300 with a stuck motor and just use it as a parts sled. It's amazing how many parts that can be reused. And cheaper the having made. Also less time spent sourcing parts or pieces needed.

[JDT]

Good advise. One can never have enough spare parts