XT/HL exhaust

[ola_martin]

I'm planning to make a exhaust for my HL-replica, left side style. I have access to 38 and 50mm stainless tube and bends. 38 is too thin. Is 50 mm too big? What will happen to the powerband if I make one? My engine is a SR with 540 hi-comp.

[Marc.com]

in theory you need at least a little back pressure otherwise you will kill the bottom end/mid range and have and engine that is tuned for the drag strip. Bengt probably didn't care about anything except wide open.

[Marc.com]

why don't you use one of Geoffs GMC left side pipes, all stainless work of art mmmm mmmm with built in muffler

Aussies dollar is worth nothing these days so good chance

[ola_martin]

Yes, I could do that, tried to ask him in a previous post here. Probably better to ask him directly.
If so I need to have it whithout brackets and also I need to cut and weld it a couple of places to make it fit, as I've tilted the engine forward and lower compared to stock a HL.
Just that I've made the rest of the bike, so I kind of wanted to make the exhaust as well. But if I need to specialorder the correct diameter tubes (think HL is about 45mm?) it will be better to buy the GMC exhaust, it sure looks beautiful. Geoffs work is very impressive.

[evo550]

My limited understanding of fourstroke exhausts is to start with a smaller dia pipe and taper to a large opening to give you the best spread of power.I would suggest asking the same question in the "Tech help" section, none of the clever people bother with us Yamaha lovers down in the cellar

[shorelinemc]

G`day 38mm is too small and 500mm too big  which are 1 1/2 and 2`` you want too use 1 5/8 tube or 1 3/4  i would only use the 1 3/4  if the engine is a hottie .you can use a small a cone in the inlet side to increase back pressure and  gas speed. info comes from having made pipes for 15yrs at Tranzac exhausts. if you want more info ring me 3821 6777  robin

[Colin Jay]

As Robin has said, 1 5/8" or 1 3/4" are the sizes used for most 500 exhaust I have had on my XT, TT and SR500s, depending on the state of tune of the engine.

Having said that, I am currently making a 2" stainless system from scrap SS bend and tube sourced from work for a XT/SR bobber that I am building. The main problem I found with using 2" tubing was that it basically can't be fitted to the std exhaust port stud. To overcome this I have made up the exhaust adoptor pictured below;



It has been a fair bit of work and the pipe is going to be faily bulky since the 2" bends are so large, but the pipe is being built for the "look" rather than as a performnce mod, so it isn't a major worry.

CJ

[Marc.com]

SR 500 bobbers are big news in Japan.

I have 1 3/4" exhaust for my Daytona head engine, but that is pretty warm

[ola_martin]

Thanks guys!

-Shoreline, I don't understand "you can use a small c".
I would have to get up in the middle of the night to call you, and I don't know how my english would be at that time I live on the other side of the world....

Does anyone know of a good place to order bend and tubes on the net? I can only find 1 1/2 and 2" here in Norway.

Would it be a good idea to start small with 1 1/2 then go to 1 5/8 and then 1 3/4. Also on the stock HL exhaust I think the tube is a bit narrower after the muffler?

[GMC]

The HL pipe won't fit the standard frame but I make a similar pipe to fit the XT / TT frame. The front half is mostly the same, it's the rear section that needs to be different.
Are you using a standard XT frame?
I make my pipes out of 1 3/4" tubing, it's what the original Aberg pipe was & seems to work okay.
I know some guys taper their pipes up to 2' but they are mostly for road racers that want to rev the crap out of them.

[HL500]

Hi Geoff, good top hear from you.

Do you think the exhaust you fabricate for the XT/TT would be quite enough for registeration or is it more like the HL version.

Carn't wait for the HL Kit to arrive mate.

John (WA)

[Marc.com]

quiet enough for registration , what kind of registration as Ii think it would not even get the offroad registration in WA

[DJRacing]

Ceramic coated TT500 pipe.

[ola_martin]

-Geoff, I made my own frame from a Husqvarnaframe. I think the frame it self is close enough that the HL-pipe would fit right on, but I've tilted the engine forward compared to the HL, so that it sits more like in a XT. Therefore the angle to the exhaustport will be wrong. Also I need to place the fittingbrackets myself...
There are some pics of my build here: http://www.adrenalintrip.net/hl500-exhaust/forum/viewtopic/60/291295?siteid=1&topictype=0

[HL500]

Hi marcFX, the question to Geoff related to an XT500 I am currently restoring.  However, as long as I have the necessary lights etc on the HL, I can have an engineering certificate completed and then submit it for rego.  As the HL will have lights etc ist not that big a task, but the cost would have to be justified.  I used to run a YZ465H with full rego on the street.  Great "road" bike and easy to get to the favourite tracks.

John