Offroadjeepins xs400 café/brat build

[offroadjeepin]

Well picked up my first xs400 this is a 81. Needs a little love but picked it up for $300 so cant complain. Runs okay needs some jetting work but that was planed anyway. So far i stripped the bike mostly down. Got the bars mocked up. Skate board seat pan is on the way. Looking to get TC bros xs650 builder exhaust heard it works on the 400? I do have a lathe so adjustments to collars will be cake.

Here's a few of my current pictures

 

[offroadjeepin]

Fixed pics

 

[xschris]

Welcome to the forum xs650 exhausts will not fit on a xs400. They are larger than the 400's.

 

[offroadjeepin]

Will i be able to use 1.5" pipe? I can make my own collars and flanges. TC bros seems to have the best exhaust kit prices

 

[offroadjeepin]

Did some measuring and it seems the collars and flanges should fit. XS650 is 70mm on centers of studs and my XS400 is damn close. 400 is 1.5" pipe and collar deal is 39mm and 650 is 38mm. The only problem i see is the lenght of collar is 36mm on the 650 and 39mm on the 400. Its only a $10 difference in price between the 650 builder kit and just the pipe kit.

 

[motoTrooper]

Seriously, you've got a lathe, if you have a MIG or a TIG welder, a good saw, and some skills you can create pretty much what ever the hell you want. Might want to dial a bit of back pressure in at the ends or/also plan on some (a lot) of rejetting the carbs. Plenty doable though. Let's see what you come up with!

 

[Greasey Fingers]

Welcome and good luck with the build offroad!

 

[offroadjeepin]

Thanks guys. My shop is pretty set-up big band saw, mig, tig, lathe, press w/ brake, plasma. Was just looking to save a little time by using the that kit. After some more looking I'll prob just piece together a kit from mandrel-bends.com since they have 2-1 collectors. I will be using a shorten MX muffler on the build

 

[xschris]

What mototrooper said I just know a xs650 header wont fit on a xs400 head. I know I have tried With some modding they will work. I would just keep in mind that the xs400 head pipe I.D. is only 1.25" and after the first inch or so it gets even smaller ( double walled pipes). So going to a 1.50" will greatly affect tuning.

 

[offroadjeepin]

So 1.5" 2 into 1 with a muffler is going to have to little back pressure?

 

[offroadjeepin]

Plan is to just make the collars on the lathe.

Any body have a link to a custom exhaust build? I cant find much, lots of 650 stuff. What about sizes seems 1.5" is to big? 1.25 is not a whole lot smaller? See lots of 400's running just head pipes with baffle inserts. There bikes run? Why is 1.5" 2 into 1 with a 450cc motocross bike muffler going to be an issue? I've jetted a handfull of non-stock bikes.

 

[xschris]

The inside diameter of the head pipe will affect the performance of a motor. Guys running head pipes and a baffle at the end are still using 1.25 id head pipes ( most often stock ones). With the xs650 bikes people most often have top put a insert in larger i.d. pipes to restore lost performance. http://www.mikesxs.net/product/07-0769.html I can imagine same results with a xs400. Other issues also might come up be increasing the pipe width. The only way to find out is to do. Since you have never run the bike stock and properly tuned ( you said it has jetting issues) you may end up with a lesser performing bike than what it could be.

 

[offroadjeepin]

Did some looking into "torque tubes". I think i will just use 1.25 tube to help with the loss.

 

[offroadjeepin]

What u guys think of 1.25" out of the heads with 2-1 collector within a fews inches of heads to single 1.5"? So basically a single 1.5"

 

[xschris]

I think if you went to a 1.25 to a 1.5 it would be fine as long as the bike is tuned for it.

 

[offroadjeepin]

Its been awhile since I've posted last. But been busy with other things. Starting to wrench on bike again. Waiting on a few parts. Picked up the left dual from a 06 crf250r still going with 2-1 head pipe. Started on seatpan/tail section. Ordered a honda grom tail light which will fit my needs exactly. Heres a few update pics.

 

[offroadjeepin]

Taillight is here. Its a motodynamic piece. Quality is awesome. Has programmable stop alert and sequential signals. Now i can continue on the tail section.

 

[levdir]

Cool, are you going to flush-mount it inside the box part?

 

[offroadjeepin]

Thats the plan

 

[Wolfe_11B]

Don't know what you decided on with the exhaust, but I just wanted to give you my 2 cents. I recently talked with someone at Cone Engineering, and they recommended me a 1.5" out at the collector. They also said if I wanted to retain any sort of a low and mid range power, then go with a slightly restrictive can or at least one that retains 1.5 in and 1.5 out. I went with one of their 18" reverse megas.