Will a 1978 YZ400 expansion chamber fit a 1978 DT400?
Also can anyone tell me what the port timing is on a DT400

Welcome to the site TC911,

A XJ400 expansion chamber ???
It's hard to tell if you're being serious . . . . . a HUGE typo ?? . . . . or just being a smart alec ?
I suspect the latter . . . please correct me if I'm wrong !

BTW . . If I thought you were serious, I could give you the port timing in three different ways . . . which would be your preference?

I am serious, I purchased a program from Ian Williams that is suppose to give all the dimensions of a expansion chamber but it’s asking for the port timing.
Any information would be appreciated.
Thanks
TC911

Ok . . sorry for doubting you

Mostly .... what I was suspicious about , was why you ask your first question:
Quote: "Will a 1978 XJ400 expansion chamber fit a 1978 DT400?"

You do realize that the XJ model is a four stroke, and they don't use or have expansion chambers ??
Such a pipe swap would be absurd, not to mention it wouldn't work

.

I did not know that
Here is what my DT400 looks like

Yours is nicer than mine . . . :angry:

Nice bike!

WoW . . Double WOW!! . Nice Bike!
Give me a few days, and I'll get those port specs to you.

But first, Can you be more specific as to what type of information your pipe programs is asking for ?

1. Measurements: . . . from TDC (Top Dead Center) to port openings . . . Expressed in MM (millimeters)
2. Amount of crankshaft rotation . . . from TDC, to port openings ... as expressed in degrees
3. Port opening to closing "durations" . . . as expressed in degrees

I will post it when I get home from work
Thanks

I'm hoping that you or some one can answer these questions
The 2 stroke wizard wants to know if it is

1 or 2 stage diffuser
bore and stroke in mm
port shape and dimensions
exhaust open period in degrees
main transfer open period in degrees
secondary transfer open period in degrees,
Rear boost port open period in degrees,the rear boost port open is the period the transfer slide of the port stays open,not the inlet duration, if it is a combined inlet/boost port lay out
the exhaust port and gasket length in mm
Any help would be a great help.
Thanks
TC911

I will say this...... and you may not like it........ But why in the wide, wide, wide world of sports are you even going this way. You mentioned a fourstroke pipe as a replacement in your first post, so that really makes the light bulb go off in my head. Leave the thing as is and enjoy it for what it is. I am not trying to be mean or anything but what you are doing does not make sense to me. That bike is real cool and I personally would leave it alone. Just so you know......I am not a major Enduro guy. I like the YZ's and MX models.