My guess is Mr. Burlybilt bought a bike with a sleeper pipe.  But until he looks for the tag we'll never know...  

Great thread here. discovered that my modified 400 came with SP 77! Look forward to trying it on the stock 400 soon.

Chuckw…I put a SP from Meis on my stock DT400C and noticed improved low and mid power increase right away. I’m too afraid to really test upper end LOL.  Honestly when I installed it and took off for the first time I nearly flipped it! I put quite a few miles on the bike before the pipe so was familiar with it’s power. So almost flipped it should warn you to hang on once you have yours installed.

Wow - I love your description of results!
Did you have to adjust jetting or anything else when you installed SP, or just put it on and cruised ?

Martin…I’ve messed with all aspects of the carb so many times that I don’t remember. My best guess is no immediate changes needed. BTW I was so impressed that I wanted one for my 78 DT400E but Meis said he doesn’t make one for that bike. Makes me think the stock pipe on the 78 must already be pretty good.

Wow, that sounds like a great improvement! Will try it out as soon as it stops raining buckets around here.

How does your 78 compare stock to the 400C? I'd like one of that vintage sometime if I come across one,

My stock 78 DT400E isn’t as strong running as my stock 76 DT400C with the sleeper pipe. I didn’t have the 78 when I had the 76 with out the pipe.  

And both are fresh restorations with new top ends. Come to think both are 3rd over too.

Had some nice weather, and finally got to ride the bike and then install the sleeper pipe.  Installed just the pipe first, and it was noticeably stronger than stock.  Then I noticed that the silencer that came with the pipe was modified also - installed that next and it made a difference too.  Bike runs strong with the sleeper pipe and silencer installed!  The bark with the modified silencer is definitely louder, it's obviously different sounding than stock.

One thing I noticed is that the sleeper silencer is a different diameter than what was on the bike. Sleeper pipe and silencer is from a 75, and the pipe and silencer on the bike is a 76.  The 76 silencer is about 1" larger diameter than the sleeper pipe silencer.  Not sure if this is normal, or someone swapped a silencer somewhere along the way, 

Great modification, really wakes up the bike!

Would love to find someone that builds these pipes for a CT3 or a DT2 I'm restoring.

Anything for LT2 ?