I removed the engine from the bike and started tearing it down.

this piston has a healthy amount of carbon on the crown.

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time to put the crankshaft installation tool from Deet through it's paces

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here is the Barnett clutch being installed.

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rest of the job was reassembling the engine and putting it in the bike. I will spare you the boring stuff.

I put on the Hooker pipe. I miss that top end too much!

I started the engine afterwards and it did not seem as mechanically noisy as it was before. just a faint ticking that seems to go away once the revs are up. bike runs every bit as well as it did before but this time, no slipping clutch.

I had taken it for a ride. it was about 8:00 in the evening and I ran the headlights on low beam. you can see how well it pulls the 60/55 watt headlight.

I opened it up ran it up to 80 mph in a short space and it put tears in my eyes! it now accelerates hard! it now only seems to slip the tire on occasion as I can feel it doing that. when I had it apart, I found out it has a 13 tooth counter shaft sprocket but has a 40 tooth in the rear.

stock gearing on a DT400 is 14/40 so it is geared down a little than a stock DT400.

at 2:40 into the video, you can see the bike strut it's stuff.

Bassani pipes !! I had one on my Hodaka Super combat along time ago , it made considerably less power everywhere than the stock pipe .

Rich

Bassani on a Super Combat? I noticed if installed on a factory bike with hotter porting it actually makes less power than the factory pipe.

I saw this on my 1970 RT1M but I also have a Bassani on a 1971 RT1B enduro. on the Enduro the Bassani works on that one fine.

on the RT1M it slowed the bike down more than the factory Yamaha MX pipe and the power curve was completely different.

the Bassani made less power from 4000 rpm to 7000 rpm.

when I put on the factory pipe it once again had that cackle and you can feel the bike pick up more once it was on the pipe.

Bassani made a DT1 250 version and it makes more power and better revs than the original Enduro pipe. this was tested on a 1968 DT1.

on the Hooker I had it on a bone stock 1975 DT400, it shifted the power curve up 1000 rpm. the stock pipe would quit pulling at 5500 rpm at peak power. the Hooker would allow it to make peak power at 6500 and it would actually rev up to 7000 but it reacted like revving the DT400 to 6500 rpm with the stock pipe installed.

a stock pipe on this bike kills the revs, it would rev to 7000 rpm but felt like it was not making much power there. it has more power than a DT400 with the stock cylinder from 2000 rpm to 6500 rpm but it starts to fall off as it should be in it's real power curve which is 6500 to 8000 rpm.

did the bike seem down on power to you Racer Clam? this bike is easily the quickest and fastest bike I currently have.

I have a stock 1975 DT400 and this bike can literally run and hide from it. neither of my Honda CR250s can keep up with it.

neither of my RT1s could not keep up with this bike too.

Dave , give me a call some time it would be fun to talk

Rich

it was great talking to you Rich. I am certainly interested in getting the crankcase port, the carb fitted with divider plates and UFO installed and getting a Webco head modded to work with a 400 CC engine and getting the torque grooves done.

here is sme pics of that Webco head I mentioned. it is for a MX360 which has a 80 mm bore and the 400 Yamaha has a 85 mm bore.

the head has a center plug so putting it on a lathe and machining it should not be a problem. the squish area has pits in it like he lost a wrist pin bearing needle or a piston ring broke and was beating around in there while the engine was being ran.

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here is a video I made today since I got a mount for the go pro that will fit on the handle bars.

basically I short shifted to 4th gear, allowed the rpm to drop to 2000 rpm and went WOT. bike does 15 mph in 4th @2000 rpm and reaches 73 mph screaming at 8500. I used the unrestored tach as the face is more accurate than the restored one I had on in earlier videos.

I plan to make another run with the Hooker after securing the Go Pro better and hope to get better footage then I will test it with a stock unmolested DT400B stock pipe.

The engine really picks up the rpm from lugging it in 4th. Reminds me of my brother's 1ST year in the Marines. He shot a video of a helicopter he was flying they nick named "The Frog". The turbines quickly spooled up the large single blade. Wish I still had that video from about 30 years ago.

Great results Bd, what carb and hows it jetted ,?