YZ400E

[James Lee]

Hi,just bought a YZ400E,my question is does the YZ465 have allot more power,I rode a 465 and was quite impressed with the bottom end and also the way it reved,my 400 feels similar to a 250 but without the top end.I think it is jetted rich but I did expect more from it.When I shift early Im sure im hearing a ping.Im very happy with the bike otherwise.Any advise appreciated.Cheers,James.

[holeshot buddy]

the 465 does have more power but not a lot more
if the 400 is set up and jetted correctly it will run great
i borrowed a yz400d 6 years ago for a thunder cross race (evo)
holeshoted and led most of the race was passed by brian flemming on a yz250h
and came second i was impressed with it shit brakes though   ha

[oldyzman]

My 400D went quite well on dirttrackbut it did not seem to rev as hard as a 250.
Did you buy your bike from a guy near Eden?? Cause there was areally nice one there for sale a while ago
Brett

[steveo247]

our yz 400E fly's..! Leaves the yz 250 k for dead in a straight line..

I dont know if it revs as hard as the 250 as my brain wont let my hand turn the throttle that far 

[crossedup2]

James

What you have got for yourself an old style big bore.
Sort out the jetting, timing and most importantly the gearing.
They just love to pull from down low and not like hugh revs.
The reeds and porting aren't set up for top end transfer so learn to live with it. You won't regret it.
One other trick is to find a "D" swing arm and it's super competitive in the pre 78 class. The only obvious changes between D and E was the swing arm.

Good luck with it.

Peter B

[JohnnyO]

James

What you have got for yourself an old style big bore.
Sort out the jetting, timing and most importantly the gearing.
They just love to pull from down low and not like hugh revs.
The reeds and porting aren't set up for top end transfer so learn to live with it. You won't regret it.
One other trick is to find a "D" swing arm and it's super competitive in the pre 78 class. The only obvious changes between D and E was the swing arm.

Good luck with it.

Peter B

The lower fork legs are also noticably different between the D and E.

[Tahitian_Red]

Besides the swingarm and forks the frame is a little different on the E model (slightly lighter and the chain rollers mounted on the frame).

[James Lee]

Thanks for the replies.I bought the bike from extreme VMX in Nerang on consignment.I just checked the timing and not sure exactly,I read a thread on it and the 2nd mark on the flywheel is inline with the pick up which is supposed to be right?I just checked the muffler and I think it was over packed.Ive removed some packing and tested in again and its still very boggy down low,I have to keep it in the rev range but it doesnt have much up top either.Ill check the jetting next.The plug looks clean still after about 45 mins riding time,so it must been lean.The 465 I rode had way more grunt everywhere than this 400,something isnt right.

[valleyam]

James

What you have got for yourself an old style big bore.
Sort out the jetting, timing and most importantly the gearing.
They just love to pull from down low and not like hugh revs.
The reeds and porting aren't set up for top end transfer so learn to live with it. You won't regret it.
One other trick is to find a "D" swing arm and it's super competitive in the pre 78 class. The only obvious changes between D and E was the swing arm.

Good luck with it.

Peter B

Hi Peter
I hope I'm not high jacking the thread, but was interested to know why you would chose the "d" steel swing arm as opposed to the "E" aluminium arm. Is there some handling gain to be made. I have a 250E not the 400E
Cheers Andy

[mitch75]

The YZ 400 D is a 77 model and can run in pre 78.
It has the steel swing arm and 78 alloy.

[crossedup2]

Mitch is right.

The E is not that competitive with bike like the H model. Apart from the minor variations between the D and E, the backwards move puts it at the end of the age group in pre 78.

My bike started as just a bare frame, no numbers stamped on it at all and no swing arm. I actually had a 250E parts bike so most of the critical gear went on to the frame. Got a swing arm from the states and a D and E motors evilbay, both in parts.

I suspect the frame had no number (and no sign of numbers) because I remember back in 1977 a friend had his 400 for about 6 weeks and the frame cracked. Yamaha replaced it at almost no cost. My frame also has a lot of welding all over it so it must be a general problem. I did notice that the engine cradel bracket bolts and all engine bolts need constant checking which would contribute to frame issues. So the truth is I can't tell if its a D or E frame.

It's a lot of fun to ride after racing mainly 125's for the past 3 years and I love the bottom end but miss the top end.

It won't be like a 465 / 490 in power, I have just got an IT490 myself and the power and top end it has is a completely different feel to the earlier 400.

Enjoy!

Regards

Peter B

[mx250]

It won't be like a 465 / 490 in power, I have just got an IT490 myself and the power and top end it has is a completely different feel to the earlier 400.

Which is not necessarily a bad thing. Too much is too much if you can't 'get it to ground' in controllable drive.

If the only difference between the D and E is an alloy swing arm I can't see why the E can't race with the pre-'78's. An alloy swing arm would make 2/3rds of SFA the difference.

[James Lee]

Just had a look at the carb and the needle was on the most lean notch.I now have it one notch from the bottom and the bike is running way better,seems to have a bit more everywhere and a nice brown colour on the plug.Im happy with the way its going now.Im thinking of buying a new exhaust system,can anyone recomend one?Can I run this bike in pre 78 if I change the swing arm?

[shorelinemc]

would have to change forks as well

[cyclegod]

Just had a look at the carb and the needle was on the most lean notch.I now have it one notch from the bottom and the bike is running way better,seems to have a bit more everywhere and a nice brown colour on the plug.Im happy with the way its going now.Im thinking of buying a new exhaust system,can anyone recomend one?Can I run this bike in pre 78 if I change the swing arm?

Here's two exhaust options

http://www.ebay.com.au/itm/DG-Yamaha-YZ-400-D-E-MX-Exhaust-Pipe-08-4413-/200670755141?pt=Motors_ATV_Parts_Accessories&hash=item2eb8e8b945

http://www.geoffmorrisconcepts.com/23/online-shop/133-77-78-Yz-400-Chamber/

My recommendation is to buy local, that way if you damage it you can get it repaired local too.