Restricted XS400 DOHC 1983

That was the most noticeable upgrade. You can see from the graph. That at higher rpms TID12-07 (part nr. 12R-10 #622) ignition angle is constant.
But keep in mind, that to get more power air/fuel mixture flow must be increased.
So 12R intake boots are a must upgrade :)
 
Just to summarize to derestrict - mine is an imported bike from germany, i found out a bit late :-(
1. Intake Boots marked 20KW on the edge replaced with Boots marked with 12R (you can see the restriction if you click on the Picture)
2. Jets changed to: #127.5 on the left, and #117.5 on the right for your mains, #35 for your starter.
3. CDI/TDI unit: from TID12-08 12F-10 to TID12-07 12R-10 (red plate)
4. Camshaft marking (E) - exhaust, Camshaft marking (I) - intake. How to see if it's 45 HP camshafts? Or is this only a SOHC topic?

And does anyone know about the camshafts, how great impact on the power output?
Or rephrased, which one of the 4 issues above has the greatest impact?

Thanks in advance
Great site
Pirok
 

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And if you take out the ignition cover, on the blue, restrictet unit, you will find resistor on the circuit side. On the red, 45HP unit, there is no resistor... I didn't disassemble it more but it may be the only difference
ignition.jpg
 
About the de-restricting of an XS400 dohc.. I'm studying my manual now and I notice this (see picture)
The 12-07 model is for the German models and the
12-08 model is for everyone else.

Can I assume that the 12-07 is the de-restricted model? or am I wrong in my thinking?

With kind regards, new Xs400 dohc owner


Schermafbeelding_2016_01_12_om_22_20_50.png
 
Your thinking is right... but they made a mistake in the manual. I thought the same but then I found out that everything marked with F (cams, ignition 12F-10, carburetor joints) is from restricted model. Look on ebay. You will find restricted ignition 12F-10 TID12-08 (blue) in germany and non-restricted 12R-10 TID 12-07 (red) in USA.
 
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Found "new" camshafts on ebay USA.
As far as I know there has never been restricted models in USA so it's there you have to search.
Recieved them yesterday so looking forward to install them and ride the bike until spring.

Take it easy!
Pirok
 
As far as I can make out, the 12E motor is the unrestricted model, however, my Maxim, is fitted with the 12R motor, (the "R" designating a Restricted motor) having one less gear, in the transmission train, softer cam's, and the restrictor's in the carb's, to bring the motor into the 33bhp, power limit's here in the UK!
However, there may be outher things, that they did, that were not made public, to stop the hoologan elements, from de-restricting there machines, Illegally? As some have tried to do without much sucess, I might add!!! The only way to really de-restrict, these is to fit the 6speed, 12E motor, as they look identical!

Merlin
 
Update on my last post! I have just checked on my TDI Module, it's on a Red plate, (as my bike is a Canadian Import) and it reads TDI 12-07 R12-01, then stamped on the plate what looks like a serial number(?) of 112 or it could well be L12?
So it seems that the restrictions DO go as far as the TDI Unit, after all?
I hope this has been of some help.

Merlin
 
MerlinDudley said:
As far as I can make out, the 12E motor is the unrestricted model, however, my Maxim, is fitted with the 12R motor, (the "R" designating a Restricted motor) having one less gear, in the transmission train, softer cam's, and the restrictor's in the carb's, to bring the motor into the 33bhp, power limit's here in the UK!
However, there may be outher things, that they did, that were not made public, to stop the hoologan elements, from de-restricting there machines, Illegally? As some have tried to do without much sucess, I might add!!! The only way to really de-restrict, these is to fit the 6speed, 12E motor, as they look identical!

Merlin
Click to expand...
You may want to double check your information. To my knowledge, all Maxim's had motors with 5 speed gear boxes, the restricted motors were never sold in North America. My bike has "12R" all over it. Also, the Canadian (and many U.S.) bikes had the German market TCI module 12-07 installed for better performance. I can tell you that there are no restrictors in my carb mounts and that I can rev the engine to the redline in first through fourth gears.
 
OK Dave, I'll take your word for it, However, from my reading from the Yamaha website, I was going on information, I picked up frm their website. I took that information as accurate, but it seems that I was wrong, then?

I'm sorry if I have confused anyone, in thinking that the manfacturer, would know what they were talking about, so it seem's like they don't after all?

I bow to your greater knowledge, of these bikes, Dave, as I have only owned mine for about 9 months, now!

Merlin
 
There is always a possibility that I'm mis-informed, which is why I qualified my statement with "to my knowledge". I'd be interested in reviewing your sources. If you have links to share, that would be great!
 
Your bike is over 30 years old, ANYTHING could have happened to it over 3 decades!

For example, the person who imported your bike could have had it modified to the restricted specification and registered as such. Just installing the restricted inlet manifolds might have been enough to convince a tax collector that it was eligible for reduced rates. Who knows?

Don't get bothered by it!
 
I'm not bothered by it Dave, I was just saying from my reading up on my particular model, and from observations, of my machine. BTW Dave I got mine started for a couple of seconds, earlier today! You were right there were 7 dirty,and loose connectors, in of all places, inside the headlight shell! I cleaned them up, and made sure they had continuity, and then foolishly, used an old and cracked screwdriver, to try Jeff's "Redneck Test" short story I ended up thrown againt my shed door, leaving it hanging by one hinge!
Still I'm glad that she is at least running, (minus exhaust pipes, and clutch cable) Thanks for your help and advice, enableing me to get her running again!

Merlin
 
I know that the topic is quite old and I think everything has already been said, but because I unlocked my xs I made such a summary. The ECU and camshafts I imported from the US (eBay) are taken from a Yamaha XS 400 Maxim. In the US market, they are all unlocked. The nozzles are from Keyster brand carburetor repair kits. Intakes I get new ones from Germany, also from eBay.
Below, all the elements needed to unlock are included in the table with the description.
XS 400 DOHC 20kW vs 33kW.png
 

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