Is my XS400 DOHC 12E (UK registered 1982) 45 or 27 Hp

medalpog

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Hello All

I bought an XS400 12E in May. It rides fine but I have always thought is felt a little 'held back'. The bike was registered in 1982, and is as far as I am aware a UK bike (not grey import). My bike has the auto indicator cancel function and the YICS system fitted.

Reading various sites today I discover that a 27hp variant was produced. Is there any way, tell tale signs, engine numbers etc. that will tell me what the HP is?

If I have a 27hp, what is needed to up it to 45hp? Is it just removing the restriction off the carb boot (between the carb and the cylinder heads), or and changing main jets, or and changing the cam shafts?

My other bike is a 1970 175cc classic, so compared to this the XS goes well.

Hope you can help as I have been unable to find any clear guidance on this.

Thanks:D
 
I assume it is a dohc bike, model year 1982 and not just a left over sohc which didn't get sold until 1982 (?)

About a year ago, there was a discussion here on the Forum about the restricted horsepower version of the 400 which was made for some European countries for new riders during their learner or under-age period.

I don't recall how it was resolved but the discussion did involve a restrictor plate.
I imagine that if one has to re-jet the carbs when one installs freer flowing pod filters, then one would have to do the same if one removed a restrictor plate.

Here's an article on the N.American Seca - the engine being the same one used on the Maxim. Unfortunately, no mention of European version - but you may find it interesting. . . Welcome to the Forum.
 
Hi Lou,

Thanks for the info and the link.

I did read a thread on this site but it finished without real clarity (at least clarity for my ability).

Am I correct in thinking that the restriction is in the pipes between the carb and the cylinder head (something to this effect was posted on the tread mentioned above)?

If so, and thinking out aloud, I investigate the carbs and find them being restricted - remove the restrictors, install new 'correct' main jets for 45hp engine and hopefully all will be well.:thumbsup:

Thanks
 
I have no first hand experience with any of this so I hesitate to pretend to be an authority and steer you the wrong way.

I did find a thread which purports to show the restrictor in a photo. Maybe it will help you if you can interpret the photo properly and if you can find the same thing on your bike: http://www.xs400.com/forum/showthread.php?t=8193

Your conclusion sounds reasonable if you find a removable restriction and are able to remove it. However, I don't know if anyone has done so.
Best of luck though and please keep us posted.
 
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