[Spanishish Berger]

I have an An400X 1999, after 12 years and many many miles the engine blew up, crank though the back of the case cutting the rear tyre in half, at 70mph, :?
I replace the engine with a same type/year off Ebay and three days later same thing but without the crank breaking :shock: , I have seen several AN400 engines with this problem and there is one on German Ebay at this moment with the centre of the piston missing so I guess the barrel and head are trashed, same as mine.
Any idea what causes this? I think it's exhaust valve breaking their heads off and cascading to a blow up-
I have rebuilt mine with a vertex piston and rebore to 425cc and a rebuilt second hand head but I don't trust the crank as it had to be trued up and was bent a bit, I'm sure it's till not right as the rebuilt engine smokes and blows out the breather badly. means the piston is not running true in the bore I think.
Anyone got a pre 2004 crank going cheap?

 

[InfernoST]

I can't help you but did have a question, how many miles do you have on it?

 

[Elliott Larron]

For some reasons those Models Under the year 2005 have been Doing that your not the first Case!! i read lots of them on those, under those years Never heard of them happening on the 2007 AN400's Yet?
Something about those Old engine designs that does that.....

Elliott,

 

[Fatjock]

My 2006 400 failed similarly recently, and has done once before......both during sustained high speed runs, three years and 4,000 miles apart. (12,500, and 16,500miles)

Normal use for this bike is short to medium commute, with a short hegher speed burst. Did this with no issues. On a longer, faster run, however..........let's just say results have been varied!


Due to internal debris, I'm going to split the cases during the repair, and when cleaning out will look for possible causes (Blocked oilways, etc.), and take care of anything I see at the same time.

This is the first time I've heard mention of this as a "known" issue.

Interesting.

 

[NormanB]

There have been a number of 400 catastrophic engine failures reported here, not very many in relation to the number of units out there but enough not to class it as a novel failure.

 

[Fatjock]

There have been a number of 400 catastrophic engine failures reported here,.......................

But are all on pre 07 models?
How many occuring during higher speed runs?

............................, not very many in relation to the number of units out there but enough not to class it as a novel failure.

Likewise with the 650 CVT failures, yet I would contest that the reporting and treatment of these are much more widespread, and for want of a better word "famous", on these forums.

I find that interesting.

 

[NormanB]

And I would contend that 650 transmission failures have absolutely no relevance or linkage to 400 engine failures.

 

[Fatjock]

And I would contend that 650 transmission failures have absolutely no relevance or linkage to 400 engine failures.

I did say that the reporting, and perception, of both occurences bore comparison. Not the actual events.

I agree the 650 CVT issues have no relevance to 400 engine failures, but considering both are low-incidence known issues, the level of discussion and knowledge for each is not comparable. That was the basis for my comments.