Considering XJ900 motor into 650 Seca frame... few Qs

Hi all,

Just wanted to thank the stars for this site... already so many questions answered. Awesome!

I'm slowly building my 650 seca into a bit of a cafe/ratter and am looking to get a bit more poke out of it. Make that a lot more poke actually. I've scoured the site and found a few people have said that you can trade in the 650 for the 900 engine, is there anyone who has actually gone through with process, I've a couple of questions (which quite possibly have been answered in earlier posts).

1. Would I swap engine AND gearbox or keep the 650 gearbox? I seem to recall that someone mentioned that the gearboxes are pretty much identical except for a ratio in second.

2. Will the rest of the 650 drivetrain hold up ok with this conversion, keeping in mind I want even more horsepower than stock out of the 900

3.Is the XJ900 Diversion engine from the mid 90s the same as the XJ900 from the 80s, ie. have the engine dimentions/mount points changed?

The reason I ask this is because i've found a Diversion engine for sale... it's 1200 f@#cking dollars (that's Australia dollars though), so I'd wanna make sure it's gonna fit. I've also found an engine from the 80s models too for $440, but this one needs a rebuild... which isn't a huge problem as I was considering getting someone to work the engine anyways.

4. A few posts have mentioned I'd need to "pull" the engine to make it fit... I'm a bit of a hack with this stuff, what does "pull" mean?

Now, I'm not all that handy or DIY, so I'll probably get a workshop to take care of it for me (I know, I know lame huh?) and I guess you're thinkin why not just buy a faster bike instead? Well mainly cause I f@#ckin' HATE the look of new bikes and I like my ride, plus I want a bit of a sleeper and something different...

So is there any Aussie members who can recommend someone in Sydney to give me a hand with this project? Engine builders? Workshops?

Thanks a bunch for your time... sorry for the epic post.

 

You can't change just the gearbox, it's not a Harley. You can probably replace the whole engine but it may require some cutting, grinding and welding.

 

I hope you've got lots of money if you're going to pay someone to swap the engine for you....

 

The Diversion engine is totally different than the 80`s XJ900.

 

Welcome to XJ Bikes Earl, and I'm giving you a thumbs up on the older 900 with a rebuild. I hope I'm right--I believe your problems will be exhaust adaptations, and maybe minor clearance issues--also in the US the 900 was digital tach, not cable--you didn't say what year your 650 was. You'll be at 130 HP with NITROUS ! Add a Maxim rear wheel and you drop your gearing almost 10% depending on the "tyre".
Of course we want pictures !

 

Welcome Earl...

I think you need to go with the 80's motor... the Divi's were a different setup...

Here's another htread about the same topic
http://www.xjbikes.com/Forums/viewtopic ... xj900.html

 

You can't swap the 650 and 900 ... the Motor Mounts don't match-up and there isn't room for the taller 900 Top Block on a 650 Machine.

The 750 shares the same Bottom-end as the 900. That's swappable. I saw a 900 Engine in a 750 Frame on eBay awhile back. It actually fit pretty good.

I have been building a 900 Engine that I want to put into my 750 Max. When I measured the clearance from the top of the Cam Cover to the underside of the Tank ... I would have to "Lift" the Tank at least an inch and three-quarters to get the Engine in there without Mod'ing the Tank ... because the Petcock would be sitting right on the Cam Cover.

This 900 Engine I have been building is For Sale.
PM me for details on a 900 Engine if you want to finish it and try putting it in anything that has wheels!

 

I'm pretty sure there is a thread here somewhere where someone has put a 900 into a 650 frame......its a tight fit but it does go in

 

"It's a tight fit but it does go in."

(Really funny retort edited-out by the Moderator ... who just happens to be me!)

I think that's funnier than what I was going to write, anyway! : )

 

That's for the advice all. I'll do some more research before I plunge in the deep end. Will post photos when/if it gets done. Cheers.