cx500 / 650

[pagan dave]

Just been on ebay and there's a cx 500 trike thats been "bored out to 650",
my w/shop manual states a different stroke for the 650 engine.
So is an overbore to 650 possible/reliable, or is he spinning a line to get a sale ?
I have my own cx trike to be.

[Mitch]

Just been on ebay and there's a cx 500 trike thats been "bored out to 650",
my w/shop manual states a different stroke for the 650 engine.
So is an overbore to 650 possible/reliable, or is he spinning a line to get a sale ?
I have my own cx trike to be.

Just checked my Haynes book of lies for the CX (not seen the light of day in 11 years) and like you say, the stroke is completely different for the two engines.

The only oversized piston rings I see are 0.25mm and 0.50mm. I somehow think it would take much more than that to get it up to 650cc (not being able to work it out off top of my head, I'd reckon it'd be more like 550cc at most). Unless this bloke's got a secret supply of special piston rings, I would think he'd be pulling folks' legs.

Maybe he's been able to get a pair of 650 top ends and barrels and somehow stick them on - that'd be the only way he could do it (Like I used to do with my z250 Scorpion - it had a top end off the GPz305 as they were the same bike)

[Creature]

also the bore linings are too thin to take 0.50 (which will give theretical 525cc - most went upto 1.0 (550cc)

[Mitch]

also the bore linings are too thin to take 0.50 (which will give theretical 525cc - most went upto 1.0 (550cc)

There you go, Haynes book of lies strikes again :D

[pagan dave]

thanx i thought as much ..........

[Mitch]

Eh up Dave, point us in this eejit's direction and let's have some sport with him shall we? (I get bored on Thursdays...)

[pagan dave]

no problems Mitch just type "cx500 trike" in e-bay search its the only one at the moment, the 650cc bit appears in the questions section at the bottom ,Although he says the log book still says 500.........hmmmmmmmmm.
Any problems the item no is 4524662077.. theres just over two days left Have fun!

[Sir Ewok]

Only other possibility is that somebody has put barrells head and pistons from 650, but the stroke of the 500 is 52 mm as opposed to the 650's 63 mm would leave you with a miserably low compression ratio. Could it have a ringed motor in it with a fake Engine number that relater to a 650?

[pagan dave]

Not sure quite whats he's doing but the cx manual sez that the barrels are part of crankcase castings and non removable. he also sez that he had it "bored out to 650 for xtra grunt"...............Yeah o.k!

[Mitch]

jeez, I remember stripping my old beast down after a firm of 'mechanix' near Mirfield (who are thankfully now defunct) forgot to replace one single o-ring when they put a new alternator in it :mad: (the reason they were defunct, is that soon after they did this I told anyone and everyone!!)

I remember the top end – containing pushrods and all that – being in the boxes and like you say the barrels being in the crankcases (otherwise, how come the spark plugs were so deep inside the top end eh?)

[Mitch]

just had a go me'sen, the rocker covers are definitely Eurosport 650's with the black bit taken off.

It's even got a Eurosport tank on!