Land of the happy Rotax

[guest207]

Here ya go Rog, before we get that freewind thread totally derailed.

[guest27]

Bugger - replied in the Freewind thread before I saw this one - yadda yadda about the headers, trying to decide on an 860 or 640 cam.

R

[guest27]

Have a couple more jobs to do on the frame and then I need to drop the engine out and pull that to bits - see what I can do to her.  Do not know if they are any good (being as it is Mez Porting they will be brilliant) but I would like a Mez Porting 3 plug 2 carb head - would look really trick and be a bugger to fit...  But I guess there are not many about and Mez is no more.

R

[guest207]

not sure if the info below is any use to you, I stole it from CCM site.

                          OUTLET                                             INLET
NUMBER     OPENS         CLOSES         STROKE       OPENS          CLOSES         STROKE
660           36.5 BBDC    2.5 ATDC       7.9             3.5 BTDC       48.5 ABDC     7.9
665           36.5 BBDC    8.5 ATDC       7.87           4 BTDC          56 ABDC        7.8
670           60.5 BBDC    20.5 ATDC     8.9             13.5 BTDC      67.5 ABDC     8.9
675           74.5 BBDC    30.5 ATDC     9.58           45.5 BTDC      71.5 ABDC     9.65
700           36 BBDC       4 ATDC         6.51           5 BTDC           55 ABDC        5.5
800           55 BBDC      14 ATDC        9.64           12 BTDC         57 ABDC        9.3
805           54 BBDC      14 ATDC        9.64           12 BTDC         56 ABDC        9.64
860           72 BBDC      40 ATDC       10.55          44 BTDC         68 ABDC        10.55
865           65 BBDC      24 ATDC        9.67           20 BTDC         69 ABDC        9.67

PS I think the 675 is the standard road cam fitted to "most" 604 CCM'S

[guest27]

Sorry meant 675 not 640.. ooops

Possibly is, not sure - I know my lump has a 660 cam in it - being as I stole it from a Jawa 500.  Has the 500 barrel but a 2mm shorter stroke and a 34mm Amal - is about as gutless as you can make a Rotax without leaving the head off.  SImple jobs are trying to up the compression and sort a cam / exaust etc.  Picked up a 40mm Amal for it and a couple of cams.  First thought I would like an 860 then found my old artical about MF racer - on which he won many things - and that was running a 38mm Amal and a 660 cam.  OK he was a bit good as a rider - but it really took off when he was riding it (illegally) on the IoM and wondered if the 860 would be too much.  I got it from a guy who had put it in his CCM and decided he did not like it.  So we will see.  First off I have to finish the frame and get the tank welded shut (has interesting carborad base at the moment as I get it to clear the carb.

I have a load of old Andover Norton bumf on the Rotax - not sure if much has changed - similar cam specs to those you have - but not as many - so I guess not much has..

R

[guest207]

Be good to see yours sorted, I keep toying with taking my 636 motor out and sticking it in a Aprillia RS125 chassis. I sort of miss my pure road single a bit. My old SRX620 from a few yrs ago is actually in gallery 1 on here so I am not a total stranger to this place. I have heard the 860 cam is not good for a road bike, makes them a bit too rev hungry and as I like the good spread of power its got now thats about it unless I can find that cheap VM44.
This place does some interesting stuff mixing 600 bore with 350 cranks to get shortstroke 500's.

http://www.barebones.net/machines.htm

And if you want real Rotax porn look here

www.porterbrothers.co.uk

I still have that Forsythe artical too... loved it.

Mick


PS I thought you said 675 anyway.

PPS you DID say 675.

[guest27]

Porter Brothers - just real porn that...

Funny the injection stuff - a couple of guys on the RD500 site have been encouraging me to go FI - cost is a big stopper here - both are fans of Microsquirt/ Megasquirt injection - having mounted it on many cars and now a clutch of Yam strokers.  Have to work within a government funded budget (Incapacity benefit) and feeding a family so most is slow and steady.  Was looking at a RS125 or RS250 chassis when this TZR one came up.  Advantage of the 125 chassis is the RHS drive - hence the RS125 rear wheel for mine - which is being machined as we speak...

Mind I have too many projects on the go and not enough haranging to get them done.. LOL

R

[guest207]

I know what you mean about too many projects and not enough funds..my clutch is naffed on the CCM now, slips like mad when it gets warm and its not a 5 min job like your good old SRX etc but thankfully I have already bought the bits. Turbo is in limbo as I dont want to take it off the road till after next weekend as I need to use it....and the Duc is begging me to buy a pair of 41mm FCR's and a new pair of belts.
Meanwhile the family need food the Mrs wants HER project done...the house!

[guest27]

Here you go Mik - home for a happy Rotax

R

ebay 300108612049   

[guest207]

Here you go Mik - home for a happy Rotax

R

ebay 300108612049   

Arrgghhh why did you do that!... its now on my watch list and my head is going YES NO YES NO!

Was a good job this one wasnt in UK too 160110420003

[guest27]

Mmmm nice - shame Aprilia dont do it them selves - either a 125 or a 250 chassis - same size I think just different construction for the 250 making it stiffer etc

R

[guest207]

Well Cagiva almost done it but lost the plot didnt they..putting a V twin Hyosongythingy engine in for cheapness is just so wrong.

[guest27]

The story of Cagiva - almost done it but not quite.

R

Off to turn some nice steel into swarf and scrap

[guest207]

Off to turn some nice steel into swarf and scrap

Steel? nothing exotic then like a nice bit of ti...or in Fluffers case conduit

[guest27]

Just making an arbor or is it a mandrel? - Cutting back inlet port to the right size and match up with the casting etc - rather than the rough steps etc.  Worked OK - amazing what can be done with a old centre drill and an offhand grinder...

So CG now has a 25.7mm inlet - should be 26 but...  smiles all round.  Mind less smily having found that the liner is only 3.bugger all mm at the bottom so boring it out any bigger may need a new liner and the pot will not fit my lathe.

All this fuss about a CG - but I am learning for the Rotax

R