|
Post by mikea565 on Nov 6, 2007 20:54:02 GMT
Actually sarting to build up the malossi motor now. New bits to go in next week, can't wait to try the zirri short 4th. Transfers partially done but returning to barrel to go bigger on the ports .
|
|
|
Post by mikea565 on Nov 6, 2007 20:55:09 GMT
yes, the left hand transfer does need extra work
|
|
|
Post by pj on Nov 9, 2007 18:17:58 GMT
yes, the left hand transfer does need extra work i wouldnt get too excited bout the zirri short 4th- its just a bit lower ratio. it wont give you anymore power. paul
|
|
|
Post by mikea565 on Nov 13, 2007 17:25:19 GMT
But what I'm hoping Paul, is that it will suit, the Zirri Silent pipe, which I am led to believe creates its power pretty high up the rev range. I'm gonna run 2.56 primary and a malossi with enlarged transfers. Not sure what to do about exhaust port ( as in I don't know what mods are beneficial ) Any tips greatly appreciated
|
|
|
Post by MiNiKiN on Nov 19, 2007 11:12:18 GMT
widen it, the Malossi piston rings can cope with up to 70% port width. Ensure you give it some nice tansition radii.
|
|
|
Post by mikea565 on Nov 19, 2007 12:09:04 GMT
widen it, the Malossi piston rings can cope with up to 70% port width. Ensure you give it some nice tansition radii. cheers so are you saying it can be widened by another 70% of its current width just at the wall of the barrel anf then blended into the port.
|
|
ozzy
Automatica
Posts: 4
|
Post by ozzy on Nov 19, 2007 16:09:42 GMT
minikin means 70% of bore. if your bore was 56mm (125cc) 70% would equal 39.2mm. its a cord width not arc. cord is messured across the barrell not along the circumfrence (arc). you work out a port based on cord width and then transfer the plan into arc widths (maths), map it on a bit of paper, make a stencile, slip the stencile into the bore, mark it out in perm' marker, then get to work with the dremel. if you give me the widths/radius's/degrees of opening, you want, i'll do you one on my 'puter and post the map here?? you can print it out check the messurements didn't get screwed up in printing, and then cut it out.... don't be tempted to raise the exhaust unless your sure the transfers are exactly where you want them; if you then decide that you need more transfer timing and the exhuast is already up you'll be jiggered once the port is up its hard to bring it down, i've tried welding up exhausts and it wasn't pretty wide and low ;D
|
|
|
Post by mikea565 on Nov 19, 2007 17:59:06 GMT
Any mods to the barrel is a whole new ball game to me. I merely want to widen the exhaust port (will this be beneficial if this is done, with the enlarged cylinder base transfer ports ?) .
Malossi has a 57mm bore.
I think (cos barrel ain't here at the mo') that the exhaust port is 39mm wide and this would equate to 65% of the bore , the current out let timing is 169 degrees.
Yours,
somewhat confused and awating further input
|
|
ozzy
Automatica
Posts: 4
|
Post by ozzy on Nov 19, 2007 22:40:00 GMT
i'd appreciate some support as to whether i'm talking cod or what please my notion is that if you've got the rest of your motor to a standard then yes you'll definately see gains from widening the exhaust. you may loose a tiny bit of bottom end but probably not unless you go mad.. what carb/inlet setup are you using? direct reed? whats the transfer timing? 169 is quite low, have you thought about using a packing plate to raise it all up? it's not all that technichal, if you get an engineer to spigot the head instead of machining the barrel then if you don't like it you just take the packing plate out and use a head gasket of the same thickness and its all back to the way it used to be also when you're widening keep an eye on the pegs that locate the piston rings, i don't know about your kit, but on other malossi kits they put the pegs either side of the exhaust port, so your limited as to how wide you can go (unless you want to ask adspeed about putting cut outs in rings). again i don't know about your kit but you need to make sure that when the piston is up around top dead center the psiton skirt still covers the whole exhaust port by at least a couple of mm. cheers, o
|
|
|
Post by mikea565 on Nov 20, 2007 20:25:49 GMT
Cheers Oz, gonna play it safe with wider only so not goin any higher on my virgin voyage. Will take your points into consideration about piston skirt and peg positions aswell as Minikins 70% and transition tips.
Just gonna do a few mm each side and not go too nuts
|
|
|
Post by mikea565 on Jan 5, 2008 14:41:44 GMT
Question: Have I openeed this inlet up enough for 25phbl on malossi reed? its perfectly matched to reed body but wondered if i need to get the dremmel out again while everythings out?
|
|
|
Post by mikea565 on Feb 24, 2008 16:16:29 GMT
casings together after droppin a coin in and havin to split em again . .top end and manifold, just fly and stator to fit
|
|
|
Post by breezer on Feb 24, 2008 16:58:46 GMT
Nice final touch that choke cable Mike! ;D
|
|
|
Post by mikea565 on Feb 24, 2008 17:07:35 GMT
placed on 4 ur benefit jim
|
|
|
Post by mikea565 on Apr 4, 2008 19:13:17 GMT
Just fired motor up tonight, sounds great. Gone for a D26, AQ266, 48 pilot and 110 main but will need to get dyno'd.Hope it doesn't heat sieze with this setup though.
|
|