tony27 Posted October 15, 2009 Report Share Posted October 15, 2009 http://cgi.ebay.com.au/ws/eBayISAPI.dll?Vi...em=300355639223 Hope this link works, see its even in the right currency Quote Link to comment Share on other sites More sharing options...
shercoman2k8 Posted October 16, 2009 Report Share Posted October 16, 2009 <Do they have the part that needs ground off? My guess here is yes.>It does not HAVE to be ground off....(that's just a great mod that Cope's working on). But a hand file will easily file down a small ridge that's on the underside of the bowl (where the overflow tube comes out)....that would be advisable. Best of balance. Neo On my keihin 28mm, there was a lug that needed ground right off for the carb to fit on the bike... Is this not on the OKO too? http://cgi.ebay.com.au/ws/eBayISAPI.dll?Vi...em=300355639223Hope this link works, see its even in the right currency Cheers! Was expecting some stupid price, they look quite smart... Going to invest in one me thinks. Quote Link to comment Share on other sites More sharing options...
neo Posted October 16, 2009 Author Report Share Posted October 16, 2009 Hi shercoman, If you use the plastic bowl it will fit without filing. But it will fit a little easier if you file a mm or two off of the the bowl overflow vent lug...underneath the bowl.....you'll know what I mean when you get the bowl. Do not file the plastic (fake) bowl nut as that will weaken the bowl. And if you twist the carb just slightly anti-clockwise in the rubber block the nut should not touch the gear case. In my experience, if you secure the carb all the way into the rubber manifold the bowl/vent/lug will always rub against the gear case....But after you have fitted the carb you can slide a thin coin in under the bowl vent/lug and that will stop the gear case wear. Best of balance. Neo PS...And after riding for some time now with my OKO26.....I'm not missing my 28mm Keihin one little bit Quote Link to comment Share on other sites More sharing options...
copemech Posted October 17, 2009 Report Share Posted October 17, 2009 Getting back to all this, I ran the 24 on two test runs last Sunday. The actual fitting is a bit of a bitch on the '07, as the tank is different form the '06. Everything is a cram! But it does go! Started and ran good initially, then had some odd running. Seemed a bit rich in the 1/8 range with the needle in mid position. So I stripped it again and did manage to at least spot a flek or two if metal in the bowl that the air blower had missed after all the grinding and cutting. Dropped the needle back to the top notch as per Marlintec spec and took it out for another run. Ran well and settled for 1.25 turns on the airscrew with the 45 pilot. Progression was good with just a slight hint of ping at about 1/8 coming onto the needle. Not bad. Still seemes to rev out fine, yet even the 112 main as installed is a bit rich to go into hypersonic mode, which is good! All said, seat of pants reaction to me was very similar to the "well massaged" dellorto 26, with a bit better low end control in the small opening range, and possibly a bit less hit on the mid to upper range which would flatten the powerband a bit. Mind you, mine has the timing set back already, which makes things slower throughout the range, the carb did not really change this overall, which tells me that it(timing) is the current limiting factor. As the "slow dog" 2.9 pretty much runs as a slow 250, I may now bump things up just a bit to the mid range of timing, 3mm slow of stock, just to quicken things a bit and see how things feel. Needle may go back to second groove, one change at a time! Overall, there does seem to be some good workability here within the range of the 24, and as Neo stated early on could become the carb of choice for many seeking better control in the sections! Quote Link to comment Share on other sites More sharing options...
ikb Posted October 18, 2009 Report Share Posted October 18, 2009 NB...the new OKOs come with an angled throttle cable tube (the tube/cap on the Keihin on this photo). Which is great but this does not unscrew like the previous carbs and the Dellorto. This may lead to cable/wire length and cable adjustment issues. I'd guess you could partly correct this by using one of those universal replace throttle wire kits. But I'm not sure how you could introduce an inline cable adjuster. If your converting from a Keihin or an older OKO just use the cap off of there. Get one of the Amal alloy twist grips they used in the 80's they have a cable adjuster built in and look more durable than the Dominos we all use. I have one on an old Motesa Ive just bought and it looks fine. they are available from most Twinshock specialists Quote Link to comment Share on other sites More sharing options...
neo Posted October 24, 2009 Author Report Share Posted October 24, 2009 (edited) Needle may go back to second groove, one change at a time! I moved the clip to the top grove today and there was a marked improvement (smother) moving off the bottom (as it was a touch rich on a hot engine).....but that might have been caused by the Boyseen reeds i'm running too. But what I don't understand is WHY? ....according to those Keihin graphs the need shouldn't effect the mix until 1/2 throttle or so....Can anyone explain why this works at all at low RPM, first 1/8 throttle? Also, I have discovered that if you use a Keihin metal bowl on an OKO carb that the bowl nut hits up against the base of the stem (the bit that holds the Pilot and Main jets) quite hard. The nut either has to be ground down (on the inside) or it might be best just to use a plastic bowl. Or make sure you get an OKO with a plastic bowl already on it. Best of balance. Neo Edited October 24, 2009 by Neo Quote Link to comment Share on other sites More sharing options...
copemech Posted October 25, 2009 Report Share Posted October 25, 2009 I moved the clip to the top grove today and there was a marked improvement (smother) moving off the bottom (as it was a touch rich on a hot engine).....but that might have been caused by the Boyseen reeds i'm running too.But what I don't understand is WHY? ....according to those Keihin graphs the need shouldn't effect the mix until 1/2 throttle or so....Can anyone explain why this works at all at low RPM, first 1/8 throttle? Also, I have discovered that if you use a Keihin metal bowl on an OKO carb that the bowl nut hits up against the base of the stem (the bit that holds the Pilot and Main jets) quite hard. The nut either has to be ground down (on the inside) or it might be best just to use a plastic bowl. Or make sure you get an OKO with a plastic bowl already on it. Best of balance. Neo That is correct, in that the needle range should take effect at about1/8 range and may effect the smoothness of transition by dropping it. Yet on mine, I pisked up the pinging a bit too much again, so I settled for second groove, which seems ok. all a tradeoff it seems! Quote Link to comment Share on other sites More sharing options...
tony27 Posted October 26, 2009 Report Share Posted October 26, 2009 Had an interesting talk with the original sherco importer here who is one of our top riders, he said that he removed the vent hoses on his cabestaney's keihin after the carb started playing around & found the issues were cured. He hasn't replaced them & recommends not running hoses if possible. When my oko turns up I think I'll not fit them at first & see what happens Quote Link to comment Share on other sites More sharing options...
neo Posted October 26, 2009 Author Report Share Posted October 26, 2009 (edited) When my oko turns up I think I'll not fit them at first & see what happens Go for it Tony. But unlike the Keihin the OKO is not effected by the tubes....I've tried it both ways and there is no difference at all on the OKO. Best of balance. Neo Edited October 26, 2009 by Neo Quote Link to comment Share on other sites More sharing options...
tony27 Posted October 26, 2009 Report Share Posted October 26, 2009 I've got a couple of thoughts on how to get around the lack of room between vent & muffler(not as extreme as copes) to try, working in a toolroom & having a understanding boss helps. Have to get the ankle & knee I damaged 3 sections into our 3 day nationals right first so the testing will have to wait. Bike ran like a charm the 2 & a bit days I managed but still not sure the plug cap was the cause of the lack of spark a few weeks ago Quote Link to comment Share on other sites More sharing options...
copemech Posted October 26, 2009 Report Share Posted October 26, 2009 I've got a couple of thoughts on how to get around the lack of room between vent & muffler(not as extreme as copes) to try, working in a toolroom & having a understanding boss helps. Have to get the ankle & knee I damaged 3 sections into our 3 day nationals right first so the testing will have to wait. Bike ran like a charm the 2 & a bit days I managed but still not sure the plug cap was the cause of the lack of spark a few weeks ago And you see , this is where I am unsuer if they have even modded (drilled out ) the carb on the cabby to run dual vent at all, and if they are just running the one tube on the muff side and or a looped over(or blocked) overflow tube, you get into trouble. Quote Link to comment Share on other sites More sharing options...
neo Posted October 26, 2009 Author Report Share Posted October 26, 2009 I've got a couple of thoughts on how to get around the lack of room between vent & muffler Hey Tony, so you don't like my spring-on-the-tube trick It will be great see what you come up with Best of balance. Neo Quote Link to comment Share on other sites More sharing options...
tony27 Posted October 26, 2009 Report Share Posted October 26, 2009 (edited) And you see , this is where I am unsuer if they have even modded (drilled out ) the carb on the cabby to run dual vent at all, and if they are just running the one tube on the muff side and or a looped over(or blocked) overflow tube, you get into trouble. We didn't get into the fine points of the caby carb other than removal of the hoses work wonders & that it wasn't due to clearance. I think the caby carb has the normal vents of any factory fit keihin, not sure if that means dual vents or not. Are the second vents normally drilled on the left/choke side like you've done to the oko? Don't remember seeing anything that side today Hey Tony, so you don't like my spring-on-the-tube trick It will be great see what you come up with Best of balance. Neo I just like tidy/elegant, guess thats the toolmaker/ocd in me My thoughts basically revolve around turning up a outlet to fit over the vent to rout the hose at a 90deg angle much like the dellorto has, fitting the dellorto angled vent is also a possiblity. Both things will let me play with where any hose I fit runs Once I've gotten my carb & done the mod I'll post a couple of pics Edited October 26, 2009 by tony27 Quote Link to comment Share on other sites More sharing options...
neo Posted October 26, 2009 Author Report Share Posted October 26, 2009 Hey Tony, Neat is good But my guess is it not so good to have a sharp right angle (like the Dellort) there. I have no figures with air but I know with water pipes one that 90deg bend is the equivalent of 7 meters of straight pipe in terms of drag/resistance. I'm just a bit concerned that all your work may be in vain. Because the OKO is fine with or without a short tube anyway. You might notice from my photo above that only the Keihin has dual vents. The OKO's only have the one on the muff side. Best of balance. Neo Quote Link to comment Share on other sites More sharing options...
trialsnutterman Posted October 26, 2009 Report Share Posted October 26, 2009 The Cabestany replica I had only had the left hand side breather drilled and it used a breather pipe made out of plastic that melts, so it would melt shut when hot. I think this is the main reason why it is better to run without the breather or better still drill the right hand breather out and run two non-meltable breather pipes. If there is another reason for not running the breather pipe I'd like to here it. Quote Link to comment Share on other sites More sharing options...
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