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Camshaft Bearing Seal http://ducatittandf1.com/viewtopic.php?f=10&t=12071 |
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Author: | 583 [ Sat Jan 23, 2021 11:08 am ] |
Post subject: | Re: Camshaft Bearing Seal |
Hi Desmorob Wow that heads are a work of art! Intersting shape they give to the inlet duct. Please Keep us updated!! Ciao Filippo |
Author: | 618F1 [ Sat Jan 23, 2021 2:17 pm ] |
Post subject: | Re: Camshaft Bearing Seal |
The JRP heads look very nice, and I knew they were doing this again. Now I see valve sizes up to 43/36 from the 42/35 that they did before. So, I have some concern, especially if you think you are going to use P cams (is that what you have?) from a SM: What is the distance in mm between the valves at rest in their seats? If it is not 5.7 to 5.9mm, or more, then there could [will] be a problem with V-to-V contact. This always seems to surprise people. 4.5mm or a bit more (stock) will let you use two H 900ss or ST2 cams, but not any of the old style"race" cams. I have just finished a set of 900 heads using Montjuich (P) cams with 5.8mm resting clearance and I ended up with .022" moving clearance on both heads. Going to test the limits on this. Posting soon in the TT/F1 string. MikeV |
Author: | Desmorob [ Sat Jan 23, 2021 3:07 pm ] |
Post subject: | Re: Camshaft Bearing Seal |
Thanks for the info Mike! I can't measure completely accurately with my calipers but it looks to be approx 4.8mm between the valve OD's in the head. I'm building them up and when I get the right shims I guess I'm going to find that I can't turn the cam over because the valves clash then? That's a bummer. But better to know now. I'll let you know. Modern cams will also need machining to fit the old style right-hand side bearing arrangement I guess? Cheers Rob |
Author: | graeme [ Sat Jan 23, 2021 4:52 pm ] |
Post subject: | Re: Camshaft Bearing Seal |
Hello Rob Like you I used 750ss front head and 650 rear head Two front 900 ie cams fit without problems Graeme |
Author: | CrankyRoller [ Sat Jan 23, 2021 6:27 pm ] |
Post subject: | Re: Camshaft Bearing Seal |
Hay MikeV that .022" is a little to close for comfort. 1 mm or .040" is min with these cams. 1.2mm with high lift variety (St2) I find it best to stay with 41/35 combination with the P cams. -Cranky- |
Author: | 618F1 [ Sun Jan 24, 2021 10:22 am ] |
Post subject: | Re: Camshaft Bearing Seal |
Hay Cranky. You must have been napping in June 2019 when Boucher and I had a two-man discussion about this —- valve overlap clearance. I do appreciate your concerns, and have faith in your recommendations, so will approach this carefully. I have not fired it up yet. MikeV |
Author: | Carlo [ Sun Jan 24, 2021 10:51 am ] |
Post subject: | Re: Camshaft Bearing Seal |
CrankyRoller wrote: Hay MikeV that .022" is a little to close for comfort. 1 mm or .040" is min with these cams. 1.2mm with high lift variety (St2) I find it best to stay with 41/35 combination with the P cams. -Cranky- I fully agree with you, I had the honor of speaking with Giorgio Nepoti, NCR, and he told me, that the exhaust valve, the bigger you put it, the slower the speed, the bike goes. . The right recipe, according to him, was this. |
Author: | CrankyRoller [ Sun Jan 24, 2021 2:00 pm ] |
Post subject: | Re: Camshaft Bearing Seal |
618F1 wrote: Hay Cranky. You must have been napping in June 2019 when Boucher and I had a two-man discussion about this —- valve overlap clearance. I do appreciate your concerns, and have faith in your recommendations, so will approach this carefully. I have not fired it up yet. MikeV Hay Mike I've been napping much longer than June 2019... kinda like Rip-van-winkle. Now have some time and access to this site to cause trouble . -Cranky- |
Author: | johnnybravo12 [ Tue Jul 11, 2023 1:30 am ] | |||
Post subject: | Re: Camshaft Bearing Seal | |||
Desmorob wrote: Thanks guys, The feed through the barrel to the heads is blocked off ok. But I didn't know about the 1.2mm restriction required in the head external feeds. That's good info. And thanks for taking the time to reply. Cheers Rob I think this is what Carlo is saying to do with the carb jets. Since Dellorto jet sizes are in mm, a 120 main jet is 1.2mm. Makes it easy to get the correct size. The threads on Dellorto jets are m5x.75 for pilots and m6x.75 fpr mains. These are main jets.
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