copemech Posted February 2, 2009 Report Share Posted February 2, 2009 (edited) Here is a helpful file of information that relates to the Dellorto carbs used on many bikes. You should be able to open it, click "file" then "save as", so you may keep a copy on hand for referance. It has a lot of good tuning and theory of operation information. Although not trials specific, most all here applies. There are some hint and tips I shall expound upon later. I do think this referance material is worthy of a 'stickie, if SOMEONE finds it! It is well done. dellorto_motorcycle.pdf Edited February 2, 2009 by copemech Quote Link to comment Share on other sites More sharing options...
jse Posted February 2, 2009 Report Share Posted February 2, 2009 I do think this referance material is worthy of a 'stickie, if SOMEONE finds it! It is well done. That is one of the best basic guides to the PH series Dellorto I've seen. Heck, Copey, PM me with your address and although I don't have any TC stickers, I'll find something for you! Jon Quote Link to comment Share on other sites More sharing options...
copemech Posted February 6, 2009 Author Report Share Posted February 6, 2009 One of the primary points that I wanted to point out to "tuners" of thest things is the transition circuit. If you follow the operational text and illustrations, you will notice that the first of the two little holes in the bore both sucks and blows! The second blows only, and is the metered one! So thusly, a pilot jet that is a bit too large can make things over rich and lumpy in the transition zone(1/8) no matter how lean the fuel screw is set. Add to this the fact that no matter how rich the fuel screw is set(many run near full out at over three turns) this will not give you a good power on the transition because you are still too lean and the needle has not picked up yet. This can lead to a lean pinging, specially at cruise settings on the loop at low openings and constant speed. Under some load! As it seems that all I can get here are the 'oxy" fuels, and up to 10% ethanol included in the mix in the normal high test pump fuel rated at 93 octane, this may indeed explain why myself and others have had pinging problems at cruise speeds and such. Where I used to run a primary jet in the 33-35 range, seems I now must run a jet of at least 38 to offset for the alcohol in the fuel and achieve a smooth transition area without ping! This has been a bit daunting i admit, but seems to be the case. I never would have thunk it early on. And I do think there is a bit of a plus in being able to run the idle settings at a much more reasonable 2 turn range, well within the controllability of the screw, rather than running them full out at 3-3.5 turns to achieve good idle and response. M2C, do as needed! Quote Link to comment Share on other sites More sharing options...
copemech Posted February 6, 2009 Author Report Share Posted February 6, 2009 That is one of the best basic guides to the PH series Dellorto I've seen. Heck, Copey, PM me with your addressand although I don't have any TC stickers, I'll find something for you! Jon I have TC stickers for you Jon, I need the fat bottomed girls ones! Quote Link to comment Share on other sites More sharing options...
peterb Posted February 11, 2009 Report Share Posted February 11, 2009 Thanks copemech, I've added this brilliant info to my list of engineering stuff. Bye, PeterB. Quote Link to comment Share on other sites More sharing options...
jse Posted February 11, 2009 Report Share Posted February 11, 2009 Thanks copemech,I've added this brilliant info to my list of engineering stuff. Bye, PeterB. Jeez, Peter, Don't tell Mark that, I'm gonna have to find him some fat bottom girl stickers now or I'll never hear the end of it........... Jon Quote Link to comment Share on other sites More sharing options...
peterb Posted February 13, 2009 Report Share Posted February 13, 2009 Woops! Maybe I'll have to send him some kiwi stickers! Bye, PeterB. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.