| ducatipaso.org http://ducatipaso.org/forum/ |
|
| Dellorto + 853 ccm big bore http://ducatipaso.org/forum/viewtopic.php?f=13&t=5898 |
Page 1 of 1 |
| Author: | micap [ Mon Mar 18, 2013 8:43 pm ] |
| Post subject: | Dellorto + 853 ccm big bore |
I have already read through most topics in the forum, and what a great source of information it is. First of all, a short introdution should be in order. I just recently purchased a 750 Sport as my first ever motorcycle, and have been messing a bit with it since. It is fitted with the Dellorto PHM 40 conversion, and supposedly fitted with a 853 ccm big bore cylinder kit. I have no proof of this, other than the word of the previous owner. I have not really been driving very much, as I didn't feel it was running well at all. First of all, I had some trouble getting the bike started. At first try, when using the choke, the engine flooded completely, to the point where gasoline was dripping from the exhaust. New plugs and a second try, this time without the choke. The bike started fine, but it was impossible to keep it idling, without using the throttle. At other times the idle speed would stay very high, after giving the throttle a little blip. I have now ended up dismantling the carbs from the bike, and this is where I could use some help. I do realise that my setup is not that common, but I am hoping for some pointers anyway. Does anyone have any idea, what kind of jets and needles would be a good starting point for my bike? This is what is fitted at the moment. Main jets 148 Slides 60/1 Needle K5 clip at top position Atomiser AB265 Idle Jet 70 Choke Jet 60 Pump Jet 45 Needle valve 250 I have a feeling my idle jet is way too big, as the idle mixture screw was only about half a turn out. Another question is, how do I adjust the accelerator pump? The screws were set different on each carb, and that seems a bit too random to me. Pictures from the workshop will follow. Cheers Michael |
|
| Author: | paso750 [ Mon Mar 18, 2013 9:56 pm ] |
| Post subject: | Re: Dellorto + 853 ccm big bore |
Michael, I cannot help but you´ll find some Dellorto files in the downloads viewtopic.php?f=1&t=1551 The only 853cc kit I`ve ever heard of is the one for the 748. I only know that you can take a 750cc 2 valver Duc to 804cc. G. |
|
| Author: | micap [ Wed Mar 20, 2013 4:30 pm ] |
| Post subject: | Re: Dellorto + 853 ccm big bore |
As I said, I have no idea if the 853 ccm is for real or not. Anyway, I have now started assembly of the carbs again. Only change I have made is change the idle jet for a 65, so then we'll see how that works. Another thing is, the carbs were only fitted with short inlet trumpets before, which I doubt did anything good for the performance. I have bought some 90 degree silicone elbows, which I plan on fitting. The problem is however, that the tank has been modified at some point, probably when the Dellortos were installed. The fuel pump, return line and breather line has been discarded, and the bottom of the tank has been welded flat. This gives very little room for proper air filters. I plan on giving the ignition some attention as well. I have noticed that the coils are two different kinds, but I haven't measured them yet. What would be a good match if I were to find some replacement coils? I have read a lot about this, but almost everywhere it is stated that the standard coils have a 4 ohm resistance on the low voltage side, whereas the workshop manual says it is 40 ohm. I have the Kokusan ignition. Cheers Michael |
|
| Author: | ducinthebay [ Wed Mar 20, 2013 5:58 pm ] |
| Post subject: | Re: Dellorto + 853 ccm big bore |
If you have the Kokusan ignition, then any coil that fits the SS or Monster series will work just fine. Dyna coils are the general default upgrade, or the ones that Ca. Cycleworks is selling. I chased a problem with my Dellortos for years, and found that the previous owner had not installed the O-rings in the manifolds, but instead opted for silicone RTV, which works fine, for a while, then breaks down in presence of modern fuels. O-rings are measured by the ID and the thickness, and can be found on line in many places for a reasonable price. While you got it apart, it would be good to check it. Use some sealing grease when you install it. For aircleaners, get two elbows and simply make a U-turn and lay the air filter next to each other above or along the carbs. I've long wanted to modify my tank that way and get the extra fuel storage. How many gallons can you now carry? Cheers, Phil |
|
| Author: | micap [ Wed Mar 20, 2013 9:55 pm ] |
| Post subject: | Re: Dellorto + 853 ccm big bore |
| Author: | micap [ Wed Mar 20, 2013 11:16 pm ] |
| Post subject: | Re: Dellorto + 853 ccm big bore |
Just a few pictures of me trying to wash the bike. It was too cold for that. From the workshop New rear fender molded on a spare tire |
|
| Author: | ducinthebay [ Thu Mar 21, 2013 5:28 am ] |
| Post subject: | Re: Dellorto + 853 ccm big bore |
Yeah, I'd say that bike has been modified a bit. No sense going back to stock on that one. Have you got a reasonable picture from the side? Cheers, Phil |
|
| Author: | micap [ Thu Mar 21, 2013 10:04 am ] |
| Post subject: | Re: Dellorto + 853 ccm big bore |
| Author: | micap [ Fri Mar 22, 2013 2:26 pm ] |
| Post subject: | Re: Dellorto + 853 ccm big bore |
A few more pictures from the workshop. Now I am just waiting for filters and better weather. |
|
| Author: | ducinthebay [ Fri Mar 22, 2013 8:25 pm ] |
| Post subject: | Re: Dellorto + 853 ccm big bore |
Well, the previous owner liked shiny black paint that is for sure. Rear frame section has been modified, probably to fit that older Sport tail section, which look good on it. Besides that, it all looks there. You can cut and fit a 91-98 SS hugger to fit that swing arm. Not the same mounting pattern but close enough to call it. Looks like a reasonable project bike. Between that and the Guzzi, you will be busy till it gets warm. Cheers, Phil |
|
| Author: | micap [ Fri Mar 22, 2013 10:18 pm ] |
| Post subject: | Re: Dellorto + 853 ccm big bore |
You are right about the paint job, but i quite like it. I did think about modifying the seat section, to show more of the rear frame section. Cutting the bottom off of it, about 2-3 cm. It is not all that clear, but the oil hoses going to the cooler is the original ones, which are far too long for the new mounting postion. Is it possible to fit hoses from a newer version, which had the oil cooler mounted near the horisontal cylinder? EDIT: I just noticed that the newer versions oil hoses are a lot shorter than what I need. Any other ideas? Cheers Michael |
|
| Author: | ducinthebay [ Fri Mar 22, 2013 10:28 pm ] |
| Post subject: | Re: Dellorto + 853 ccm big bore |
On my current Sport project, I am putting the oil cooler above the front cylinder head. I haven't completely sussed out the hoses or the routing, but if you look at several different Ducati models, you will be able to find hoses on e-bay, and adapters for the hoses to attach to the cases. Or you can source some new hoses through someone line Venhill or some such company. Its not a topic that has been discussed much here that I can remember. I agree that the back end of the Sport frame should be more visible. I am doing the same on my current project. Cheers, phil |
|
| Author: | Andrew2 [ Fri Mar 22, 2013 10:43 pm ] |
| Post subject: | Re: Dellorto + 853 ccm big bore |
I had the same problem with my MHR early in it's life.The idle would either be 2000rpm or it would stall.It turned out that my valves (shims) needed adjusting.Once I set the correct gap the problem dissapeared.Just a thought. Cheers Andrew |
|
| Page 1 of 1 | All times are UTC |
| Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group http://www.phpbb.com/ |
|