It's Running

[frankfast]

I finally was able to get my 350 Scrambler (now a bonafide roadster) up and running today. I wish to express my sincere gratitude to Eldert (who provided me a couple of needed bits) and Bob (for his extensive knowledge). The top end was fried due to a broken oil pump. It now has a White cam and screw adjuster rockers and new oil pump gears. I checked the head after running it for a while and it was getting plenty of fresh oil. It needed a squirt of starting fluid to get it going but once warmed up it idled fine. I have to spend some time tidying the electrical connections but it is mostly done and looks the way I had envisioned. It's great having this resource to rely on. Thanks guys.

[MotoMike]

Frankfast

Great!! It sounds like it has been a long haul. got any pictures?

[frankfast]

These were taken a while ago before realizing the oil pump was gone. It still looks the same because only internals were changed. I replaced the velocity stack with a KN and rerouted the oil breather line so it wouldn't be so noticeable.

[MotoMike]

She looks great. good job and now you get to rider her too.

[DewCatTea-Bob]

" It now has a White cam "

____ It's great that you've got your DUKE into running condition before the riding-season was over-with, and that you're getting the chance to feel how a 350-DUKE runs with a cam that takes good advantage of the fact that it's a big-single ! - (And that's all I would've hoped to get any credit for.)
Now hopefully you'll find a way to measure your 350's performance before you replace the White-cam with a G&W-cam ! _ Don't you have a friend with a bike that's not much of a mismatch to run against? _ With hopes that you do, then besides all-out acceleration-races through all the gears, up to 80-MPH or so, (like most everyone likes to do),, you should also compare high-gear 'roll-ons' ! - That's when two bikes are already holding-abreast at about 30-MPH in either 4th or 5th gear, and then the sign is given for both to open-up at full-throttle to see how long both will stay about even-steven up to whatever speed that one has pulled-ahead over a bike-length from the other and is clearly pulling-away at a rate which indicates that the match is over-with.
The idea with this type of match-off is for both bikes to find whatever HIGHer gears will keep the two bikes as even-steven for as long as possible (before one significantly leaves the other behind), and keep notes of the chosen gearing and at what speed the test-match came to an end. _ That way when ya make any expected performance changes, you'll then have an established base for comparison (with the same friend & his unaltered bike).
__ I've of course gone on many many rides on all my DUKEs over past decades, but I must say that many of the most memorable were those from when a friend & myself went-out racing our DUKEs together out on the back-roads !! - Got to be my best DUKE-memories (and also amongst my best life-memories!) !
If ya try that, I'm sure that you too will have some good-times fun.


Fun-Cheers,
-Bob

[dsmess]

It looks terrific!

I'd like to hear some details about the oil pump failure. What was broken?

Scott

[frankfast]

Sorry for the delay in responding. Haven't had computer access for a week. The end of the shaft on the oil pump gear broke off where it meshes with the gear driven by the crank. Therefore no oil delivery.

[dsmess]

Hmm, not good. I hope the crank Rod bearing is ok. I guess the weakest point of the shaft is the keyed area that fits in the gear slot. I would like to understand what caused the failure. I have seen worn shaft ends, but never a broken one. I think the worst case stress on the pump shaft is at high revs with a cold engine. This combo will put a lot of torque on the shaft pushing the more viscous oil thru the lines (pressure has increased). The bypass valve is supposed to open to avoid failure. Perhaps yours was stuck. Anyway, it is a good idea to warm up your engine carefully, with minimum revs, and periodically check the shaft for wear. the Ducati oil pump is incredibly compact, but not robust compared to other motorcycle pumps I've observed.
Plain bearing type motors of course require a larger pump providing higher volumes in order to reach the needed pressures.

Scott

[DewCatTea-Bob]

" I guess the weakest point of the shaft is the keyed area that fits in the gear slot. I would like to understand what caused the failure. I have seen worn shaft ends, but never a broken one. "

____ Actually, sheared-off oil-pump drive-shaft tips are not too uncommon !
__ It seems you've missed other threads which have already touched-on this busted oil-pump topic. _ You can see the one where 'frankfast' first brought-up his pump-issue, within the 'Camshaft Data' thread,, and also my related-comments, found on the next page -(2) of that thread.
(Whenever you'd like additional info on most any topic, then try entering key-words [of whatever the topic] into the provided search-box [in upper-right corner], to then find other postings which likely also touch-on the same topic.)
Happy-reading !


Hopeful-Cheers,
-Bob

[frankfast]

I'm very satisfied how this single is running with the white cam and have decided not to exchange it for the green/white cam. Now that the Duck is running I have to take it on an extended trip in order to gain confidence in the electrical system employed. In an effort to simplify things, I installed a very small rectifier and a small 6 volt battery. I tried to run it without a battery but the spark was too weak. I now have a good spark but I'm not sure that the rectifier will keep the battery charged or keep it from over-chargeing. I'm not using a regulator hoping that the battery will act as a sump for voltage produced without over-charging. Of course running lights or not running lights will have an effect on the system. I guess we'll see.