450 Scrambler /jupiter project

[MotoMike]

-still need to adjust exhaust valve shim. should i sand the current one down with emory or is there a prefered precedure for this?
-occasionally after running the bike a couple of mins and then trying to restart it when (warm/hot) i feel like there is little or no compression when kickstarting) this was why I originally and maybe prematurely jumped to conclusions thinking timing was far off. i also noticed whnn running no more than 5 minutes that the exhaust header was actually glowing in a well lit garage.. could both of these symtoms be caused by the exhaust valve having no clearance against the shim?

-JJ

My thought is that if it is zero clearance when cold, I'd expect it to be putting a bit of lift in there when heated. I don't know If I would want to grind down my winkle caps that much. i think there is some guidence on the site here that says it is too much. I got my caps from Nigel Lacey. Even with shipping from the UK he was the best deal. A good source for gaskets too. Not to mention that he has a wealth of knowledge which he readily shares. I have been told that the current non desmo Dukes use these same caps, so if you have a Ducati dealer near you could probably pick some up. They are extremely hard.

Can you run it long enough to check the plug? sounds like it might be a lean condition. Looks like you are on top of it. Good luck.

[DewCatTea-Bob]

By: john jupiter...
" -reassembled oil pump and timing spindle gears with spindle gear set to the line, not the dot. "

____ If you had seen any signs that someone-else had ever had that F/R.side-cover off, then it's somewhat likely that they had then set the ign.timing-spindle to the dot instead of the dash/line, (thus likely making it impossible to properly set the ign.timing retarded enough by means of the points-plate slot-range).
Since the static-timing is supposed to be set at TDC, it's then not possible to get any real notable kick-back, so when a 450 does quite so, then the ign.timing is set too advanced.


" felt a few backfires during the kick process but it didnt try to break my foot and launch me this time, "

____ So since you may have (unknowingly, due to hastiness) retarded the ign.timing (back towards stock), this could thus be the (logical) reason for that noted (& somewhat positive) change.
__ The ign.timing should be checked, to be between 4-degrees BTDC & right-at TDC.


" I removed my intake manifold to take a look at the rubber insulator gasket(it measured 35mm which seems like an incorrect size for a VHB29. "

____ The I.D. of a stock manifold-rubber is 32mm (due to being fitted-OVER the 29/32mm manifold-lip). _ Seems a new-one is in order, (as the one you currently have may be from a bevel.Ltwin).


" -still have some air/gas mixture blowing out of the carb more than i would like. not sure whats causing this or how concerning this problem is. "

____ Do you mean while the engine is running, or just during failing starting-attempts ?


" -still need to adjust exhaust valve shim. should i sand the current one down with emory or is there a prefered precedure for this? "

____ I-myself never try to do this but, for under .002" (on a previously unaltered shim), ya can use a 'flat-stone' (& lot's of time) to flatly stone-off a bit using figure-8 sliding-motions only.
__ Seems you need another v.shim-cap that's at least .004" thinner (than the unit currently on the exhaust-valve).


" (does anyone know if Desmo shims from a 900twin are the same as spring head shims for a single???) "

____ That may depend on the year (decade) of the '900-twin'... Certainly all old/bevel-type cyl.heads use the same type of valve-shim/cap.


" -occasionally after running the bike a couple of mins and then trying to restart it when (warm/hot) i feel like there is little or no compression when kickstarting) "

____ A fair sign that your ex.valve clearance is very near zer0 when cold, and the hot/expanded valve then allows significant leakage.


" this was why I originally and maybe prematurely jumped to conclusions thinking timing was far off. i also noticed whnn running no more than 5 minutes that the exhaust header was actually glowing in a well lit garage.. could both of these symtoms be caused by the exhaust valve having no clearance against the shim? "

____ Yes, of course. ... (How could "far off" timing possibly cause those same two issues ?)


Dukaddy-DUKEs,
-Bob

[machten]

" (does anyone know if Desmo shims from a 900twin are the same as spring head shims for a single???) "

All the bevel twins (that use shims) and two valve belts use the same shims as the singles - 8mm diameter. The 4 valve belts use 7mm diameter shims.
You can see them here, but you'd think you could get them from your local ducati dealership.

http://shop.bevelheaven.com/SearchResult.aspx?KeyWords=shim

Kev

[DewCatTea-Bob]

The exhaust valves tight and i cant get a .002 feeler in.. What is the easiest way to adjust this? Do i need a special tool?

____ Finally remembered to look-up a link on this topic for you John ! ...
This link: viewtopic.php?f=3&t=319 , is to a related thread which is currently at the bottom of page-6 (of these topic-threads under this 'Ducati Singles Talk' section). _ The post that's of most relevance to your particular question is the 4th-posting, within that thread.
__ After you've read-through that associated thread, if you still have any related questions, then please ask them with a new-post -(by you, within that thread) !


Hopeful-Cheers,
-Bob

[john jupiter]

Thank you Bob, i was able to locate the shims at the local dealer but believe it or not they wouldnt sell one to me. I thnk the mechanic had them in his box and wouldnt let the parts dept sell them.. Its amazing how helpful everyone is on this board. I always try and support the local businesses but the information is ALL on this site and mail order is friendlier than my dealer(who will remain anonymous). VERY LUCKY to have his board!

With another few hours and a little luck she should be running better by the end of the weekend!
-john

[machten]

If you're trying to buy the mechanic's shims, he sure as hell won't sell them to you, any more than he'd sell you his special tools. Sound's like your local shop doesn't sell them, but look around the Duc Shops outside your area. Some will somewhere. (or at the end of the day - once you know what sizes you need, bevelheaven.) This is exacly why I did the big buy up of shims when VeeTwo closed down.

Kev

[DewCatTea-Bob]

Im going to try and make a tool since i dont have a timing wheel or timing needle.
Do you know what size thread on the end of the crank is so i can try and make something that will work?
-john

____ Well John, I've finally gotten-around to looking-up a link to a related thread, for you to check-out ! ... viewtopic.php?f=3&t=383&p=2584#p2584
This link is to the most relevant post concerning your related inquiry, and is found within the related thread currently found at the bottom of page-4 of these topic-threads (within this 'Ducati Singles Talk' Section of this w.site).
__ If you still have any questions after reading-through all the posts within that associated thread, then please be sure to ask whatever detail you wish !

____ When I had mentioned in my original reply-post (to your related inquiry-post) that I would later look-up & add links for you, I had then expected to do so within the same day ! _ But I guess I continued to be too busy, and later afterwords, I must've kept forgetting about it whenever I could've gotten it done (sooner).
So while I really don't mind looking-up & adding such helpful links,, if you're in more of a hurry to find already established related threads, then you need to get in the hang of using the 'Search...' box that's found at the Top-Right of most every page here at this w.site... Just enter a couple key words and then click the Search-button,, and then you'll hopefully be taken to a page listing at least one related-post which contains your desired topic-matter, for you to then scan-through and hopefully find pretty-much exactly that which you're wishing to learn of.
____ Long ago I've wanted to archive all the old threads (no longer showing on the first two pages), into four Main (tree-type) Sections -('Frame/Body'; 'Engine/Motor'; 'Electrical'; & 'Other/Misc.'), so that members don't have to spend so much time wading-through so darn many pages of past-threads in hopes of possibly finding a related thread (on their topic of interest, which may not even exist yet). _ But I think Jim (at least at the time) preferred for everyone to just use the Search-feature which this w.site conveniently provides.
__ However, it seems most new-members keep (understandably) preferring to simply start/open a new-thread on whatever their particular topic of interest is, and thus contribute to the ever growing number of thread-pages... Which is certainly some sort of self-causing predicament !
In any case, it seems something ought to be done to help prevent such fairly constant repetition. _ So if anyone else has any other good suggestions to possibly more easily help those looking for particular information (without adding to more thread/post duplication), then please mention your thoughts.


Hopeful-Cheers,
-Bob

[john jupiter]

Update:
-recieved and installed valve shims( exhaust shim now has .0035 of clearance, intake has .0025)
-cleaned carb, Replaced carburetor float needle(Rubber tip on old one was falling off)
-replaced choke piston
Using a 50 idle, 135 main, v7 needle on middle groove, 265t atomiser. Without air filter.
Mix screw 1.5 turns out, slide screw 2 turns out.

-- idle wanders and unless slde screw is set to idle at 2k rpm it will stall withing 20 seconds, after letting out a backfire.
-- when put into gear and ridden, it boggs down to the point of almost stalling until reaching about 20mph. Sounds like im too rich??
Carb still shoots fuel backwards when trying to start it. Backfires out the carb when stalls..
Any suggestions?

[DewCatTea-Bob]

" -recieved and installed valve shims "

____ How did you go-about obtaining shims which ended-up with such closely correct clearances for you ? _ Did you merely have good-luck or are you omitting mention of your related troubles ?


" idle wanders and unless slde screw is set to idle at 2k rpm it will stall withing 20 seconds, after letting out a backfire.
-- when put into gear and ridden, it boggs down to the point of almost stalling until reaching about 20mph.
Carb still shoots fuel backwards when trying to start it. Backfires out the carb when stalls..
Any suggestions? "

____ First, be sure to report such issues only with the use of a fresh spark-plug, (as used plugs can contribute to all sorts of such related issues), and check that it's gaped correctly and it's ign.coil wire-lead/cable is without issues.
And also make sure the ign.points are gaped at least .012".
__ Also the engine will run with much different characteristics depending on whether cold or hot and if the enrichener-circuit is cocked-open or completely shut-off, so make sure to include whatever those particular conditions are, whenever covering any particular issues of the sort.
And please avoid noting any conditions experienced during warming-up periods, as there are then too many variables to iron-out (through that relatively short period).


Hopeful-Cheers,
-Bob

[Bevel bob]

A simple experiment (easily reversed), close the points gap by 3 thou, if the symptons improve then the timing is too far advanced.Possibly too rich too.Check fuel level .Valve clearances are smaller than i would trust, valves tend to sink into seats and close up clearances.As DCT says , a stock of new plugs till the problems sorted, cleaning plugs is not reliable.