Dynojet kits

[Duncan]

Decided to give my bike a treat to celebrate 40,000 miles and fit a DP open air box, K&N filter and Dynojet.

All pretty straightforward looking. Just whip the carbs off and pop the jets in, couple of hours work at most. Wrong.

Remove seat to raise the tank.
Disconnect and plug fuel lines.
Remove battery.
Undo airfilter box lid and discard old filter.Undo ignition coils and sender modules and place to one side.
Split 2 parts of air filter box, place screws to one side, remove a few more hoses and hey presto airbox comes off.

Dynojet kit is a fascinating thing and inexpensive to make in quantity, 6 main jets of 3 different sizes costing about £2, 2 springs (50p), 2 needles (£1.50), a few O rings and washers (5p), 2 stickers (8p), plastic box (£1.25) - total cost about £5 to make and £85 in the shops!!!! Thats a nice earner for someone for sure.

Tops off the carbs, changed springs then the fun started.

Float bowl screws all seized in place and Mikuni screws are made from cheese. I have an impact driver and the correct bit that gets 6 out and resort to a chisel on the other two.

Reassemble with new screws and go to adjust mixture screw. One is fine under its rubber cover and adjust it. The other one has been subject to Galvanic corrosion.

Any metallurgists here will be able to tell you that corrosion occurs where dissimilar materials are put together and this increases in the presence of salt and water. Between Brass screws and Zinc alloy castings is a very high potential for corrosion and mine was corroded solid. Easing oil made no difference so out come the drills and out comes the screw.

So, its down the machine shop to get a thread retapped and a new screw then that simple couple of hour job can be finished.

[crust]

let us know how this progresses Duncan as this is something I'm planning at the moment.

Most interested to know if the performance increase is worth the effort/cost

:) Crust

[Duncan]

The saga continues............

Try and get a thread recut. Langham Engineering and Nourish Racing engines dont have anything with that fine a thread. Its an M6 x0.5 pitch, a superfine pitch metric whereas standard is M6x1.0 or 0.75 for fine.
Ring my gas jet suppliers, they have plenty of BA threads but no fine metrics.
Chase a few other contacts and still no luck.

Then find a tap at Cromwell tools £24 ouch!!! Couple of other suppliers quote me silly money. Get an offer of some secondhand carbs from one of our lot.

Then I try Tracy tools in Devon. Tap £3 delivery next day. So here I sit waiting for postie.

[A Yerbury]

oh dear mate! getting to the carbs on these things is a joke, one reason why I considered pod k n s but was warned not to. lucky for me the previous owner did the mikunis and the kn just straps in place of the air box. how does the dp open box work with the lid of the air box as thats effectively done away with due to filter? good luck anyhoo.
Yerbs.

[Duncan]

Got it going tonight.

It fired immediately and settled to a nice idle.

Bike ran great although it is a little lean down low and will need a tweak on the impossible to reach mixture screws. Currently bottom to middle is as before, Up top the breathing is improved and it goes like a scolded cat. The open airbox and K&N make a great noise and once I have fine tuned it then it will be fine. Yerbs, it just a case of cutting the entire airbox top off and jetting accordingly, have a 170 main jet fitted.

Went out tonight to a bike meet in Wincanton, did about 90 miles. Managed to card 2 Monsters, a red 600 and a black 900 on an N plate, import KPH speedo.

[JJCool]

Im Getting all this done by BSD in Peterborough, Will also let you know how it all goes, When i get it back, Should be Saturday!!!!

[A Yerbury]

maybe I have a diff kn filter, the airbox is nt cut just replaced completely by filter. filter is then held in place by those (stupidly designed) 4 metal braces. at least it goes eh?

[MikeBurns]

Hi Duncan,

Where did you get the replacement adjustment screw from?

I've tried everywhere to get on.

Mike

[Keabs]

Feeling your pain there Duncan - a 1 hour job always extends to 6 or more doesn't it.

I wouldn't wince too much on the price of that Dynojet kit - there's a lot of R&D that goes into those kits, and yes most of it is done by now but, hey, they did it and deserve their rewards I think.


Would have thought that a spray of WD40 and leave it a couple of days would have solved the mixture screw siezing, but if you aint got the time, you aint got the time.

They go well when they're breathing properly tho, eh? :D

[Duncan]

Hi Duncan,

Where did you get the replacement adjustment screw from?

I've tried everywhere to get on.

Mike

I borrowed it from AK but have to replace it.

Theres a company called Allens in Nottingham shoud be able to do the screws, they do all sorts of Mikuni kits.

[MikeBurns]

I had the same problem, the rubber bung came out and the screw welded itself to the barrel. Nothing would get it out, I even socked it in penetration oil for 4 days.
I’ve now been trying to find a new jet screw for two week. I tried I had the same problem as you, the Allen’s and they couldn’t help, they suggested Ducati direct. Let me know if you have any luck. I did find out that the carb is the same as on a TDM850.

Mike

[Duncan]

Mike

Was going to try this crowd.

TTS Performance Engineering
15 Quorn Way, Grafton Street Industrial Estate, Northampton NN1 2PN, UK.
Tel: +44 (0) 1604 636363 Fax: +44 (0) 1604 636344

http://www.tts-performance.co.uk/dynojetpage.shtml






D

[Keabs]

Mike,

Have you tried applying a bit of localised heat. Pointing a heat gun at the affected area might help separate the 2 metals . . .

[Duncan]

Keabs

Theres a rubber O ring that heat would finish off but no amount of heat or easing oil will shift these screws. I've been in Engineering for 25 years, rebuilt loads of old bikes, even worked on vintage engines and when these things seize you wont see a worse mess. Its just bad materials selection by Mikuni. Even a left hand fluted drill which frequently unscrews seized screws as you drill, failed to get the screw out until it had drilled it away. The galvanic corrosion means the screw slot just corrodes away and that the screw and carb body become as one. Its not nice and totally unlike a steel screw in ally.
If youre careful you can drill a screw out and go up in pilot drill sizes till just the bit in the threads remains and this comes out like a twist of swarf leaving the thread in the body intact. Tried that and the twist remained, seized solid so I had to get a fine thread tap. Because the brass screw is relatively hard compared to the ally body, you still run the risk of ripping the threads out as you remove the brass twist.

I've heard of Ducati dealers scrapping carbs for this problem. It aint nice.

[NattyBoy]

Bloody hell Duncan..I fell guilty selling it to you now !!!! Still have some of the 600 full DP kits if anyone wants one..

Nat

[Keabs]

No worries Duncan. Looks like you'd already had a good crack at it, but thought I'd throw that in the pot too. :)

[JR]

Dunc,

I know it is after the event, but for future reference, someone who might have been able to help or point you in a closer direction : Lee Howell, Works Manger, Cyril Minns Engineering Ltd (Precision Engineers and Toolmakers) Gladstone Road Kingswood Bristol BS15 1SW Tel 0117 967 1834.


JR

[Duncan]

Located the mixture screws today. Nice part number on a Ducati microfiche, only problem, Ducati Bristol cant order it, despite their microfiche system having a part number, the parts ordering system doesnt recognise it, doesnt carry a description, price, stock level or availability. They are going to sort the discrepancy after the hols.

Meanwhile, Fowlers of Bristol have a TDM 850 microfiche with the identical part, the part exists and is on back order, for delivery on 5th June.

There are also quite a few Yank sites selling Plastic mixture screws which are elongated with a knurled end for easy adjustment. They do want $21 each for thse.

[lox]

Hello mate, you don't know me but it sounds like you are having as much fun as I am.I bought this 900 in Feb(my first Ducati) Probs:-
1,carbs full of sh*t
2.piolt jet, screws knackerd and seezed in and had to be
drilled out and replacement screws had to be ordered from italy. :(
3. Bike was supposed to be stage 2 dyno but wasn't, all standard apart from knackered K & N air filter
4. Was supposed to have new timing belts but hadn't had new belts in a long time, so ended up putting new timing belts, oil, plugs and oil & air filter on it. :mad:
5. Found out back tyre had a slow puncture, so put new tyre on then found out tapered spacer and chain tensioner brackets at the end of the swinging arm had been put on the wrong way some time way back, you can imagine the damage that has done? Oh yeh the circlip was put back knackered. :eek: I have sorted that lot out.
6. Front discs warped, replaced them.
7. This weekend i found out my head stock bearings are on the way out
8. The fork stansion where set at different heights through the Yoke and the back suspension rose was adjusted out of line with each other on the swinging arm. :eek:

This is what happens when you are blinded by a pretty bike and loud cans and you can't take it for a proper test drive.

Can;t wait for the next thing for me to find on it or should I just go and get a new monster. :rolleyes:

Its not just you having all the fun, hope you get it sorted soon. ;)

Rich :burnout:

[Duncan]

Rich

Stick with it and go through it with a fine tooth comb. Once you get rid of the previous owners bodges you should have a good bike there.

My problems are self inflicted, having decided to upgrade a few things. I often say, if it aint broke dont fix it!
Raised the needles in the carbs a notch today and its running a beaut. Dynojet has also improved MPG slightly, a bonus worth having. On balance, once the pain is forgotten I will have a better bike.

D

[lox]

Hay Duncan,
Went out blast with a few mates around the North York moors(Hart beat country)yesterday,the appears to be running bobon :D Hayhay!!! Couple of the lads had a go and now wont one(they ride a thundercat&firestorm).You cant beat the real thing though ay!
Rich :burnout:

[Yellow 97]

Well after having parted with 80 quid for a dynojet kit and removing carbs i too have bowl screws made of jelly Bikes done 2200 miles so do i hack the bleeders of or drill them out...i've tried every thing except an impact driver, my trust hammer and screwdriver trick never worked either NOT ONE SCREW >>>>>oh well :confused:

[Duncan]

I had to use a chisel on a couple and once they moved a touch, they were fine. My 1980 Suzuki uses the same screws and had the same problems so in 20 odd years Mikuni have learnt diddley squat.. The screws in Mikunis have a different angled screwdriver drive from everything except one of my Impact bits. Theyre soft as cheese too and I managed to get most out with the impact wrench (carefully) but the chisel was the only solution for 2 of them.
If you want to drill them, a left hand fluted drill will naturally loosen the screws as you drill, try Tracy Tools in Devon who have a fantastic mail order service and are cheap.
http://www.tracytools.com/

Feckin Jap crap carbs!

[Yellow 97]

:) Well and old trick my dear old dad taught me years ago worked a treat and now all screws are out anybody else ever has trouble try this
If you find that the screwdrivers makes a mess of the head just junior hacksaw across the centre about 3/4 the way down, then get a flathead haxagonal tip (the type you get in kits with millions of bits that you never use ) make sure its slightly wider than the cut you just made and hammer it into the groove then get a medium sized adjustable spanner onto the tip and hey presto.The hammering of the tip makes sure its snug and also vibrates the thread enough to just help break the seal.

Anyone know how to get a knackered sump plug out ?? Had to drian the bike by taking out the filter and tipping the bike over