the last thing to do for this project.

 

fuel light finally came on riding around today, 13.5 litres, 275km. not too bad, but you'd expect a 400 to do pretty well.

still fun to ride.

 

If my maths are right that works out 56mpg, sounds very reasonable.

 

took minnie to the dyno today to see how the 2-1 works. not well - red is the 2-1 curve. pretty much dyno'd how it feels on the road. goes well under 8, no point going over. i was going to set up one of the previously dyno'd muflers to give just the change due to the 2-1 header, but didn't get to it. might do it in future. i never really revved it hard before the 2-1 went on, so really didn't notice the crap (ish) top end in comparison to the previous. maybe i need to make a twin muffler bracket and cut down the other one.

it was a bit on the rich side, so i thought i'd try it out without an airbox lid.

a bit better, but the mixture change was pretty extreme. more than i think i've seen before on a 2v motor. bad to worse pretty much.

i tried it with lid and without the snorkles, which helped a bit, but still too lean on the needle. i have some of the original 400ss carb springs, that are a lot lighter. i might try them, not sure if that'll make it better due to more opening lifting the needle more, or worse because it'll have less vacuum over the jet and the needles aren't tapered enough anyway.

i rode it back from the dyno with one snorkle in, and without the baffle that i have been running for a little while. it's still loud with the baffle, just a little less offensive. felt a bit stronger without it.

baffle in versus baffle out.

i don't have any air/fuel for the original exhaust and mufflers, as the bike killed the dyno on those trips. the rpm and air/fuel were shutting down when we tried to run it. the only change has been resistor spark pugs, which is what you need to run with the ignitech anyway. the ignitech has the same advance as the std boxes. well, maybe i should check that - it should have the same advance. lack of advance hurts the top end, i know that from the previous 750 engine testing.

so maybe it was rich anyway. although i ran these same carbs years ago when it was a std 600, and i would have thought with a smaller engine it should be leaner due to less suck. the 400 and 600 are fitted with the same carb spec. i did shoot some video through the airbox lid without an air filter fitted of the slide, and it did look like it was lifting all the way up. i was wondering if it would, given it's a pretty big carb for a 400.

 

the carb slide video. 2,000 to 10,500 rpm.

 

That's exciting, fascinating to watch a CV carb slide in action like that, too bad you couldn't video both carbs at once.

I really like this trace:

all those dudes running open headers and thinking loud equates to more power should study this one.

Dyno test of a stock bike would still provide your best base line, highly advisable to have one of those done before setting out to modify any motorcycle engine imho.
Thank-you for sharing

 

the two lines in the above graph represent std headers with megacycle (local brand) slip on mufflers that always work very well on any bike i have dynod them on (that's the blue line) and my 2-1 being the red line. the 2-1 is longer overall, and has much less muffler volume. it's louder, again i would say because of the volume and also the muffler body diameter and the outlet position. but the megacycle are open, perf core style mufflers. ie, loud.

also i have concerns that the 2-1 merge may actually allow flow from one cylinder to go back up the pipe toward the other cylinder. not so bad from the vertical as the pipe in is angled, but from the horizontal it can. that's possibly an issue.

also, i fitted my old ignitech unit before these runs, and it's much nicer taking off from idle with the ignitech, but although i did check the timing with it and the oem units to make sure they were the same, i don't know if i did that test up over 9,000 rpm. the choppiness of the curve looks rather similar to what i saw when i was playing with the ignitech back when the 750 engine was fitted. the choppiness can be chain and sprocket related, but that hasn't gone to shit in the 100km since the blue line run. fuelling changes didn't make a big difference either, although it did go from too rich to too lean. the last run i did had the mixture back at 13.5 or so in the crap top end area, so that pretty much rules mixture out.

this old ignitech has a delay, that gets worse as rpm climbs. the newer units (this one I've had since 2005 or so) don't. i thought i had allowed for it in my curve, but maybe not enough. i did have the oem boxes with me at the dyno, but my time was pretty much up there and i had to get back to work anyway so i didn't. one thing i hate about not having my own dyno running is that all the things you think of later when it's too late.

so as it sits at work now (waiting for a nice day and time to go for a ride, it's pretty hot here now) it has one of the megacycle mufflers fitted to rule that change out, and i'll put some oem ignition units in my pocket and fit them on the road. i really can't see the exhaust alone hurting it this much, as nothing i've done exhaust wise in the past has, but i'm often wrong.

anyway, with regard to the "Dyno test of a stock bike would still provide your best base line, highly advisable to have one of those done before setting out to modify any motorcycle engine imho." comment, not sure if you're taking the piss or not, but.

Brad The Bike Boy: Another dyno debacle with Minnie the 400 - Ducati Monster 400 dyno runs

 

...

also i have concerns that the 2-1 merge may actually allow flow from one cylinder to go back up the pipe toward the other cylinder. not so bad from the vertical as the pipe in is angled, but from the horizontal it can. that's possibly an issue...[/url]

Hi Brad,
It would be interesting to see the effect of a revised merge. I'm making 2 merges at the moment, one out of 1 3/4" and the other out of 1 7/8", both will merge into 2 1/2" tube, ovalized at the junction. I've read somewhere that the headers should merge at 15 degrees, but I've just cut a 90 degree bend in half and started from there.

 

Ducati 400 specs claim 43 horsepower @10,500 is that extremely optimistic?

 

on this dynojet 250, which reads lower than the older 150 they used to have, it has gone as high as 41 (first time i took it there). the next time (in the link to my blog, see the last graph there for the output wackiness) it made 38 or so max. so i'd say the claim is as good as any of their claims. i ignore any manufacturer claim anyway pretty much, i find them kind of meaningless comparative wise. in the 89 400ss manual they claim 45 at 10,500, in the 1994 ss manual they claim 42 and the 2001 m400 they claim 43. so mine is as on the money as you could expect. it's funny, the way it starts you'd swear it has no comp, but it seems as expected otherwise. i haven''t comped it since i put the new pistons and reco heads on, maybe i should.

 

Man, that dyno run looks strange. especially that erratic section. like some reversion phenomenon choking the engine right around 7500 to 9000. Over 9000 once you got the A/F values back down a little with the lid on and no snorkel, power came back almost to the stock system.

The system probably doesn't like the angle the exhaust gases merge as you have said. And the unequal lengths of the primaries may plan a role as well.

Kudos to you for finding out, though. Can't wait to get mine on a dyno.

 

i rode it today with one of the previously used megacycle mufflers rigged up, and both ignitech and oem kokusan ignition units. i think it's the muffler.

maybe more dyno on friday.

 

if both pipes were coming from the same side i would do this, but with them coming from opposite sides of the motor you need to put a 180 into one of them, and/or move the merge out to the right and then it starts getting pretty long.

anyway, in my case it was a rush job time and effort thing. i had a day to use what i had to make it fit and i was going for a look. not that i expected it to work this crap, but i'd not tried it before. it's a learning process - it either works or it doesn't. you just move on as required, but it's always much nicer when it works - that way you don't have to do it again differently.

the actual stamped steel plate cross over that it originally has is not an issue - an st4s will make 120 hp through it as easily as a 996 will make 120 hp out of a nice x pipe collector. how far my welded on curve sections bring the join toward the exit (as in not close enough) might be an issue. all other variables will be removed next dyno session. if my theory about the muffler is true then i need to work out how to get it back to the look i want.

 

Seems to me that they prpbably designed and built the system originally with a fully welded/fabbed tubing x-pipe then someone told them it needs to be mass produced faster and cheaper and the stamped piece was a created as close to the original as possible.

 

so i got the lovely cnc'd caliper adapters, and i sent the floating disc carriers out to have them reanodised as they had been gouged a bit and were a bluey-grey colour. i got them done in gold, hoping it'd be like the original brembo carrier gold. but it's flat and bright at the same time sort of thing. i don't want to strip the hard ano off because i want it there for wear resistance, but maybe i just need to paint them a little, softer gold.

whadayas reckon?

 

I'd leave it.
But stuff like that is so personal.

 

so i got back to the dyno today finally.

red is the original headers and two of the megacycle mufflers. blue the 2-1 header with the danmoto muffler from the previous. green is the same as that run, but with one of the megacycle mufflers instead of the danmoto. bit richer, more power - possibly different wideband sensor to the last runs. wacky. yellow is with one of the airbox lid snorkels removed. nowhere near as lean as the runs from last time with a snorkel out, not sure why.

so it dyno'd like it felt with the megacycle muffler - better, and pulled through the top end nicer. still down on power though.

so, some conclusions of sorts.

1/ muffler doesn't work.
2/ 2-1 header doesn't work.
3/ it's way too rich. i will ignore that for as long as i can't be fucked pulling the airbox out and playing with the jetting.
4/ original headers don't work anymore due to the lack of muffler mounts due to the ducabike rearsets. one has dug oneself a hole.

dyno time is getting expensive, plus it's time away from work i don't have to waste. maybe i need to get the data logger out and have a go with that. it's a 400, it's not going anywhere fast so on road tuning is an option of sorts.

 

not really with the makeover, but as sort of the last stage of engine playing with stuff i put some 620 cams into it and got to the dyno today.

Brad The Bike Boy: Minnie the 400 Monster gets 620 cams: One has one's arse handed to oneself yet again.

 

I'm surprised you are not getting more power up top and so much more down low over standard. Typically, street engines are choked up top intake, exhaust and tuned for mid range power.

 

it's a 400, but otheriwse everything around it - airbox, carbs, exhaust - is the same as that fitted to the 600, 750 and 900. so all the bolt ons make 80hp easily on a 900. apart from the hurt any std muffler or airbox inlet will put on volumetric efficiency, none of it is sized to restrict this little engine at all. it's undervalved as well, but i'm not going to pull the heads and get into that. if you want one of these to go better, you fit a bigger engine.

 

As it sits now. well, i got the rearsets on to position the rear brake master so i could measure how long the brake hoses need to be and i'll get them made this week.

i downloaded some free cad and drew the rear brake caliper bracket, then sent the drawing out to a water jet cutter. i was pretty pleased with this - something i had't done before, and it worked!

and it finished. The inner sleeve piece is a 17mm front axle sleeve nut from a 41mm Showa fork that I bought a few of many years ago on a specials release. Machined down to reduce the final od of the outer spacer, which is a shrink fit on the inner sleeve so all 3 pieces are now an assembly. Due to the design of the wheel, there's not a lot of clearance between disc bolts and bracket.

 

nice fabbing brad
jeezus yeah not lot of clearance
if a guy was concerned the bracket could be clearanced to half thickness in that zone

thats just the kinda thing i'd be looking at/ chain off of course ,up on a swinger stand just spinning it round .lookin at it mind wandering
then i would get some kinda idea ,sidetracked,and standing up i would reach down to steady myself
right in the path of those rotor bolt heads
thats the way i would do it bludgeoned n bloody

 

you'd only do it once.

well, if you had any sense you would. i'd do it every bloody time i touched it. again and again and again.

 

new muffler. i go and pick it up tomorrow morning. v excited.

 

i made some little brackets to lower the front mudguard 22mm to suit the smaller tyre.

i fitted the new brake hoses i had made up. lengths worked out well, which is always a nice surprise. given the caliper face for the hoses is almost vertical, i didn't think of getting some shallow angle banjos on the hoses at the caliper end, but it certainly would have made it nicer to fit them. i had to angle them out sideways a fair bit to allow getting a spanner on the bleeders. took a shitload of bleeding to get it sort of ok. i was curious to see how it'd work with the 13mm master. it was very firm with the single caliper, almost wooden like, so i thought i'd give it a go. i've got the 15mm master that came off the 851 somewhere, so i can fit that if needed. i put the 16mm remote res master than came off my sport 1100i to that, but i want the coffin style on this bike.

 

took a shitload of bleeding to get it sort of ok.

Did you try taking the calipers off and pushing the pistons all the way back in then remounting? That up n over hose can trap air, too.

After that, zip tie the brake lever closed overnight, rebleed in the morning.

 

started with pistons back (calipers, esp rh, were dry), calipers off and rolled around all angles while tapping, tapping hoses with bike lent to both sides, lots of slow/fast lever cycling with bike lent to left. just really odd. it's on the sidestand at the moment with the lever zip tied. will hopefully get into the factory today to see if it comes up. i don't really know where my 15mm master is, and it has been off a bike for 15 or more years too, so it might be rooted.

with the single caliper it was rock hard and almost wooden, like the master was too big. this gets pressure at about the same lever travel, but the lever goes to the bars pretty easy. i need pressure as it's back to organic pads for the cast iron discs. didn't expect it to be this hard.

rear caliper has both the hose entry and bleeder at the bottom, couldn't be worse location wise, and the master has the outlet at the top with a 90 degree down on the hose from there. bled straight up. bastard.

 

I always fill mine through the bleeder screw using a really big syringe and a chunk of plastic gas line, makes it super easy to get the air out. Highly recommended if you have never tried doing it that way.

 

i have one of them. i actually tried that the other day on another bike that turned out had a blocked compensating port in the master. thought the pressure might forced it through, took a drill bit instead.

i was going to do that on the rear, but figured that the upside down caliper would benefit from being right side up, so i passed it up above the swingarm and held it up. seemed less messy in theory.

not sure if this one has some air in the calipers (one has been off a bike for 10 + years) i can't shift or what, but it's a real pita. the small master shouldn't effect the bleed as such, but maybe it's masking it a bit? dunno.

 

no change to the front brake. went for a ride - it works, with a lot of lever travel. you could pull the lever to the bars if you wanted, but i think by then it'd be stopping very quickly. perhaps a little too. pads need to bed in a bit too, but it just felt like the master is too small. woka woka woka. the 15 is 33% bigger, the 16 51%. think i'll go the 16. i get a nice new lever that way too.