Ducati Monster Forum

A customer has a Scrambler 800 similar to mine and wants it freed up for trackdays.  I notice that my own bike gets breathless pretty quickly with an airbox and intake architecture that looks like it was designed to promote sleep apnoea or asthma! It makes the airbox of the Sports classic and air cooled Hypermotard look like high performance kit!

A mate has a Scrambler 800 with a WASP kit (which are no longer available). The WASP kit gives a major mid range boost in torque and hp but with no top end increase. I rode my mates bike and it felt like a well tuned carby M900 with great torque.

The customer bike will be tuned with various parts available to emulate a poor mans WASP kit. The ingredients for this tune include major intake mods as it will be a track bike (an unusual  choice for a track bike). The local race track complex has various dirt tracks and an asphalt circuit and has a Supermoto layout available, so maybe the bike choice makes perfect sense.


I got inspiration from a Scrambler 850 big bore built by KAMNA and decided on the following.

1.K&N pod filter
2. PCVI
3. Powercommander O2 emulator
4. Smart Moto PAIR delete kit and device
5. Free flowing exhaust of customer choice
6. Dyno tune
7. Airbox delete
8. Mini K&N filter for the breather.


Brad Black informed me that the Scrambler 800 has long duration cams (I'm guessing to compensate for the single throttle body). The compression is at least 11:1 and the valve sizes appear large enough if I can confirm them based on the 796 models. I've seen dyno charts with a 10hp increase in peak power with similar mods.

So I'm hopeful.

 (https://live.staticflickr.com/65535/53433945402_71b4617f4b_k.jpg) (https://www.flickr.com/gp/150482584@N03/Qi02NVN616)20240101_195829 (https://www.flickr.com/gp/150482584@N03/Qi02NVN616) by Tony Kokonis (https://www.flickr.com/photos/150482584@N03/), on Flickr

Intake is very close to ceiling of the airbox. The cut away is for the filter which is fed through a small hole. The air filters via the walls of the cylindrical filter, travels upwards then has to flow over the small gap down into the throttle body. A torturous route.

(https://live.staticflickr.com/65535/53435191159_144da1ef7f_k.jpg) (https://www.flickr.com/gp/150482584@N03/64fqJ807Qz)20240101_195939 (https://www.flickr.com/gp/150482584@N03/64fqJ807Qz) by Tony Kokonis (https://www.flickr.com/photos/150482584@N03/), on Flickr     



The pod filter has a nice velocity stack inner radius.

The airbox incidently severely blocks airflow to the rear cylinder. With it removed the substantial cylinder cooling fins get a good shot of air. Important for a track bike.

Cool  8)

My 800 got new 44mm intake valves (stock exhaust valves). That was enough for my 99bhp (Kämna calculation). I have more mods than the Scramblers you're talking about and working on. Compression equal. 900i cams.

IMO for any kind of performance improvement on this budget bike; the geometry, suspension and brakes are MUCH more important.

Very true, but the motor is very restricted. Its not too bad street riding as there is strong low rpm torque, but when making demands of the motor, it is very noticeable and frustrating. With my bike stock is ok as the speed limits are 50-60 mph or 80-100 kph. I have my Gixxer for the track. [evil] Both my mate and the customer note how the motor struggles . I suspect the rear cylinder over heats in our summers with a drop in power. When I rode a Scrambler around Chianti, I was surprised how restricted the motor was.

Suspension upgrades are very likely. My mate with the other Scrambler has fitted an Ohlins shock and complete fork cartridge upgrade kit. Most people also fit lower bars.

That's great power. A good outcome!

I still have to confirm the Scrambler valve sizes if they are 796 sizes or older 800/900 sizes.

 [popcorn]

Where'd he source the WASP kit?

From WA, but they stopped making them when I inquired, so I looked at Kamna for ideas.

(https://live.staticflickr.com/65535/53473162641_b65c000f0b_h.jpg) (https://www.flickr.com/gp/150482584@N03/7094bRPY95)IMG_3692 (https://www.flickr.com/gp/150482584@N03/7094bRPY95) by Tony Kokonis (https://www.flickr.com/photos/150482584@N03/), on Flickr  


(https://live.staticflickr.com/65535/53473466248_97441898c7_c.jpg) (https://www.flickr.com/gp/150482584@N03/HV09Z43Qn3)20230822_001531 (https://www.flickr.com/gp/150482584@N03/HV09Z43Qn3) by Tony Kokonis (https://www.flickr.com/photos/150482584@N03/), on Flickr 

Front cylinder exposed for easier servicing and top cooling fins get airflow.. Rear cylinder has exposure to air cooling with the airbox removed. A mate with a WASP kit reports cooler operating temps of the rear cylinder. Half the valve cover is normally covered by the lower airbox which completely blocks airflow over the motor.

  (https://live.staticflickr.com/65535/53472256612_cd45c9529e_k.jpg) (https://www.flickr.com/gp/150482584@N03/88qZsmg0X4)IMG_3691 (https://www.flickr.com/gp/150482584@N03/88qZsmg0X4) by Tony Kokonis (https://www.flickr.com/photos/150482584@N03/), on Flickr



What lurks high under the tank.

    (https://live.staticflickr.com/65535/53473581525_70e6bef7d4_k.jpg) (https://www.flickr.com/gp/150482584@N03/94n1PLxX1f)IMG_3690 (https://www.flickr.com/gp/150482584@N03/94n1PLxX1f) by Tony Kokonis (https://www.flickr.com/photos/150482584@N03/), on Flickr  


This track bike gets PAIR block off plates for accurate dyno tuning with AFR meter. Also removes items to declutter for easier trackside work and better airflow to the motor.

Brad informed me that the SC800 has 44mm inlet valves and 38.5 exhaust valves, so I'm happy about that.

Dyno session this week to tune the PCVI. An O2 Optimiser controls closed loop tuning and a Smart Moto emulator covers the PAIR removal. The bike will be a heavy weight supermoto/track bike for the local track that covers a range of disciplines.

Bike had an initial dyno run to get it going. Runs like an M900 with open airbox, jet kit and light flywheel.
Will finish off the dyno tuning when we settle on an exhaust configuration. Haven't tuned the front cylinder yet or fine tuned both pots as yet to decide on  2 into 1 (doubt it), 2 into 1 into 2 like an 1100 Evo style or 2 into 1 into 2 like a 900 Monster.
There is a Zard low mount pipe that has two outlets I'm considering. I tried to graft a set of Termis on from an 1100Evo but the lack of ground clearance is an issue and a fair bit of friggin' around.
Open to any suggestions.

Initial dyno mapping gained 8hp. We held off on the fine tuning and individual cylinder mapping until we test the exhaust. The dyno operator feels there's 3-5 hp more to be gained from individual cylinder mapping and another 3-5 hp with a 2-1-2 system. First run will be with the new pipe and if it makes more hp we'll keep it on and finish the tuning. If it's a dud we can revert to the 2-1 pipe and finish the tuning.
Well see.

 [thumbsup]

Impressive!

I've been checking dyno charts for various exhausts and I think a 2-1-2 pipe should make significant gains in the midrange rpm which will be useful at the tight and technical local track.

Interesting, I´ll follow this, looking forward to some dyno graphs. If you can get that much improvement without opening the motor, that´s really great!   

I rode a friends scrambler quite a lot in 2022, I actually found the motor quite OK, but the suspension was really, really bad. I hear that bike is now beeng upgraded with an Öhlins shock, and Andreanio cartridges. I´m looking forward to a test ride this summer :-)

I think the improvement is because the motor is so restricted, rather than any special tuning tricks ;D

Kamna built an 850 big bore Scrambler with 45mm inlet valves, porting and a K&N pod filter with a PCV. It made 87ps.

https://www.ducati-kaemna.com/tuning/best-practice/2-valve-tuning/ducati-scramber-800-tuning

https://www.ducati-kaemna.com/media/igallery/s/i/silvio_schulze_-_scrambler.jpg

Kämna has always used "calculated" power, like Ducati did. Roughly 10% high.

I know of dynos that have varied by 10%+ and they were dynojet 250 models. Even the updated software reads 10% less hp. I have to take that into account comparing dyno charts on the same dyno 10 years apart.

, but of course, the changes are what you evaluate by - so it's not very important.

Should have the final dyno tuning completed as soon as the alternate exhausts are completed. A Delkevic 2-1, Zard 2-1 dual outlet and Zard 2-1 dual outlet race pipe. The Zard pipes are crash damaged pipes I'm repairing with the help of a mate who was a boiler maker. He works like an artist. They are expensive exhausts, so finding beat up examples was a necessity. The ultimate pipe would be an Akrapovic 2-1-2 if i had the money.

Cognisant of issues with 2-1 exhausts on larger desmodue motors (750+), I was caught between packaging and tuning issues. The Scrambler is a low bike and twin shotgun mufflers can ground easily in the canyons. It explains why the Zard and Termignoni race pipes are high rise "Scrambler" types. Since I regularly take the GLW pillion, the pipes will be tucked into a ow mount location. The Zard pipes mimic the 2-1-2 design, but housed within a mono muffler design and I'm trying to get that result within the tight confines of the little Scrambler. Another detail was having the crossover as short as possible before the muffler entry. What I'm trying to do is adhere to a blend of the 2-1-2 configuration as the Monster/888 crossover style influenced by the M1100 Evo 2-1-2. Historically these appear to be two of the best exhaust designs for larger desmodues. That's all theory however, and only dyno time will tell.

 
Links to vendors regarding each pipe to be tested. The high pipe will be fitted low to the stock headers.



 https://www.ebay.com.au/itm/144527622152?chn=ps&_ul=AU&norover=1&mkevt=1&mkrid=705-139619-5960-0&mkcid=2&mkscid=101&itemid=144527622152&targetid=1741701787098&device=m&mktype=pla&googleloc=9071295&poi=&campaignid=18278742238&mkgroupid=141565058112&rlsatarget=pla-1741701787098&abcId=9301725&merchantid=118974818&gad_source=1&gclid=Cj0KCQiAz8GuBhCxARIsAOpzk8zI8HBcAQ1ZVkU7WPf4-L9Zf14s-LpTIu5Q4vaOuUPn2iqTj1GmYTYaArJIEALw_wcB


https://www.ebay.com.au/itm/395052555946?chn=ps&_ul=AU&norover=1&mkevt=1&mkrid=705-139619-5960-0&mkcid=2&mkscid=101&itemid=395052555946&targetid=1741701788338&device=m&mktype=pla&googleloc=9071295&poi=&campaignid=18278742238&mkgroupid=141565058112&rlsatarget=pla-1741701788338&abcId=9301725&merchantid=494523409&gad_source=1&gclid=Cj0KCQiAz8GuBhCxARIsAOpzk8y-S0UvUkEuEM6CVPgUazJqJLzpFf5ENo2H0_KaHshscv1ZhkKgfJQaAteBEALw_wcB



    https://delkevic.com/18-stainless-steel-oval-muffler-to-fit-scrambler-800-2015-2020/  

    

The old spaghetti crossover worked well also IIRC.

Yes it gave an increase in peak hp. I thought of having two of these with a crossover added like the stock system but the feed pipes to the mufflers would not be the same length. Unsure of it will be an issue. It would be an expensive test.


https://redirect.viglink.com/?format=go&jsonp=vglnk_170863573772911&key=7380040348cb056f0e988195afaf9852&libId=lsxpke1a01000c6m000UL46cpq1vu&loc=https%3A%2F%2Fducatimonsterforum.org%2Findex.php%3Faction%3Dpost%3Bquote%3D1470120%3Btopic%3D79771.15%3Bnum_replies%3D27%3Bsesc%3Dd1592da8d13c5793d5ac3e285f599b21&v=1&type=U&opt=true&out=https%3A%2F%2Fdelkevic.com%2F18-stainless-steel-oval-muffler-to-fit-scrambler-800-2015-2020%2F&ref=https%3A%2F%2Fducatimonsterforum.org%2Findex.php%3Ftopic%3D79771.15%3Btopicseen&title=Post%20reply&txt=https%3A%2F%2Fdelkevic.com%2F18-stainless-steel-oval-muffler-to-fit-scrambler-800-2015-2020%2F

I've noticed that the dyno charts of the various Scrambler (performance orientated vs style orientated) exhausts available appear to give about 2- 3 hp at the top and bottom end with the midrange the same. Most appear to be types of 2-1 systems. I haven't yet found a dyno chart for the Akrapovic 2-1-2 twin shotgun style mufflers. I'm interested to discover the influence on the power characteristics of the 2-1 style system and how it interacts with the 2-1 single TB manifold and long duration cams.

The high rise scrambler race system arrived , but the muffler was completely gutted. It's a pretty involved and expensive welding task to rebuild it with dual cores so I'll leave it to another time. The dyno test will be with the short twin outlet Zard vs long Delkevic 2-1. I think the main test here will be length of the link pipe although the Zard internals are a bit funky. The Zards internals have a short link pipe entrance to an open cavity tube lined with baffles surface then perforated core mesh surrounded by fibre packing, then it enters a Y tube exiting to twin large diameter outlets. The homolgated version has a cat in the cavity and 10-15 mm db killers in the outlets. The non homologated version has no cat and larger diameter, removable db killers. This Zard Linited Edition pipe has had its db killers removed and no cat, so it's clearly for race use only.

Dyno time will tell.

Edit.
Second dyno session completed. I had a closer look at the dyno chart. Gained another 2-4 hp right through the range after tuning the front cylinder. The dyno operator said the difference in mapping required was substantial. 5 ft/lbs of torque gained at 3000 rpm. About 3 more peak hp but good gains in torque and hp through the whole rev range. An increase in response and smoothness was reported by the owner during ride testing.The gains match those from similar intake, exhaust and tuning mods achieved by others locally. It highlights the severe restriction of the oem airbox design compared to say an 800 Monster. About 12 peak hp was gained, or rather to be more accurate, 12 hp was recovered! This also highlights the value of individual cylinder tuning on a V/L twin.

Common map vs individual cylinder mapping. From my page.

https://www.facebook.com/photo.php/?photo_id=887711399817468


Local shop results to indicate before and after from stock vs the mods mentioned. Link provided to comply with copyright. Looks like a Termignoni high rise full system and they dyno tune/flash the ECU. Kudos to them. From their site. A good reference and about the same result. Brad bikeboy uses these guys so thats a strong recommendation.


https://dynobike.com.au/product/ducati-scrambler-800-stage-2-custom-tune-15/

In regards to exhaust, the Delkevic conventional 2-1 with 450mm oval muffler was used. Note that the Delkevic site indicates more lower and mid range power with the shorter mufflers in their range while using the same mid pipe. This indicates the influence of total pipe length. The effect was more pronounced the shorter the muffler. 350mm and 225mm length mufflers were available.
The shortest Delkevic muffler matched the gains of the Termignoni and Zard  2-1 full systems when compared to their respective company dyno charts.

Hello,
don´t know if you also read other forums; there´s quite an interesting thread there concerning exhausts:

https://www.ducati.ms/threads/exhaust-design-question.751516/#replies

It´s well worth the effort to go through!

Good article.
I thought of doing a 2-1-2 ala Ducati M900 style with two of the Delkevic pipes, but a short and annoyingly loud 225mm Delkevic muffler would achieve the same goal within a pony or two. The Zard short muffler may have given more mid range but the owner couldn't stand the noise. Reducing overall length of the system by 200-300mm should help the midrange from what I've seen of dyno charts.

We are going to try another exhaust on this bike seeking more power through the rev range. Various dyno tests supplied by different exhaust manufacturers seem to indicate that the current exhaust is too long by approximately 225-300mm depending on pipe diameter. The pipe to be tested will probably not make more peak hp, but my enquiries appear to support a shorter total exhaust length giving 2-4 more hp throughout the bottom end and mid range. My local dyno guy has had this view from the beginning, so we'll see if he's correct. The decible level reported by the manufacturer is moderate for a perforated core, straight baffle type muffler with claims of a deep note rather than a high frequency raspy sound.
I'll update when we try it.

Tested a short loud muffler (Verex) with an instant gain in midrange response reported by the rider under acceleration. Unfortunately the angle of the pipe sent the resonance right into the right ear of the rider. He went back to the pipe that left the noise behind him, so we didn't get back to the dyno. There is a full header set available that routes like an early Monster 2 into 1 system that will have shorter overall length (and not shroud the cambelts). I can't recall who makes it, maybe Spark or some such. I still think a Monster 800 set of headers with twin mufflers modified to fit is the best option.