TomTom's 570 70 degree engine tinkering.

Did a bit of fiddling today and sorted the throttle cable, tomorrow the head will come off for porting it to fit the new TB. A lot of material has to come out going from the current 42mm to 46, 2mm all around the circumference! Got new blades for it, frrr

I had a bit of a problem with the KTM intake rubber not fitting the 570 head, turns out I got the wrong intake rubber, new order for the good one from KTM 950 -05, marked 60036044000 INTAKE BOOT 03. Ill make a complete list of bits and bobs with part numbers later in the final post when conversion is done.

Seems all parts are covered now(lol!) and I can get down to grinding the head beginning of next week.

Edit: KTM part no 60036044000 confirmed to do the job.

A pic of current vs replacement, its a bit bigger and a lot longer arrangement no doubt.
Dont get me wrong here, it isnt better the bigger it is, just right is what you want.
Getting it to fit the bike will be...lets say interesting but doable

Diameters;
OEM TB is 44mm on top and tapers down to 42 before the butterfly and then stays at 42.
New TB is 50 on top down to just below the butterfly where it tapers down to 46 and stays 46.

Lengths;
The intake port from the flange to the valve is around 90mm.
OEM TB is 80mm, plus the rubber 'stack' of 20mm -> total length around 190mm.
New TB is 100mm, plus a 55mm stack -> total length 245mm.

190mm will from experience give a smoothed out delivery but torque will be traded for it. Cam duration is fairly short so maybe with the new TB it wont get too wavy but better tq. Just guessing here, time will tell.

I can do it the other way around. Im going to fit the TB first, but I can do that as an isolated event still.
Infact I have three setups to try if Im feeling ambitious, form of the day will dictate
Im quite soft for the all three option if enough people are interested in me doing so, just inspire the old goat to do so

-TB with OEM exhaust, oem ecu and bazzaz FI unit (What I had, just TB differing)
-TB with OEM exhaust and FP ecu (having access to ignition advance)
-TB Doma exhaust and FP ecu

A stock bike with slipon I can get on the dyno, have a race buddy from the ice that asked, we were quite even on the ice before I modded my bike, should be a valid reference for a stocker.
All else will be with my bike, ported head and the FP piston, that is.
Meaning we will never know what a bigger TB does to a stock bike, but I dont think its too interesting as its too much work, do the high comp and porting first Id say.

Obvious first mod is the seat mod.

Managed to sort the head today, not much left of the flange but enough.
Unstrapped the electricals and then its not an issue making the TB fit the bike, may have to trim the stack a tad as its close to the frame LH plus the rubber boot needs a few mm's. Also bought the 450 boot just incase its better suited for the job, with the oem TB its situated far left while with the new one its much more centered, we'll see.

Now just an awful lot of cleaning ahead...sigh...and then some dyno fiddling.

Most of the cleaning up done, yay! As its been taken out of trails service and replaced by a younger **** Ill take the opportunity to give it a thorough clean up plus new plastics, think Ill call her the mean house wife from now on zzz hehe.

Thinking about testing, I wont test the oem ecu as I dont have the vacuum sensor for the Speed-Density map anymore with the new TB and this controls a lot of the fueling below seven degrees openings(or so), so itll be a pain to start and keep it going, off the list.

Bike is now setup with oem exhaust and FP-ecu ready to start, just waiting for a new injector as it got broken in the transport back here then, if most of the liquids stay inside the engine, a dyno test

Bike is started. No issues, started right away, idles well and good response blipping it.

@HusaBELG; I have the dynos from last year, OEM exhaust ported head mapped with the bazzaz unit, and the seat mod aswell. So there will be four different setups to overlay.

Put it on the dyno and everything worked ok until first WOT pull when the head gasket blew, ************* I reused the old one so I got myself to blame for being a tight arse haha. New gasket ordered and will be here tomorrow.

FP setup seems to work really well, bike starts up like oem and while warming the engine up in the dyno I didnt notice any problems with transitions at all, impression being its a well done job, given I have the map in there now for the full system.
Have to mention support is top A from FP, stand up guy no doubt.

New head gasket in Ill do the usual 2x4 runs to establish power and then cool down and fit the full doma.

Oh the joy of tinkering...(long post releiving frustration)
Talk about projects can be uphill sometimes.
First the head gasket, thats alright as I did take a chance there, ripped the head off and a new gasket went in, pushing the start button with a fresh gasket, wont idle sputters a bit and I had to open the blade more to have it idle, dribbles and smokes...wtf??? Tore the head cover to check timing, no problems timing is correct.....I noticed the starter acting a bit weird, seemed battery power decreased quite rapidly...mkay, put a bump starter on and no improvement?? Is the bike hard to turn over?, plug out and turned it, nope normal. Massive headscratching or headache if you will :/

Just prior this I took the head off and assumed it had something to do with that, change something and its likely something went wrong because of that, indeed it is likely so but doesnt have to be. Took a brake and a few bells started ringing (not the normal bells and voices inside) battery!? I was (falsly) thinking if I just get the bike started the generator will produce enough to overcome a weak battery, yes thats true for a battery in need of charging, however if it has collapsed it will **** just about everything up and thats why the bump battery didnt work either, so I went hunting for a new one today, put it in ey presto everything back to normal, phuckiiiiing pjew

Now Im pretty much drained mentally. Tried the bike on the dyno with the map FP provided, it did ok, same numbers up to 8k and then just went sideways. As I broke the AFR bung on the oem exhaust and just welded it shut I cant measure AFR and with all this **** happening I just dont have the drive to map this setup to find out what it could do as Im not even going to use it, hope you understand. So far not much to learn other than the big TB doesnt make low to mid worse, it shouldnt as the restriction should be in the port.

Started mounting the doma system, looks like its a good fit but also a bit longer which is good, rear frame had to come off but thats no biggie, Ill go down and work some more tomorrow, now time for a pint, cheers berg nuttas

Thanks for chiming in! I think its hard to get this engine screaming. Ill tune this engine but dont expect too much, 60 something, perhaps get more tq, shape of curve is important aswell, early grunt is top, going round a corner you can blip to a slide instantly.

Torque Monster said:

It took me a ton of time to get my 663 dialed in, lots of fiddling with the mapping and such. Fun frustration is what I call it.

Low battery, weak battery has been a source of hair pulling for me many times. Once the system gets low my thought is that the spark diminishes to a weak level that won't work or it goes away all together. My battery of choice now after trying a few is a Yuasa Z7S, nothing else period.

FYI - on my 663 I run the stock throttle body bored out a few mm's to I believe 44.5. On dyno runs I do not see any fall off because of a lack of flow. I had my head flow benched with the same throttle body and it flows fine. Put 70+ hp runs down. Biggest difference is the huge change to fueling over say a stock map. Even fiddled with different timing as I can change that with my Vortex ECU, didn't do anything huge to the hp so we just stuck to the stock timing map.

I have messed with a 70 degree motor as much as anyone from what I can tell, other that maybe a pure race shop. Very little on my setup is stock or unmodified.

Cheers
Chris

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bushmechanic said:

thanks for this thread its nice to read about other peoples fun frustration

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Youve had your share I bet reading your threads (kudos!), prolly why its fun to you here No worries, if you read a thread and nothing has gone wrong the whole truth havent been said or the project scope is just too lame