Bump, fired up my car last weekend.

Does anyone know the thread pitch for the exhaust port on the head? (where the header screws into with the adaptor)

braaaap! bbbbraaaap! popopopop brAAAAAAAP! excellent


its a runner! finally, its a runner!

what a saga! (i better be logged in this time now!)

so. i discovered i had a hsp warhead. pos but i blew the engine, so an ideal victim!

enter the asp 30. yeah, not an os...i do have the os, but its sorta saved, on a shelf.... not a car version

but anyway! its an ASP30 with an os crankshaft! and starter bits. tigerstart but methinks ill track down the puller... sick of flat batteries!

flywheel, badly mounted, i always intended to make a proper taper lock but im lazy so just bored it out and bolt it up tight

made the stub? what do you call that thing? spigot shaft from a suitable looking bolt, excellent 1/4x28 tap added to my collection of unusual taps

filled the back of the flywheel up with lead...extra weight on a 4 banger cant hurt... unless the glue lets go and im in the way!

carb issues... always carb issues. just ordered a perry...3600? should be ideal. was running a different one on a custom manifold but iunno... theres this nasty big gouge in the plastic body as the barrel closes for idle, and i can only explain that by a lot of backfiring! (or sand and as it happened on a bench well away from any sand...)

other option carb im sticking my nose into is the ENYA 11cx70. 10mm shank, 5.7mm bore... twin needle... spigot for an air filter... fingers crossed!


BUT! onto my first few drives with four strokers!

power? who said power? theres heaps! heaps and heaps! just brief and sorta runs out quick sounds nice though! it was getting better after a good run in, but the carb wouldnt let me get nice lean top and keep idling...pesky thing. lo needle screwed all the way in, idle all the way in! squeeze line and it revs up heaps at "idle". this area needs work!

so. im impressed enough to continue!

i have a HSP, with a 47/42 tranny. appears the onroad version has the same box, but with a 44/39 combo... that is, 3 teeth less....

im currently running hpi pinions and bell, 17/22, with a 23/18 in reserve to try. i think ill need it.

(noone ever told me the neat trick that with gears on common shafts, as long as the total teeth in each combination is the same, they work...its sort of obvious though now...in hindsight)

but!

i get both trannies, pull em apart, and hopefully end up with a 47/39!

in combination with a kyosho 14 or 15 pinion with my hpi 22 or 23, i should get a major ratio change! ie, 15(14):47 1st (3:1!) to a 23(22):39 2nd (nearly 1.5:1).... weee! i want it shifting just before redline, then bang! down she goes again! instead of the current "was that a cough at idle or a shift?"


a big issue is the shift spring! stock is too hard! the tiny ones from AFX slot cars are too soft! all i can think of is a locksmith for finding anything suitable...

but then, running a 15 or 14 on 47 instead of the 17 im using means it wont spin so fast in first, meaning the spring can be a lil bit softer.... but at the moment you can barely tell its shifted...probably 3krpm if that... so...springs or...drill holes in the little weight/pawl? an idea i spose...

*bounces up and down impatiently waiting for more parts to arrive*

ill get this thing GOING! already shredded a set of tyres and guzzled 1.5 L of fuel! in the first day!

oh...and found a neat lil 20-25mm fan that runs on the reciever pack... for the mini electrics but hey! its perfect for this application!

Maybe I should rephrase my question. Is the threads on the exhaust port the same size on the .26 and .40 or is there a difference in diameter?

Hope this helps.

http://www.osengines.com/parts/xr35230.html
OSMG5772 45169200 Exhaust Pipe Nut F90-240

http://www.osengines.com/parts/xr34150.html
OSMG5776 45769200 Exhaust Pipe Nut FS-20/26S

I have both the FS40 and the FS26 but have not tried the nuts to see if they are the same. If you want me to try then let me know.

Yes, if you can see if one threads to another, that would be a bunch of help for me. My header is slightly bent, so I'd like to try the flexible header available as option for the .40.

http://manuals.hobbico.com/osm/fs-26sx-c-cx-manual.pdf
http://manuals.hobbico.com/osm/fs-40s-c-cx-manual.pdf

I did check both manuals and apparently, they use the same exhaust pipe lock nut, #8 on both manuals. However, the .40 uses an additional exhaust gasket?? Not sure why....my .26 certainly does not has it and not listed in the manual.

Sorry for the late reply.
I looked at my FS40SC and the FS26SC exhaust nuts.
They are NOT the same. The FS40SC exhaust nut is a bigger diameter than the FS26SC exhaust nut.

stands to reason. bigger engine, bigger pipe, bigger nut stupid asp30 has a different nut again, really coarse thread. 14mm nut. cant wait til it explodes! im trying, but it seems determined.

ill be brief this time. still waiting on gear box parts to continue the thumping, but i have solved the shift spring problem. i realised guitar string wound on a 1.6mm rod is ideal! can make springs of almost any desired strength!

so now i have it shifting nicely at about the rpm i want 10k or so. you dont hear any change in engine note. it just suddenly spins the wheels and takes off! oh, for a slipper clutch on this thing!

might need it when the shift jumps to an 8 tooth difference!


i really have to get my weekends back onto practical concerns...

Thanks for confirming. Looks like I'm back to square one with finding a header for my FW04 or making my own.

I cross referenced the exhaust nut/gasket and they are the same as the
http://www.osengines.com/parts/xr36108.html
http://www.osengines.com/parts/xr35230.html

which can be found at towerhobbies:

http://www3.towerhobbies.com/cgi-bin...5772&search=Go

or you can the exhaust pipe and brass washer and exhaust lock nut

http://www3.towerhobbies.com/cgi-bin...5756&search=Go

Hope this helps. Maybe you can use the above engine's exhaust pipe and attach a muffler... hmm maybe I can make my FW04 4 stroke into a rear exhaust with the above pipe kit...

If you're working with the ASP head, the exhaust thread is neither M9x0.75 like the FS-26, nor M10x0.75 like the FS-40. The ASP FS30 has an M10x1.0 thread. Some Saito engines use the same thread, but I'm not sure if you'll find a suitable pipe and nut.

Greg

Anyone ever heard about OS Engines FS "30" CX Pull Start Four Stroke Engine.

For a very short time right before OS Engines phased out the pull start engines they made a small run in the 30 size???

Is this true??

I have the engine in my possession and here are some pictures ..as you can see the block has the black factory coating, that's all I can see that makes me not think it's a farce.

Can someone tell me if this is true, I should just contact o.s. which I will do after this post, but I wanted to know if anyone had ever heard of this???

sincerely johnny

Wow, I never heard of this. Please let us know the reply from O.S.

9/32 brass pipe bent to fit to the stock pipe...cant seem to find anyone with stainless in stock and the nut, managed to find some strange gas fittiing! could have machined down the elbow supplied but somehow i lost it just as i needed it...erm... it reappeared shortly afterwards. the exhaust makes a mess of the plastic expansion chamber!

this is one conversion that takes research. and some fabrication.

the bit of information i would LOVE is the cam durations!

surely someone that owns a 26C can be a gentleman and find a degree wheel, a dial indicator and post a chart of the cam durations? stock versus C version...? ive read this thread through. and others elsewhere. im yet to find out the lifts and or durations.

and as i dont think im ever going to get my hands on a C type cam, i have no option other than to rely on someones thoughtfulness...or work it out the hard way! i wonder what the profile is in a cbr125? while hard, the cam isnt impossible to make... easy conversions, anyone?

anyway, ive had it apart for a while, just got it back together today. had a set of fs30 (os) cams that i tried...it went worse. or seemed to, at least. made quite a few changes, and not sure which ones doing what exactly...back to asp tomorrow. i should take my own advice and map out the stock cam timing...

im thinking that by shimming the cam over slightly, you can either retard or advance the cams some due to the spiral gear?

still waiting for my latest carby.

im using the 40C manifold, and it seems to not like plastic bodied perry carbs
so ordered the enya 11cx70 carb. hoping...waiting...

measuring from the lifter, with no clearance, im getting around 305 degrees duration on both intake and exhaust. standard OS fs26s.

.........intake exhaust
open 65BTDC 85ATDC
close 120BTDC 30ATDC
max 90ATDC 110BTDC
mm lift 1.75 1.4

this is only a rough measurement, not using a pointer on my dial or really zeroing it to TDC...but close enough.

i dont think there can be much difference between the cams themselves.

someone can always prove me wrong of course... by measuring their "c" cam... or i could possibly even email os and ask.

the valves are larger on the c version, yes? what about rocker ratio? same as a stock or different again? a slight change in ratio can make a big difference on how far the valve travels... just those two things alone can account for the extra performance. ive noticed that rockers are available still...

when you consider that in porting a full size engine, removing minimal material can result in failry impressive gains, im sure an extra 0.5mm of valve lift combined with, say, 1mm extra diameter can make substantial differences when the original intake is only 5mm to start with...

and other than the odd one or two, noones done the c cam in a stock 26. and noones definitively and conclusively then proven that its all in the cam... the stocker has a fairly extreme profile already...


anyways! my video arrived! i have one wireless camera! thinking i use a lil 2s lipo cell to power it, with a 5 volt regulator to replace the reciever pack. how to mount it so it doesnt vibrate to pieces will be tricky!

i wanna show off my shift pattern... with final ratios of approx 9:1 and 4.5:1, it seems perfect sounds like the real deal and actually takes off in 2nd now!

Any one have a used cam 26 c. And 40 c . I think I can make them at work and maybe make alittle hotter ones , think there would be interest if I sold them ??? I can buy new 40 c cams on eBay now . If you have one for sale either one shoot me a price