Author Topic: summer projects (Read 10716 times)

Bowtie316 · « **Reply #15 on:** June 28, 2014, 11:34:15 AM »

Wow, way to make use of all that room in there!

udontknowme · « **Reply #16 on:** June 29, 2014, 10:27:15 PM »

ill probly angle it back alittle more but i think its not far off from where it needs to be

udontknowme · « **Reply #17 on:** June 29, 2014, 10:31:44 PM »

ill probly angle it back alittle more but i think its not far off from where it needs to be

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udontknowme · « **Reply #18 on:** July 01, 2014, 12:19:23 AM »

hey guys this cylinder for my other engine showed up and i think its gonna work like a charm. what i currently have going is a 92x82 but the damn thing has a goofy piston design so it leaves a short circuit hole at tdc which prevents the aux port from being made very large. since im already using a honda rod i got a idea to see how a 89mm borex80mm stroke cylinder looks on the 82mm lower end. the honda piston has a few mm lower wristpin height than the ktm so i throw on a spacer plate i had laying around to roughly compensate for the pin difference just to see what everything looks like. honda piston fits right in like it was meant to be there and fully covers the aux windows plus it will conect right up with the honda rod thats already in there. i wish i would of thought about this before i spent any time fooling with the 92mm cylinder

heres the underneath with both pistons. you can see where the escape hole is on the ktm piston

ktm piston
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honda piston
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i drew lines marking the side skirt at tdc of each piston. blue is the honda and red is ktm. i added the green circle to show how much larger the aux ports can be in the lower portion with the honda piston which is a good thing and i cant wait to see how this thing turns out

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couple pics of the pistons differences

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i dont know what the original timings were when the 89mm cylinder was on the 80stroke crank but with the 82mm stroke and the random spacer i put in it ended up 190/130. so ill make some various thickness spacers and gaskets so i can mix and match to get it at a good starting point. probly lower the timing alittle so if i want to use any upward angle on the transfers i can because right now they enter the bore pretty flat around 7* i think and no way to put any up angle on em with out raising the timing. exh will be plenty low enough i can raise it where ever i need to. i think im gonna try and keep the exh kinda low probly low to mid 190's and just under 70% then make them aux huge and wide as hell. that should give me alot of blowdown and not ruduce the powerstroke to much

udontknowme · « **Reply #19 on:** July 06, 2014, 05:36:45 PM »

moved the front angles back alittle and traced where everything runs into the bore. i think it should work ok

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udontknowme · « **Reply #20 on:** July 07, 2014, 01:18:21 AM »

ordered piston and headgasket and couple other small things. hope to fire up this turd bucket by the weekend and see if its a complete failure or not :thinking: :jumping0041:

udontknowme · « **Reply #21 on:** July 09, 2014, 01:11:30 AM »

well since im waiting for the piston figure i just as well do some work on the reed block. had good luck in the past removing dividers on other oe reed blocks so ill try it on this one. was looking at another oe block i had laying around from ktm and the rectangle holes in the block are nearly the same size as the open size of the petal and wondered why the honda rectangle hole is quit a bit smaller than the petal opening. never tried this before but i made the block hole 2mm longer. then had boyesen make some 2 petal reeds

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udontknowme · « **Reply #22 on:** July 20, 2014, 12:25:10 AM »

hey guys i got this together and ran it last weekend but it has some problems. most of the torq seems to be too high in the rpm range. for flat drags i think it would be ok but i ride more on steeper hills that can have a tendency to pull the rpm down and if the torq isnt there your screwed. port timing might be a bit high is what im thinking. started working on another cylinder today that should work better

udontknowme · « **Reply #23 on:** July 30, 2014, 12:49:29 AM »

well its back together with different cylinder different porting. i think it will work alot better below the powerband. ran it in the garage for min but wont be able to ride until friday. a while back i had a idea what would happen if the reeds could open farther. thought of a simple answer how to do it with a spacer under the stopper. im not sure yet how well it will work but theres only one way to find out. ill test it out probly within the next few weeks

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Hawaiiysr · « **Reply #24 on:** July 30, 2014, 02:37:53 AM »

I don't even use the petal stops.

udontknowme · « **Reply #25 on:** July 31, 2014, 08:41:05 PM »

did you notice it run better ? ive heard the petal should lift approx .3 x the free length. which is about the same as what the simulators say that ive seen. problem is im not sure you can get these reeds to lift 11mm. might hit the floor and roof but i havent really checked. maybe theres not enough pressure differential to even pull em open that far anyways. alot of questions and hardly any answers

toydoc · « **Reply #26 on:** August 01, 2014, 04:16:04 AM »

IMO, Bad idea not to use any stop at all (or spacer). Bend the tips of the stop out to your spec, trim the stop ends back some if it's hitting roof, I'd set them to 10mm. Your reed mod looks alot like the very first billet V-force. and they work super.

It looks like your running a single reed. I'd fab up a extra tension reed and see if you get some TQ back into your motor. Dig up some used reed pedals, cut them down to 1/3 length and lay them on top of the reed pedal you run now. Run it and see if it helps. Cut them back more to add rpm, retest.

Very nice work by the way

Jerry Hall · « **Reply #27 on:** August 01, 2014, 10:59:03 AM »

Quote from: udontknowme;38603

well since im waiting for the piston figure i just as well do some work on the reed block. had good luck in the past removing dividers on other oe reed blocks so ill try it on this one. was looking at another oe block i had laying around from ktm and the rectangle holes in the block are nearly the same size as the open size of the petal and wondered why the honda rectangle hole is quit a bit smaller than the petal opening. never tried this before but i made the block hole 2mm longer. then had boyesen make some 2 petal reeds

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What thickness petal are you using in the last picture? Are those TDR reed petals?

I have make similar reed cage modifications in the past, but had problems with the petals cracking in the middle because the petals are trying to fold inward during the compression phase of the crank case. The petals trying to fold inward, would also ware the rubber coating off of the sealing surface due to the petal abrasion as the petals were deflecting inward on the large cage window.

When I made petals thick enough (.022" to .025" thick) that they would not fail, but were too stiff. Low and mid range power suffered with the thicker petals. I think the petals that ran the best were around .016 to .018" thick, but would fail.

udontknowme · « **Reply #28 on:** August 01, 2014, 11:35:28 AM »

theyre just boyesen reeds. .020" thick. i thought about trying some carbon fiber but i think they might be thinner and probly not a good idea on a large petal . i could image a thin petal (under .020") buckling if its surface area is too large without enough support from center dividers, although ive used .020" boyesens on other blocks and havent noticed the center folding inwards so maybe .020" is just barely strong enough. plus i was thinking a very large super thin petal may not do well at high rpm if it has to lift a large distance. vf cages seem to do well with very thin carbon petals but it seems like they only have to lift a short distance during each cycle

udontknowme · « **Reply #29 on:** August 03, 2014, 02:04:03 AM »

i got the cage out and put the spacers under the stoppers and the cage is back in. end of the week ill have a answer wether it does any good or not. at this point i dont see how it couldnt do some good. 7mm lift seems very small. ktm is 10mm lift without any modification although the cage is wider and not as tall so that probly factors in. not able to use epoxy on this cylinder because the cage barely fits in the intake with the spacers but i keep seeing large amounts of fuel collecting at the back of the intake and that was the reason i had tried the epoxy last time. seemed like if some of the hiding spots were eliminated it might do some good.

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