tortron Posted November 6, 2020 Share Posted November 6, 2020 what about that bolt that fell out of the engine at 0:09 3 Quote Link to comment Share on other sites More sharing options...
Raizer Posted November 6, 2020 Author Share Posted November 6, 2020 1 minute ago, tortron said: what about that bolt that fell out of the engine at 0:09 Lol you weren't supposed to notice that! /Na, clutch cover is just sitting in place with only one of the 4 screws holding it still, that one was just sitting in it's hole. Quote Link to comment Share on other sites More sharing options...
Raizer Posted November 6, 2020 Author Share Posted November 6, 2020 Lol fuck, been talking with Jonny, sounds like the squish etc I set it up to was pretty much where he found the knock limit of avgas, that'll do it! Guess making a couple combustion chamber inserts with lower compression will be a great first project to learn how to use my new lathe. /Who's got a hook up on drums of methanol? 2 Quote Link to comment Share on other sites More sharing options...
chris r Posted November 6, 2020 Share Posted November 6, 2020 On 06/11/2020 at 09:25, Raizer said: She even gave me my own chopping board just for engines haha Before or after you spilled 2t oil on it 2 1 Quote Link to comment Share on other sites More sharing options...
Raizer Posted November 7, 2020 Author Share Posted November 7, 2020 6 hours ago, chris r said: Before or after you spilled 2t oil on it It was high temp paint not oil/shush! So that rules out the too much compression theory then. Guess it's just a case of just send it and fix what breaks. 1 1 Quote Link to comment Share on other sites More sharing options...
tortron Posted November 7, 2020 Share Posted November 7, 2020 could still have a funky flame front causing pinging/pre ignition My bike seems a lot happer with some extra clearance 1 Quote Link to comment Share on other sites More sharing options...
Raizer Posted November 7, 2020 Author Share Posted November 7, 2020 27 minutes ago, tortron said: could still have a funky flame front causing pinging/pre ignition My bike seems a lot happer with some extra clearance Re-measured the squish before and dunno why, but I measured a few points of the squashed solder and it gets tighter towards the centre rather than looser, that could have an effect! Jonny had a different piston in it at one stage, guessing he set the combustion chamber up to match an earlier piston. So I'm thinking of attempting to cut a new squish angle to match the piston I'm using and also skim the mounting flange to gain a touch of compression while I'm at it. 2 Quote Link to comment Share on other sites More sharing options...
tortron Posted November 7, 2020 Share Posted November 7, 2020 Yeah in my experience you want it tight around the edges Lol I believe mine was creating a ring around the outside, then a tight point, then the combustion chamber. Doughnut of doom 2 Quote Link to comment Share on other sites More sharing options...
Raizer Posted November 7, 2020 Author Share Posted November 7, 2020 Yeah squish angle is backwards I reckon. Checked several points around the bore multiple times to confirm and keep getting the same results 1 Quote Link to comment Share on other sites More sharing options...
Raizer Posted November 8, 2020 Author Share Posted November 8, 2020 Let me preface this by saying I have next to zero idea WTF I'm doing with a lathe!!! Got it to about .05 run out, after about 45minutes fucking about! Did mange to get the face dead on though in much less time Took a bit of a guess at the angle/did a fair few dry runs just eyeballing the tool path. Couldn't get anything close to a clean cut though, the carbide tip wanted to leave gouges, so yeah spent a while with a file then different grits of paper Have ended up with a squishband starting at 1.09mm tapering to 1.16mm, in the correct direction this time haha! If I had more confidence I'd be attempting a 0.34 skim off the flange to drop that down to .75 squish, but for now I'm going to see how it goes as is. Fingers crossed this actually helps ha 5 Quote Link to comment Share on other sites More sharing options...
Raizer Posted November 8, 2020 Author Share Posted November 8, 2020 And proof it does actually move Jetted way too rich currently so it just 4 strokes instead of coming on pipe lol 3 1 1 Quote Link to comment Share on other sites More sharing options...
Raizer Posted November 9, 2020 Author Share Posted November 9, 2020 Have got 0.10 to 0.12 clearance up the top of the bore, should be more like .05 to .06 really. Looked at FR80 and A80 pistons, but the compression heights and lengths rule them right out. I'm already running a +1.50 TM75 or TS75 piston, looks like TKRJ used to also do +1.75 and + 2.00 kits but I'm having absolutely zero luck finding even a part number for either of them. Yamaha Beluga 80cc looks to be the closest I can find, would need 3.2mm taken off the skirt and the head would need about .3 less gasket, but they aren't the most common piston either and it'd put the bore right at the max that I'd be comfortable with. 1 Quote Link to comment Share on other sites More sharing options...
tortron Posted November 9, 2020 Share Posted November 9, 2020 pin punch the piston skirt or maybe get it teflon coated? 1 Quote Link to comment Share on other sites More sharing options...
Raizer Posted November 9, 2020 Author Share Posted November 9, 2020 2 minutes ago, tortron said: or maybe get it teflon coated? Quote Link to comment Share on other sites More sharing options...
tortron Posted November 9, 2020 Share Posted November 9, 2020 https://hpcoatings.co.nz/services/advanced-engine-coatings/ i dunno how thick it would be tho. Was looking into it maybe a year go for GN for fun. saw a dr200 build with all the head, springs etc done 1 Quote Link to comment Share on other sites More sharing options...
Raizer Posted November 10, 2020 Author Share Posted November 10, 2020 Spent most of yesterday and last night scrolling through more piston catalogues than I care to think about trying to find a match, zero luck though. Emailed TKRJ and IKYP in Japan as well as Wiseco, J.E and Pro-X about +1.75 or +2.0 TS75 pistons, TKRJ said they used to make them but I'm 20 years too late, IKYP don't deal with the public. Wiseco said no problem at all, but it'd come under "custom piston" so minimum order is 12 and $$$. No one else got back to me. @GuyWithAviators likely has a worn out PW80 piston for mock up/experimentation as they look close. DS80 and JR80 use the same piston and are damn close, but the "compression height" is around 3mm lower which would fuck my port timing completely. So current plan is put it back together with the current piston and ride it while I try to track down a U70/TS75/RV75/A80 cylinder to use as a donor and build it around a 49mm DS/JR80 piston. 1 Quote Link to comment Share on other sites More sharing options...
Raizer Posted November 13, 2020 Author Share Posted November 13, 2020 4 Quote Link to comment Share on other sites More sharing options...
tortron Posted November 14, 2020 Share Posted November 14, 2020 how good is it when someones disc brake is bigger than your wheel 1 2 Quote Link to comment Share on other sites More sharing options...
Raizer Posted November 14, 2020 Author Share Posted November 14, 2020 Gave it a good amount of hard nang this morning, didn't feel like it was trying to lock up once, so I think it's safe to say the new rod kit is good lol I paid for a carb with the quick change jetting cap, I'm going to use the quick change cap!! Also think I've sound a solution to my piston slap woes, have come across a few NOS Taiwanese kits here in NZ! Have put my hand up for 2 for now, one is going to just be a bit of an experiment test bed, plan to attempt removing the liner, adding the extra ports like my current one and seeing if I can make a head on the lathe and get it to run. I know with the Taiwanese kits that I shouldn't expect great things from the piston and to keep the compression and RPM on the lower side of fun, but if the liner is decent enough there is factory size (47mm), +0.50 and +1.00 TKRJ pistons in stock with a supplier here in NZ which I know will take the abuse I have planned for it. IF I manage to pull that off then the second one will be getting a new Wiseco or Melling cylinder sleeve and 49mm Wiseco piston from a late model 80cc and another new head, that should give quality oversize piston options for years to come. 8 1 Quote Link to comment Share on other sites More sharing options...
tortron Posted November 19, 2020 Share Posted November 19, 2020 i assume you watch this guy, but maybe just make a piston eh 1 Quote Link to comment Share on other sites More sharing options...
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