@lllDennis I read that the port timings were off by 3mm because apparently the barrel was based off a dtr200. How true that is...
Would love to see before and after dyno pulls though. See how the stock Athena compares to a modified one.
I have compared Athena 170 kit vs 3MB P (and 2RH) cylinders, the only 2 things that's off the athena kit is the piston taller than the stock,the ports are exact copy off the 3MB just a bit wider and the c port is little lower and matches more a 2RH cylinder
The 170 is a mix between the 200cc casing (for the cooling canals and ypvs location) and 125 portmap internally.I searched for a piston that has the dimensions of the 56mm and with bore of 65mm but there is not,only some aftermarket forged that are max 61mm have the right piston height (pin to top).
For reference I’m running about 1mm squish on my engine with programmable ignition, I was melting the tip of the standard range spark plug after a top gear hoon but I think I was a fair bit further advanced than standard on the top end, I’d maybe stick to 1.2-1.3mm, I’m sure that’s the standard figure but my Frankenstein engine with different barrel and head measured something crazy like 1.8mm as it was! So it’s worth checking..
also to note for the future, you don’t want to go any less than about 0.8mm squish on these engines as the Conrod stretch at high rpm will smack the head.
@SpookDog yeah thats what i was planning on doing to be honest running it nice and gentle at least for the first 500 miles or so and just gradually increase it. I cant imagine the change of reeds doing a noticeable difference with the mixtures so i'll just as you say keep an eye on the plug after a couple rides or so and take it from there. Looking forward to finally getting it back on road! 🤣. Its been left in the corner of the garage as i got another bike
@RubberSalt youve told me most of this as answers to all my questions, still my mind ends up blown after reading this😂 its alot of good information to take in, or try to atleast
Thanks for putting all that together
Well this is all rather very interesting, very very interesting indeed...
After reading that that I might even scrap my plans of a 200 after reading this and seeing what was once an idea become something of a possibility and with both a 4DL setup and 4FU setup spare it’s not like I haven’t got ammo. I haven’t mentioned this either but I also have a spare 4DL head. More ammo?
Also @RubberSalt I have as much to learn as I believe you have to offer. Very well written, whilst I admit it’s out of my depth (at the moment) it’s still easy enough to follow. I also use my phone so I know it can be a pain sometimes. Me and @Arild met the same way you did and had been chatting for a while now, helping each other out and talking about the unexplored possibilities for the DTR so I just got to say welcome aboard and thanks from me and on behalf of my little Swedish g. I appreciate you helping him out a lot, I could honestly only wish to be able to do what you have 😂
Anyways I do believe this could be quite a most interesting endeavour.
Hi all thanks for all the advice it’s really helpful! Yeah he had to skim a lot off because it looks like someone Had prized off the head before with a screwdriver or something and made a big gouge in it! I’ve ordered the copper gasket (budget reasons 🤣) so I’ll try that and see how she goes but if not I’ll give a new head a go. I’ll post an update soon
Some have a diamond shape on the pulley end but they all take the same pulley - worth noting so that when setting up you get it the right way round. Best thing thing to do would be to feel up the port with the exhaust off.
I have both a 3SH TDR125 and a 3XP 200WR if you need any info - both engines are in one piece though so cant comment on the internals right now 😉