karlok
L plate rider.
Posts: 15
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Post by karlok on Sept 9, 2023 9:44:14 GMT 1
Hi guys, I'm new here, been searching through the forum about this, because it is probably written somewhere but I can't find it.
Its a RD250LC in question.
Will Ypvs pipes fit on LC models and clear the centre stand?
I would like to use Ypvs pipes on my build, the plan is to install 392 athena kit (already in the post) on the LC bottom end ( welded adapter plate). The cylinders will be using pneumatic power valves.
Is there any blueprints for aftermarket exhausts, as I will have to cut off the flanges probably due to using that kit it is possible that custom pipes will have to be made.
Hopefully its the right thread for the question. Thanks
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Post by headcoats on Sept 9, 2023 11:11:23 GMT 1
When you say 250lc is it a ypvs model otherwise the Athena kit won't fit
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Post by tacky1 on Sept 10, 2023 1:45:44 GMT 1
I think Toomey exhausts and Wicked motorsports make adapters for the exhausts to fit the Athena cylinders.
A lot of owners do this swap.
I’ve never seen an Athena cylinder kit on an LC. Different bolt pattern etc.
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Post by JonW on Sept 10, 2023 2:15:12 GMT 1
Hi guys, I'm new here, been searching through the forum about this, because it is probably written somewhere but I can't find it. Its a RD250LC in question.
Will Ypvs pipes fit on LC models and clear the centre stand?
I would like to use Ypvs pipes on my build, the plan is to install 392 athena kit (already in the post) on the LC bottom end ( welded adapter plate). The cylinders will be using pneumatic power valves. Is there any blueprints for aftermarket exhausts, as I will have to cut off the flanges probably due to using that kit it is possible that custom pipes will have to be made. Hopefully its the right thread for the question. Thanks
YPVS pipes do fit on an LC's frame with the C/stand usable. eg my 251LC has them fitted. you just elongate the rear mount. Pneumatic PVs on Athena? Can you link to where you saw this kit? Athena is all non-pv AFAIK. As has been said, only later ypvs bottom end fits the athena as its designed for the banshee. |
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Post by midlifecrisisrd on Sept 10, 2023 9:25:35 GMT 1
Am I reading g it wrong or when he said "welded on adaptor plate" did he not mean to make the cylinders fit?
I've seen YPVS cylinders on an LC with the top case modified
Steve
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karlok
L plate rider.
Posts: 15
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Post by karlok on Sept 10, 2023 10:16:57 GMT 1
Hi everybody, Steve is right.
Its an 83 RD250LC, so 392 Athena kit does not bolt directly on. The plan is to machine 10mm off the cases and weld adapter plate of same thickness so that the cylinders can be mounted.
Cylinders are valveless from factory, I will make an attempt to install pneumatic power valves from a rotax 787 motor.
Thanks for the exhaust information, helps a lot.
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Post by rigga on Sept 10, 2023 11:22:31 GMT 1
Well that's some project, very interesting build, please post pictures and info as you progress it.
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Post by headcoats on Sept 10, 2023 12:14:56 GMT 1
It is an interesting build but why not just buy a ypvs bottom end and leave your original cases intact
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karlok
L plate rider.
Posts: 15
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Post by karlok on Sept 10, 2023 15:55:31 GMT 1
That was an option too, but if I were looking at that, it would just be a complete 350 ypvs conversion. But where is the excitement in that?  I think this will be kind a unique, with all numbers still matching. |
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Post by veg on Sept 10, 2023 16:31:58 GMT 1
Welcome in. Sounds like you’ve got your work cut out but good on you, we do love projects. Good luck with it. Oh and start a build thread with loads of pics 👍
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Post by Gitram on Sept 10, 2023 18:25:47 GMT 1
this sounds interesting, there's probably quite a few folk on here, (me) who have an old LC set of cases with a bit of a desire to have a bigger motor but who don't want to find a valve bottom end..
marti
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Post by JonW on Sept 11, 2023 1:58:23 GMT 1
To be honest while it seems not a simple project at the outset if looking at it it gets easier when you think it through.
ie. it cant be that hard to copy the dimensions from the ypvs and then lazer cut some thick alloy plate and thread it...
...and cut out a few more and sell em... Then there would be an instant 'kit' for those wanting to do it.
Simply buy the plate from whoever cuts em and get your local engineering shop to mill off the existing top and weld on the new and then cut it back flat if you make the plate a bit thicker then you can mill it etc.
The bit im keen to see is the PVs on the Athena.
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Post by abar121 on Sept 11, 2023 16:39:23 GMT 1
Welcome, please keep us updated on this fantastic project.
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Post by muttsnuts on Sept 11, 2023 20:55:35 GMT 1
I have a prototype adapter plate for the LC to Athena barrels on the bench, I am just playing (when I get chance) with exactly how thick I need it and how I can make it into a kit form as I get asked alot for big bore LC's and while I have my 68mm LC barrels on test, I am someway off making them for people as time isn't my friend right now !
Will be interesting to see how you get on with the project, good luck
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karlok
L plate rider.
Posts: 15
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Post by karlok on Sept 12, 2023 10:10:08 GMT 1
@muttsnutts
Are you planing on using 110mm rods?
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Post by Tobyjugs on Sept 12, 2023 10:29:39 GMT 1
I have a 400cc engine using 110 mm con rods (68 mm pistons) and it has been very reliable. Power is not that high at 72 pk, it's never been mollycoddled.
This winter I hope it will be developed into a 400cc engine with guillotine valves.
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Post by muttsnuts on Sept 12, 2023 20:54:44 GMT 1
@muttsnutts Are you planing on using 110mm rods? that is my plan |
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karlok
L plate rider.
Posts: 15
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Post by karlok on Sept 13, 2023 9:28:36 GMT 1
I have a 400cc engine using 110 mm con rods (68 mm pistons) and it have been very reliable. Power is not that high at 72 pk, it's never been mollycoddled. This winter I hope it will be developed into a 400cc engine with guillotine valves. I'm not looking for high HP figures, your ones look very good! I doubt that my project will be finished this winter due to working abroad most of the time... Good luck with the project! Where can I find more info about your project, any dyno graphs, videos of it driving? Thanks |
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Post by Tobyjugs on Sept 13, 2023 12:27:53 GMT 1
Hi Karlok mid 70 hp should be easy enough to achieve with the Athena set up.
I Will try to find the links or threads with what I did to achieve the power I had.
There are a few members that have experience with the Athena kits.
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Post by Tobyjugs on Sept 13, 2023 12:48:55 GMT 1
I have a 400cc engine using 110 mm con rods (68 mm pistons) and it have been very reliable. Power is not that high at 72 pk, it's never been mollycoddled. This winter I hope it will be developed into a 400cc engine with guillotine valves. I'm not looking for high HP figures, your ones look very good! I doubt that my project will be finished this winter due to working abroad most of the time... Good luck with the project! Where can I find more info about your project, any dyno graphs, videos of it driving? Thanks I have just put the build to the top of the restoration page for you to have a read. If you click on any picture I have posted you will end up on my Flikr page. Scroll through the pages for lots of pictures and dyno graphs. |
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karlok
L plate rider.
Posts: 15
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Post by karlok on Sept 14, 2023 10:49:19 GMT 1
After viewing Tobyjugs's RD and other rebuild topics.
It seems that there is a big number of RD exhaust manufacturers in UK? Is there a list or models, shipping these otside UK could be a potential problem.
Are there any other exhausts available in EU except GR,JL,Tyga?
I know that exhausts are one of last steps in a build, but waiting time on these seems to be very long.
Thanks
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karlok
L plate rider.
Posts: 15
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Post by karlok on Sept 30, 2023 5:50:45 GMT 1
Me again, is anybody using 350 oil pumps with 390 athena kits?
I would like to keep the autolube for ease of use and perhaps todays modern oils can be run at a little leaner ratios?
Previously I had experience with dtr125 and athena 170 kit with 30mm dellorto and autolube adjusted a bit tighter and there was no issues with the bike, even did a trip around Europe (5000km) with it during summer with a passenger (Portugal was hot, 38 degrees).
But later when stroked and bored it to 221cc I went premix.
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Post by rigga on Sept 30, 2023 7:57:44 GMT 1
Arrow on here can modify the oil pump for most big bore motors out there, so premix is not the only option when you go big.
Several owners are running bored and stroked lumps, and still using the pump.
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Post by arrow on Sept 30, 2023 9:43:55 GMT 1
Arrow on here can modify the oil pump for most big bore motors out there, so premix is not the only option when you go big. Several owners are running bored and stroked lumps, and still using the pump. Thanks rigga. At 392cc you are right on the lower limit of oiling with the 350 pump. Therefore, the pump must be in A1 condition (no cam wear, etc). It would be better to uprate the pump by 12% to bring everything back to standard. This requires six modifications. |
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karlok
L plate rider.
Posts: 15
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Post by karlok on Oct 2, 2023 8:28:03 GMT 1
Great news.
Arrow, is it the same for you if modifying 250 or 350 pump?
Is this a service that you offer or a manual/instructions?
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Post by arrow on Oct 2, 2023 9:27:21 GMT 1
I would change the internal gear in the pump to make it 350 and then do the modifications.
There are no instructions on offer! You would also need to find a 350 wormshaft.
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karlok
L plate rider.
Posts: 15
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Post by karlok on Oct 2, 2023 10:34:06 GMT 1
Replying in PM as we are having a double conversation here and there, thanks.
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Post by arrow on Oct 2, 2023 11:07:19 GMT 1
👍
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