seb
L plate rider.
Posts: 13
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Post by seb on Apr 2, 2018 20:25:20 GMT 1
Hi, My first post here, after finding this forum a couple of days ago. I've had my 1984 RD350LC2 (31K) for about 18 years now. Completely overhauled the engine when I just bought it; all new bearings, new clutch plates, crank rebuild, barrels bored & new pistons etc. Since then it has run about 15.000-18.000 km (I live in the Netherlands). A while ago the left-hand piston has seized while driving not too aggressively on the highway (must have been somewhere around 4500-5500RPM as I was driving way below the speed limit of 120km/h - 75mph). After the engine had cooled off, the crank would move again but after a quick peek through the exhaust port there was enough wear visible to make the decision to open up the top end. So I'm afraid it's time for a second round of rebuilding the engine. One barrel needs a hone at least to remove the very mild piston scratching, the other barrel I haven't checked the state of the cross-line pattern yet. Not sure whether I'd need to bore them again already after 15k-ish kilometers, any advice on that? I've found that the Power Valves are no longer connected properly, lots of play between the two valves. Some time ago I found a guy selling an unused set of TwoStrokeShop.com Power Valves and he stated that they were specifically for the 31K model, the same as I have. Since he was selling some other 31K stuff as well, I thought things would check out and I had the valves shipped to me. Today I have test-fitted them, and I'm not quite sure whether they are the correct type for my bike. The outer diameter of the valves is a bit smaller than the original one, and also the length of the valve-part is slightly shorter than the original one. The overall length seems to be about the same between original and new.   When I test-fit them without the bushes and seals, there is a lot of play in all directions. And when I look into the barrel from the exhaust port, the new PV just seems too small.   I'm hoping that someone on this forum can help me out whether this is the correct valve set for my bike? |
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Post by Mr Kipling on Apr 2, 2018 20:49:13 GMT 1
mmm not too sure on this myself TZR 250 valves are shorter in width .. havin said that I have a set for 1ua barrels I,ll have too check this out myself too...
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Post by stusco on Apr 2, 2018 21:12:44 GMT 1
Maybe they are 250
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seb
L plate rider.
Posts: 13
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Post by seb on Apr 3, 2018 9:48:25 GMT 1
Thanks for the replies.
I'll take measurements this evening and will post them here.
Are there any drawings available of what the dimensions between the different versions of Power Valves should be?
Have done a search around the Internet but haven't found it yet.
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Deleted
Deleted Member
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Post by Deleted on Apr 3, 2018 12:59:17 GMT 1
Welcome In seb
Someone will be along here soon with measurements for you
When you say your PV's aren't connected and there is a lot of play, is the jointing clamp in the middle of yours still intact, you may just need a new joint, which Norbo sells on his online shop linked to this website
If yours are kaput, I think Legend or Economy cycle sell some billet ones for about $100 USD a pair
Pretty sure Norbo does a set too
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Post by marrcel on Apr 3, 2018 14:29:05 GMT 1
Welcome seb
I live near haarlem in holland. I have some spare cilinders. I can check or show the sizes. 😉
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Post by kostas on Apr 3, 2018 15:36:19 GMT 1
Welcome to the forum.
It’s quite obvious that the spare valves you have are not the right ones for your motor.
Also unless you’re are worn out there is no reason to fit new ones.
After 15000 klm you can’t rely on visible cross hatching to judge if your cylinder is due for a rebore or a hone.
You got plenty of trouble free use out of your rebuild motor so it is time to go over it again.
Take it apart and check your gearbox and crank properly and replace the crank seals, which is damn important with those bikes. Send your cylinders to a reputable shop to measure and repair as needed.
It did seaze for a reason ...
Kostas
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Post by Mr Kipling on Apr 3, 2018 18:43:16 GMT 1
My 1ua billet valves fit 100 % perfect all round , fit flush as described they would with the ports etc , ne excess play anywhere.. I have a tzr powervalve here measure the depth of the cylindrical part an I,ll compare... interestingly my valves are even identified 1ua on the ends..  |
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seb
L plate rider.
Posts: 13
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Post by seb on Apr 3, 2018 19:52:45 GMT 1
Indeed the engine has seized for a reason and therefore it does deserve a proper rebuild. I had already planned at least new seals for both crank and gearbox and ofcourse also check (and replace if necessary) all bearings. It's quite well possible that my crank would need a rebuild/replacement as well, but I haven't opened up the engine far enough yet to be able to check. Already looking around for a replacement crank though, as I have read that it's best to rebuild the original crank only once? The power valves in my bike are quite worn at the coupling ends. Both valves and the jointing clamp have not been OK when I bought the bike and back in the day I had made an attempt of repairing the worn coupling-end with (what I think is called in English) malleable metal and then grinding down the jointing clamp a bit to make it fit more tightly. This has surprisingly worked well for quite some time (better than expected) but now it's starting to show some serious play again. I might consider repairing them the same way again as a last resort but I would really prefer to put in some new valves and a new jointing clamp. Here's the left-hand valve with its measurements.  @ Mr Kipling and / or marrcel, if you're able to compare them to your 1UA versions or any other version, this would be of great help! By now I'm quite sure that they don't fit my 31K so perhaps I can sell them on to someone who needs them and then purchase the correct ones for my 31K. |
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Post by Mr Kipling on Apr 3, 2018 20:03:42 GMT 1
The billet valves for 31k,s 1ua,s are exact replicas but differ only by the fact they fit sides an top of exhaust ports perfectly , just like when u have a stage 1 tune...
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Post by Tobyjugs on Apr 3, 2018 21:49:36 GMT 1
If the crank is original you should be able to rebuild at least one more time. The problem i have found is trying to get the spare parts (thrust washers etc) quickly here in Holland. The UK is much more easier.
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seb
L plate rider.
Posts: 13
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Post by seb on Apr 4, 2018 18:48:55 GMT 1
So the only difference between 31K and 1UA would be the shape of the cutout to match the port and difference would not be the width or the max diameter of the largest round part.
In that case my valves would most likely not fit any 350, so perhaps RZ250 indeed?
I have searched for any photos or drawings of other YPVS valves to figure out what I have in my hands, but haven't found much useful.
Most likely they ARE intended for some model of Yamaha, since all other parts of the valves are similar to my 31K valves.
I have also sent an e-mail to the guy who used to run twostrokeshop.com to ask him if he could help identifying them for me, but I'm not really expecting to receive a reply.
Two of the three e-mail addresses bounced the e-mail back immediately and I highly doubt if the third one will actually get delivered. But it's worth a try.
It's much easier to get them to a new owner when we know what it is... :-)
Does anyone have RZ250 power valves lying around and would be willing to measure and compare them with my measurements?
Tobyjugs, my crank has already been rebuilt once, would it still be okay to do this another time? Perhaps you know any good shop or mechanic in Holland who could help me out?
Parts would indeed be more easily available through some shops in the UK, as the company who did the rebuild last time in the early 2000s already had a difficult time ordering the correct parts back in the day.
That company doesn't exist anymore so I'd need to find a different company.
I've also found several new cranks being sold on ebay (they would also be shipped from the UK), are those any good? They state that they're not original (some mention Taiwanese, some mention nothing) but ofcourse they all say they sell a good product. If anyone has any (good or bad) experience, this might help me make the right choice.
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Post by Mr Kipling on Apr 4, 2018 19:03:25 GMT 1
I had a search also with no joy on identification , I popped a pic of mine back up in your thread.. Atb in identifying them...
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Post by Tobyjugs on Apr 4, 2018 22:07:02 GMT 1
So the only difference between 31K and 1UA would be the shape of the cutout to match the port and difference would not be the width or the max diameter of the largest round part. In that case my valves would most likely not fit any 350, so perhaps RZ250 indeed? I have searched for any photos or drawings of other YPVS valves to figure out what I have in my hands, but haven't found much useful. Most likely they ARE intended for some model of Yamaha, since all other parts of the valves are similar to my 31K valves. I have also sent an e-mail to the guy who used to run twostrokeshop.com to ask him if he could help identifying them for me, but I'm not really expecting to receive a reply. Two of the three e-mail addresses bounced the e-mail back immediately and I highly doubt if the third one will actually get delivered. But it's worth a try. It's much easier to get them to a new owner when we know what it is... :-) Does anyone have RZ250 power valves lying around and would be willing to measure and compare them with my measurements? Tobyjugs, my crank has already been rebuilt once, would it still be okay to do this another time? Perhaps you know any good shop or mechanic in Holland who could help me out? Parts would indeed be more easily available through some shops in the UK, as the company who did the rebuild last time in the early 2000s already had a difficult time ordering the correct parts back in the day. That company doesn't exist anymore so I'd need to find a different company. I've also found several new cranks being sold on ebay (they would also be shipped from the UK), are those any good? They state that they're not original (some mention Taiwanese, some mention nothing) but ofcourse they all say they sell a good product. If anyone has any (good or bad) experience, this might help me make the right choice. Your question about the quality of the new replacement crank shaft i cant answer even though i have bought 2 now. The biggest problem is the cost to repair the crankshaft you have against a replacement crankshaft from the UK. I suggest you get in touch with PSTuning in Holland and Norbo on this site via PM. Tomorrow i will see Pieter and will speak to him about your crankshaft. Have you given your bike a hard life? I'm not so bothered about my own crankshafts and where they have spread i have pushed them back together and welded them as i don't mind taking a chance after inspecting the crankshaft. Also i don't mind stripping an engine and rebuilding it. Plus i always have a spare engine to refit if needed. Touch wood i have had no crankshaft failures, but i did have a twisted crankshaft which was rebuilt by PSTuning when i first started getting my LC on the road. |
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Post by bare on Apr 5, 2018 3:28:16 GMT 1
Actually MY TSS billet valves ( of the Initial batch tho) despite Being UA designated... didn't match the Ex ports worth a Shite.
Took me an Hour apiece with a Die grinder/burr to make them so
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seb
L plate rider.
Posts: 13
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Post by seb on Apr 5, 2018 7:40:10 GMT 1
Mr Kipling : Thanks for adding the pic and the search.It appears that there is just not that much info around about the 250 or any other models. Tobyjugs : thanks for your help & info on the crankshaft. I did find PStuning using google a couple of days ago, thinking this might be a good option. Then I read about it being best to re-build a crank only once and that got me in doubt of a rebuild being the best option. I did not really give the bike a hard life, but I'm not sure about what the previous owner might or might not have been doing to it. Given that the bike had run about 40-45K kms (IIRC) when I bought it and that it had 64.25mm pistons in it when I first overhauled it myself, it is not unlikely that the crankshaft had been rebuilt before. bare : That sounds awful. I think you mean that you had to make the "cut-out" to match the exhaust port shape better? But I assume that the large diameter does match your barrels with a tight fit, at least a tighter fit than in my picture? 
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Post by JonW on Apr 6, 2018 23:32:18 GMT 1
My TSS 31K PVs lined up perfectly, I reckon you got sent the wrong ones bare.
Seb I have 250 PVs here I can check measure for you next week, but I really doubt anyone would make billet PVs for the 250. Outside of Japan very few countries took the 250, we had a bunch of them but most ended up as 350s eventually, one of the reasons why im building one.
The ground edge is interesting on these, I dont remember any of our having anything so severe. The size (where the edges wrap around the piston area) certainly looks like it fit a bike with smaller than a 350 bore. ie 350 piston is 64-66mm, the 250 is 54-56mm to give you an idea.
Sadly I doubt you will get any reply from Steve about these, TSS is long gone now.
I did suspect that these might be TZR / TDR, as that would be a bigger market i would think. Sadly I know nothing of the TZR world so dunno if they ever made em, but it makes greater financial sense as people raced the TZRs etc. However I dont think they look like those after a quick google, but there are many models of TZR and pics of their PVs are not easy to find.
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Post by bare on Apr 7, 2018 18:36:45 GMT 1
bare : That sounds awful. I think you mean that you had to make the "cut-out" to match the exhaust port shape better? But I assume that the large diameter does match your barrels with a tight fit, at least a tighter fit than in my picture? Yess the cutouts were Too small about a 1/4" below the Stock UA ex port top when the other side was flush... Grrr. Also the resultant throat profile wasn't ideal either needing a fair bit of carbide Burr time TSS was BIG on babble.. not so much on substance. Big round bits weren't a tight fit in their bores. But same fit/ same diameter as the OEM ones. |
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seb
L plate rider.
Posts: 13
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Post by seb on Apr 9, 2018 7:36:53 GMT 1
Indeed I didn't expect to really hear from TSS / Steve, but it was worth a shot. I also did not find any useful information about 250cc valves, but given the width difference between these and my 31K ones, I think they could quite well be meant for 250cc barrels. JonW, I would really appreciate it if you would be able to compare the dimensions of my valve to your valves. Since I'd need other valves anyway, would the billet valves from fastfromthepast be the go-to valves for my bike? |
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Post by JonW on Apr 9, 2018 8:34:49 GMT 1
Indeed I didn't expect to really hear from TSS / Steve, but it was worth a shot. I also did not find any useful information about 250cc valves, but given the width difference between these and my 31K ones, I think they could quite well be meant for 250cc barrels. JonW, I would really appreciate it if you would be able to compare the dimensions of my valve to your valves. Since I'd need other valves anyway, would the billet valves from fastfromthepast be the go-to valves for my bike? Just measured them... theyre close to the RZ250 PVs but not the same. A few mm out in some dimensions. So yes I agree they are some kind of 250 id say... Yes the FFTP ones would be much better than these for you, maybe not perfect but if you have a Zeel/Iggy then you can set the heights anyway. |
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seb
L plate rider.
Posts: 13
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Post by seb on Apr 10, 2018 6:58:25 GMT 1
Just measured them... theyre close to the RZ250 PVs but not the same. A few mm out in some dimensions. So yes I agree they are some kind of 250 id say... Thanks for measuring! So not RZ250, but definitely some kind of Yamaha valves I'd say, as the rest of the shape matches the Yamaha valves too well. And most likely some kind of 250cc twin engine. Yes the FFTP ones would be much better than these for you, maybe not perfect but if you have a Zeel/Iggy then you can set the heights anyway. I'd be running them on a stock bike with stock ignition, carbs & exhausts. Would repairing the couplings & joint clamp be a better solution than replacing them with FFTP ones, since the rest of my bike is stock? |
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Post by JonW on Apr 10, 2018 8:16:00 GMT 1
Well they still could be RD250 ypvs, but badly made or something, but the chamfer on the face is not something any of mine have either.
If you can weld your own cast ally, they repair the ones youve got. if not then the FFTP ones are superb value, tho not exactly lining up in your bike. To be honest it wont matter. Yamaha never made an OEM 1UA PV set, they just ran the 31K version and it still made enough power.
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Post by wreckrat on Dec 1, 2018 22:04:57 GMT 1
My 1ua billet valves fit 100 % perfect all round , fit flush as described they would with the ports etc , ne excess play anywhere.. I have a tzr powervalve here measure the depth of the cylindrical part an I,ll compare... interestingly my valves are even identified 1ua on the ends.. |
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Post by wreckrat on Dec 1, 2018 22:06:33 GMT 1
Hi Mr Kipling, I may need a pair of power valves for my 1WT..... I believe 1UA are the ones for me, could you tell me where I can get a pair?
Cheers
Andy
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Post by tony1964 on Dec 1, 2018 22:47:10 GMT 1
Martin at Mad Biker Designs does them, about £165.
Tony
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Post by steeley on Dec 2, 2018 5:59:52 GMT 1
Hi , as the other folk have said the new valves are for a 250 . I had the same sort of problems years ago with a second hand set and ended up buying new .
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Post by Mr Kipling on Dec 2, 2018 17:06:34 GMT 1
My 1ua billet valves fit 100 % perfect all round , fit flush as described they would with the ports etc , ne excess play anywhere.. I have a tzr powervalve here measure the depth of the cylindrical part an I,ll compare... interestingly my valves are even identified 1ua on the ends.. Hi fella had my valves a while now made by TSS , As others have suggested Martin at MB DESIGNS.CO.UK can supply u a pair of correct valves , i believe he,s are sourced from the US nowadays .... Atb.. |
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Post by JonW on Dec 6, 2018 3:10:45 GMT 1
FFTP has em for $99... Great value, didnt that get said above? Im sure Martin is a great bloke but you could spend a lot on post, import taxes and still come out ahead. FWIW £165 is $210 in today's money. Im all for supporting the local guys, but, well...
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Post by Mr Kipling on Dec 6, 2018 17:02:43 GMT 1
FFTP has em for $99... Great value, didnt that get said above? Im sure Martin is a great bloke but you could spend a lot on post, import taxes and still come out ahead. FWIW £165 is $210 in today's money. Im all for supporting the local guys, but, well... Hi Jon , just mentioned Martin as I know he sends the correct valves for 350 as peeps mention being supplied 250 valves of some sorts , yeah FFTP are great value as well if u don't need too add import taxes.. Didn't take notice of where matey was based , sorry for treading on anyones toes... ::) |
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Post by JonW on Dec 6, 2018 23:09:44 GMT 1
FFTP has em for $99... Great value, didnt that get said above? Im sure Martin is a great bloke but you could spend a lot on post, import taxes and still come out ahead. FWIW £165 is $210 in today's money. Im all for supporting the local guys, but, well... Hi Jon , just mentioned Martin as I know he sends the correct valves for 350 as peeps mention being supplied 250 valves of some sorts , yeah FFTP are great value as well if u don't need too add import taxes.. Didn't take notice of where matey was based , sorry for treading on anyones toes...  No toes stepped on at all Mr K. I just like the price of these and while i dont begrudge anyone making a living, I dont see how the same PVs cost so much in the UK, especially if bought in bulk from the source as an authorised dealer etc. The usa never got the 250 so FTTP will not be selling any valves other then the 350 ones for the RD/RZs. FWIW The TSS factor in this equation is gone, they went bust 5 or more years back so no mis-selling of anything now. |
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