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Post by jon on Dec 22, 2016 9:10:35 GMT 1
Jon, Veg isn't the only one taking interest. Myself and I guess a few more are too.
I totally agree with the areas you've circled.
I also agree these frames could benefit from strengthening. Sure they are fine without, but when built the suspension technology wasn't what it is today. If the frames had been as stiff as they are today you would have noticed the suspension being even harsher.
I have already strengthened my YPVS frame with an extra frame spa and other areas.
In fact I am doing this right now as my current job on the LC. I'm spreading the frame, and in the process adding thicker tubing to the centre stand cross member as the original one showed a slight bend.
The swingarm brakets will have an spacer and another bracket of the same shape welded to the outside of the frame tube. I'm using a YPVS pivot bolt.
The end of all the tubes you mention as unwelded will be welded fully. I'm not sure to be honest if this will strengthen it any, but it seams (sic) the right thing to do.
I'll decide on the rest when I get round to it.
Jon
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Post by veg on Dec 22, 2016 9:25:26 GMT 1
It's design and material evolution though isn't it. As tyres have improved so have suspension units as have frame design which has had a knock on. When the LC and pv were first designated we didn't have radial road tyres nor beam frames for road bikes (or even race) upside down forks with cartridges wouldn't be around for years. In isolation they handle reasonably well. The problem is introducing later technology into the equation that then highlights the short comings. This however is what a lot of us enjoy be it from an aesthetic, engineering or performance perspective. I will probably look at my frame for my other build and see how it can be improved
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Post by veg on Dec 22, 2016 9:30:10 GMT 1
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Post by JonW on Dec 22, 2016 14:01:51 GMT 1
Cool, thanks for chiming in Jon! Interesting youve been round much the same thought process as I have with your build. Today I cut off a set of ypvs upper triangulation gussets which i will reuse and also the under side oval tube's forward braces. Sadly I no longer have the swingarm pivot area or i would be unpicking that and reusing some of it as like you I will improve this area, I looked out a ypvs swinger pin today for the job, noting it was the same 16mm as the LC. Of course with my build im going to use the RGV swinger (cut down and rethreaded, and 20mm OD) with larger bosses on the frame that reach almost to the motor, if you look at the LC's setup its really quite crude in this area, with a washer that sticks out towards the motor and the backside isnt even fully seam welded! The other area I looked at was to put another spar between the headstock and the top shock mount. I dont have the OEM airfilter so have a lot of room in this area, I just need to relocate the coil. I also considered tying these frame tubes together as well. Other than that Im going to plate the front tie bar mounts as well across the bottom, Ive seen these crack on some bikes with more power than standard, easy enough to weld the inside and then make up a plate to go across the lot with a bolt hole in it.
Veg, I agree. I love the LC as it came out of the box, with shit brakes on the 250 and everything LOL! But when youve the power of the bigger motors and youve moved to modern-ish suspension, wheels and tyres and brakes... then something needs to be done and if youre good with a welder (or have a mate who is) then its no big deal to make some improvements. Of course the general design and layout cant change the whole point is that its still an LC for me, so we have to work within those boundaries. I did some reading around the TZ350 frames and couldnt really find any great pictures, I did see a bit of discussion where people said plates do nothing and tubes do the business, which makes sense. The other issue is that the engine still needs to come in/out and youve wiring to run and other stuff so it has to be practical for a road bike.
All interesting stuff, I just wish I had kept the ypvs swingarm area on the old frame i cut up, Im kicking myself that i chucked it out, right now im considering some serious bending and shaping to reproduce something like those for my build, but it would be simpler with the OEMs. Ive PMd the seller of the cut up frames in the sales section so we'll see how that goes. Exciting times!
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Post by veg on Dec 22, 2016 14:17:52 GMT 1
just got my lc2 frame home and will be watching this as it will have modern suspension, wheels tyres and brakes and probably a 421 engine so will need it to be braced. My 4LO build whilst having a new WP shock and LC2 forks etc is still running 18in wheels single disc and a TZ700 top end, the frame hasn't been braced as it is how it would have been back in the day. 2 contrasting bikes with no doubt contrasting handling. Good luck
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Post by JonW on Dec 23, 2016 0:35:04 GMT 1
The LC2 frame will be interesting to modify, not least as Im using that one as the basis of my mods for the LC LOL! Anyway, Im not sure what would be best to look at with regards design for that, how many modern bikes have similar frames etc? I remember getting off my R1 and riding my RD350R, you could feel the rubber band frame moving about and the cheaper suspension wobbling as well. Id never noticed until I bought the R1 LOL. Sure, we'll never make the old frames as strong as a modern sportsbike and it would be very interesting to destruction test them and see just how bad the old stuff is in various planes. To be honest Im amazed that Yamaha were still playing with bracing and strengthening design in the 80s really, Id have thought the LC would have been stronger (tho its only containing 40ish bhp of course) but under the modern (for the time) aesthetic the LC is quite old skool really and where it really shows is with its clothes off. The more i look the more it seems obvious what needs to be changed to improve it, but maybe thats cos we've a cheat sheet in the form of the ypvs unit. The move to the perimeter frame of the ypvs seems obvious when you hold a bottle of beer and have your mate try to wrest it from your grasp, elbows together its harder to stop him than when you move your elbows apart. I like to think Yamaha's engineers proved it that way too... bike building seemed more like blokes in the garage back then compared to now haha! Im excited to prove that the work im going to do is valid by riding my two LCs back to back, assume you guys feel the same.
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Post by twostrokejoe on Dec 23, 2016 9:50:45 GMT 1
Hi lads, you are not on your own. I find your debates on the engineering factors ( to do or not to do ) very interesting. Though not really participating in the thread I am taking notes. We had an off 2years back on R6 IOM and the rear shock ripped from the mounts and a buddy 35 years back on ypvs rear shock top brace bent under race conditions. So I understand your concerns and am particularly interested in rear end modifications and the engineering thought process behind it. Manufacturers are still trying to get it right. We will get there and have fun doing so. Enjoy your projects.
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Post by JonW on Dec 25, 2016 13:59:56 GMT 1
Thanks Joe, Im glad to know more people are reading this.
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Post by Tobyjugs on Dec 26, 2016 12:34:27 GMT 1
I'm watching with interest as well. 3 weeks ago i went to buy a SZR rim and ended up going 3 houses further along from the buyers house to look at a couple of TZ's. There was a special made Harris TZ and just like in the picture just about every corner of the chassis was braced with a plate. I some times wander about the wheel spindles. They are pretty small in diameter on a standard bike.
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Post by paulincayman on Dec 26, 2016 16:32:14 GMT 1
Gents, I've been following this thread closely too...and I'm also a great fan of imagineering.. My 4lo is now in my shed having just completed its journey from calgary via Montreal..phew..( sorry it was in crate ,I didn't ride it here), and want to stiffen her up for the 385 and suspension mods I'm fitting. Learning loads here..! Now back to the turkey.. Cheers Paul
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Post by jon on Dec 26, 2016 16:41:26 GMT 1
Jon, I personally think trying to graft a YPVS swingarm pivot bracket onto an LC would be more difficult than modifying whats there. I am spreading my frame to allow up to a 160 section tyre with good chain clearance between the frame tubes and tyre. I will also be strengthening the original swingarm pivot brackets. My dimensions will end up the same as a YPVS, and I will be using the YPVS pivot bolt and making the spacer have a lug on it to hold the bolt just like the YPVS. Jon
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Post by JonW on Dec 27, 2016 3:54:41 GMT 1
Jon what you have in your pic was what I was thinking of doing originally, I just thought the ypvs version would look more 'factory' when done but youre right, no sense reinventing the wheel etc. My plan was to build a spacer/boss the same OD as the RGV swingarm tube and the ID the same as the RGV swinger pin, weld that over the LC plate (having removed the tacked on washer first) holding it with the ypvs pin (with a spacer between the OD of the pin and the ID of new spacer). Then seam weld those in and then after weld on a sandwich plate to the frame as per your pic, perhaps boxing the lots after. My thought after was that using the modified ypvs parts would perhaps not make it easy, but the look might be right which is important here.
A question Jon, why not use the pin from the swingarm youre grafting on? The RGV is 20mm, much thicker than the 16mm LC/ypvs.
Toby, wheel spindles are not a problem for me, Im using RGV not lc/ypvs.
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Post by jon on Dec 27, 2016 11:40:55 GMT 1
Jon, what you say about using the correct spindle for the arm I am using makes sense.
However, I don't know what arm I'm using yet.
I think the 16mm should be more than enough, and in fact I believe the swingarm I'm toying with (FZR 3EN) is only 15mm diameter.
Either way I could always drill the frame out larger if need be if I start with 15mm or 16mm.
Jon
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Post by JonW on Dec 27, 2016 14:31:41 GMT 1
Yeah my feeling was that 16 is a bit small as later bikes are bigger etc but of course the pin is only there to pull the parts together, it really pivots on the bearings, not the pin. Same with axles, which these days seem thick as sausages instead of the LC's toothpicks LOL! Yep, if you have the frame done for 16 you should be fine as you say, easy to drill out as needed
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Post by jon on Dec 27, 2016 14:46:31 GMT 1
Jon, As an engineer I remember working out the sizes of bolts required for a given situation a college. When I say 'I remember', I remember calculating it at the time, but have forgotten how to now.
I always tend to over engineer things. I keep reminding myself of a car seats. Most are held to the chassis by 4 x M8 machine screws, and some have the seatbelt mounted to the seat. If this can survive a crash with the weight of a person decellerating from high speed, then I'm sure a 16mm swingarm pivot can withstand more than a YPVS motor can throw at it.
Jon
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Post by JonW on Dec 27, 2016 22:57:05 GMT 1
Good point, Ive got more than a yovs going thru mine.
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Post by kman on Dec 28, 2016 1:24:24 GMT 1
Have a look at what a tz shaft measures. They put out 70+hp
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Post by JonW on Dec 28, 2016 12:26:36 GMT 1
Looked a bit on google, cant find the info about the TZ swinger pin. happy to hear about it tho if you have the info.
I should also say that the TZ350, while probably useful in this context, hasnt been that helpful for the frame stuff so far as they were expendable and i couldnt even find a pic of an OEM one that was useful to compare to the LC, only aftermarket units.
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Post by kman on Dec 28, 2016 21:09:44 GMT 1
Hi Jon. I'll have a look md get back to u
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Post by JonW on Dec 29, 2016 23:22:18 GMT 1
Jon kindly sent me a link to this page: fzronline.com/forum/viewtopic.php?t=1272 where a poster has some computer generated info on upgrading the swinger pivot pin and mentioned that going to 20mm wont really gain anyone much. Interesting... I've also done a bit of reading and one of the things that it seems will actually improve a swinger pin is using one that is not drilled out for grease like the LC pin. So considering the ypvs unit is the same OD and not centrally drilled for lubrication, hence solid, then maybe that's where i should be heading, the same as Jon is. This means for me that it's a simpler conversion and can always be redrilled if needed. I've also considered that maybe i was upgrading 'cos i could' in this area, when really the issue is the bits in between the swinger area and the headtsock really. Also, the RGV pin is hollow, not solid which makes me wonder about its suitability now, it may be fatter but perhaps the ypvs unit is its equal in strength...
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Post by bare on Dec 30, 2016 18:53:58 GMT 1
IMO it's not the swinger pin that's the wiggly bit problem. Rather the Pivot mounts and the largely unsupported frame tubings that poorly fix those pivots. Going to take a serious bit of care/thought to add genuine rigidity to our frames. IF seriously concerned I'd start looking for the Ali frame from an FZ400.. Bit rare these days tho.
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Post by jon on Dec 30, 2016 20:41:48 GMT 1
Bare, your right in a way, why not just transplant a 2 stroke engine into an FZR 400 frame. It actually makes a lot of sense. Or better still an FZR400RR.
But for us old time 'fanatics' who like the style of the LC over any other bike available for sale, but want to improve on the old girl because modern technology has advanced to the point it can be transplanted then why not?
Jon
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Post by 4l04ever on Dec 30, 2016 21:27:26 GMT 1
I do happen to have an FZR400RR frame in my back garden.....but will not be putting an LC or YPVS engine in it......the 3MA frame next to it will be having one though.
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Post by JonW on Dec 30, 2016 23:41:24 GMT 1
Bare, Im fixing the pivot mount area, I wouldnt have considered a fatter pin without doing that, it would just mean less steel there. There is a lot of thought and care going into this, and no I will not be using another frame, as has been said before this is about building a 'better LC', not moving to an alloy framed wonder.
Please people, no more talk of alloy beam frames as its not useful in this context. The steel double cradle is what we're dealing with, its a totally different thing. You can see why the manufacturers moved to them of course, the extruded parts are easier to fabricate and they provide amazing rigidity, but we dont have that luxury if you want to keep the LC's look.
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Post by 4l04ever on Dec 30, 2016 23:52:47 GMT 1
Let's make it better, stronger, faster.....the 6 million dollar LC :-) I like the sound of that.
Loads of track LCs had various bits of bracing added. We could do with an engineer type person who is good at stress analysis etc to find the weak points in the frame design. I think Dale P4L08 off the old forum was into that sort of thing. I think I still have his old mobile number somewhere, unless we have anyone else into that stuff on here now?
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Post by Tobyjugs on Dec 31, 2016 11:32:51 GMT 1
I was part of a team and we measured how much the main engines were flexing on a well known ferry service between Hull and Rotterdam. Me and my mate were the happy helpers and prepared the engines during the daytime and then the professors came down in the evenings to measure the distortion. Don't know how much it would cost but you could stick strain gauges on all the areas you think are weak (thats the easy work) and feed it into a computer with the correct program to see whats happening (thats the hard work) Plus you need a lunatic to put it through it's paces on the track with really good tyres
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Post by 350guy on Dec 31, 2016 18:31:58 GMT 1
Hi all:
I am reading this very informative post and by no means I am even an inch closer to the level of expertise that each one of you have here. However, I am in the process of dismantling the LC frame (My first LC) from the basket case bike that I bought. The bike was involved in a bad crash and it seems like it was impacted from the sides. From the looks of it the tail end of the chassis has drifted considerably towards the left. I can post pictures of the bare carcass, if that would help in determining the weak spots or areas that need and have room for strengthening. Yes, your input/suggestions will also help me in getting the chassis road worthy.
Kind regards,
Daryl
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Post by paulincayman on Dec 31, 2016 23:14:54 GMT 1
As above but hopefully not a bent frame to contend with...looking forward to some conclusions to implement.. BTW. Happy New year !
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Post by JonW on Jan 5, 2017 22:04:46 GMT 1
My frame modifications have started; so far the long tacks on the top frame spars have been completely welded along with any other part welded sections (leaving water exits as required). The other areas where the welds were not completed or not completed on both sides have been filled in and Ive started making plates up for the swingarm and will use the ypvs pin. Consensus around the workshop (race car shop where lots of bike guys work or turn up and nose around) was that its much stiffer already just for completing the part done welds, so that was good to hear. Some did say that part done welds can be stronger if done properly, but agreed that in this case it was Yamaha doing only what was necessary for the power of the engine and grip of the tyres for the era, so thats why these frames work on an LC, but perhaps not so well with the mods I have.
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Post by Tobyjugs on Jan 6, 2017 0:06:00 GMT 1
can't wait to see the finished article
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