Author Topic: RD350 Track Bike build  (Read 10204 times)

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Offline 5port

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Re: RD350 Track Bike build
« Reply #210 on: January 06, 2021, 08:17:15 PM »

Thank you for recommending Dan's video, what a great setup bike and it's certainly an enjoyable 15 minutes of track riding.

Luckily there was a run off area there  ;D

Hi Richard!

Yes, a good vid from Dan Peacock!  The vid shows clearly how heavy high speed braking can lift the rear wheel and badly upset the handling of even a modern racebike.   ???
Cheers

5port
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Offline 5port

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Re: RD350 Track Bike build
« Reply #211 on: January 06, 2021, 09:15:46 PM »
So, maybe now, just a few words about oil for the forks.  Generally, Yamaha knew quite a bit about their products.  They tested and experimented to get the best results and, where they were wrong, they changed things.  The oil they recommended for the early TZ forks was 10W-30 engine oil and they stuck with that.  This is the same recommendation they give for the RD250/350/400.  :)
The simple Damper rod damping is closely controlled by the damping orifices and, they have to be sized to match the viscosity of the oil.  Yamaha chose the best visco-static oil that gave the results they wanted and, for these damper rod forks, that was 10W-30.
  On a 20*C day, these forks will settle at about 26/27*C oil temp when in use.  It is possible to study the temp/viscosity of oils at these temperatures and see what oil viscosity the forks were designed for and, that viscosity comes out at about 125 cSt @27*C.   
Today, 10W-30 or 0W-30 are right in the groove for 125 cSt @ 27*C.  The modern 0W-30 has the most stable viscosity in the range 20 to 30 degrees falling from 170 @20 down to 105 @30. The 10W-30 is slightly thicker when cooler with 190 @20 down to about 105 @30.   The difference of viscosity in this 20 to 30*C temp range is quite marked for different oils and is important for our simple damper rod damping, the upward curve of viscosity with lower temps is very marked, particularly for some other grades.
 I will be starting with a Synthetic 0W-30 and blending with a synthetic 0W-40 or synthetic 0W-20 for any higher or lower viscosity that seems needed.
Yamaha make some references to using speciality fork oils as the user chooses. The TZ 250/350 manual quotes "wt" of fork oil "10,20,30 according to preference".  As straight SAE grades, that covers around 180 down to 80 cSt @ 27*C.   That sounds fair enough but, I have found references that show each speciality fork oil maker achieves vastly different viscosities, despite the "2.5/5/7.5/10/15/20" shown on the bottle.  The best advice from specialists is to get the most info you can, chose a brand and stick to it as you try different "weight" Fork oils as, switching brands will likely mean different viscosity.  ???  OTOH, Multigrade SAE like 0W-30 is a much tighter viscosity grading as, it has to meet the Cold "0W" specification and the Hot "30" specification.  This makes the temperature related viscosity ratings much more accurate across the temperature range between minus 17.8*C to plus 100*C.  :)
Whatever oil you chose, you might want to consider the temperature of the fork operation.
Cheers

5port 

Edit:  Just a few words about the lighter oils that go in more modern forks.  Manufacturers give their advice and I suggest using that.  ;)  The more modern forks use various variable flow damping valves. It seems that generally, these types use a thinner oil than the old RD orifice type damper rods.  That does not mean they have less damping, just that they use a different method of damping.  Overall, the modern fully adjustable properly set-up forks probably have a better balance of control under different loads than the old RD ones.  My own opinion is that the old RD type can have a very good performance set up but, it will be best in a fairly narrow range of conditions.  I think my track forks with firmer springs will probably be good at high speeds but may feel a bit firm at lower speeds.  I hope to find out.  I have ordered my 0.8kg/mm RaceTech springs from TW Suspension, Teut the owner says they should be here by end of Jan.   :)

   
   
« Last Edit: January 13, 2021, 10:04:12 AM by 5port »
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Offline 5port

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Re: RD350 Track Bike build
« Reply #212 on: January 09, 2021, 09:45:13 AM »
My Christmas Pressie has arrived!   :)
Avid followers of this topic might recall  that I had no Footrests.   ???  I wanted a lightweight set and, possibly the early OE TZ type with the small tube triangle welded on the frame and cable operated rear brake would have been the lightest.  However, that needs some good frame mods and expensive TZ/copy bits.  The gear lever is simply reversed for the TZ but that gives you the upside-down gear lever movement.  Mick Abbey said to me that I would definitely make mistakes with the reversed gear lever and, it is just a lot easier for a lifelong road rider to have the LC style linkage and go with what your brain is used to!  :D  I think he is right.
Good old rearsets might have been OK but, most seem to be pretty clunky, heavy and worn.  A lot are based on the original Steel plates, with shortened brake lever.  These are heavy, and mostly retain the heavy steel brake shaft with a clumsy actuating linkage.  Of note, all options seem to be quite a price.   There are options of modern bike alloy versions that might fit with just an extra little mount welded on.  But most are for rear disc and I was wanting the "could be old" look.
I eventually saw the "Vintage Rider" ones from USA.  They are simple and use a rear brake cable mod!  They also just use the two bolt mounting and, dispense with the OE steel plates and the brake shaft/arm.  :)
6 weeks later.. they have arrived!
I am very pleased with these.  The quality is good and the levers are bushed with Phozzy bronze.  I love the cable brake.  Weight should be quite a saving overall.  They come with heavy steel mount bolts so, I have bought Titanium to upgrade those.   :)
Price was high, £295 inc post, plus £80 odd tax and handling.  So, £400 all in with the Ti bolts.  They were on offer as well, so maybe watch for that as you could pay more. :'(
There is scope for someone with machining facilities to do this much cheaper.  But, I am happy with what I have bought.  Pics to come eventually.
So, that's a Merry Christmas!

5port       
 
« Last Edit: January 09, 2021, 10:47:03 AM by 5port »
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Online tony2stroke

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Re: RD350 Track Bike build
« Reply #213 on: January 09, 2021, 11:40:56 AM »
I had an RD80LC back in the late 80s, used rear peds as rear sets and used a turned round gear lever, as you say changing from 1 down then up, to 1 up then rest down, I never got totally used to it and made wrong changes lots of times, so I would say that is money well spent, specially on a track bike where a mistake could go badly wrong.

Offline 5port

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Re: RD350 Track Bike build
« Reply #214 on: January 09, 2021, 01:34:28 PM »
I think you are right Tony.  Even just on a trackday I am going to need every braincell just to stay out of trouble so, using half my brain to change gear is not a good idea!  :D
BTW, I will try and get the complete parts together and try to compare the rough weights for standard and other rearset setups. ;)

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Offline 5port

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Re: RD350 Track Bike build
« Reply #215 on: January 12, 2021, 10:11:33 AM »
Took the plunge with the RaceTech springs, £160 odd.  Not cheap and I have had other springs made for less than £100.  However, I think the RaceTech ones are high grade and, the price is not bad compared to some.  ???  I have ordered from Teut at TW Suspensions as he is a specialist and I try to support that.  I will keep you upto date on these, promised by end Jan.  :)
Overall, I see huge differences in the cost of bespoke suspension parts etc.  There is no denying that things needing labour and special manufacture cost £££.  I think it is easy to see how the big names like Race Tech and Ohlins etc probably do great products at the ££££ range. What I don't see is an easy path to deciding what is worth buying in the mid-range of price.  Seems very difficult to know if it is worth spending £500 on a pair of rear shocks or, if you have to spend £1,500+ to get a worthwhile improvement?  Well, I am spending neither at the moment, I have new £150 Hagon's on the back and I think they probably work OK!  Possibly the best boing per bump!  :D

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Offline 5port

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Re: RD350 Track Bike build
« Reply #216 on: January 13, 2021, 02:40:44 PM »
Managed a couple of pics of the rearsets.

The gearchange side is quite straightforward.  Main plate just bolts on with no old steel part fitted.




The rear brake side is a bit more complicated with the cable operated rear brake and alloy stay.



 :)

So, I got the weight of these at 1609g with all the steel bolts and everything included.  The Titanium bolts reduce the weight to 1500g.  I think I should get that down another 50g with lightening holes in the thick alloy stay and counterboring the alloy footpegs.  That should see an overall reduction to 1450g or, 10% below the supplied weight.  Not able to do the comparison with standard parts at the moment but, these rearsets replace: both large steel footpeg/exhaust plates and bolts, the steel brake axle/arm, the steel brake torque stay, the steel brake lever, the steel gearshift lever, both footrests (and the footrest bar) and the steel brake operating rod.  That lot is quite a bit of metal.  Just in my mind, I guess that if you include the footrest bar the standard bits would be around 3kg total, maybe?  so, possibly, this set-up is 50% of standard weight?  Certainly a lot lighter !  :)

5port 



 
« Last Edit: January 14, 2021, 12:16:12 PM by 5port »
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Online tony2stroke

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Re: RD350 Track Bike build
« Reply #217 on: January 13, 2021, 05:16:32 PM »
They look nice  8)

Fair bit of weight saved too.

Offline 5port

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Re: RD350 Track Bike build
« Reply #218 on: January 13, 2021, 06:45:54 PM »
Yes, and I think they should be fairly functional as well.  I have Raask rearsets on my 400E with Ace bars and I expect a similar crouch.  Rides nicely like that, but not for too many miles. 
Overall, I will be glad when the weather warms up a little and I can get the serious bike building going.  I suspect I will trial fit these footrests to check for any issues first.   :)
Cheers

5port
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Offline Motty

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Re: RD350 Track Bike build
« Reply #219 on: January 13, 2021, 07:16:02 PM »

Overall, I will be glad when the weather warms up a little
Warmer weather cannot come quickly enough for me
“...inside every old person is a young person wondering what the f*@k happened.”
Terry Pratchett

Offline Fredswat

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Re: RD350 Track Bike build
« Reply #220 on: January 15, 2021, 04:21:06 PM »
This is going to be one nice bike when it's finished. Love the rear sets. Your attention to detail is fantastic.  I would like to do some sort of hybrid race bike at some point in the future. 
74 RD200a
74 RD350A
77 RD400c
81 RD350LC
89 TDR 250
72 Kawasaki H1d
75 Kawasaki Z1b 
06 Kawasaki Z1000
71 Suzuki T500R
76 Suzuki Gt750
89 Suzuki RGV250 Vj21
75 Honda cd175 
85 Honda c90
03 Aprilia RS125
48 Royal Enfield J2

Offline 5port

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Re: RD350 Track Bike build
« Reply #221 on: January 16, 2021, 11:43:42 AM »
This is going to be one nice bike when it's finished. Love the rear sets. Your attention to detail is fantastic.  I would like to do some sort of hybrid race bike at some point in the future.

Thanks Chris!
I hope that it will turn out in a "used, very tidy" state.  The used race parts like clip-ons, instrument mount and tank etc are going on in as-used condition.  There is a lot of new race/track parts like seat, front muddy, levers, grips and tyres. Then there are the road bike used bits like engine, wheels and frame. 
It is surprisingly difficult (to me!) to do a really good TD3/TR3 copy, the roadbike bits are just so different.  I think Stevie747's RD350/TR3 roadbike  is a really good looking special that took some dedication to do.  Also, Dan Peacock's YR5 road/track special is a very good bike.  Real 50+bhp and serious track modifications.  I think both those builds are great!  :)
Cheers

5port     
5port

Offline Fredswat

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Re: RD350 Track Bike build
« Reply #222 on: January 16, 2021, 04:21:54 PM »
This is going to be one nice bike when it's finished. Love the rear sets. Your attention to detail is fantastic.  I would like to do some sort of hybrid race bike at some point in the future.

Thanks Chris!
I hope that it will turn out in a "used, very tidy" state.  The used race parts like clip-ons, instrument mount and tank etc are going on in as-used condition.  There is a lot of new race/track parts like seat, front muddy, levers, grips and tyres. Then there are the road bike used bits like engine, wheels and frame. 
It is surprisingly difficult (to me!) to do a really good TD3/TR3 copy, the roadbike bits are just so different.  I think Stevie747's RD350/TR3 roadbike  is a really good looking special that took some dedication to do.  Also, Dan Peacock's YR5 road/track special is a very good bike.  Real 50+bhp and serious track modifications.  I think both those builds are great!  :)
Cheers

5port     
Just thinking back Chris. Years ago I did have an RD400c with a 400e top end on.  It had been put into an RD350 air-cooled frame that had been converted to a mono shock from an LC .  It had hand made cross over expansion chambers with TZ end cans, an aluminium tank like yours, a TZ race seat, clip-ons and rear sets, as well as Borini alloy rims .  It was done by Harry Barlow if you remember him.  He was quite a name in two stroke tuning and side car racing as well back in the day.  It was really light and it went like stink. It had wider tyres on. The front was a cut slick from a proddie racer. I wasn't sure it was road legal but at the time I didn't worry too much.  I do remember that if you braked hard whilst entering a corner it had a tendency to want to sit up.  I changed the front tyre for a slightly narrower road tyre which transformed the handling.  The only other things I did to it were to Paint it a shade of really bright yellow and fit some flat bars.  I wish I still had it . It used to pull the best power up wheelies I have experienced on a bike, the front would just lift gently with the throttle.  I will dig out some of the old photos of it I have in the shed and put them on the forum.
74 RD200a
74 RD350A
77 RD400c
81 RD350LC
89 TDR 250
72 Kawasaki H1d
75 Kawasaki Z1b 
06 Kawasaki Z1000
71 Suzuki T500R
76 Suzuki Gt750
89 Suzuki RGV250 Vj21
75 Honda cd175 
85 Honda c90
03 Aprilia RS125
48 Royal Enfield J2

Offline 5port

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Re: RD350 Track Bike build
« Reply #223 on: January 16, 2021, 06:43:02 PM »
Sounds very good Chris.  :)  Most Clubmans racebikes were like this decades ago, the best bits put together.  Of course, most people had bugger-all money to spend and, almost everything was 2nd or 3rd hand or, bust and mended.  I think things changed after the early '70's and real technological improvements got going.  Today, you just cannot be competitive in most sports without a big wad!
However, there is a way of going back to "the days", and having a bit of whatever you prefer and, I think old Jap roadbikes are one of the few ways that are relatively cheap-ish still.  Unfortunately, I don't think the competitive side of old "Clubmans" sort-of bike racing is very representative, I think money still wins! Some of the "classes" allow surprising things.    ???
Cheers

5port       
« Last Edit: Today at 09:08:42 AM by 5port »
5port