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Post by Tobyjugs on Jul 18, 2018 21:55:30 GMT 1
I have been waiting to hear details about a flat tracking event to be held in Rotterdam. Tonight i was told it has been cancled and will be replaced by a run what ya brung 40 metre sprint race over sand.
This is organised by the cafe racer crowd i sometimes join for rides.
I feel i have to do my best to represent the two stroke bikes and try to open a few eyes.
I'm not so bothered about the CX500 type racer. I want to try and beat a modern retro cafe racer bike
I have two bikes i could campaign.
My bike which i could fit 150 rear WET racing trye on. The engine is now a bit tired but drives very good at low rpm. The gearing is 16/42 and slowly revs out in top gear.
The other bike which Kees uses is fresh from the press. I think the power is somewhere between 65 to 70 pk. Not looked at the gearing but it does roughly 80 mph at 7000 rpm and when you pull the throttle open it just pisses off to the horizon. It's got standard size BT45 tyres.
Does anyone know which size tyre would be best in soft sand. I suppose thin at the front is good?
I don't have a lock up clutch so i will probably fit 6 of Norbo' TZ springs unless some one has other suggestions to consider.
What would be the best type of handle bars? Drops to help keep the weight over the front of the bike or standard to help wrestle the bike over the sand?
I have never tried this sort of thing before so lots of advice needed. Even like the best method to launch the bike.
Cheers Tobyjugs
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Post by bazzer5115 on Jul 19, 2018 7:44:03 GMT 1
I’ve done Weston beach race a few times,
It feels like the sand robs 50% of your power.
A good spread of power (wider power band the better)or else you can rev the nuts off the bike in one gear,change up and the bike won’t pull the next gear.
And remember motocross bikes have a lot closer ratio box than road bikes,so the problem will be worse.
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Post by Tobyjugs on Jul 19, 2018 14:23:58 GMT 1
I’ve done Weston beach race a few times, It feels like the sand robs 50% of your power. A good spread of power (wider power band the better)or else you can rev the nuts off the bike in one gear,change up and the bike won’t pull the next gear. And remember motocross bikes have a lot closer ratio box than road bikes,so the problem will be worse. Thanks Baz i will check out my sprocket assortment. I think it will be dry sand would you choose a 150 or 110 width tyre? |
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Post by Norbo on Jul 19, 2018 15:49:37 GMT 1
I must admit i cant help with the set up as ive never done anything like this but bloody hell i bet its fun
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Post by bazzer5115 on Jul 19, 2018 16:57:54 GMT 1
The wider the tyre the less likely it going to “sink into the dry sand”
You can ride a motorcycle in dry sand(difficult I admit ) but try doing it on a push bike(and I have) and it virtually impossible.So i guess wider is better👍
Riding in wet sand compared to dry sand is like night and day.
Stand up,and keep your weight over the rear at all times.The front will be uncontrollable,so keep it light,because to much weight on the front will cause it to dig in and wash out.
Try to steer by shifting body weight not by turning the steering.
Oh and good luck😀
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Post by veg on Jul 19, 2018 17:02:21 GMT 1
Mate of mine does flat track and sand racing on an xl500 will see if he can offer any advice but he is away at the moment
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Post by donkeychomp on Jul 19, 2018 21:42:01 GMT 1
High wide bars to wrestle the bugger into some form of submission!
Alex
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Post by Tobyjugs on Jul 19, 2018 22:28:36 GMT 1
Thanks for the replies.
Ive checked my sprockets. The smallest front sprocket i have is 10 teeth and the biggest back sprocket i have is 45 teeth. I hope this can drop the gearing down a bit. Buuuut if the sprint is only 40 meters what about a long first gear and just rev the crap out of it and nail it without changing gear? what do people think of that ? good or bad idea?
So it looks like one will be difficult to drive as it has clip ons, i think i will put most of the effort into the bike Kees uses as that has standard handle bars on it at the moment.
Are the 350 lc and YPVS sprockets interchangeable? i don't mean the thickness of the sprocket but the PCD of the holes for bolting them onto the sprocket carrier.
Hi Veg i hope your mate can give me some advice.
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Post by bare on Jul 19, 2018 23:19:48 GMT 1
A 10 Toother !! Yikes.... that's likely an output shaft sized tube with warts.
Really tough on the pore chain. Don't be using it for too many miles.
Don't believe LC and Valvies use the same sprocket bolt circles
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Post by donkeychomp on Jul 19, 2018 23:50:25 GMT 1
10? Never seen one that small!
Alex
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Post by JonW on Jul 20, 2018 0:33:38 GMT 1
LC is a 530 and ypvs is 520 chain, so not the same in that respect, otherwise ok.
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Post by steve h on Jul 20, 2018 2:09:55 GMT 1
Just watch out for the cat shit Tobyjugs.
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Post by bare on Jul 20, 2018 3:25:52 GMT 1
LC is a 530 and ypvs is 520 chain, so not the same in that respect, otherwise ok. Hardly... 530 and 520 only differ in widths. Yess 530 is like Caterpillar track. But Neither is even similar to that used in Go Kart racings which often do use 10 tooth sprockets.. Cuz their chain is Much smaller / flexible ... able to negotiate 180 degree direction changes with less damage |
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Post by midlifecrisisrd on Jul 20, 2018 10:40:21 GMT 1
Never mind a tall first
Get to some sand and find out if you can dump the clutch in second and get it spinning
Steve
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Post by reggieperrin on Jul 20, 2018 11:09:51 GMT 1
Are you ABSOLUTELY certain it's only 40 metres..? not 400 metres..??
If it's only 40 metres, you'll be better of with just one gear and tune the rev range with the sprockets..
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Post by jon on Jul 20, 2018 17:12:02 GMT 1
LC is a 530 and ypvs is 520 chain, so not the same in that respect, otherwise ok. Hi Jonw, I think Tobyjugs was asking if the PCD of the holes in the rear sprocket was the same? I think you were referring to the front? If so, then no. LC is four hole mount and YPVS is 6. Think the YPVS PCD is bigger too. Jon |
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Post by Tobyjugs on Jul 21, 2018 18:22:58 GMT 1
Never mind a tall first Get to some sand and find out if you can dump the clutch in second and get it spinning Steve Hi Steve good idea i Live close to the beach so will be testing this out once i get a tyre. |
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Post by Tobyjugs on Jul 21, 2018 18:26:27 GMT 1
Are you ABSOLUTELY certain it's only 40 metres..? not 400 metres..?? If it's only 40 metres, you'll be better of with just one gear and tune the rev range with the sprockets.. Hi Reggie i've asked to confirm this and said i will prepare a bike and now it's gone all silent. They could be worried about the wrath of a two stroke Ha Ha |
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Post by Tobyjugs on Jul 21, 2018 18:38:26 GMT 1
LC is a 530 and ypvs is 520 chain, so not the same in that respect, otherwise ok. Hi Jonw, I think Tobyjugs was asking if the PCD of the holes in the rear sprocket was the same? I think you were referring to the front? If so, then no. LC is four hole mount and YPVS is 6. Think the YPVS PCD is bigger too. Jon Yes your right Jon i was on about bolt spacing, I am very limited on sprocket choice for the 4LO bike. One of Bare's comments got me thinking, is it possible to combine a machined thinner 530 back sprocket to use a 520 front sprocket. I will check that tomorrow. |
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Post by Deleted on Jul 22, 2018 14:02:55 GMT 1
Can you get one of those sand tyres to fit, the one that has what looks like rubber cups along the circumference
Or is that illegal
Id gear your power rev range by sprocket size, if its inly 40m youll only need one gear if 400 perhaps 3
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Post by mattybeckett on Jul 22, 2018 15:48:43 GMT 1
I'm sure you will be fine with the lowest gearing possible and some flat wide bars. First or second gear should then do the trick with plenty of revs if only 40 metres. These tyres are good in the sand.  |
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Post by donkeychomp on Jul 23, 2018 0:38:53 GMT 1
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Post by Tobyjugs on Aug 11, 2018 14:12:07 GMT 1
I thought i should update this thread. Shortly after my last post I was told to go to France for 60 days, I tried twice to sprint on the beaches next to me, but the first time plod was about and due to the stretched swingarm brigade, and then the next day the kite surfers were getting uppity because I was obviously killing all the Dolphins and Whales by riding my bike on the beach (Had a real ding dong with one of them) Thought it was better to leave before they phoned Plod.
If any one is interested in the event try googling Rotterdam Dirt Ride. I have a plan of the circuit and a nice flyer but I can't upload it at the moment
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Post by donkeychomp on Aug 11, 2018 22:13:31 GMT 1
Who told you to go to France? And why 60 days? One again are you sure this race is only 40 metres....I could run that before you get any traction at all  Alex |
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Post by Tobyjugs on Aug 11, 2018 23:29:19 GMT 1
Who told you to go to France? And why 60 days? One again are you sure this race is only 40 metres....I could run that before you get any traction at all Alex work asked/told me to go to France. I will be back for the fun but little time to try and get that extra bit of edge. No work no fun. I don't mind if you can run faster than I can take off as long as I beat a few big diesels and make people think about our little strokers😁 |
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Post by donkeychomp on Aug 12, 2018 0:10:14 GMT 1
40 metres? What's the point in that. And on sand it will be very hard to determine who crosses the line first.
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Post by fozzy17 on Aug 12, 2018 7:50:31 GMT 1
road my lc on sand last year at pendine sands took it up to around 90mph no issues at all, it was compact, getting off the line you have to be more gentle but just run it as it is, there is a big avent at pendine every year
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Post by fozzy17 on Aug 12, 2018 7:52:11 GMT 1
the hot rods
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Post by fozzy17 on Aug 12, 2018 7:55:49 GMT 1
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Post by Tobyjugs on Aug 14, 2018 11:48:45 GMT 1
Nice video Fozzy I did not expect to see that many hot rods!. The course I will take part on seems to be dry sand.
Below is a diagram one of the organizers sent me. On the straight it is written as 60 meters for the sprint. Is 60 meters OK for you Alex?
Gideon one of the organizers told me the rest of the circuit is made up of different surfaces with a mud hole on the back straight. In the middle of the circuit is a playing field for what they are calling Polo.
The whole idea for the day is to push yourself and your bike to do something different. It's not supposed to be a competition but I really want the little two strokes to open a few eyes and hopefully win some respect from the diesel brigade. So I am treating it a bit like one
Below is the flyer Gideon sent me. What's nice is if you go on the web site it's all written in English.
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