Steelies Posted June 6, 2012 Share Posted June 6, 2012 heh, hope it's a clearance engine in case your cambelt goes Quote Link to comment Share on other sites More sharing options...
japawagons Posted June 6, 2012 Share Posted June 6, 2012 For a normal (or V) belt the maximum power is: Power = (P1 - P2)*w*® Where P1 is the tension in the tight side, P2 is the tension in the slack side. w and r is the angular speed (rad/s) and radius of a pulley (both measurements taken of the same pulley). Tensions are related by P1/P2 = exp(u*theta/sin(a)) where u is the coefficient of friction, theta is the contact angle of the smaller pulley, and alpha is the semi-angle of the wedge (if you are using a V belt). Looks like I learn something useful at uni afterall... I would imagine toothed belts get a lot more fucktardly complicated with deflection of the teeth and yadayada. They'd probably just snap before anything. So basically your saying if it slips, tighten the belt and if it snaps it was too much. Pssshh Coefficient of Friction Pssshh 1 Quote Link to comment Share on other sites More sharing options...
Testament Posted June 6, 2012 Share Posted June 6, 2012 pretty sure cambelt could transfer 25hp or so at least. no worries. Quote Link to comment Share on other sites More sharing options...
slacker.cam Posted June 6, 2012 Share Posted June 6, 2012 With toothed belts you will generally strip all the teeth off them before they snap. We tried a toothed belt for the final drive instead of chain in a 100hp bike motor open wheeled racecar once and the belt lasted about 0.1s before the teeth were goneski. Quote Link to comment Share on other sites More sharing options...
Llama Posted June 6, 2012 Share Posted June 6, 2012 So basically your saying if it slips, tighten the belt and if it snaps it was too much. Pssshh Coefficient of Friction Pssshh Yup. Or increase the slant of the V (I suppose they only come in a few sizes though?) This is quite different to chains, where you have to make sure you you have the required minimum sprocket size if you want your chain to last. I was going to mention that tiny sprocket earlier in the thread (or was it yowzers?) is far too small, but it looks like he changed it anyway. With toothed belts you will generally strip all the teeth off them before they snap. We tried a toothed belt for the final drive instead of chain in a 100hp bike motor open wheeled racecar once and the belt lasted about 0.1s before the teeth were goneski. that would make sense, since the shear on the corners would be much higher than you could expect in the belt itself. Quote Link to comment Share on other sites More sharing options...
mark105 Posted June 7, 2012 Author Share Posted June 7, 2012 that got technical. cam belt works lush as, if anything the V belt is the shit link. fixed a bunch of design flaws that were discovered after late night blatting round the block/ i should have welded some shit better, a couple of tacks were not enough haha. got home from work in the day light today and decided to hit the drome, by the time we got there it was pretty much dark so forgot about photos and got down to business. first run 81km's on the old gps speedo. then some shit rattled loose and didnt end up tensioning v belt right so did some shit runs. then i did a 83km's run. so yeh first proper run on the drome and did 83km's with a led headlamp strapped to my helmet and it was very dark. keen for some racing now. Quote Link to comment Share on other sites More sharing options...
shizzl Posted June 7, 2012 Share Posted June 7, 2012 i guess the smaller the contact area for the belt to grip the higher the chances of it loosing teeth like a waihi gold miner.. Quote Link to comment Share on other sites More sharing options...
mark105 Posted June 7, 2012 Author Share Posted June 7, 2012 also any one know where to get something like this cheap/in a kitset/does some one have a circut i can build. http://www.trademe.co.nz/motors/motorbi ... 913241.htm kind of keen to know some rpm's as i dont know how much over 4000rpm it will do with sticking a flywheel/rod/something into my balls. Quote Link to comment Share on other sites More sharing options...
japawagons Posted June 7, 2012 Share Posted June 7, 2012 i'm sure jesse has those at work. or am I just making things up? Quote Link to comment Share on other sites More sharing options...
Yowzer Posted June 7, 2012 Share Posted June 7, 2012 Used to, shall check if I still do. I had one once but it seems to have spazzed out and stopped working. Dunno where it is anymore Quote Link to comment Share on other sites More sharing options...
KKtrips Posted June 7, 2012 Share Posted June 7, 2012 also any one know where to get something like this cheap/in a kitset/does some one have a circut i can build.http://www.trademe.co.nz/motors/motorbi ... 913241.htm kind of keen to know some rpm's as i dont know how much over 4000rpm it will do with sticking a flywheel/rod/something into my balls. You could get a pushbike speedo and calibrate it to show Xkm/h and have a correction factor for RPM Quote Link to comment Share on other sites More sharing options...
japawagons Posted June 7, 2012 Share Posted June 7, 2012 I thought I had spied one there at some point or in your catalogue maybe. Quote Link to comment Share on other sites More sharing options...
Steelies Posted June 7, 2012 Share Posted June 7, 2012 can you take a signal form the coil and use it to run a random gauge of some sort? i guess then measure with mech. tacho and mark gauge haha Quote Link to comment Share on other sites More sharing options...
mjrstar Posted June 7, 2012 Share Posted June 7, 2012 kind of keen to know some rpm's I have one similar you can borrow for a bit if you want... (I'll have to make sure I know where it is though) Quote Link to comment Share on other sites More sharing options...
KIRK Posted June 7, 2012 Share Posted June 7, 2012 work out approx rpm from the speed and gear ratio? it wont go far past like 5- 5.5k on stock valve springs. Thats also seems to be the recomended limit for a stock flywheel according to americans on the internet. For the rod its more about how much slop is in the bigend bearing. Lots of play and they more likely to break. Also any knicks or dents in the rod from bush mechanicing can cause failure. Just dont rev the shit out of it without load and run the right amout of oil(not too much). Does it make any bad bearing type noises at idle? Also put the shroud on lol Quote Link to comment Share on other sites More sharing options...
Yowzer Posted June 8, 2012 Share Posted June 8, 2012 Shrouds are for sissies It is geared to do aprox. 80kph at 4k rpm, so a speedo should give a decent indication of engine rpm anyway. Quote Link to comment Share on other sites More sharing options...
mark105 Posted June 8, 2012 Author Share Posted June 8, 2012 yeh i noticed front wheel has a speedo drive on it due to it being a motorbike wheel, so just need to find suitable rangi speedo and calibrate to suit and sweet as. im going to machine the fins of the flywheel and prob leave it at that, if it will do 5k rpm with out dying im all happy with that. Quote Link to comment Share on other sites More sharing options...
Jase Posted June 8, 2012 Share Posted June 8, 2012 have chaly speedo and headlight bucket here, also sure there's a dt200 speedo and tach in the shed Quote Link to comment Share on other sites More sharing options...
mark105 Posted June 11, 2012 Author Share Posted June 11, 2012 rigged up the DT200 speedo i got from jase, figured out afterwards that my front wheel is much smaller than bike speedo came off so will be interesting to see how far out it is, speedo goes to 140km though so much better than the 60km max the original chally speedo has. gave carb a epic clean up and checked all the seals, everything is in pretty good nic though some seals could do with replacing but not to phased at the moment, biggest problem i have is it has a little brass float in it and the damn thing keeps filling up with fuel and not closing the float bowl. i have soldered it up twice now so hopefully i have found all the holes. i also pansied out and hooked up the rear brakes and put the flywheel cover back on as keegan bitched and moaned haha. but it means you can lean your leg up against motor so you can lean into the corners better. dad has given me some ideas from the old indian engines and has suggested i mod how the points are mounted and hook a cable operated advance setup on it so i can retard it for starting then when im cranking can advance it up for a bit more power. so going to look into this. Quote Link to comment Share on other sites More sharing options...
UTERUS Posted June 11, 2012 Share Posted June 11, 2012 Should still start ok with heaps of advance, I run 8 degrees over stock(28 degrees) and it's sweet with heaps of choke. Quote Link to comment Share on other sites More sharing options...
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