Mark3 Posted June 2, 2009 Share Posted June 2, 2009 Hi all Bike is running great after months of work but rev counter stops working from about 4-5000 RPM. Not precise coz my head is up. Engine is reving past that, and I'm just using my ears to change gear as you should anyway. There is no cable on these counters, so must be an electrical/connection fault, but it seems strange that it works normally up to that point. It's like the needle is jammed (its not) Has anyone had a similar problem? I dont suspect it is particulary specific to this bike. Would the CDI have anything to do with it? It would be nice to know when red line is approaching at least. p.s. after 150kms of running in, I let her accelarate freely tonight for the first time. 120ks in 4th and she was dissapointed I changed up. As soon as I got home, had the torch on everything checking for leaks etc whislt still running her. Not a sign and those pesky exhaust gaskets and seals arnt leaking. What a difference having both power valves working in tandem. When I took the head apart the jointer was missing completly! The other major fix was replacing the reed valves. The old ones didn't close fully, and had cracks. So much so that there was blackening on both carbi slides. Brings back fond memories of my youth. I have had bigger faster bikes, but nothing beats the feeling of an RD clearing her throat and pulling hard. Sublime. Happy camper # 1 : ) Link to comment Share on other sites More sharing options...
JimR Posted June 2, 2009 Share Posted June 2, 2009 Hi all Bike is running great after months of work but rev counter stops working from about 4-5000 RPM. Not precise coz my head is up. Engine is reving past that, and I'm just using my ears to change gear as you should anyway. There is no cable on these counters, so must be an electrical/connection fault, but it seems strange that it works normally up to that point. It's like the needle is jammed (its not) Has anyone had a similar problem? I dont suspect it is particulary specific to this bike. Would the CDI have anything to do with it? It would be nice to know when red line is approaching at least. p.s. after 150kms of running in, I let her accelarate freely tonight for the first time. 120ks in 4th and she was dissapointed I changed up. As soon as I got home, had the torch on everything checking for leaks etc whislt still running her. Not a sign and those pesky exhaust gaskets and seals arnt leaking. What a difference having both power valves working in tandem. When I took the head apart the jointer was missing completly! The other major fix was replacing the reed valves. The old ones didn't close fully, and had cracks. So much so that there was blackening on both carbi slides. Brings back fond memories of my youth. I have had bigger faster bikes, but nothing beats the feeling of an RD clearing her throat and pulling hard. Sublime. Happy camper # 1 : ) Hi Mark, this does sound like a cdi problem as the rev counter info is drawn from the CDI .. this may point to the dynamic ignition timing (curve) being incorrect or just a bad connection from the CDI to the rev counter ! Regards Jim Link to comment Share on other sites More sharing options...
Mark3 Posted June 4, 2009 Author Share Posted June 4, 2009 Thanks Jim. I will follow up your lead, and will post my results. All the best Mark Link to comment Share on other sites More sharing options...
JimR Posted June 4, 2009 Share Posted June 4, 2009 Thanks Jim. I will follow up your lead, and will post my results. All the best Mark Hi Mark, thats fine ... I would be interested to see what the fault is as I guess the bike you have is somewhat different to the UK spec ones!! Regards Jim Link to comment Share on other sites More sharing options...
Mark3 Posted June 7, 2009 Author Share Posted June 7, 2009 Jim The bike I have is an RD from Hertsfordshire! Us Kiwi's had the RZ from 84-86 till they moved prod to Brazil late 80's, i think. The salt air, and all year round riding here meant there are very few left in this part of the world. As the local wrecker says, "the pin's were pulled" long ago. The last true RD in NZ b4 they swapped to the YPVS RZ was the LC. That was a great bike. I had a naked one about 82 and without the YPVS its was all or nothing. I had a CR125 Elsinor as a first bike, so the LC was just a road going version with indicators. I had never ridden a YPVS model till this one (since Oct08) it is quite different. Very mellow around town and for the commute. 3 - 4,500 rpm and you get that burbling, slightly erratic crackle like purr with a nice little push, but then when the intrutions on your in built rider intution drops to low threat level, and your spooled up in 3rd, the jump from there to 9-10k is magic. The shame is that to keep them in that state of tune now costs in time & $$, but if you dole yourself out meager doses you can still have a heap of fun. Cheers, Mark Link to comment Share on other sites More sharing options...
JimR Posted June 7, 2009 Share Posted June 7, 2009 Jim The bike I have is an RD from Hertsfordshire! Us Kiwi's had the RZ from 84-86 till they moved prod to Brazil late 80's, i think. The salt air, and all year round riding here meant there are very few left in this part of the world. As the local wrecker says, "the pin's were pulled" long ago. The last true RD in NZ b4 they swapped to the YPVS RZ was the LC. That was a great bike. I had a naked one about 82 and without the YPVS its was all or nothing. I had a CR125 Elsinor as a first bike, so the LC was just a road going version with indicators. I had never ridden a YPVS model till this one (since Oct08) it is quite different. Very mellow around town and for the commute. 3 - 4,500 rpm and you get that burbling, slightly erratic crackle like purr with a nice little push, but then when the intrutions on your in built rider intution drops to low threat level, and your spooled up in 3rd, the jump from there to 9-10k is magic. The shame is that to keep them in that state of tune now costs in time & $$, but if you dole yourself out meager doses you can still have a heap of fun. Cheers, Mark Hi Mark our no valve motors were called RD also ... but I do remember seeing an RZ (non valve) on my visit to Japan in late 1980 which in outward apperance was the same as our RD ... so perhaps the bike was called RZ for some markets & RD for others but as your bike is UK spec my point should be valid .. early LC's used to have problems with the pulse coils this gave problems with misfires etc the later bike with the electronic tacho was supposed to be 'flawless' and the only prob I ever had was the connection from the CDI to the counter getting manky at the CDI box. From memory I cannot remember the wire colours but it wont be too difficult to work them out. Regards Jim Link to comment Share on other sites More sharing options...
Mark3 Posted June 13, 2009 Author Share Posted June 13, 2009 Hi Jim I sent the bike off to company specialising in instruments. They tested and determined that there was a fault within the tachometer movement. Once stripped, repaired and re-tested the rev counter is working as it should. That does leave me with one problem though. The realisation that when I am at 8,000 rpm there is still 2,000 to go till red line. : ) Link to comment Share on other sites More sharing options...
JimR Posted June 14, 2009 Share Posted June 14, 2009 Hi Jim I sent the bike off to company specialising in instruments. They tested and determined that there was a fault within the tachometer movement. Once stripped, repaired and re-tested the rev counter is working as it should. That does leave me with one problem though. The realisation that when I am at 8,000 rpm there is still 2,000 to go till red line. : ) Hi Mark, thats cool just run it up to 10k and see how well it goes ! Regards Jim Link to comment Share on other sites More sharing options...
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