Impressive! What modifications? I had a 1990 KMX125 . It had a DEP Sports system and most likely was derestricted as it would hit just under 90mph on the speedo
My apologies, I did not give any context in the video. The bike was in to have the ignition programmed. However as usual there were other issues, mainly jetting and basic ignition set up., it took most of the day to sort this out and we didn't get to the fun part. We did do a hand full of power runs with the best peak 38bhp @ 12100 rpm (a little high due to slightly lean jetting) . We will be doing another session next week, when we will be programming the ignition properly. I would not expect to exceed the 38hp achieved all ready but will hopefully broaden the power range and rideability.
My apologies, I did not give any context in the video. The bike was in to have the ignition programmed. However as usual there were other issues, mainly jetting and basic ignition set up., it took most of the day to sort this out and we didn't get to the fun part. We did do a hand full of power runs with the best peak 38bhp @ 12100 rpm (a little high due to slightly lean jetting) . We will be doing another session next week, when we will be programming the ignition properly. I would not expect to exceed the 38hp achieved all ready but will hopefully broaden the power range and rideability.
My apologies, I did not give any context in the video. The bike was in to have the ignition programmed. However as usual there were other issues, mainly jetting and basic ignition set up., it took most of the day to sort this out and we didn't get to the fun part. We did do a hand full of power runs with the best peak 38bhp @ 12100 rpm (a little high due to slightly lean jetting) . We will be doing another session next week, when we will be programming the ignition properly. I would not expect to exceed the 38hp achieved all ready but will hopefully broaden the power range and rideability.
@@billfoster213 It is a disc valve. The manufacturer claimed that it had 43hp back in the 80's, we are not sure if that is crank or rear wheel. Bare in mind this is a high reving twin with low torque so all though the hp numbers sound impressive its not going to pull your arms off lol.
@@john63397 cool. I had a Suzuki that was Disc vavle intake, and I modified the disc by removing material from the opening edge, 3mm, and squaring the exhaust port, in addition to a home made expansion chamber. This was 50 years ago. Best of luck with your racer.
My apologies, I did not give any context in the video. The bike was in to have the ignition programmed. However as usual there were other issues, mainly jetting and basic ignition set up., it took most of the day to sort this out and we didn't get to the fun part. We did do a hand full of power runs with the best peak 38bhp @ 12100 rpm (a little high due to slightly lean jetting) . We will be doing another session next week, when we will be programming the ignition properly. I would not expect to exceed the 38hp achieved all ready but will hopefully broaden the power range and rideability.
Thank you for posting - interesting. I just wondered why so much needed to come off the mating face areas. Is it because you are going to use the shorter (pre 1988) type piston (albeit for a 50+ mm diameter piston). It's just that I am aware of pre and post 1988 pistons (I wasn't until a few weeks ago). The post 1988 pistons are longer. (I'm talking about AR80s here, I don't know about the AR50 arrangement). Perhaps the cylinder is different too. Who knows.
This head was machined for the big bore 93cc 53mm bore kit. The head is/was a stock 50cc head so a lot of material has to come out of them to achieve the correct compression ratio and profile. A short reach plug will be needed too.
fair point, I have sorted it out now. Too late for this vid but this next one is better ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-rJN-1zYcZpI.html
I'm loving this series, back when I was 16 I'm sure i was told one of the kx80 engines bolted straight in? Perhaps one of the early engines..Or is that just another of those myths us 16 year olds spread as gospel 😲
aah the good ol "ar" series,had a 125,unrestricted.mild tune..not the best looking mini stroker but it went and handled well.i miss that bike,still a kwak man,2 zzr's now 12+14.
Hopefully i will be taking it out for a spin tomorrow to get a few miles on it . John is an absolute magician !!! Ive seen his other engines and they are insane 🤣
the standard 4 plate 80 clutch is only good for about 12hp. The plates used in this engine are specially made slightly thinner so that we can get 5 in the standard clutch
It won't be spectacular, the objective here is rideability and sensible rpm. From experience, on this engine the Nikkon will peak at about 8500rpm and will make about 13-14hp and the Firepower will make 15-16hp @ close to 10000rpm (about the limit for road riding imo). I have engines that will make far more power but they are no good for normal road riding.
