Hello All

Warning: May contain rambling

I been lurking around here for a while, finally decided to post about my experiences for those with too much time on their hands. Looking back my honda experience started with the purchase of an 1981 yamaha SR250. I rode it for a while and thought it would be a good idea to repower with something with a bit more power. So i brought a front end damaged 2009 KLR650 with the intention of putting the single cylinder engine into the SR. At some point, i'm not sure when, i decided it was a bad idea, the SR250 was a total deathtrap, the brakes worked but if your used to modern twin disk brakes with four pot calipers a 30 year old cable operated drum set up feels down right deadly. So i started to look for another donor chassis, enter a 199? MC-21 with no: engine, fairings, front wheel. I started to look for parts to complete the chassis on our version of e-bay called trademe, i kept seeing a complete NSR MC-21 for sale, now i've never ridden a decent two stroke, so i thought here was an opportunity to own a piece of automotive history before they go the way of the fax machine. I was the emotional purchaser, hot and uncollected, i knew i was going to end up with it the only uncertainty was the price. The seller spoke in riddles, buzzed like a fridge and sounded like a detuned radio, we talked but i never felt like he said much. So, down to brass tacks, compression was around 140-145 for both cylinders. He said it hadn't gone for 6 months and said it just needed some gas down the carbs, after some kicking and prodding it fired up, mucho smoke and by Jebus it was loud, it crackled and spat. Awesome. Distant memorys of my well spent youth at race tracks loomed up. The only disappointment was the lack of that eye watering acrid quality in the smoke i remember, the oil smelt positively polite. Aargh. We loaded it up, i took all the little bits and pieces he had, he lent me a manuel but it had been photocopyed so many times alot of the diagram and picture where'nt much help. I'm also the sort of person that likes to playing with things before reading about them. The bike has been modifyed, loud pipes, 3.5 inch front rim, tyga tail section, fiberglass front fairings and dry clutch. As soon as i got it home i wanted to take it for spin, but i kept finding problems and as the beers started to dull me, i realised those two words that blight everything i buy, 'needs work' apply here as well. Gutted. I can't imagen taking it to a shop to get fixed, I've spent 20-30 hours working on it already and yes sitting on it making two stroke noises counts too.

Hello and welcome to the forum.
_________________
If I have to take the carbs off once more...

Thread needs photos. I'm very visual.

Welcome to the fold. You haven't really done an NSR build until an engine has sat on the kitchen bench, some part or another has been in the oven/dishwasher while the missus is out and you started the bike with the back door open and filled the house with nice blue aroma.

You may also take the above as mandatory inclusions in your story

Heya

I spent ages trying to get the airbox on it, put it just would'nt slide on the carbs, after an hour or so i realised you had to take the top half off the box to get the rubbers over the carbs, at this point of found the air filter was in 3 pieces, not sure what would happen if one of the bits fell into the carb and jammed it. I've also found a number of unconected nipples and hoses, the diagram on the tank shows a '3-way' connection but theres only 2 hoses conected to it, on mine the two hoses are connected but the 3rd part of the '3 way' is unconnected and open to atmosphere, what looks like the gearbox breather is'nt connected to anything either, which would suggest if the gearbox pressurises for any reason the lubricant will end up all over the motor and work it's way to the back tyre, that ca'nt be right. The kickstart lever retaining bolt was loose and just need to be tightened, the gear lever selecter retaining bolt was tight, but the lever clamp was loose on the spline. I removed the bolt to find the threads rounded at the end of the bolt. I ran an M6 tap through the gear lever selecter clamp and cleaned the thread up and fixed a new bolt. Next i found on two of the three bolts on the rear suspension leakage that the head of the bolt wasn't hard up against the linkage plates, futher examination showed the nuts on these bolts where finger tight. I was lucky my friend where the bike is stored as an extensive tool kit as the fittings where abit tricky to get at. Next was the aggrivating pool of oil that was always under the bike, man, i seriously dislike oil leaks on so many levels. It seemed to be coming from the front sprocket cover, i suspected either the gearbox selector staft seal or the gear box output shaft seal. I popped the sprocket cover off both seals looked fine. The oil looks like it was leaking from some kind of eletrical sensor. I undid the sensor retaining bolt and withdrew the sensor from it's housing. The sensor from memory has 4 wires at the end of it so i suspect it's more then just an in/out sensor. The sensor has a pin on the end of it with a smaller pin located at 90 degrees to it axis at the end of it. If i look into the housing there appears to be a recesses for both pins to locate into. I suspect that the smaller pin was never located into the recess when the sensor was fitted, the neutal light has never worked so i'm thinking this might be why.
Cheers

Robert

Heya

As part of the process of removing the sensor i had to drain the gearbox fluid, on examination of the fluid there was a collection of rubber sealant and 'gold dust', which suggests something made of bronze in the transmission is failing. Things always start this way, i buy something and i say to myself i'm just going to use it, i don't have the time to study its habits, there is no shame in mindless consumerism, but i can't. I refuse to admit it but i can already feel the grease under my nails and the smell of an oil and workshop soap bouquet. My camry is 10,000km overdue for an oil change and the transmission fluid appears to contain rust, but i don't care and have no plans to do anything about, but the idea there may be damage in the transmission of a bike i've done barely 400 meters makes me want to stop the world and tell anyone dumb enough to listen that terrible things are afoot and changes must occur before the earth can rotate again. And thats where the bike is at the moment. I can see iamb going to have to remove the transmission cluster and examine the all bearings and bushs, the previous owner said he has never ridden the bike with the dry clutch set up, maybe it's just the transmission running in . Somewhere i can hear the mechanical gods laughing their collective arses off. When the pervious owner started the bike up he showed me how the power valves reset themselves, i took this to meaning there was a problem in somewhere in there. When i got it home i took the tank off it and watched the valves reset themselves. I checked the cables that actuate the power valves and found some fraying in the cables at the power valve end of the rear cylinder. I suspect the frayed parts of the wire cable where jamming on the black plastic cable sheath preventing the power valve reach it's setting position. There's something Unhonda going on here, i suspect cable brackets at the power valve end are the wrong way around or something because all the cables show signs of wear, it's like the angle that the cable exits it's sheath is too extreme and there failing in fatigue.

cheers

Robert

Welcome, some sentence structure and paragraphs will go a long way to making it readable.

It sounds like most project bikes, it idles, but doesn't run properly....a bottomless pit of money later and you have a bike.

Heya

I replaced the frayed cable with one of the spare cables i got with the chassis i brought for the single cylinder conversion, it was even thoughtfully labeled. It showed signs of deterioration but was in better shape then the original, i removed the damage from the spare cable with a bench grinder and fitted it. I noticed the power valve actuation plates have holes in them with a dimple behind them, i can only assume that the hole and dimple have to line up when the engines off. For some reason the last person to set the power valves put the locking nuts on the bottom of the power valve actuation plate rather then the top. I turned the ignition on and the flicked the kill switch to on and watched the power valve actuation motor cycle back and forth, rather then just move then stop, I figured i had set too much tension in the cables which had prevented the motor reaching its set position, so it was hunting back and forth. I loosened both the pull and push cables and turned the bike on watched the motor perform like it did before i replaced the cable. I'm going to have to make new cable inners for the power valve cables, they all look various degrees of tired.
After i had replaced the cable i put the tank and tail section on fired it up. Dropped it into first and feed the clutch out, i could feel the tallness of 1st gear, i didn't stall it, if i had of i would of never heard the end of it from my friends. I slipped out on to the road of the industial estate where i store the bike. In the summer twilight wearing only a t-shirt, shorts and safety shoes, i just took it too 9k and short shifted, it gets real light in the front esp. with no front fairing. Having said that i'm a fatty at around 100kg, i imagen with a lighter rider and more aggression it would flip in 1st. I did maybe 400 meters and parked it up. I think i've gone almost as without a decent manuel.

Cheers

Robert

Heya

I went on a mission last night to try and resolve my neutral light and oil leak issues, I pulled the neutral sensor out and replaced the it's o-ring, hopefully this will solve the oil leaks. After removing the sensor i shone a light into the sensors housing as i changed gears I could see that the recesses where the pins at the end of the sensor fit, would rotate, So it appears the mechanism that gives the sensor input is working, although i'm not sure if it's orientated correctly. Closer examination revealed there are more then the 4 wires going into then i thought. Why would a neutral sensor need any more than either one or two wires, the answer came when discovered the wire diagram here. It's not just a neutral sensor it's also tells the PGM what gear the bikes in, following the wires back i discovered that the pervious owner had combined 3 of the wires in too 1, I'm think he did that to fool the PGM into thinking that gears 4,5,6 are actually 4th gear, the only reason i can think of to do this is to fool the PGM that the bikes is going slower then it is. Perhaps to get around a speed limiter maybe someone who know something about NSR's can confirm this. I have seen the neutral light come on at weird times, so i'm leaning towards maybe the sensors faulty. Tonight i'll test for continuity across the sensor as i change gears on each of the wires to it. As the gearbox must be in one of seven positions, I think if the sensor is detecting neutral the green and red wire should be earthed, failing that i'll check it's not the other way round and it's the other 6 wires that are earthed. if there all the same when it's in neutral then i'm picking it's the sensor.

I really have enjoyed working on the bike, most of my pervious bikes where ZXR400's and their much harder to work on. Everything on NSR seems well thought out and logical from what little i've seen. The electrics also seem far more advanced for it's age then anything else i've owned, I feel if the designers had been allowed to push a bit further with just a few tweaks it could of had various ride modes, all the eletronics is there it just lacks the ability to change the engine mapping at the touch of a button like some modern bikes.

I'm almost looking forward to removing the transmission.

Cheers

Robert

Welcome to the board, sounds like a lot of work but NSRs are always worth it

pics please!

Heya

I spent a couple of hours testing the gear position sensor. Going backwards fast, the sensor only seemed to find N,1,2 the rest of the gears failed to earth any of the inputs. The sensor showed it was in 2nd gear when it was in neutral, and when in N or 1 it showed it was either in 4,5,6 gears, not sure which as the all 3 inputs have been twisted together, I need to disambiguate inputs to find whats what. Having said that i get the feeling the sensor is history, It feels, well, limp, sometimes it clicks other times it just turns freely. I thought i'd check the project chassis to see if there was a sensor there, instead i find all seven wires have joined together and earthed, more vandalism.

I could'nt figure out how the thing runs when the PGM has no idea what gear the bikes in, but i guess there must be a default map when the G.P.S gives no out put, i.e between gear changes, otherwise it would backfire every gear change.

I'm going to ring around and see if i can get another one from the local honda dealer. My normal theory on the cost is think of a reasonable price double it, then add 50% of original estimate. I think NZ$100 or US$85 seems fair so, I'm picking it'll be around NZ$250 or US$215. There is also a dismantler with MC-28 engine, i might try there too.

The speedo does'nt work either, I think i'm missing a peice, i tryed looking on the parts pictures here, but i ca'nt see the peice that conects the speedo drive (white round plastic bit with a key recessed out of it) to the gearbox output shaft. There are two unused tapped holes in the end of the output shaft, maybe something bolts in here?

Cheers

Robert

Heya

I ca'nt find what drives the white bush on the end of the speedo drive located in the left side engine cover. The parts list here shows the
Number #21 44808-KV3-701 Joint Speedometer, Number #22 44830-GS3-000 Cable ASSY. speedometer, but it does'nt show what drives it. I haven't checked it but i suspect there is a gap between the gearbox output shaft and part #22. There is nothing to drive Part #22. The transmission parts list. doesn't show anything on the end of the gearbox output shaft. Thats not there. I might have a go at making something up. It be useful if knew what it looked like. Little help....

The temp gauge as never worked either. I removed the coolant reserve to find the sensor, which was attached to the thermo housing, the plug on the sensor looked fine, i gave the inside of the plug a light filing just incase it was connectivity issue. And clipped the plug back on the sensor, i had expected to find a two pin plug, not just a single wire, i remember seeing two wires going to it on the diagram. Sure enough i found the earthing connection in a different position on the thermo housing ,there was nothing plugged into it, the plug was right next to it, just needed to be reconnected, temp gauge is now a runner.

I'm slowly getting the electrics back to spec., I just want everything to work as honda intended.

cheers

The speedo drive engages on the end of the output shaft, there is no additional part inbetween.

Heya

It's weird my relationship with time and the bike. The more time per day i get the less i get done per unit of time. One curve against another. I only had an hour and a half in two days, but managed to get a bit done.

I put the gear position sensor in again. So i've given up on getting the neutral light to come on till i buy a new sensor. I rang the local honda dealer and the part was around (NZ)$120 or (US)$100, which was very reasonable, the parts are in japan and it being xmas it'll probably take 8 weeks to get here, i'm happy, i'm just glad the parts are available.

I'd had assembled the tyga tail section, attached all the indicators, plate light, tyga LED tail light a couple of nights ago. The first time i tryed the tail light, the tail lights LED wouldn't work with the headlight on, i thought that there must be a broken wire in the switch block and cursed myself for selling the spare one i had off the other chassis. Then i remembered that LED's drop out below a certain voltage unlike normal bulbs that almost work down to zero volts, i unpluged the headlight bulbs and the LED's lit up so it was just an flattish battery, i wonder if it's possible, say in the case of an: alternator or voltage regulator failure or sad battery, if the bike would cotinue to operate but the LED's fail?

I connected the tail section wiring, and checked all the lights work, everything was fine till i got to rear brake, the lever went to the stop and worse still the brake light didn't light up either. Two more problems to add to the list. I think i'll just swap it for the one on the other chassis and let future Rob deal with it.

cheers

Heya

I refilled the transmission, with 15 minutes left i thought i should try get in running again, it's a couple of weeks since it ran and it doesn't like standing. I'm not sure about this with everyone else but it's not a natural motion, kicking it over. I always feel like somethings in the wrong place or something. After a couple of minutes kicking i resorted to walking it, like everyone else that owns a dog. I have to say though, there is a kinda primal thing going on when I kick it over, i imagen it's the same as any person that kicks or pull starts any bike or yard applyance thats poorly maintained would feel, a sorta mildly sucessful hunter gather feeling, when it fires and runs, which only comes with the knowledge that anything could happen.

I started with 2nd gear, but soon realised 1st gear is insanely high so that became the gear of choice. The neutral light came on and stayed on. I'm starting to think that all the people that died on this bike are inhabiting it. Sweating profusely and begging for mercy, I'm heading up the road away from where it's stored going, no, we need to turn back, but i kept going, maybe after 200 meters of ever decreasing pushing it fired, up the road again, it felt guttless till the other cylinder fired, mother mary.

Cheers

Heya

With only 5 minutes left, i learn two more things about the bike, firstly there is no way it will pass a warrant of fitness with 'those' mufflers on, you ca'nt talk over them. I got a standard set of mufflers with the bike so i'm going to have to fit them, i recall having a memory of the pervious owner saying that they where hard to change.

I rode the bike back to the garage where it was stored, it was idling nicely, i reached down and pulled the choke level back and forth, and the learned the 2nd thing, the choke was not connected or just not functioning, i would of expected the revs to change as i adjust the choke but the revs stayed the same. Another problem to add to the list.

I parked the bike and went home, a couple of hours of later i realised i'd fail to see if the speedo or temp gauge worked, when i was riding it.

Thanks for your info Satchriossi, i'll try to check if it works next i time i go out.

Cheers