Engine runs rough

At the moment, the engine runs really rough. It was putting out a dense grey smoke but this was because I had set the oil pump up WAY too rich. After setting it properly, the smoke levels returned to normal immediately.
It struggles to rev and huffs and puffs and misfires.
It appears to be running on both cylinders. But running really rough. It will not idle most of the time. Certainly not ride-able.

Initially I thought it was electrical. I pulled apart all the connector blocks and sprayed them with CRC and/or BrakeKleen and/or contact cleaner. I think I have probably done this to each connector block at least 3 times now. I also made sure that the battery was good and fully charged up. I could see spark at both spark plugs and both plugs were getting wet.

1) COILS, CAPS and PLUGS
I checked the resistance of the plug caps and it was zero, so I bought 2 new NGK caps/leads at NZ$42 each, with an inbuilt 5kOhm resistance.(NGK TB05EMA)
This made no difference.

Note that NGK plugs with "R" in their description (such as BR9ECM) means that the plug has an inbuilt 5kohm resistance. I am not too sure if you are supposed to use a 5kohm lead with a 5kohm plug, but that is what I am doing until I learn otherwise. NGK link.

I checked the resistances at the coils and they were zero across the terminals and about 3.3kOhm to lead end.
This gives a total resistance of 3.3k + 5k in the cap = 8.3k.
I know that 3.3kOhm seems a bit low across the HT coil, but a friends bike that was running sweetly measured the same.
I even swapped coils/caps with him, and still no difference.
I got a new set of NGK BR9ES plugs at $8 each and tried them. No difference. (The BR9ECM's were $25 each; I ordered 2 but then the bike shop rang back later and said that they would rather not get them in as they would have to buy a box of 10 and they didn't want to have 8 plugs sitting in the warehouse for ever. Welcome to New Zealand.
I set the plug gaps to 0.6mm
I also checked that the grounding of the earth wires on the wiring loom was good.
I unwrapped the front 2/3rds of the wiring loom and checked that it was all OK.

2) PGM II
I put my PGM on my friends bike and it ran OK. So I guess My PGM is OK

3) TPS
I measured the resistance across the Throttle Position Sensor (both ways) and made sure it made sense.
It varied from around 3kOhm to 5 kOhm from memory.
The power valve drive motor behaves properly with TPS connected and disconnected

4) PICK UPS
I fitted the flywheel pickups and wires from my spare engine. No difference.
I checked that the flywheel was on properly and couldn't float around on the crank giving bad timing signals.

So then I thought, well maybe it is carburation:

5) CARBURETTORS
I fitted a set of carbies from a friends bike that was running OK. No difference.
Both his and my carbs are set to standard settings with slightly different needles BPJ/K instead of BPG/H) and his float level was set to 16mm instead of 13mm.

???)  I am at a loss to explain why it doesn't run properly.
A) Maybe I have made a mistake during engine assembly, but I can't think what.
B) There is no little tacho wiring loom in place, but I seriously doubt that not having the tacho wired up would cause any problems. I actually just disconnected it on my friends bike and it did not affect how it runs.
C) Maybe there is some random problem in the rear part of the wiring loom?
D) I will check the compression on both cylinders tomorrow, just in case that sheds any light on this problem. It feels like good compression with the kick start.
E) I guess it could be a leaky centre main bearing seal, but this is brand new, so seems unlikely. But I guess I will have to do a crankcase pressure test the way things are going.
F) I am running V-Force III reed blocks. I doubt these are the cause of any problems?
G) I am running single ring Wossner RM125 pistons. They have a shorter skirt, but still block the exhaust port entirely at Top Dead Centre.

It is really quite frustrating to have such an elusive problem right at the end of the complete rebuild of this bike. But I guess this can be viewed as perfectly normal?

It goes!

Today I replaced a needle valve in the RH carby before fitting the carbs.
I fitted the two stroke oil tank and exhaust pipes.
The thermostat octopus arrived from Yahoo!Japan via Gary Gower and I fitted that and the radiator and the catch tank.
I put the tank and seat on and after about 6 kicks it fired into life.
The smoke was more grey than blue and very dense out of both pipes. It remained this way for the first two runs of about a minute each at low revs just above idle, then it stopped and wouldn't go again. Probably fouled plugs? Not too sure. Hope the grey smoke doesn't mean water in the system.

Just after first engine start-up

First impression of the dry clutch is that it sounds really crap. Even more so when the clutch is pulled in. But I will come to appreciate it over time I am sure. :-)

Spark at plugs & PV movement. Wanted Parts list.

I finally worked out that the engine kill switch on my bike is wired up completely wrong.
The switch is open when set to "run" and closed when set to "off". This is the reverse of what it should be, and lead me to think that the kill switch wires should be open when trying to set the power valve to the "Hi" position with the TPS disconnected. Wrong!.

In order to set the power valves, you must have the Kill switch set to "run" and this means that the two Black and Black/White wires should be connected. Then with the TPS switch unplugged, turn on the ignition key and the power valve pulley will rotate to where the computer thinks the fully open position for the power valves is. Now you can adjust the cables so that the power valves are exactly in the fully open position.
Note that the TPS connector block is a mongrel of a thing to pull apart.

Finally, after a bit of head scratching due to the incorrect kill switch leading me astray, I have been able to get my power valves operating correctly and now have spark at the spark plugs.

There is now light at the end of the tunnel. I just need to source a few little bits and do some minor work and it will be finished and working.

Things I need to source:
00) Correct kill switch! 03/01/2012 in the post.
01) Mini wiring loom for tacho/temp gauge. (bidding on Yahoo!Japan) 02/04/2012
02) Rear bottom fairing mount bracket.
03) Speedo cable. (bidding on Yahoo!Japan)02/04/2012
04) Radiator cap 06/01/2012 Arrived in post from Paul along with kill switch.
05) Pillion foot pegs. (bidding on Yahoo!Japan) 02/04/2012
06) Upper front RH side fairing mount that also supports small two-stroke oil tank 02/01/2012
07) Dzus fasteners for fairings. (Have fitted some but need more)
08) Rear seat latching mechanism. (bidding on Yahoo!Japan) 02/04/2012
09) Front Park Light and wires. 22/04/2012
10) Radiator bottom bracket. (bidding on Yahoo!Japan)
11) Brake hose clamp on bottom triple clamp. (bidding on Yahoo!Japan)
12) Front brake reservoir mounting bracket.

Things I need to do
1) Tape up the wiring loom after having pulled it apart for thorough inspection 02/01/2012
2) Fit new carby float bowl seals. 04/01/2012 The leaks basically stopped after having petrol in the bowls for a few days.
3) Fix broken air valve wires (green connector block)
4) General assembly of carbs, two-stroke oil tank, radiator, thermostat and radiator overflow tank and exhaust pipes. 04/01/2012
5) Make the fairings fit. Not a small job.

Unfortunately, it is the holiday period so it will take a bit of time to get this sorted out. Maybe about another 2 weeks. There is now nothing but some assembly time stopping me from firing up the engine.      :-)

Some little issues holding things up

1) I can't get the power valve motor to move when I turn the key on.
2) The wiring loom has been altered in a way that has to do with the engine kill switch and the front brake switch.

But I couldn't resist just having a quick mock-up of what it is going to look like with the fairings on.
New tyres on today. Bridgestone BT-090's. NZ$400. 110/70/17 front and 150/60/18 rear.

I'm not too sure that I can live with the Chinese fairings long term but they will do for now.

Carbies assembled

Today I assembled a set of carbies from a big bunch of bits.
That's it.

I discovered that I am missing a few parts:

Needed: A small wiring loom for the gauges

Needed: The rear seat release latch

Assembly of the entire bike

This week I have spent the best part of 4 days working on assembling the NSR250.
It has taken a lot longer than I anticipated and there is still quite a bit left to do.

At the start of the week I only had the swingarm attached to the frame, and a complete engine.
Now I have the motor in the frame, and the subframe on, with front and rear suspension fitted along with triple clamps. I pulled the front shocks apart and checked them out. The rear shock has already been reconditioned by Goudenz Gisler of Tuakau. I have zip tied the shock remote reservoir in place.
The wiring loom is about 90% connected up.
The powervalve motor and cables are assembled but need setting.
The brakes are on, but no front mudguard yet.
Handlebars and switch gear are on.

I spent a lot of time cleaning and lubricating everything as I went. Very time consuming.

I need to attach the carburetors, airbox, water tank, two-stroke oil tank, drive chain, radiator, pipes, mufflers, fairings and tank. That might not sound like much, but it will take me a while to check over the carbs and I'm not yet sure if I have all the radiator hoses.
I also need to assemble the tank so that it is 1 piece.
I still haven't assembled the headlight, screen and indicators into the front fairing.
I am waiting on a set of Bridgestone BT090's to arrive.
I do not have the bolts needed to attach a lot of the fairings.
I appear to have misplaced the brake/tail lights.

It is Christmas day: I started working on the bike at 7am and stopped at 9pm. Pretty sad huh.
Looks like Boxing Day may be a similar thing.
Anyway, here are some pics:

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NSR250 Conrod Kits

I got a package in the mail today;  4 x NSR250 conrod kits.

Clearly, the crank pin is not needed, but I failed to specify that. D'oh.

These new conrods weigh 156 grams. The standard Honda conrod weighs 155 grams.
These new conrods are a bit thicker in the stem near the small end, so I suspect (I can't say for sure) they will be able to handle a bit more stress due to higher revs/heavier piston/more power etc.

The big end bearing weighs 25g
The small end bearing weighs 12g
The thrust washers weigh 6g each (total of 12 grams)
This gives a total of 205g

The big end pin weighs 176g but is not needed as it is an integral part of the crank web.

I am actually going to sell a pair of these to anyone who wants them. NZ$340 + freight each. (NZ$680 for the pair) Not cheap I know. That includes bearings, washers and bid end pin.


Now if only my man making the 2 central crankshaft webs wasn't quite so busy!
Patience.

In due course will be revealing the source for these NSR conrods ( <--click) on the new forum, just to give that site a bit more exposure.