Progress update....or not.....

[Smallkat]

BTW, I've had my eye on an X7 for a while. Belters. Ran one in Saudi Arabia in those summer heats. Fast little things and light as a feather. As my bones get older, the attraction of lighness apeals more and more.
Cheers all.

I've got a right shitter project one that I want top money for (and I'm not joking). Will post pics if interested.

[Smallkat]

Hi, I have a 400 as well, not any problems when I was running it until the Cdi unit failed and I put it off the road. That was a few years ago, getting it fixed up now, replaced the Cdi twice . You will enjoy it when you finish sorting it out. Here’s my 400 along with my 250, pictures around 12 years apart, 250 one today.

Love that Yoshi exhaust.

[Smallkat]

This is where I earn my money! My clue came from the coils, the clutch side coil was hot, the other cool. Have a set of new coils, fitted them, ran it up for a while, coil still running hot.
Measuring voltages. 13v nominal on both coil supplies. Output to TCI, 12+ volts on R/H side coil, 10v nominal on the left hand coil. All cable resistances at 0 ohms to TCI. Turns out that the transistor controlling the L/H coil has gone leaky, allowing 2 volts to earth. (8amp supply, drop of 2volts = 16 watts of heat dissipation, the reason the coil was warming up). In use, the transistor was getting hotter, dragging down the voltage at the coil. Bit complex to describe, but new tranies ordered and a standby TCI. I WILL get this one right....
Cheers

Please excuse my ignorance, but what is the TCI? Where is the transistor for the coils?

I've changed my coils and leads, but would like to eliminate any further problems in the future.

[Uncle Bob]

Please excuse my ignorance, but what is the TCI? Where is the transistor for the coils?
I've changed my coils and leads, but would like to eliminate any further problems in the future.

TCI - Transistor Controlled Igniter
as opposed to
CDI - Capacitor Discharge Igniter

https://www.shindengen.com/products/ele ... %20energy.

---

JohnD - what transistors did you use? I was looking at using these once I get around to taking a dead original TDI apart (got from another link regarding I think Bandit 400 TDI repair).
https://uk.farnell.com/multicomp/tip150 ... dp/1440104

Cheers

UB

[Smallkat]

Ah, okay, thanks for that Rob. I've changed my ignitor, so hopefully no problems for me there.

[johnD]

Hi Uncle Bob. The unit I have uses a power Darlington NPN transistor (2S)D1071 for each coil.
This is a Chinese unit marked CD11.
I have some old units that my mate had liing around, one off a Suzuki VX800 V twin. This also uses these transistors but, worryingly, they were both blown, shorted Emmiter / Base.
I am waiting for some replacements to arrive, (bring back Maplins!).
I await the arrival of the new TCI to make some comparisons.
I did have my doubts about the unit, I have already re soldered the clock crystal leads that was dead, or more likely making intermittant contact and giving the eronious signals on the odd occasions the unit fired up before.

The transistors etc. are in the black box on the rear mudguard, Smallkat.
Im still trying to get my head around the timing pulses that these boxes require. The timing rotor has a series of 'tangs' that pass the pick up coil. These have odd spacings rather than a regular pattern, the pulses I measure on the scope show a very unusual mark space ratio. Must make sense to the microprocessor, but makes substituting this TCI for something else problamatic. I have looked at the rotor from a 600 / 1200 Bandit but this is a small, horse shoe shaped device, (just what I would expect), that would be difficult to mount on the 400s set up. So, for the moment, I (we) are stuck with the Chinese replacements......
Stand by for further updates, this HAS to be on the road for the first Bike meets of the season, mid March. I will NOT be beaten! Freeeeedom!!!
Cheers.

[Smallkat]

I am so glad I didn't buy that bike now! I'd have followed JohnR's helpful advice by now.

[johnD]

In actual fact, Smallkat, I doubt it would have taken you anything like the time Ive spent in trials and errors. You might have gone the same route with the carbs, but pretty soon you would have tried your igniter. That was the heart of my problems and took nearly a month to sort. That the igniter is still faulty has only added to my frustrations and time spent, mostly waiting for bits to arrive from faraway lands. Remember too, the weather has been arctic for a month or more, no way my old bones can take that anymore, even with the garage heater burning up my pittiful pension it was just too cold.
At least now I know my way round the machine, which makes any future problems that much easier to diagnose. On the occasions I've actually ridden it, I'm more than happy with its performance, light(er) weight and comfort. That it is virtually unmarked with only 10,000 kms on the odo does make the effort worthwhile, not sure of its value but I dont think I will lose too much if I sell in the future, rareties like this must, surely, be increasing in value?
Cheers.

[Smallkat]

One of the first things I did with mine was to completely dismantle the carbs, ultrasonic clean and reassemble to factory specs. I'm sure you have read my project thread!

You really have done well to persevere with your one. You will be the model expert by now! Hopefully in the summer I could have a ride down to you and have a look at it.

[johnD]

Hi smallkat. More likely I'll be taking a ride up to your mansion. There is a new venture started in the Thornton area dealing in classic bikes, from mint to project. Be a nice little ride out and some fish and chips too, if I can still afford them that is.
Looks like more arctic weather on the way so March appears to be another miserable month. Means I don't have to break my back getting this finished....... If ever!

Now, a totally unrelated question. The choke cable. I have a rather tortuous cable that, it appears, came from a 1000 Kat. It actually fits, but the choke 'lever' dial does not appear to have a locking mechanism to hold the choke on when warming up. Anyone give me a photo of your side panel and the choke dial to see what I'm missing.

Cheers.