Keith Angus

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  • in reply to: Supa 5. Stuttering at low revs. #15883
    Keith Angus
    Participant

    When I ran a Supa5 it was always a bit rough at low revs – it only runs happily over 3000. There is negligible oomph below that. When I complained to the dealer about surging on overrun he opened up the idle jet to 0.5 mm, so presumably a 50 jet. I didn’t notice any difference. Other jets should be corrected. The proper manual for the 250, in the supplement for the Supa5 says main jet 135, needle jet 70 (without cross bore). For the older four speed the main jet is given as 140, needle jet as 70 (no mention of cross drilling), starting jet 110, slow running jet 35, float needle valve 20, slow running screw 1½ revolutions open. I assume the difference in the main and needle jets is significant – the rest remain the same.

    For the needle position:

    “Needle position from top 4 to 5 (5 for running in). Besides the driving habit, the sparking plug appearance is decisive for the adjustment.”

    Have you checked the cold start plunger? If the rubber stop in the end of it doesn’t seal on the jet it can cause odd problems with the running. When mine was a bit worn I prised it out and turned it over. That improved things a bit.

    If I had one now I would look at one of the Bing carbs offered by some of the German spares dealers. It’s a better carb.

    Also bin the Haynes manual and get a proper one. I bought a genuine MZ one and found it so much better. It left with one of my Supa5s, but I since downloaded one from somewhere – can’t remember where but they are out there.

    in reply to: 12v Battery for TS250/1 Supa 5 #15718
    Keith Angus
    Participant

    Your battery should be fine. Bear in mind that the much later Saxons, with a decent alternator, had a 5.5 Ah battery as standard. I have fitted 9 Ah, but the battery is not a problem given a good generator. My bikes do not need LED bulbs to maintain good charging.

    As for the surging, it seems to be a carburettor problem as much as anything else. Turn the tickover down as low as you can get away with. Some folks set it to the minimum, which means the bike won’t tick over, and you just have to keep your hand on the twist grip when stopped. On my Saxon it is very low – the tacho pointer doesn’t move off the bottom stop which should mean it’s lower than 500 rpm. (The handbook says 1250 revs, but I can’t see why.) You may be able to get a better carb. Some of the German suppliers offer a modern Bing carb set up for older MZs, but the cheapo Chinese copies of “better” carbs are generally reported to be rubbish. It seems to me that the cure is a good carb and electronic ignition, allowing a low tickover.

    When I had my 250/1 I just lived with it. The other problem can be bogging down if you try to bang open the throttle while below 3000 rpm. On the hill I used to live on in Wales that meant I had to grind to a stop and start all over again. If I hit the bottom of the hill at just over 3000 revs I could sail up it.

    in reply to: Saxon Tour Resurrection upgrades #14137
    Keith Angus
    Participant

    One of mine has the square section arm, and the other round. Never noticed any difference in ride, but the brake rod needs a joggle in it to fit around the box section.

    in reply to: MZ TS250 First gear knocking #14136
    Keith Angus
    Participant

    Don’t know if you have found the answer to this, but I had the same on my TS250/1. First gear had lost a tooth. Bear in mind that the first gear is used as part of the kickstarter train, so it takes some extra punishment, especially if you have an engine that needs a few kicks to get it going. I could have lived with it, but was worried about where that odd tooth had gone in the gearbox?.

    in reply to: MZ Saxon 301 Fun Factory manual? #13170
    Keith Angus
    Participant

    This seems odd, since I bought my Saxon manual and parts lists from the club. Pester an official or two – I’m not sure who is responsible for manuals.

    Keith

    in reply to: 250/300 gearbox #12895
    Keith Angus
    Participant

    The only difference between the early Supa5 and later model gearboxes is the slot in the input shaft to drive the oil pump. Also the oil drip tray is exactly the same in the Supa5 and Saxon (ETZ301) engines I have worked on. I’ve also never had any of the gearbox problems described, so I reckon that’s just a phase they went through. One of my current Saxons is running with a few gears from a Supa5, but I can’t remember which gears or which engine!

    in reply to: ETZ250 Side Stand Issue #12538
    Keith Angus
    Participant

    Should be straight and certainly not cracked!

    in reply to: Skorpion Tour and 500R fork oil #12537
    Keith Angus
    Participant

    The ETZ 251 manual says 230 – 250 cc, 350 to 370 mm high. Measure the height with a bit of rod right down the middle of the fork. They also emphasise it is important to get both forks to the same level. As for grade of oil, I wonder if the spring is already a bit stiffer to take account of the extra weight. You may need to experiment. I got very good at swapping forks around when I was testing three sets to find out which ones leaked.

    Keith

    in reply to: ETZ 250 – Bottom-end torque and riding position #12347
    Keith Angus
    Participant

    Quietly swap the engine for a 301 while no-one’s looking. Boring it out might be enough. Maybe fit the Bing carb and electronic ignition at the same time. Or get an old TS250/1 engine and sneak that in. I believe (never having ridden an ETZ250) that both before and after were better for the torque band.

    in reply to: TS250 rubber inlet pipe #12346
    Keith Angus
    Participant

    Among the changes was the design of the combustion chamber (and cylinder head finning) to avoid overheating when thrashing the engine. The tube length would be part of the inlet tuning, and presumably the newer engine was that bit different. I don’t know if there were any equivalent changes to the exhaust.

    in reply to: Clutch #11897
    Keith Angus
    Participant

    As summarised above the clutch cable pulls on an arm, which rotates a nut on a five start thread. This pushes a boss on the end of the clutch which connects to a pressure plate on the opposite face of the clutch. Therefore this is moved away from the main clutch body, relieving the spring pressure on the plates.

    If your clutch is not releasing properly make sure the arm is set correctly as per the manual. After that it is just a matter of routine cable adjustment

    in reply to: Worn gears #10753
    Keith Angus
    Participant

    Some of the gears have a sort of copper plating which looks brown after use. It’s nothing to worry about. What sort of mileage is the bike? I’ve never noticed gear wear as a problem, but I have had a few break a tooth.

    Third & fourth are near the middle of the shafts, so I would not expect bearing noise from them – more from gears which are nearer one end or the other, first and fifth. Then it might indicate damage to one bearing or another.

    If you’ve got the engine apart why not replace the bearings anyway? That’s what I always do. Engine rebuild – all new bearings and seals. Look for respectable bearings like SKF, FAG, NSK, and make sure they are the correct clearances, C4 for crankshaft and C3 for gearbox, as detailed in the manual. The clearances matter, and proper fitting, again detailed in the manual.

    in reply to: ETZ251 Electronic Revcounter / Tacho #10750
    Keith Angus
    Participant

    I’m not clear whether you are running a Saxon, but on those the green wire comes from one output of the alternator, so this feed AC to the tacho. Since the frequency depends on the engine speed, that’s all you need.

    I know when I first looked at the Saxon wiring, long ago when i got my first one, I found the tacho arrangements confusing, but they are actually quite simple – at least in wiring terms.

Viewing 13 posts - 1 through 13 (of 13 total)