ES150 will not run right!!

[ScotBob]

Hi all please settle in for a long read:

I bought a 1976 ES150 a few months ago, the bike has been converted to an Enduro type special (I would post photos but have no clue how to, when I click the "Img" button (Img) appears at the bottom of the message but no option of how to select or insert it?)

So back to the bike;

The bike had a number of issues when I bought it, but it did actually run ok and in fact I did a few 100 mile plus days on it without issue, then one day it died without warning, I thought fuel and put it on reserve (nothing) so thought maybe fuel tap blocked, so bike was pushed to a fuel station and filled up whereupon it started again but took a lot of frantic kicking. Thereafter it started playing up, it would be difficult to start hot, would cough and splutter, bog down and cut out. All symptoms pointed to a fuelling issue so the following tasks were completed:

Fuel tank cleaned out, new fuel tap fitted, cap breather hole checked and clear so not vapour locking, fuel hose replaced with in line filter, carb stripped, cleaned and rebuilt.

The bike would still not run, it would not rev out in low gears and would not pull in high gears it would just bog down and grind to a halt.

Next step was to look at potential ignition problems to rule that out, so the following work was done:

New: plug, HT lead, plug cap, points, condenser, coil, timing set and good. Bike would start hot and cold, idle nice but would still not run at all under load.

Next I purchased a new pattern carb; bike would still not run, then I tried a range of jets and needle settings and symptoms remained the same.

Next I tried new parts in the original carb with all standard settings, needle, jet size, air screw, float height etc bike would still not run right.

Next up I fitted a Mikuni carb, still no different and the same symptoms.

So the bike starts and idles, revs out cleanly when static but hold it on a steady throttle at high revs and it backfires through the air filter (if that makes sense) air filter was also replaced and still no difference.

The above backfire symptoms then lead me to thing perhaps the exhaust was the issue, this was then removed stripped and cleaned but still the bike will not run!!

So the above is only part of the problem, stay tuned for part two:

Oil Leak:

Following each test ride whilst making the above mentioned changes, the bike would leak oil profusely.

So next up, the RHS cover came off and the leak appeared to be in the layshaft area, so I replaced the oil seal and gasket put it together and it still leaked. I removed the cover again and ran the bike with the sprocket off to see the where the oil was coming from, the oil is coming through the hole in the layshaft that the clutch rod goes through. So next I though too much oil? drained the gearbox refilled to correct level and still it leaked. Then I thought perhaps the breather is blocked so ran the bike with the oil fill bung out, when static the leak stopped but under load it still leaked. I have also checked the breather drilling at the base of the cylinder and its clear through to the crank.

In summary;

Complete fuel system has been replaced, complete ignition system has been replaced, oil leaks through centre of the layshaft (clutch actuator rod hole) could the issues be related?

Bike starts effortlessly hot and cold, revs out with no load but backfires on a steady throttle. Bike will not rev out in 1st or 2nd gear, it will gain a little speed in 3rd but will bog down totally in top and will usually just cut out.

As a last resort i'm thinking crank seals but I really am at a loss as to what is causing this and would be grateful for any insight members may have.

[Gerryman Ts125]

First obvious point! have you contacted the seller? What did they say? Can they shine any other light on your problems. You seemed to have ruled out most of the mechanical problems (apart from how does it look when you run it with the points cover off) My TS 125 - 150's all did what your saying. My problem was traced to the bolt that holds on the cam, that the mechanical points ran off was slack/worn.
And the charging system was shot.

[Guesi]

Did you change the oil seals on the crankshaft ?

[Puffs]

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[ScotBob]

First obvious point! have you contacted the seller? What did they say? Can they shine any other light on your problems. You seemed to have ruled out most of the mechanical problems (apart from how does it look when you run it with the points cover off) My TS 125 - 150's all did what your saying. My problem was traced to the bolt that holds on the cam, that the mechanical points ran off was slack/worn.
And the charging system was shot.

Bike was running fine when I bought it and as mentioned I did a few 100 mile plus runs without issue, so will not be taking issue with the owner. I have run it with the points cover off and all seems ok, charging system and battery have been checked out and all is ok.

[ScotBob]

Ta for the pic of your very yummy bike in the other thread!

Yes the issues can be related: the clutch side crank seal may have been pushed out, causing a sudden poor performance, and pressure in the gearbox causing the oil leaks. Is the plug wet with oil? Smoke? Smell of the smoke? If that seal is out, I'm actually surprised it would still run... But maybe just a lip tore off, or the integrity of that seal got compromised some other way. But that seal might well be it.

Other than that, in the summary you say "complete ignition system has been replaced", but have you replaced the coil? That too might be a cause for these sort of symptoms.

Yes, coil was replaced.
Plug actually looks like all is good, beige in colour and not wet.
Have also checked breather is ok so crankcase not getting an overpressure to force the oil out, again this was ok too.

I think the issue must be crank seals as there really is nothing else I can replace that would give the symptoms.

[ScotBob]

Did you change the oil seals on the crankshaft ?

No, I think that will be my next job as I've tried everything else I can think of.

[Puffs]

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[AlanJ]

Hi Bob,
Great pic, sad to hear of your problem, but, I must agree with Puffs and Guesi about the main seals because the seal on the left side could allow pressure on the gearbox and therefore causing your pressure problem. before you do anything else, take the carb off and place a tissue over the manifold opening, and
on kicking it over the tissue should be sucked to the surface, but, if not, then you have a seal problem. Just for your info, my 77 250/1 TS, on the clutch side
lhs, had the original seals and they failed by shrinking in the housing and of course allowing pressure in the gearbox and oil into the crankcase. You don't
have to split the crankcase on the 250/1 but I have a feeling you will have to on your 150, anyway Guesi will put you right on this I feel sure.
Take care and safe riding. Alan.

[ScotBob]

Hi Bob,
Great pic, sad to hear of your problem, but, I must agree with Puffs and Guesi about the main seals because the seal on the left side could allow pressure on the gearbox and therefore causing your pressure problem. before you do anything else, take the carb off and place a tissue over the manifold opening, and
on kicking it over the tissue should be sucked to the surface, but, if not, then you have a seal problem. Just for your info, my 77 250/1 TS, on the clutch side
lhs, had the original seals and they failed by shrinking in the housing and of course allowing pressure in the gearbox and oil into the crankcase. You don't
have to split the crankcase on the 250/1 but I have a feeling you will have to on your 150, anyway Guesi will put you right on this I feel sure.
Take care and safe riding. Alan.

Thanks Alan; not heard of that trick before, i'll give it a go when I next tinker with it. I've ordered up a rebuild kit in anticipation of changing the crank seals, what is the consensus of what seals to use as in the brown or blue?

[Blurredman]

Hi,

I haven't anything to add to this thread that hasn't already been said..

Other than: Welcome fellow ES'er..!

Interesting looking bike you have.

[AlanJ]

Hi Bob,
For what it's worth, all my 3 Z's have the same seals, and they are yellow and twin lipped from Burwin's Martin/ Ann on 07726 000075
They might be all the same on the Z's but me, not having worked on any 150's, I don't know if that's correct. Anyway, Martin will know.
Alan.

[ScotBob]

Some pics:

[Puffs]

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[breakwellmz]

Some pics:

Lovely looking bike it has a very 60s ISDT look to it, such a shame it has suddenly (and strangely) become problematic.
Is this the same bike? - https://www.ukgser.com/forums/showthrea ... y-third-MZ