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I think the diagnosis of a missing tooth from 1st gear is probably correct. In my experience this is usually connected with attempts to free a stuck clutch. As someone has already noted, 1st gear is part of the kickstarter mechanism.
Unfortunately you either live with it and hope the broken tooth stays out of the way, or its a total engine strip.
Don’t think Roger has seen this post but I can answer it on his behalf as he gave me the Vape unit to investigate after he converted his bike back to 6v electrics.
The cdi unit itself worked fine under test on one of my other bikes. The problem turned out to be the charging coil on the alternator, which is one of the earlier type with an external trigger coil.Eventually it failed completely. There were clear signs of corrosion on the whole unit and as the bike was used for MCC type trials and green laneing, I suspect it had been soaked a few times which will not have helped the very fine windings.
You can buy a replacement stator unit from Vape but its near £90 before you get into the complexities of importing from the EU these days. As an alternative, I converted the unit to a DC cdi system with separate conventional coil and using the original trigger. It works on the bench and the timing seems to be about right. Covid-19 restrictions and the cold weather have prevented a road test but I am hopeful it will work, if so the cost was about £13 for a Chinese made cdi unit.
The drawback is of course you need a battery as it is no longer a self energising system, but the 12v charging side continues to work fine, the windings on the stator for this are far more robust.
Helped to pass the time during lockdown.
Another benefit in my view of the earlier ETZ250s is the larger frame and 18″ wheels front & Back so you only need one spare inner tube. I don’t really like the ETZ250 power characteristics much either. I am told the porting on the 251 versions is milder but I cannot say I really noticed this when I have ridden one.
A few years ago I modified an ETZ250 by fitting a TS250 top end. This is a bit tricky as the stud spacing for the two is different and the ETZ barrel is longer needing a 15mm spacer to bridge the gap. But that does provide a means to sort out the stud spacing. It worked well enough for me to use the bike for a year or so including an E2E ride. Later the engine was fitted into a Trophy and sold with that bike.
However, by a curious quirk of fate it came back into my possession a couple of years ago and is currently fitted in an ETZ250 special I am working on.
It would in truth have been a lot easier to simply fit a TS250 motor into an ETZ250 chassis, they drop straight in, but at the time I wanted 12v electrics and the oil pump. On reflection I may very well fit a TS250 motor to my special with a Vape kit and accept the pain of premix.Somewhere I have a drawing of the spacer, and its somewhere in the back numbers of MZ Rider – about 2009 I think.
I think the suggestion to try a Supa5 first is sensible, you may find you don’t really notice much difference enginewise. But you will probably notice the cramped riding position. My bike has a raised seat and dropped footrests to make it more comfortable.
I acquired an ETZ engine recently (same gearbox) which was described as having a very similar fault to yours. Difficulty in selecting 3rd gear and frequently jumping out even if it did select.
When stripped I found that the circlip that holds 3rd gear in place had come out of its groove. It had moved about 6mm towards 1st gear. My diagnosis was that this prevented full selection of 3rd gear most of the time hence jumping out. Occasionally it would select sufficiently for the undercut to pull the gear fully engaged but not enough to pull the circlip back into its groove. Next time 2nd gear was selected it pushed the circlip back again so repeating the cycle.
I have yet to establish why the circlip came out of its groove and it does not appear to be worn. Nor is there any serious wear on the bits that normally cause 3rd gear jumping problems so running with it like that does not seem to have caused any collateral damage. However, I am not confident enough of the diagnosis to rebuild the engine as yet so cannot prove my diagnosis.
Regradless, sooner or later you are going to have to strip the engine to investigate.
Most likely it’s because the output gear has not been shimmed properly. Different thicknesses of thrust washer are available to reduce set the clearance. Too big a gap and you get the knocking noise which goes because operating the clutch closes the gap. Very common on rebuilt motors and since the shims are only available in a limited range of sizes, not always possible to get rid of it completely. Its an irritating noise but not life threatening.
To fix it you need to remove the clutch which requires a special puller. I am sure you know not to use a 3 legged puller as advised in the Haynes Manual.
Other possible causes are worn main bearings or a worn clutch support bearing in the outer case.
Hope that helps
PeterF
Hi Gordon,
I find they come out easily enough if you heat the case to about 100c then bang it sharply on a surface (bearing facing downwards) Use a piece of wood to protect the mating faces. Sometimes it needs a couple of bangs or a bit more heat to get it moving.
PeterF
Hi Tim,
In 12 years I have fitted several Powerdynamo systems as they used to be called though they were always made by Vape. Both the older type with the external sensor and the new type where the sensor is internal. I have always fitted mine with the black ign coil at the top as shown in the instructions.
Indeed I have just fitted a 2nd hand external sensor type where as delivered the black coil was at the bottom. I found it easy to turn it to the top position but you need to make sure none of the wires get trapped in the process. The unit is working fine even though there is no provision for timing adjustment. You do need to follow the instructions regarding which pair of fixing holes to use in the back plate.
Some, possibly all the Vape units are designed to be used on twins of the Jawa/CZ type which require 2 sparks at 180 degrees per revolution and the rotors even when supplied as part of an MZ kit often had two pickups. I guess that gives a wasted spark. I don’t know whether the black coil needs to be in a different position if fitted to other makes. But for MZs mine have always worked with the black coil and the external sensor at the top.
Hope that helps.
PeterF
Standard 1.5mm pitch 10mm bolt will do the trick. Needs to be quite long – about 70mm at a guess A fine thread is used on the 7mm bolt which secures the points cam and stator to the crankshaft.
Hi Ruud,
I think your problem is something to do with Forum site privileges. If I look at your original post when logged in as an administrator, I get a whole series of options in the line alongside the date of the post including ‘edit’. When i log in as an ordinary member, the only option I get is to reply to a post.
I have no idea how to adjust that situation, it’s something the webmaster may be able to investigate. For the moment I think all you can do is reply to your own post to alter/update whatever it was you wanted to edit.
Sorry i cannot be more helpful
PeterF
Hi Ruud,
If you view your own post(s), you should find an edit option somewhere on the screen. the other option is to click on the mz riders Club name (top left) and use the dashboard menu to get at your posts.
Peter
Hi Keith,
I have no experience of trying to drill a disk, I suspect its not worth the effort. Unless there is something wrong with your front brake its more than adequate for the weight of an MZ. In theory I suppose it might clear quicker in the rain but I have never noticed any particular delay with mine – unlike some of the early Japanese s/s disks which needed a full revolution before anything happened.
Regarding s/s spokes it depends on what yuu are comparing them with and where you get them from. The MZ chromed spokes will always eventually rust, s/s ones never rust. If you buy from certain German sources, the s/s spokes are actually cheaper than the chrome ones- around £28 a set.
try http://www.meinzweirad.de/ you will need google translate then look in the section called ‘Landing Gear’. Be aware that postage is quite high but is the same however much you buy so stock up with other goodies as well or do what I do and buy for your mates as well to share the postage.
Peter
Hi Ron,
Bit late responding to your plea – sorry been away. Before anyone can help you need to supply rather more information. Most importantly what bike are you working on and whether it still has its standard electrics (6v dynamo for the earlier bikes and 12v alternator for the ETZs).
Secondly a bit more about the circumstances, has it suddenly failed or is a new to you bike you are trying to get running. Given a something to work with I am sure someone can help.
regards
PeterF
Hi Rob,
Lost motion on the kickstart is quite common and I don’t think its related to the spring (sorry Stuart). There is a a peg which pushes on the plate that holds the starter pawl out of engagement. As the starter rotates the peg releases the plate and a spring pushes the pawl forward. It may be possible to adjust the position of the peg on its splines to get it to release the plate and thus engage the k/s a bit sooner. However, I have never seen any instructions on how to ‘time’ the k/s in any of the manuals.
Sadly the only way to resolve it is to remove the outer cover (leaving the k/s in position) to examine the parts. My explanation is rubbish but its all pretty obvious when you can look at it.
Be aware there was an earlier type of mechanism used on 4 speed engines mainly. Does the same job but in a slightly different way and is completely interchangeable but only in toto.
Regards
Peter
Hi Mike,
I wouldn’t worry too much about trying to measure it. The inner thrust washers only come in 3 sizes so whatever you measure the end float to be, in the end you have to compromise with one of the 3 washers.
If it was me I would buy one of each size (they are not expensive) and just try them all starting with the thickest. Apply finger pressure to the out washer and if the clutch centre gear spins freely and/or has detectable end float then you probably need to replace the outer thrust washer which only comes in one size. Otherwise repeat test with the next size down etc etc. What you want to achieve is a gear that spins freely but has as little end float as possible. You will find your fingers are very sensitive to movement and binding.
One thing to be aware of is that these thrust washers do wear on the inner cutaway section so measuring the overall thickness is not always a good indication of their operational thickness. Sometimes all you need is a new one of the same thickness as already fitted. Same applies to the outer washer.
Regards
PeterF
Sadly you cannot fit ES type forks to a TS frame. Tried it years ago. First problem is the major difference in the headstock bearings. Even if you solve this problem the TS frame is not long enough and the ES forks will clout the engine. You would need to lengthen the TS frame by circa 4″. Don’t ask me how I know!
I do have a set of leading link forks built originally by Mark Dicker for sidecar use with a TS250. Never tried them in anger but they look the dogs whatsits.
PeterF