160ho clutch or g-box??

[AntNZ]

I'm thinking I will replace this engine with a daytona 190, do the daytona's have stronger gearbox's then the zongers?? I have a v2 headed HO as a spare at the moment but dont expect that to last too long with the extra power/strain on the g-box.
If 2nd gear has gone with only 6hrs on it??.....not good!
It started playing up the first time I hit the track and really started working it.

 

[gottagetacheaperhobby]

Its the weak link in the box to, yx and zongshen 160 engines seem to kill 2nd, whereas most 190s with gearbox problems its 3rd that plays up. Maybe get the replacement hardened by a local metal fab shop...

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[AntNZ]

Its the weak link in the box to, yx and zongshen 160 engines seem to kill 2nd, whereas most 190s with gearbox problems its 3rd that plays up. Maybe get the replacement hardened by a local metal fab shop...

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Can ya just get the standard gear hardened?? Can ya get just 2nd gear or do I have to get the whole gearbox/shaft??

 

[AntNZ]

Ok, got the case's split so time to resume this thread.....

There is no damage to any of the gears so have no idea where to go from here.......

suggestions please spanner spinner's??

 

[motodevo]

Wear on the shift forks?

 

[AntNZ]

Wear on the shift forks?

on the actual forks or the shift drum?.....The forks themselves dont look worn...

I dont know which 2 gears mate up to provide 2nd gear...if its the 2 I think then they are only just engaging, not even half the gear if you know what I mean?
I have had 2nd gear issues at times with this engine from day 1, almost like they forgot to put a shim in.....but dont know exactly what it's supposed to look like..

 

[motodevo]

I dont have a 160 but i remember there were mods a few years back guys were doing to the 155 to reduce the slop in the gearbox.

Edit: heres a few things to tryclick me

 

[AntNZ]

I pulled the shift drum out and one of the forks has a lot of wear in t and also looks to be a little bit bent, the angle of the worn part indicates that it is bent!
Is it worth trying to straighten the fork and build the tabs up again with a bit of weld??

Am I better off just getting a new shiftdrum??

 

[motodevo]

If it were me, I'd get new. I have welded up worn shift forks on old honda 50s before and they eventually failed again with about a 1/5 of the power of your motor. Then i would check and eliminate as much slop in the new shift drum before i buttoned it up again.
I would think they are heat treated/hardened to prolong wear, the heat of welding them would probably make them weaker, you could just give it a shot but i know i would rather not be splitting cases anymore than i had to and if one of the fingers of the shift drum snapped you would probably need to replace a gear or gear set too. Atleast you now know what's wrong

 

[AntNZ]

Cheers MD, like I said....had problems with 2nd in this engine from new so fork was probably bent from day 1.

I now have renewed faith in the strength of these HO g-box's.

What can I do to tighten up/eliminate slop with the new shiftdrum??

 

[motodevo]

From what I've read, if its still got the gear indicator switch on the end of the shift drum then ditch it and when you put the bolt in shim it up with washers to make sure it has no movement. Loctite that bolt and the shift star bolt/screw on the other end. Make sure once the cases are back together the is no play in the shift drum from side to side. Some guys have deleted the centre case gasket, will close it up 0.4 - 0.5 mm and just used a smear of liquid gasket(like permatex aviation sealer). Me, I'd get a couple of centre gaskets from pit bike shop (my local shop sell them for about 8 bucks for a full set. Put it together, shift drum bolt in and torqued, and check it for side play. I clamp the cases to the bench and check it with a dial guage, if it had more than about 0.01"/0.25mm side i would buy a shim 0.05"/0.125mm to 0.01"/0.25mm thinner than the play. Most bearing shop, Enginering suppliers/specialty bolt shop sell shims in 0.05" increments, just measure the shaft diameter and get a shim with the same internal diameter. In saying that, if both the drive and driven countershafts had the same amount of excess play too i would just delete the centre gasket.
Obviously run it through all the gears by hand and confirm all is ok before going any further.
It seems that a lot of the zonger g box problem are down to that shift fork (which only affects 2nd), if theres play or wear it doesnt fully engage and when it skips ypu can hear it clicking, sounds like the chain is skipping on the sprocket.
Like i said, never opened up a big zonger but seeing your pics, your shift fork wear explains why 2nd is not engaging. Before digging too far into it, get you new fork or complete shift drum, make sure that fork is tight on the shift drum, if its not tight on the shift drum no amount of shimming will fix it at all. If it is all good, bolt the cases back together and go from there.

 

[AntNZ]

for those in the know, which gear is 2nd gear??, which is the one that usually fails?, might get it hardened before I put it back together.

cheers

 

[AntNZ]

......???????

 

[AntNZ]

for those in the know, which gear is 2nd gear??, which is the one that usually fails?, might get it hardened before I put it back together.

cheers

Please.....somebody????

 

[motodevo]

I dont know off the top of my head(only usually replace a whole gearbox, otherwise i need to work it through all the gears to get my head around it) i usually just put the gearsets in the left case (on its side) with the shift drum and spin through the gears on the shift drum and see which one engages in each position if i need to work it out, it will be the one next to your worn shift fork and the corresponding gear on the other shaft

 

[AntNZ]

Cheers mate, tried to work it out like you said but not easy, hard to know which gears are free spinning and which are driven.
Its a spare engine so have just bent the fork back straight and got it sitting flat against the gear now, was on an angle before.
It shifts through the 4 gears smoothly so might just bolt her back together and see if it works......
Oh, and I did damage my flywheel with the 3 jaw pullers like you said:hmmm:
any idea where I can get a flywheel from without the stator??

cheers

 

[AntNZ]

Is it too damaged to use again if I can flatten the bubbles out??
has these in 3 places...

 

[gottagetacheaperhobby]

I have a adjustable timing stator if you want to upgrade the stock one..

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[AntNZ]

I have a adjustable timing stator if you want to upgrade the stock one..

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cheers stu, I already have a new stator, whats your opinion on the state of the flywheel I posted pics of???

Thought you would chime in earlier as I know you have had a lot to do with these engines....
As I said, I just bent the shift fork straight again....is that just a waste of time or not???
Do you know which gears in the earlier pics are the ones that fail??
struggling to work out which 2 gears mesh to create 2nd gear??
Think I got it sorted but doesn't seem to matter what I do the 2 I think are 2nd never seem to fully engage each other....

 

[gottagetacheaperhobby]

I would replace it if it was me.
Shift fork I would replace as well as once something's bent it usually bends again.. You have it apart so better to sort it now IMO..
I'm not sure on which two gears mesh for second gear sorry, why not harden the whole box, shafts included?

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