Flywheel swapping

[tony27]

I had my 380 shear the woodruff key 1/2 a lap into practise at Whakatane yesterday & have discovered the taper is pretty marked up, is it possible to use a sidepiper flywheel on the later bikes?
The sidepiper flywheel I have sitting here has a lot more letters stamped on it
I'll try & get a couple of decent shots & post them tomorrow

[090]

The old boy reckons that till the yellow tanker at least are all the same. Same crank and gears as well.

[Bamford#69]

Hi,
Ive weighed these flywheels
250 twinport           1630g
250/360 side pipe    1650g  (same part #)
125,250,380/400     1885g  (same part #) from a 74 parts book
988 Enduro has a different part#  I would assume it would be a heavier flywheel.
you can see the extra size of the heavier flywheels
 a 74 CZ part # is 980-61-110. is that the same as a 71 72 73 ?
 
 these figures are assuming that the ones I weighed were the original fittment and not swapped previously.
cheers

[tony27]

Looking at the parts book that shows all the years part numbers on CZmadness it appears that the part number stayed the same from 68 until post 75, might take both to work & weight them next door at the plastic moulders
I'll spend a bit of time & see whether I think the damage is removable or if I need to get off my fat ass & finish the suzuki conversion

[Bamford#69]

Hi,
the CZ  parts books list similar, but different part #s

the sidepipe parts book, lists the number as 980-61-010.

the 74 parts book lists the number as         980-61-110

cheers
 

[tony27]

Trust me not to see the extra 1 in the number.
Looks like I won't be using the sidepiper flywheel anyway, the thread for the puller has been beaten up a bit 
Anybody got a spare or should I just do the ebay thing?

Taper damage
Taper damage
73 flywheel
Sidepiper lettering

[jimg1au]

before you buy an other one try to lap the flywheel and taper with valve grinding paste.its the taper fit which holds the flywheel on not the keyway.when you have finished clean it down and put a small amount of coarse past on the taper and lock the flywheel on.a old trick my brother (jap454) told me works.
jim

[tony27]

Thanks for the advice Jim, had already decided on trying to lap in the tapers & brought home the tin of lapping compound from work
Spent an hour or so removing the transferred flywheel taper from the crank with diamond files then lapped the flywheel taper in as best I could, I reckon I've got about 70% making contact- too many deep marks to get out
Will see if I can source a new key tomorrow or maybe make 1 out of silver steel if I have to

[Bamford#69]

Hi,
if you are sure the taper is a good fit and the keyway isn't damaged use a Yamaha key #90280  03017,
should be available from any Yamaha dealer
cheers

[montynut]

After lapping the flywheel on a motoplat ignition I had a problem with it still shearing the key. I finally found that the flywheel was going on the taper just enough so that when the nut was tightened down it was bottoming on the crank and flywheel together instead of just clamping the flywheel if that makes sense. Basically the nut was tight and the flywheel was held firmly in place but was not pulled and locked onto the taper. This meant that the key was carrying load instead of just locating the flywheel in its correct position. I made a stepped washer so that all the nut clamping pressure was exerted onto the flywheel and no more problems. It is worth checking as I have only found this on one of my bikes. The same result if the key is even a few thous high meaning the tapers can not lock together

[jimg1au]

i found the same problem with the drive side on my 1972 380 made mods and it works great
jim

[bazza]

tony what model suzuki parts were you going to use?

[tony27]

Have a ts400 flywheel mounted on cz taper with the stator plate turned down to fit, cdi is ts185er & I havent decided on whether to run the ts185 coil to a single plug or a rd400 coil which is narrower & fires both plugs at the same time
Mainly I need to find time to go back to work with the bike to make coil mounts & extend the wires from the stator

[tony27]

Have gotten round to making the coil mount for the RD400 coil & have spark but no joy in getting the bike running, nice red foot from a couple of kickbacks though
How do you set the timing with this set up?

[Ian P]

Need a dial guage. Then set at 3.5mm btdc. Should work fine