Yamato 80 or 102 point ignition issues

[ZUL8TR]

Pont cam

Check that point cam isn't cracked, Seen that enough to mention it.

It is new, BTW poor design because the keyway slot lines up with the thinner part of the cam. They changed this on the 102

[ZUL8TR]

update

Thanks for all the info, really appreciate it. I never realized this ignition was an issue with the Y80. Since just an AOMCI meet guy these days I will leave it as it is and adjust often as it is very easy to adjust timing with dial gage and buzz box. I will put in new points (Kawasaki 21008-028) since the present ones have been in there since I bought the Y80 back in 1978 from Dick O'Dea.

I will nixt the dial gage to check the lateral crank movement and just set the piston at the desired advance and hook up the buzz box and see if it goes on and off as I push on the crank.

As far as easy start in water that is a pleasure but I never test alone there are always other boats at the AOMCI meets to assist.

I checked the side play at the top roller and crank as suggested and it is there (bummer) enough to upset the timing. Oh well! this engine still runs great has 150 compression and fast enough for me on my 82 Karelsen pickle I refurbished back to life that Ron Selewach had in storage, presently in the 63+mph area.

[BillCNC]

Pete,

If the engine goes slightly out of time, it might be possible to time it with that in mind. I wonder if it's possible to log the amount it is out and see if it is an amount that is continually repeated.

If so, ... you might be able to time it knowing that when it goes out of time, ... it actually puts it in the correct timing. Not sure if that makes sense.

Then again, ... I'm shooting in the dark here and I could be just talking from my back-side.

Regards
Bill

[ZUL8TR]

timing

Pete,

If the engine goes slightly out of time, it might be possible to time it with that in mind. I wonder if it's possible to log the amount it is out and see if it is an amount that is continually repeated.

If so, ... you might be able to time it knowing that when it goes out of time, ... it actually puts it in the correct timing. Not sure if that makes sense.

Then again, ... I'm shooting in the dark here and I could be just talking from my back-side.

Regards
Bill

Bill

Not excatly sure, but I have set up a stationary index mark on the block and with the dial indicator placed timing marks on the rope wheel edge at 0.180, 0.200 and 0.220" piston positions for the top and bottom cylindere. I will use a timing light and see what is going on at different revs for top and bottom piston. At least now I can quickly check it. May never be resolved with the stock roller bearing clearance set up?

Pete

[BillCNC]

Pete,

I wonder if you'll get the correct readings your looking for running it static.

I'm sure the varying water pressure/drag on a prop during racing conditions might be a little tough to replicate while running a static test. I would think the rapid rpm changes back and forth is whats causing it.

It would be nice if there was an on-board data logger that could see it while actually running in a race.

Whats the alternative, ... new bearings?

Bill

[Matt Dagostino]

Correct

It is new, BTW poor design because the keyway slot lines up with the thinner part of the cam. They changed this on the 102

I had this happen in my Yamato 80 years ago. I have the cracked cam on the bench as a reminder to ALWAYS check it now and then on my current Yamato's.

[bill van steenwyk]

Pete,

If the engine goes slightly out of time, it might be possible to time it with that in mind. I wonder if it's possible to log the amount it is out and see if it is an amount that is continually repeated.

If so, ... you might be able to time it knowing that when it goes out of time, ... it actually puts it in the correct timing. Not sure if that makes sense.

Then again, ... I'm shooting in the dark here and I could be just talking from my back-side.

Regards
Bill

As I am sure all who are interested in this thread and have contributed to it realize, the 80 rotates 360 degrees while running. Unless the wear on the rolls and crank where it runs is exactly the same during all degrees of rotation you are always going to be "out of time" and the variance will exist from factory spec that small amount while the engine is running and may not neccessarily be the same at 90 degrees as it is at 180 and so on based on different amount of wear on the needles and the place on the crank where they sit.

As previously mentioned the best thing you can do with the engine in the original design state with no modification to the top bearing or crank is assure you have a bearing that fits as closely with the least tolerance as possible. The other solution if your motor is strictly a lake racer with no requirement to meet a sanctioning bodies rules is to convert to a CD ignition which is quite easily done.

As mentioned I have three of these conversions for sale, one with Motopla components, and two Konig component style. If interested you can contact me by PM. Two of them are for an 80 and one for a 102/202.

ADD: If interested in these ignitions with the modification to the top bearing that is required, I can furnish part numbers for the bearings used, the mod to assure proper lube, and a photo of how the lube line is run and from where.

[ZUL8TR]

Cd

As I am sure all who are interested in this thread and have contributed to it realize, the 80 rotates 360 degrees while running. Unless the wear on the rolls and crank where it runs is exactly the same during all degrees of rotation you are always going to be "out of time" and the variance will exist from factory spec that small amount while the engine is running and may not neccessarily be the same at 90 degrees as it is at 180 and so on based on different amount of wear on the needles and the place on the crank where they sit.

As previously mentioned the best thing you can do with the engine in the original design state with no modification to the top bearing or crank is assure you have a bearing that fits as closely with the least tolerance as possible. The other solution if your motor is strictly a lake racer with no requirement to meet a sanctioning bodies rules is to convert to a CD ignition which is quite easily done.

As mentioned I have three of these conversions for sale, one with Motopla components, and two Konig component style. If interested you can contact me by PM. Two of them are for an 80 and one for a 102/202.

Bill

Getting a good fitting top OEM bearing sounds like hit or miss since I do not have access to a place to go with a box full to check the fit.

Tempting to go CD but as you stated in an earlier post on Page 1 I would have to change the top roller bearing to a ball bearing with machining to get accurate crank centering. At this time I will leave it alone as it runs good enough for a lake racer. I will look into a 302 replacement.

Regardless of risk of refunds they had to do for the paramutual racing for a DNF I still can't figure why they didn't use a ball bearing at the top like at the bottom crank, failure would be less of an issue?

[bill van steenwyk]

Bill

Getting a good fitting top OEM bearing sounds like hit or miss since I do not have access to a place to go with a box full to check the fit.

Tempting to go CD but as you stated in an earlier post on Page 1 I would have to change the top roller bearing to a ball bearing with machining to get accurate crank centering. At this time I will leave it alone as it runs good enough for a lake racer. I will look into a 302 replacement.

Regardless of risk of refunds they had to do for the paramutual racing for a DNF I still can't figure why they didn't use a ball bearing at the top like at the bottom crank, failure would be less of an issue?

Based on one of your previous posts, if you can run 63, that would seem to be good based on having a good starting, fun ride.

As to why they designed it the way they did, I have no idea. Perhaps the small amount the timing fluctuated while running did not bother them, or affect the performance of the engine enough that it was an issue for them or perhaps one needle bearing like it is was less expensive than two ball bearings like the modification Harry did to my motor. I am sure two ball bearings are more expensive than the one needle bearing they used. Also you have the lubrication issue. It is impossible to get enough lube to the two ball bearings, especially the top one, without an "outside" source of lubrication as Harry did, because he did not do it like that the first time and the top bearing quickly gave up the ghost, even though the bottom bearing was not sealed and offered a path for the gas/oil mix up through it.

Who knows what thoughts lurk in the minds of engineers!! Maybe the Shadow??

[ZUL8TR]

bearings

Based on one of your previous posts, if you can run 63, that would seem to be good based on having a good starting, fun ride.

As to why they designed it the way they did, I have no idea. Perhaps the small amount the timing fluctuated while running did not bother them, or affect the performance of the engine enough that it was an issue for them or perhaps one needle bearing like it is was less expensive than two ball bearings like the modification Harry did to my motor. I am sure two ball bearings are more expensive than the one needle bearing they used. Also you have the lubrication issue. It is impossible to get enough lube to the two ball bearings, especially the top one, without an "outside" source of lubrication as Harry did, because he did not do it like that the first time and the top bearing quickly gave up the ghost, even though the bottom bearing was not sealed and offered a path for the gas/oil mix up through it.

Who knows what thoughts lurk in the minds of engineers!! Maybe the Shadow??

As long as it keeps giving me that fun fast ride I'm happy. Looking at the parts exploded view for the 102 and the 302 they have the same type design single caged roller bearing at the top of the crank as the Y80. What is different with those engines that have apparantly no ignition wandering issues like the 80 has?