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Offline SachsGS

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Another Vintage Project, 1968 DT1
« Reply #45 on: February 06, 2012, 03:42:11 PM »
The piston looks like it has little blow by.Why not measure the top end, it may still be fine.I recently found an old KX and the top end is brand new.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline citabjockey

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Another Vintage Project, 1968 DT1
« Reply #46 on: February 06, 2012, 06:18:54 PM »
This top end is the least of my worries on this bike. As I can go up to 6th over there are plenty of options. The fork tubes, transmission, the seat, getting things rechromed, repainted, etc are going to be much larger road blocks.

If the piston and bore does measure up I may just slap it back in there. As Sachs says, it does look to be in pretty nice shape. As I can go up to 6th over there are plenty of options. Of course putting the existing piston back into a bike I hope to have "new" in most respects doesn't really feel "right"...
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
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Offline SachsGS

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Another Vintage Project, 1968 DT1
« Reply #47 on: February 07, 2012, 03:32:55 PM »
The cylinder liner gets awfully thin on those 5th and 6th overbores. On some of the old 360/400 Yamahas I've seen the hone break thru. to the alu. cylinder on the 6th bore.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline cnrcpla

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Another Vintage Project, 1968 DT1
« Reply #48 on: February 07, 2012, 03:41:38 PM »
Sounds like maybe you shouldn't go for a 6th bore even if you had to.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline citabjockey

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Another Vintage Project, 1968 DT1
« Reply #49 on: February 07, 2012, 03:51:28 PM »
Right now the liner measures about 4.5  mm thick. Must have started out as 5 mm (its a 1mm overbore now). So that removed 0.5mm off of a 5mm liner. If I go to 6th over that will remove another 0.125 from it. Hard to say if that is going to make it break. A good question for my engine builder expert. Thanks for the heads up on this guys.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
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Offline citabjockey

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Another Vintage Project, 1968 DT1
« Reply #50 on: August 11, 2012, 11:02:08 PM »
Did some cleanup on the outside of the motor. Then started to remove some extras. Off comes the left side main seal:


Then the sprocket


Open up the clutch cover. On a mission to find out why it will not shift gears. Lots of sludge in there...


Take out the clutch and primary drive:


Then removed the shift shaft and actuators. The secondary actuator did not seem to engage the pins on the drum. After remove that gear I find that the drum refuses to turn. So I guess this is a split case job:



« Last Edit: December 31, 1969, 04:00:00 PM by ' »
Yamaha CT3, RT3, MX125, SC500, Toy Prius, Diesel F250 (it all balances out)

Offline SachsGS

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Another Vintage Project, 1968 DT1
« Reply #51 on: August 12, 2012, 03:35:12 PM »
I just intercepted the remains of a 68 DT1 on the way to the dump.The motor is actually in nice shape. ;D
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline citabjockey

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Another Vintage Project, 1968 DT1
« Reply #52 on: August 12, 2012, 04:40:31 PM »
Score! You going to start a thread?

I just intercepted the remains of a 68 DT1 on the way to the dump.The motor is actually in nice shape. ;D
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
Yamaha CT3, RT3, MX125, SC500, Toy Prius, Diesel F250 (it all balances out)

Offline SachsGS

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Another Vintage Project, 1968 DT1
« Reply #53 on: August 14, 2012, 04:10:35 PM »
Nope, other projects in the pipeline. I think I have enough parts to complete a 1975 Hercules 175 6A (rare bike) so that will probably be next. ;D
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline citabjockey

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Another Vintage Project, 1968 DT1
« Reply #54 on: August 14, 2012, 08:52:25 PM »
Cool bike. Is that a 7 speed?

Nope, other projects in the pipeline. I think I have enough parts to complete a 1975 Hercules 175 6A (rare bike) so that will probably be next. ;D
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
Yamaha CT3, RT3, MX125, SC500, Toy Prius, Diesel F250 (it all balances out)

Offline SachsGS

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Another Vintage Project, 1968 DT1
« Reply #55 on: August 19, 2012, 03:45:00 AM »
No, it is a six speed and is a rare oddball - only produced for two years (74 and 75). ;D
« Last Edit: December 31, 1969, 04:00:00 PM by ' »