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For Sale / Re: THROTTLE ASSEMBLIES
« on: April 05, 2024, 06:52:04 PM »
That's a Gunnar Gasser
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Suzuki / Re: 74 ts 185 suzuki
« on: December 31, 2023, 07:55:30 PM »
Should be a copy of the G.E.M catalogue in the manuals section if you're after a model number, can look tomorrow if it's not there anymore
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CZ / Re: 981 Clutch oil seals and tank colour
« on: December 14, 2023, 04:17:55 PM »
Jetting seems close to what I used when my bike was still piston port except I ran a 45 pilot jet, can strip down the carb & confirm tomorrow
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CZ / Re: 981 Clutch oil seals and tank colour
« on: December 07, 2023, 02:10:25 PM »
Yeah I have the 74 parts book as well, the 73 manual from bear motorsports has the parts book in the back as well so it's well worth getting, also have their sidepiper manual
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CZ / Re: 981 Clutch oil seals and tank colour
« on: December 06, 2023, 12:30:41 PM »
Clutch seal is 50x65x8 The seal I have sitting here has 2 lips, 1 at each side
O-ring for clutch hub is 26x2
O-ring for primary gear that seals the clutch basket is 35x4
O-ring for kickstart shaft that sits inside the cover is 20x2
Hope that helps
O-ring for clutch hub is 26x2
O-ring for primary gear that seals the clutch basket is 35x4
O-ring for kickstart shaft that sits inside the cover is 20x2
Hope that helps
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CZ / Re: 981 Clutch oil seals and tank colour
« on: December 04, 2023, 07:17:12 PM »
I use a viton seal for the clutch, deals with heat better than the normal nitrile seals. Can't remember the size at the moment but know like all the seals & o-rings they are available from most bearing or seal suppliers
I feel that where the leak generally comes from is not the seal but the o-ring on the back of the clutch hub, the step that the o-ring sits on is larger than the o-ring thickness so all the sealing work has to happen on the outside diameter. I modified my sidepiper clutch by having the step ground down to 1.9mm & a new thicker washer made to keep the stack height the same, basic idea was to sandwich the o-ring, so far it's worked perfectly
I have a look in my parts book on Wednesday for the sizes if you want
I feel that where the leak generally comes from is not the seal but the o-ring on the back of the clutch hub, the step that the o-ring sits on is larger than the o-ring thickness so all the sealing work has to happen on the outside diameter. I modified my sidepiper clutch by having the step ground down to 1.9mm & a new thicker washer made to keep the stack height the same, basic idea was to sandwich the o-ring, so far it's worked perfectly
I have a look in my parts book on Wednesday for the sizes if you want
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CZ / Re: 1973 PARTS BOOK
« on: November 08, 2023, 07:38:41 PM »
Glad you found it helpful. Have dealt with Gerard a few times, definitely knows his stuff
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CZ / Re: 1973 PARTS BOOK
« on: August 02, 2023, 03:35:06 PM »
Looks like you're right Scott
www.4speedsforward.com has the Grand Prix motorcycles shop manual that shows the part numbers for the 73 models even though the rebuild stuff is for the 72 & earlier models
http://4speedsforward.com/CZ_Books/GPCCZ/GPCCZ.htm
www.4speedsforward.com has the Grand Prix motorcycles shop manual that shows the part numbers for the 73 models even though the rebuild stuff is for the 72 & earlier models
http://4speedsforward.com/CZ_Books/GPCCZ/GPCCZ.htm
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CZ / Re: 1973 PARTS BOOK
« on: July 20, 2023, 06:53:13 PM »
If CZMadness is still up you'll find it there, other option is to get a hard copy from bear motorsports
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General Discussion / Re: Could someone from NZ post me something to Australia?
« on: March 07, 2023, 06:37:29 PM »
Do you reckon you could get them delivered to me by next Wednesday? Flying to Melbourne on Thursday which would really cut down both the postage cost & time
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Tech Talk / Re: Air cooled twostroke, best head gasket material?
« on: January 23, 2023, 07:03:37 PM »
Copper transfers heat quite well which is why it's used on the base of cookware, have TIG welded copper before & it takes longer to get the heat in but once up to temp it retains more meaning you have to move quicker
Aluminium head gaskets are meant to be single use & can't be annealed unlike copper
Aluminium head gaskets are meant to be single use & can't be annealed unlike copper
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Suzuki / Re: They are still out there.
« on: October 18, 2022, 02:08:09 PM »
Not that hard to do an oval bore carb, have a couple of 30mm Oko d-slide carbs that use the 28mm body then offset 2mm towards the top & use the same setting on the boring head. The bore is technically more a figure 8 & behaves like a 28mm at lower openings but wide open is 30mm high by 28mm wide
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CZ / Re: CZ numbers???
« on: July 06, 2022, 01:05:34 PM »
Falta model 250s are 980 series, the 513 is the later centreport motor that doesn't have a rear transfer port.
Luckily most parts are the same, pistons & rod kits are the common to all but the twinports. Main difference with the Falta & 513 model 250s to earlier 980 models is the internal rotor ignition which use a different sized taper on the crank. Pre73 models also use a taperlock in the primary drive gear instead of a keyway
Clutch parts are common with all 980,981 & 984 motors, the 513 uses a different dry clutch with a large number of small fingers, it can be fitted but needs the primary drive gear & clutch gear as the basket screws to the gear rather than using the special nut to retain it
Parts are extremely easy to get, CRHighperformance is the nearest place in the US & is great to deal with, in the UK CZStuff is good, I also use Etovar.cz for a lot of the smaller parts. There is a company in Poland I've dealt with a few times that has multiple eBay accounts
Luckily most parts are the same, pistons & rod kits are the common to all but the twinports. Main difference with the Falta & 513 model 250s to earlier 980 models is the internal rotor ignition which use a different sized taper on the crank. Pre73 models also use a taperlock in the primary drive gear instead of a keyway
Clutch parts are common with all 980,981 & 984 motors, the 513 uses a different dry clutch with a large number of small fingers, it can be fitted but needs the primary drive gear & clutch gear as the basket screws to the gear rather than using the special nut to retain it
Parts are extremely easy to get, CRHighperformance is the nearest place in the US & is great to deal with, in the UK CZStuff is good, I also use Etovar.cz for a lot of the smaller parts. There is a company in Poland I've dealt with a few times that has multiple eBay accounts
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General Discussion / Re: How much $'s to be able to load pics?
« on: May 30, 2022, 07:33:56 PM »most of the old Photos were hosted thru a site called Photo Bucket which was a host ( 3rd party ) ...but was shut down a few years ago .Photobucket still exist but doesn't have free accounts anymore that allow sharing to websites, Zuckerberg strikes again
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General Discussion / Re: Number Plate colours
« on: October 22, 2021, 05:32:53 PM »
I'd say a typo, 263cc lets a 250 have a few oversizes without having to change classes & is a number that rings a bell for the big bore class