Piston to cylinder clearance
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Piston to cylinder clearance
My SB50 cylinder is at the machine shop and I need to know what the clearance should be. I bought the RIK 44mm kit from Taz. Anyone that has done this before please chime in, the sooner I know the sooner its done!
87 Elite 50
99 Aprilia SR50 Carb polini
02 Aprilia SR50 Ditech busted soon to rock gy6 150cc power!
1973 Suzuki TS185 smoker!
2002 KTM Duke
99 Aprilia SR50 Carb polini
02 Aprilia SR50 Ditech busted soon to rock gy6 150cc power!
1973 Suzuki TS185 smoker!
2002 KTM Duke
Re: Piston to cylinder clearance
Bueller, Bueller... Seriously , no one has any input on this one?
87 Elite 50
99 Aprilia SR50 Carb polini
02 Aprilia SR50 Ditech busted soon to rock gy6 150cc power!
1973 Suzuki TS185 smoker!
2002 KTM Duke
99 Aprilia SR50 Carb polini
02 Aprilia SR50 Ditech busted soon to rock gy6 150cc power!
1973 Suzuki TS185 smoker!
2002 KTM Duke
- paulpauly7
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Re: Piston to cylinder clearance
tye clearence on o stock cylinder shoul be the same for the over size piston so check the manual and go with that
86 Nifty Fifty (spree)
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92 yz125, 94 crm250
ZX disk brake
Kitico 120kmh speedo
AF18 ZX ported
Polini corsa
Malossi crank
CTmani
24mmOKO
40pilot118main
Scorpion pipe
8.44 to 1
Michelin s1
71.3mph
92 yz125, 94 crm250
- patthesoundguy
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Re: Piston to cylinder clearance
Yup the manual should totally have the clearance in there. Its a pretty crucial number t have before you bore the cylinder. Too tight and the piston won't have enough room to expand when it gets up to operating temps.paulpauly7 wrote:tye clearence on o stock cylinder shoul be the same for the over size piston so check the manual and go with that
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85 Aero 80 stock
84 elite 125 stock
84 Spree stock
84 Spree Dio AF18E MHR Cylinder Arrow Pipe 28mm OKO
80 Express, 47mm DR BBKit, Weak Ends Intake, Boyesen Dual stage reeds, 19mm Delorto carb, MLM pipe
79 Express
85 Aero 80 stock
84 elite 125 stock
Re: Piston to cylinder clearance
The manual specifies .004 as a service limit but does not mention what the initial clearance should be...what do ya'll think?
87 Elite 50
99 Aprilia SR50 Carb polini
02 Aprilia SR50 Ditech busted soon to rock gy6 150cc power!
1973 Suzuki TS185 smoker!
2002 KTM Duke
99 Aprilia SR50 Carb polini
02 Aprilia SR50 Ditech busted soon to rock gy6 150cc power!
1973 Suzuki TS185 smoker!
2002 KTM Duke
Re: Piston to cylinder clearance
Sb50 .0014-.0020 is what should be the clearance.
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Re: Piston to cylinder clearance
Thanks, Baka!
87 Elite 50
99 Aprilia SR50 Carb polini
02 Aprilia SR50 Ditech busted soon to rock gy6 150cc power!
1973 Suzuki TS185 smoker!
2002 KTM Duke
99 Aprilia SR50 Carb polini
02 Aprilia SR50 Ditech busted soon to rock gy6 150cc power!
1973 Suzuki TS185 smoker!
2002 KTM Duke
Re: Piston to cylinder clearance
Ok so my Elite ended up with a .003 piston-cylinder clearance and it heat seized at 30 miles in the break-in period. I pulled it apart and found marks on the piston either side of the exhaust port and some scratching on the cylinder walls. I gave it a quick hone and lightly sanded out the piston scuffs . I rode it around yesterday and it seemed to be fine but today it won't start. Both of my scooters with larger bores are becoming nightmares! Wish I had left them stock...
87 Elite 50
99 Aprilia SR50 Carb polini
02 Aprilia SR50 Ditech busted soon to rock gy6 150cc power!
1973 Suzuki TS185 smoker!
2002 KTM Duke
99 Aprilia SR50 Carb polini
02 Aprilia SR50 Ditech busted soon to rock gy6 150cc power!
1973 Suzuki TS185 smoker!
2002 KTM Duke
- tazland001
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Re: Piston to cylinder clearance
What is your compression?
Taz
Taz
Re: Piston to cylinder clearance
I have 120 psi...
87 Elite 50
99 Aprilia SR50 Carb polini
02 Aprilia SR50 Ditech busted soon to rock gy6 150cc power!
1973 Suzuki TS185 smoker!
2002 KTM Duke
99 Aprilia SR50 Carb polini
02 Aprilia SR50 Ditech busted soon to rock gy6 150cc power!
1973 Suzuki TS185 smoker!
2002 KTM Duke
- tazland001
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- Joined: Thu Apr 30, 2009 11:46 pm
Re: Piston to cylinder clearance
120 is fine. You might have fouled your plug.
Also did you rejet the carb on the 44mm?
Taz
Also did you rejet the carb on the 44mm?
Taz
Re: Piston to cylinder clearance
Yeah I put an 82 main in there, plug looked ok. After the seize I got it running but it just sounds awful, kind of rattly and has a big vibration off throttle. I replaced the crank bearings during the rebuild including the small end conrod one. I believe its fubar
Before the seize it was nice and quiet and smooth-running...
Before the seize it was nice and quiet and smooth-running...
87 Elite 50
99 Aprilia SR50 Carb polini
02 Aprilia SR50 Ditech busted soon to rock gy6 150cc power!
1973 Suzuki TS185 smoker!
2002 KTM Duke
99 Aprilia SR50 Carb polini
02 Aprilia SR50 Ditech busted soon to rock gy6 150cc power!
1973 Suzuki TS185 smoker!
2002 KTM Duke
- tazland001
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- Joined: Thu Apr 30, 2009 11:46 pm
Re: Piston to cylinder clearance
The 82 sounds a bit lean. I will chime in on this thread a little later tonight again.
Taz
Taz
Re: Piston to cylinder clearance
I think I messed up because I didn't have the clearance figured out before i went to the machine shop. He said the final clearance came in at .003 which is close to the max tolerance (.004) I think instead of a heat seize the piston was slapping and got stuck...
87 Elite 50
99 Aprilia SR50 Carb polini
02 Aprilia SR50 Ditech busted soon to rock gy6 150cc power!
1973 Suzuki TS185 smoker!
2002 KTM Duke
99 Aprilia SR50 Carb polini
02 Aprilia SR50 Ditech busted soon to rock gy6 150cc power!
1973 Suzuki TS185 smoker!
2002 KTM Duke
Re: Piston to cylinder clearance
usually to tight a clearance would cause heat siezes easier. piston slap from to much clearance just cause faster piston wear and blow by easier. sounds more like you had either a lube issue from not enough oil and fuel or motor wasnt heat cycled enough and broken in properly or you have a leak somewhere.
Nothing like getting stroked!
Thanks to my sponsors
Nos Energy Drinks,themopedcompany.com,nwautoevents.com,Cycle Gear
90 honda dio sp 72cc
87 elite 50 s with 86cc watercooled mini stroke
87 elite 50 race bike mhr 72cc
91 yamaha tzr 250r
Thanks to my sponsors
Nos Energy Drinks,themopedcompany.com,nwautoevents.com,Cycle Gear
90 honda dio sp 72cc
87 elite 50 s with 86cc watercooled mini stroke
87 elite 50 race bike mhr 72cc
91 yamaha tzr 250r