sleepy hollow
New Member
Killed my old top end from running without an aircleaner, dumb choice, what mods should i do to new top end to gain performance
porting new top end ht bicycle engine 80cc
- Thread starter sleepy hollow
- Start date
MotorBicycleRacing
Well-Known Member
Re: porting new top end ht 80cc
Dave Rust builds the fastest 66 cc bikes on the track and is
the only seller that I know of that offers a professionally ported
cylinder.
http://www.arrowmotorizedcycles.com/shop-now---high-performance-ported-cylinders.html
Hopefully you didn't damage the bottom end too.
Dave Rust builds the fastest 66 cc bikes on the track and is
the only seller that I know of that offers a professionally ported
cylinder.
http://www.arrowmotorizedcycles.com/shop-now---high-performance-ported-cylinders.html
Re: porting new top end ht 80cc
Hi, u didnt say whether u wanted 2 port 4 increased top end performance (where u'll loose bottom end performance), or 4 increased low & mid range performance (where u'll loose top end performance). Which ever way u go, 2 increase in 1 area means loosing in another. Then, 2 get the most out of ur port job, all other aspects of ur motor have 2 b made 2 compliment ur port split & duration, so they all work in conjunction 2 achieve ur goal. Cheers
Hi, u didnt say whether u wanted 2 port 4 increased top end performance (where u'll loose bottom end performance), or 4 increased low & mid range performance (where u'll loose top end performance). Which ever way u go, 2 increase in 1 area means loosing in another. Then, 2 get the most out of ur port job, all other aspects of ur motor have 2 b made 2 compliment ur port split & duration, so they all work in conjunction 2 achieve ur goal. Cheers
truckd
Well-Known Member
Re: porting new top end ht 80cc
Does anyone know what the numbers mean on the piston? I have 2 PK 68.5/80cc engines and there is a #4 on one piston and & #5 on the other piston and just got a puch head 70cc Hi Hi compression and need to know what theses #'s are and the difference between the piston's if any??
Does anyone know what the numbers mean on the piston? I have 2 PK 68.5/80cc engines and there is a #4 on one piston and & #5 on the other piston and just got a puch head 70cc Hi Hi compression and need to know what theses #'s are and the difference between the piston's if any??
young grease monkey
New Member
Re: porting new top end ht 80cc
If you do a complete overhaul you will see gains across the rpm range. Only working on the top end will force you to compromise.
If you do a complete overhaul you will see gains across the rpm range. Only working on the top end will force you to compromise.
Re: porting new top end ht 80cc
Hi, as ur uping the compression it'd b adviseable 2 at least upgrade the small end bearing. Measure between the piston pin bosses, NTN does a 10x14x16.5 if it'll fit it'd b best, otherwise use 10x14x15 bearing, but Young Grease Monkey gave good advise, tear it right down & do it properly. Cheers
Hi, as ur uping the compression it'd b adviseable 2 at least upgrade the small end bearing. Measure between the piston pin bosses, NTN does a 10x14x16.5 if it'll fit it'd b best, otherwise use 10x14x15 bearing, but Young Grease Monkey gave good advise, tear it right down & do it properly. Cheers
truckd
Well-Known Member
truckd
Well-Known Member
Re: porting new top end ht 80cc
All of the fasteners/bolts have been up graded as well and yes the head bolts will be Allen keyed, the head was just placed on the engine for photogenical purposes.
I don't know if you have visited my thread Blood Thursty but you can see what the bike looks like(1911 Indian BTR) so this engine has to be right & tight!! and will be starting another shortly after this build
All of the fasteners/bolts have been up graded as well and yes the head bolts will be Allen keyed, the head was just placed on the engine for photogenical purposes.
I don't know if you have visited my thread Blood Thursty but you can see what the bike looks like(1911 Indian BTR) so this engine has to be right & tight!! and will be starting another shortly after this build
headtrama
Member
Re: porting new top end ht 80cc
the head bolts should be studded , To tell you the truth I have never had a issue with the stock head studs. Get yourself some open head nuts and torque them down to 13 pounds . Spray the head gasket with copper coat and you shouldn't have a problem.
the head bolts should be studded , To tell you the truth I have never had a issue with the stock head studs. Get yourself some open head nuts and torque them down to 13 pounds . Spray the head gasket with copper coat and you shouldn't have a problem.