Scooterotica

these are twisty THE FOUR NATIONS BALLCASTLE last year...........
The shamrockexpress and a bit of road racing!!!!!!!!!!!!!!!
Eden filming on his GT240, Martin on his targa twin and Shamrockexpress on the HB 250 challenger to be fair I knew what was round the next corner being local the other lads did,nt...............

On with another 250

set to public so anyone can view the album

https://www.facebook.com/media/set/?set ... d18a8fc1e2

hi,
been reading this thread as i am probably going to need a 60mm crank with a 18mm gudgeon pin, as im thinking of fitting a gas gas cylinder to a lammy engine case ive bought, its already had a rotax cylinder on it, air cooled, but i want to go liquid cooled hence why im thinking of a gas gas cylinder, anyway cutting to the chase, hows the crank holding up, how much are they, and where from,
many thanks,
holty

The cranks are arriving in Jan, they are 60 and 62mm stroke with 110 rods, silver plated race big end bearings and 22mm id small ends to suit both 18 and 16mm gudeon pins. You'll be able to buy from Gran Turismo (send me a PM) or through GT distributors. Price is £204 inc VAT.

Rich_T wrote:The cranks are arriving in Jan, they are 60 and 62mm stroke with 110 rods, silver plated race big end bearings and 22mm id small ends to suit both 18 and 16mm gudeon pins. You'll be able to buy from Gran Turismo (send me a PM) or through GT distributors. Price is £204 inc VAT.

Looking forward to these.

Rich_T wrote:The cranks are arriving in Jan, they are 60 and 62mm stroke with 110 rods, silver plated race big end bearings and 22mm id small ends to suit both 18 and 16mm gudeon pins. You'll be able to buy from Gran Turismo (send me a PM) or through GT distributors. Price is £204 inc VAT.

thanks for your reply, looks like a great bit of kit to me, do you think it would cope with a 74mm piston, balance wise i mean, im sure the rod would be strong enough ?
cheers,
holty

Rich_T wrote:The cranks are arriving in Jan, they are 60 and 62mm stroke with 110 rods, silver plated race big end bearings and 22mm id small ends to suit both 18 and 16mm gudeon pins. You'll be able to buy from Gran Turismo (send me a PM) or through GT distributors. Price is £204 inc VAT.

I for one am looking forward to these cranks becoming available so expect a PM from me when they do so. My only issue now is whether to go for a 60mm? 62mm? ... or cancel Christmas for the kids and buy myself a couple of presents

Probably worth waiting for. I'm using the GranTurismo prototype crank and it works a treat 1000km later:
https://tv175.wordpress.com/2015/11/08/ ... mag-house/

holty wrote:

Rich_T wrote:The cranks are arriving in Jan, they are 60 and 62mm stroke with 110 rods, silver plated race big end bearings and 22mm id small ends to suit both 18 and 16mm gudeon pins. You'll be able to buy from Gran Turismo (send me a PM) or through GT distributors. Price is £204 inc VAT.

thanks for your reply, looks like a great bit of kit to me, do you think it would cope with a 74mm piston, balance wise i mean, im sure the rod would be strong enough ?
cheers,
holty

Balance is a subjective thing. I have a graph that is posted on the Gan Turismo Performance FB page. This graph tracks the % force imbalance against piston weight. It is easy to track and see not only the effect on GT cranks but also other crank types for comparison. All these cranks and rods are modelled in CAD with material mass assignments and CoG's. The resulting forces are then compared to each other and expressed as a % of balance. Where the graph crosses "0" is where force across the block = force along the bore. If the % is "+ve" then there is a bias towards force along the bore, if the % is "-ve" the there is a bias towards force across the block. Key point to remember is that this data is totally independent of your engine mounts. How your scooter rattles has got a lot more to do with specific frequency of your mounts and mount production batches change significantly.

Rich_T wrote:

holty wrote:

Rich_T wrote:The cranks are arriving in Jan, they are 60 and 62mm stroke with 110 rods, silver plated race big end bearings and 22mm id small ends to suit both 18 and 16mm gudeon pins. You'll be able to buy from Gran Turismo (send me a PM) or through GT distributors. Price is £204 inc VAT.

thanks for your reply, looks like a great bit of kit to me, do you think it would cope with a 74mm piston, balance wise i mean, im sure the rod would be strong enough ?
cheers,
holty

Balance is a subjective thing. I have a graph that is posted on the Gan Turismo Performance FB page. This graph tracks the % force imbalance against piston weight. It is easy to track and see not only the effect on GT cranks but also other crank types for comparison. All these cranks and rods are modelled in CAD with material mass assignments and CoG's. The resulting forces are then compared to each other and expressed as a % of balance. Where the graph crosses "0" is where force across the block = force along the bore. If the % is "+ve" then there is a bias towards force along the bore, if the % is "-ve" the there is a bias towards force across the block. Key point to remember is that this data is totally independent of your engine mounts. How your scooter rattles has got a lot more to do with specific frequency of your mounts and mount production batches change significantly.

Ya.

So when is it available?