Here is the AIRSAL 70cc liquid-cooled big bore kit with cylinder head for MBK 51 / Motobecane AV10. This AIRSAL T6 is a T6 model because it has four intake ports and a two-part exhaust port, and it is made of Nikasil-coated aluminum. Its intake port timings are quite low (around 118° depending on the squish clearance and cylinder head type), and the cylinder has a bridged exhaust port with a relatively low port timing (around 162°). A very pleasant surprise: the bridged exhaust port has a factory-applied material correction! The piston is a single-ring design to minimize friction.
We still regret the significant lack of attention paid to the skirt and other aspects! However, let's be clear, this cylinder is designed to produce a robust, torquey engine at a very low price. A skilled tuner can still extract some truly astonishing performance from this cylinder by modifying the port timings, exhaust port shape, skirt, etc. The 118° intake port timing leaves considerable room for improvement on the exhaust port by raising its port timing to gain power and higher RPMs, especially when combined with a good exhaust like the MVT SP3 70, or even for a more subtle approach with a good MVT SP2 exhaust!
We recommend the following with this cylinder : 17mm carburetor, reinforced crankshaft and bearings, expansion chamber exhaust, grade 9 spark plug, crankcase alignment.
The pack contains :
Notice 4-port cylinder with 47mm diameter exhaust bridge, liquid-cooled Single-ring piston Piston pin Segments d.47 x 1.5mm Complete gasket set Crab-type piston clips
As an option, we offer a Stage 1 preparation. This includes selecting the best part from our stock, significantly improving the shape and exhaust port timing, and a special modification of the skirt and piston based on our best tests. We recommend port timings of around 118°/178° depending on the squish clearance set by the end user. We suggest a 0.7mm squish clearance and a 13.5:1 compression ratio. Bore and end gap checks are also included. This preparation requires an additional 2 to 10 days depending on our availability. It requires tooling and approximately 2 hours of work on the cylinder. The price reflects this.
Product Details
01141247pr.st.1
New product
Data sheet
Cylindrée réelle
72.52cc (on the stroke of the original crankshaft 41.80mm)
Ideal for refurbishing your AIRSAL 47mm, can also be mounted on the kits which are at the origin of the bi-segments! In addition to this, you need to know more about it.
A kit that makes an excellent compromise between torque, power and service life. At always defying all competition. It is one of the only large-diameter liquid market kit for MBK 51.
!!! Available in limited quantity!!! With 6 intake transfers, a large W exhaust, a 46mm diameter and an excellent finish, the POLINI kit is one of the most powerful and racing 70cc for MBK 51!
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