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Cylinder Re-Boring

We at Cava Motorcycles  do on average 30 - 40 Re-bores a week from 50cc mopeds UP, So what! I hear you say Anyone can do a re-bore can't they? Why should you send your cylinder to Cava Motorcycles?

Well here is why...

1 I've seen freshly bored cylinders with too much piston clearance.
2 Port edges not dressed which would eat the piston rings alive.
3 Cylinders which have not been honed and out of round. (Oval)
4 I've seen cylinders that have had their coatings bored out of them then ran!
5 Twin cylinders with odd size bores!
6 Cylinders bored out on a lathe.

Crankshaft Rebuilding

Most Motorcycle shops can rebuild crankshafts, very few are good at it!

Crankshafts for single cylinder two stroke engines consist of Counter weights, thrust washers, crank pin, big end Bearing and a connecting rod. These components must be assembled to Exact specifications. Even 1 thou out of specification will cause vibration. Vibration will rob you of your horsepower, reliability and it drastically reduces engine life.

I’ve seen brand new factory crankshafts off by as much as 5 thou center to center, The record goes to a local competitor who thought that 15 thousandths of an inch was close enough!
We’ve assembled hundreds of crankshafts to specifications as close as 1 tenth of a thou! This takes patience, time, and experience. Don’t trust this type of precision work to the first person you meet with a press and hammer.
The problem with getting your crankshaft rebuilt is it always looks ok. Most people don’t own the proper equipment to check the shaft when it returns from the shop. Motorcycle mechanics know this! This ensures that you get what you pay for.

Now this is why you should trust your crank shaft with us.

Cava Motorcycles - Specialists in 2 Stroke and 4 Stroke Engines

Cylinder Re-sleeving is a viable and cost effective method of repairing your cylinder.We are probably the longest established and most experienced Re-sleeving company in South Africa, with over 30 years experience, we make our own sleeve-liners in-house using the highest quality materials.                              

Why sleeve it?

Firstly it is more economical than plating. Once a cylinder has been sleeved if you wear it out or damage it you do not then need to have it completely re-conditioned as it is re-borable to 8 times.  With piston kits available in most of these over sizes.  This represents a massive saving over re plating every time you damage your cylinder. There are myths and old wives tales saying that there may be poor heat transfer or lack of power after a sleeve has been fitted, rubbish! There are Honda MX bikes in production now with sleeves, Class 1 Kart engines are sleeved and rev up to 18,000 rpm with no loss of power.  Plated cylinders are cheaper to manufacture in the first place but more expensive to repair.  It is not necessary to use different rings in modern sleeves. Call us for further details.

Motorcycles & Quads whether you are a road or competition rider we hope you enjoy the season ahead.   Unfortunately there will be times when this is interrupted by breakdowns. Our aim is to get you going again in as short a time as possible, whilst providing a top quality service at a competitive price.  

 However whilst you obviously need to get damaged cranks, cylinders etc., repaired it is important to try to identify the cause of the problem ie if your cylinder has overheated and seized the piston, are the crank seals worn out causing the engine to run a weak mixture and overheat? It can be very disappointing to spend hard earned cash on repairs only for the same problem to occur immediately after a repair.  So do check it all out. If we are carrying out your repair we will always be happy to try and give advice.