We call this a relative compression check as it does not give you an actual compression number in PSI but lets you quickly compare cylinders. In this example a 5 minute test told us this customer has a mechanical compression problem which required further investigation. As it turns out the valve clearance on Cyl 2 was tight. The other information we can gather from this is starter and battery condition. Peak starter draw should be under 400 amps and battery voltahe should not drop lower than 8 volts. This test costs only $27.50 and is a great way for you to get a quick check on your motor, battery and starter health !
Came across this interesting tidbit when working on a Suzuki RMZ450 while looking at a ignition waveform pattern. It appears that Suzuki is actually firing the spark plug twice at rpm's all the way up to 4,500. They are obviously doing this to improve low speed running. At over 4,500 rpm when the engine is running more efficiently they revert back to firing the spark plug only once. All engines misfire off and on especially at lower rpm's when volumetric efficiency is low. The longer spark duration that occurs when firing the coil twice helps improve the chance that ignition will occur at these lower rpm's.
Just added this Variable Speed Belt Sander to help with both the quality and speed of fabricating one off parts.
Damaged and /or ripped Carburetor Slide Diaphragms that have deteriorated from use is becoming a more common occurrence on older bikes. We are able to repair many of the carburetor slides by changing the damaged rubber only. Below is an example of damaged slides from a VT1100 Honda Shadow. These slides were no longer usable and are no longer available from Honda rendering the carbs useless.
This is an example of what we do here that a lot of shops can't and won't get involved in. This is a non rebuildable stock shock from a vintage 1984 Yamaha RZ350. The customer was looking for an upgrade in suspension so we gutted the rear shock and using a KYB 40mm valve body, some machining and ingenuity we were able to dramatically improve the action while saving the customer a good bit of money over buying a complete aftermarket shock. The nice part is the bike still looks stock. If you have a project and a realistic budget give us a call!
It should read whats new for Cycle Improvements.
Diagnosing engine problems with the use of a Digital Oscilliscope is not new for the Auto Industry but is very rare in the Bike Industry. What is an Oscilliscope? It really is just a much much faster graphical way of looking at voltage and current over time as compared to a volt meter. Whay is this important or even necessary? With the advent of ABS brakes and and CanBus type Networks that control and talk to your bikes "Black Box" it is impossible to analyze or measure these signals with anything but a scope. Many newer bikes now use a computer Network much like the Computer Network you might find at your work. It is not now or never has been imho acceptable to fix any problem by guessing or replacing parts until you fix the problem. The investment in this equipment is large, the learning curve is big but the benefits that the both the customer and the shop will gain are immense. Let me show you an example.
Below is an example of a "bad cylinder compression waveform" from a twin cylinder Yamaha using a scope. This is much like checking a cylinder for compression with a compression guage but as you can see you can gain a far greater insight on any possible mechanical problems. This engine has good compresssion when checked with a guage but to a knowledgeable eye looking at the waveform reveals a camshaft valve timing problem. That would be impossible to determine by conventional testing methods.
In the waveform below you can see the results of correcting the camshaft timing on the waveform pattern. This is an example of a "good compression waveform" and the bike now runs good.
I have been involved in mechanics and motorcycling from a young age. I formed Cycle Improvements in 1981 and still have the same passion to learn today as when I started. Hope you find this blog interesting and educational.