You may notice in the first picture that the far left Intake camshaft holder is marked with an E1. This holder unfortunately should be on the exhaust side. This R6 engine was bought by a customer off Ebay to replace his damaged motor. He brought it in for us to install and suggested taking the valve cover off to inspect and check the valve clearance before installing. This is one of the reasons why I would always recommend and rather rebuild a motor than buy used. This motor ran like this and ultimately caused some damage to the cam and journal. Lesson- you have no idea what your getting when you buy used.
Left Picture - Sometimes when mounting accessories with multiple attachments points it's a real pain to get a few of the bolts started if things don't quite line up. I trick I use is to thread a nut on the bolt & grind at least a 7mm long taper on the end down to a dull point. (a new longer bolt may be needed). Thread off the nut. Now when you insert the bolt, push to help align it with the hole while turning.
Right 2 Pictures - If you have a hole with slightly damaged or dirty threads and you do not have the correct tap you can make up a cheap thread chaser from a bolt of the correct size. Using a file you can cut a longitudinal V channel at the end of the bolt. You need to ensure that the 90 degree edge is leading in the direction of travel. The back edge of the travel gives the chips somewhere to go.
This is cylinder head where the valve guide has become loose in the head and the guide hole no longer provides enough of an interference fit to securely hold the guide. Using our new State of the Art Rottler Seat and Guide machine we repair this by machining up a centering sleeve and using this to allow us to ream a larger concentric hole. We then custom machined a new guide from Ampco 45 that gives us a .04mm interference fit. The guide is cooled and the head warmed up to install the the new guide. After sizing the id to fit the valve we will recut the valve seat.
Things you may not know.
1 - An engine will run richer in taller gears. This is due to the acceleration rate being slower & allowing more time for the carburetor to deliver fuel. Fuel flow always lags behind air flow as fuel is heavier.
2 - The longer you hold the throttle open the richer the jetting. Same reason as above.
3 - If you snap the throttle open & the engine doesn't respond - 90% time it's lean. Same reason as above.
4 - CV Carbs deliver fuel in response primarily to rpm, a piston slide carburetor responds to throttle percentage opening.
5 - When your jetting is correct a carburetor will work good in a surprising large range of air temperatures and humidity. If it doesn't then your jetting is on the fringe of the optimum setting.
6 - Slightly lean and your engine response and performance will be poor, slightly rich and you will likely not notice a problem. This is why most jet kits are setup on the rich side of optimum to avoid customer complaints.
7 - Airbox modifications or removal will have the biggest impact on jetting.
8 - On a CV Carb, you do not control the rate of acceleration....that is set by the size, number of vacuum slide lift holes and stiffness (rate) of the slide lift spring.
This is looking down into the intake tract of a 2006 Suzuki GSXR750 with 66,000 km. As you can see there is considerable carbon deposits built up on the back of the intake valve. This is a fuel injected engine and the injector sprays on the back on the hot intake valve to help vaporize the fuel. Higher than normal intake valve temperatures and poor quality gas can aggravate this condition. Another issue is Ethanol in fuel. This can cause a variety of issues especially in vintage bikes and 2 strokes. Most gas has up to 10% ethanol in it and is best to use gas with the lowest amount or none at all. Some stations sell ethanol free Shell 91. I personally do not believe fuel additives can remove these deposits once they have formed but there maybe a case for using them from new to help prevent the buildup in the first place. There is a product we carry that has many good customer reviews and also acts as a fuel stabilizer (see picture below). Keep in mind that carbon deposits act like a sponge and when built up severly enough on the back of an intake valve like this can actually have a profound effect on how much fuel is being delivered. This can cause your engine run leaner then intended, reducing both performance, mileage and drive ability.
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.