More TRX Internal Discoveries 




The balance shaft on the left has been lightened. Its weight was reduced by about 400 grams.


The ring broke at the end. The broken piece rattled around inside the combustion chamber for a bit before exiting.

After spending a considerable amount of time machining it (cast iron) I found the benefit of the lightened balance shaft to be barely noticeable and the vibration a real problem. It will let the engine rev a little quicker, but there's a phenomenon that occurs when under hard acceleration or just quickly revving the engine. The quad literally squats a couple of inches closer to the ground when revved! When racing or riding for short distances I don't think it is much of a problem but when I ran my TRX with the lightened counter balancer for a long ride the vibration numbed my hands and arms past my elbows.
 
The broken ring here is a perfect example of bearings that were just a little too loose. The main, top end and/or big end rod bearings being too loose will allow a small degree of rotation. The ring stayed together as long as it could but eventually it reached the end of its ability to bend without breaking. Please click here for some photo's of a grooved cylinder wall that started to eat its rings from a loose top end.


The Honda strapped crank without its "tin can" attached.


The stock clutch basket showing major wear.


The model year is cast in the iron of the cylinder liner.


The 1985 ATC250R transfers. The 1986 TRX's are similar.


The 1987 transfer ports.


The 1988/89 transfer ports.

The 1987 main transfer port tunnel is very rounded. In 1988 all the port tunnels were rounded, but not as much as the 87 mains.


Oops! The reed spacer is on the wrong side of the reed valve. But that's not all...


The reeds are Boyesen dual stage, but they're fitted on an old style FMF RAM valve. It's not a good combination.


The reeds don't cover the open area of the cage. Because of this the engine is hard to start and doesn't run very well.


When run this way for a great deal of time they "groove" out. The wear here is obvious.

What does this photo have to do with the TRX or two stroke engines? Well, nothing. It's a container of tie-wraps that I picked up at one of the club stores. On the label it lists "hundreds of uses" and has some illustrations indicating some popular ones. Apparently it never occurred to the packaging department to use tie-wraps to secure small bundles of the different size tie-wraps inside the container. Instead they opted to spend money for rubber bands to secure them. Isn't this what they don't want you to use? This is a prime example of the back end not knowing what the front end is doing... Ugh.

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