ORIGINAL: mnemennth
Well, actually... the idler DOESserve a purpose, though it may not seem like much.
When you drive a long chain or cogged belt, the tendency to skip is a function of the amount of load vs the number of teeth engaged at each end. Adding that idler pulley engages 2 more teeth on the driven cog, which decreases dramatically the tension necessary to keep the belt from skipping. This is made much more critical because of the small number of teeth actually engaging with these tiny cogs. Just that extra 2 teeth engaged cuts the tension required to prevent skipping in half; this drastically reduces loading on those tailshaft bearings that love to fail. This is especially important here because we are twisting the belt 1/4 turn. On the bigger models we have a larger diameter tail tube, therefore larger diameter cogs with more teeth engaged and less loading per cog, so less tension is required and the extra 2 cogs engaged difference that idler pulley makes are not as critical.
Right now, I'm not certain if y'all are agreeing with me that the Assan is a greatly underrated Gyro, or poking my giblets over it... so, "Hell Yeah!" where appropriate, and Razzzberries to the rest!
PPPPPPPPTTTTTTTTTTT!!!
mnem
So THERE!
The idler was the first thing that went in the bin on my 450 Gt's. They ran so hot that the bearing would sieze up, or they had so much play they were trying to push the belt off the side of the rear pully. I understand the theory behind why they are there but mine was much better without it.