Hi,

Just finished chainging out my comp sprocket to a 24 tooth from stock 25. Bought the HB 125 hydraulic chain tensioner to keep the primary chain automatically adjusted. Thing is I can't stop worrying aboutthe chainbeing to tight when it's hot. Good grief the chain spec cold is 5/8 to 7/8 inch play.

Question for those in the know. How can this auto tensioner which instructs to actually 1/16" preload the chain cold expect it to have enough play when it all gets hot and is tighter yet ? How does it compensate for the natural chain tighening when everything is operating temp ? Thanks for any imput. Judd

 

While you're waiting for your answer, could you tell me who makes or sells the HB 125? Thanks.

 

Not that I have one, but it's similar to most auto tensioners. The initial spring load is to put postitve pressure during cold operation. From there, the spring compresses as the chain gets tight. If you were to check it when hot you would see the chain as seeming to be tight, but if you push down on the chain there will still be some spring play left in the adjuster. This is not an eccessive amount of pressure on the chain in operation and to me it's better than having it flopping around in there. Study how all this works and you will see that the intial cold setting and preload is most important. It will look after itself from there, same as the HD auto tensioner. Set it up wrong, and you run out of spring effect in a hot condition. From playing with my HD tensioner you would have to work at screwing it up, although some people are capable of it. If this is a hydraulic type tensioner, the hydraulic part does nothing but act as a shock absorber for the unit to keep the shoe from bouncing up and down from a chain with tight spots or varying tensions as the sprockets are turning. It has no effect on chain tension, but will help the spring live a lot longer as the systems varying pressures would be pounding the spring aggressively. The dampening effect of the hyraulic slows this process down to avoid spring damage and fatigue, same as the shocks on your cage. I know this is a bit long winded but I've always believed in order to fix something you need to know how it works . After that, it's a piece of cake.
Hope this helps take some of the mystery out of your tensioner. From what I've heard, they seem to work quite well.
Ron

 

I think I understand how they work now, I just want to know who sells this specific auto tensioner, the HB 125.

Any idea if it's better than the HD #40063-05A?

Thanks.

 

Who the hell knows which is better. The HD unit has a spring loaded ratchet for initial setting and preload. Sets itself and looks after any need adjustment from there. Once the chain and shoe have worn in on a new bike the HD unit may have clicked into another notch to compensate for it. The HB-125 may need the preload checked and reset. After that , smooth sailing for a long time. HB-125 spring travel is vertical, meaning that the shoe and spring move at the same rate. The HD unit is angular in that the shoe moves much more that the springs in deflection. This low level of spring travel may not need a damper to eliminate spring fatigue. Can't comment on the shoe material on the HB-125 as I've never seen one but after 5k on my bike I was hard pressed to even see where the chain was running on it with the HD.
The only thing that may be noticable between the two in operation is that the lack of a damper on the HD unit when in decel the springs compress and there is considerable lash in the driveline, as in loose chain from decel to accel. Both will compress but the hydraulic will slow the process down somewhat. It will also slow the retension also so one may in the end be not better than the other. This trait seems to bea negative effect of auto tensioners compared to the old rigid mount shoes.
Two methods of accomplishing the same goal of a simple task. I would not feel handicapped with either one, however the mounting in the primary will dictate which one will fit.
http://www.legendmcs.com/Driveline/d...ncers-new.html
Ron

 

Hi Gatorwalt,

check here: www.sohotbikes.com

 

Mr. Dull? Man, where'd you get that name. Must be fun at a party..........

Anyway, thanks for the advice............and, cheer up!!!!

 

I have one and it works really well.