3 Speed Manual

Posted: Wed May 02, 2007 9:41 pm Post subject: 3 Speed Manual

I took the HPI 3 speed manual copied the text and uploaded the pics to Imageshack. The only thing missing is truck dissassembly.

Factory Settings
The 2 clutches of both the 87218 and 87220 versions of the three-speed transmission come pre-built. At the factory they set the grub screws in the second gear clutch at 4 1/2 turns out from fully wound in. The grub screw in the third gear clutch is set at 3 turns out from fully wound in.
These are base settings and may not suit your particular equipment set-up so may require adjustment to gain the optimum performance. There are a lot of different combinations that require different settings of these clutches. The settings may need adjusting for the following circumstances:-

•Different power outputs from the engine (this is effected by engine size, fuel type, fuel nitro content,
tuning, ambient conditions)
•Different gearing (clutch bell and spur gear)
•Different size tyres
•Different surfaces and track layouts

There are a vast amount of combinations and unfortunately we can’t test them all for us to be able to advise on what settings should be used in your particular circumstances. We advise you to start with these initial factory settings, try them out and then adjust the clutches to give the optimum performance.
The first gear ratio in the three-speed transmission is very short. The first gear has been optimised for the best acceleration from a standing start. Sometimes it is hard to hear the change from 1st to 2nd gears, it is not as pronounced as the 1st to 2nd change with the two speed transmission
To check that the two gearshifts are happening you can support the truck with the wheels raised off the ground. With the engine running increase the throttle very slowly. You should be able to hear the two gear changes quite clearly using this method.

How to Adjust the Second to Third Gear Shift Point
The second to third gear shift point is adjustable from the outside of the transmission just like the first to second gear shift point of the standard two speed transmission.
To adjust the point at which the gear shifts you need to first stop the truck and stop the engine. Then remove the rubber cap in the side of the gearbox, this allows you access to the clutch that engages the third gear.

Rubber cap being removed

Make sure that you are turning the correct screw in the transmission; there are two screws on the clutch. The one that adjust the clutch will be the lower one when adjusting through the opening in the gearbox.
When adjusting the settings you need to turn the screw clockwise for a later gearshift and anti-clockwise for an earlier gearshift. Make the adjustments in 90-degree increments. Make a change and then drive the truck to test the effect of the adjustment. Continue to do this until you have the optimum gear change.
The optimum gearshift will occur just before the engine is going flat out. If the shift is too early the engine will bog down when the truck changes up a gear. If the shift is set too late the clutch will not engage and the transmission will not shift up a gear.

First to Second Gear Change
To adjust the second gear clutch requires disassembly of the Savage 3 Speed transmission as the 2nd gear clutch is located between the 1 and 2nd spur gears in the transmission and there is no external access to allow you to set the change point without disassembling the transmission.
To adjust it you first need to take your transmission out of the car and then open it up.

(We’ll assume you can look at your manual or find other documents on the disassembly of the Savage)

Now you need to open up the transmission. Remove the cup joints from the front and the rear of the transmission. The brake disk will come off with the rear one. Now undo the seven screws that are on the outside edge of the transmission casing.

Open gearbox:

The clutches for the second and third gears are located on the middle shaft with the 3 larger gears. With the
transmission apart you should be able to first remove the bottom shaft. Now you will be able to remove the middle shaft of the transmission.

With this removed you now need to take off the 3rd gear clutch. The clutch is the silver coloured disk shaped part inside the third gear spur gear on this shaft. Please note the orientation of the clutch as it will not work properly if replaced the wrong way around, it is a good idea to mark the face of the clutch before taking it off. To take this off you need to first remove the grub screw that is screwed through the centre of the clutch (not the adjustment grub screw which is off set from the centre). Then you need to remove the screw shaft that is under the grub screw you have just taken out.

You will now be able to remove the third gear spur gear with clutch and bearing and the second gear spur gear. Now you will be able to see the second gear clutch.

To change the settings of the clutch you need adjust the grub screw that is offset to one side in the second gear clutch. For an earlier shift from first to second gear you need to turn the adjustment screw anti-clockwise, and for a later shift you need to turn the screw clockwise. Change this setting by turning the screw the desired direction by 90 degrees.

Now build up the centre shaft of the transmission (ensure that the 3rd gear clutch is replaced the correct way
round) and then rebuild the transmission.

You will then need to rebuild your Savage. To rebuild the truck replace the parts in the reverse order that they were removed.

Now with your rebuilt truck you are ready to try out your new first to second gear settings!


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