Some Araldite, A Borrowed Servo, Some Spare Fuel, And The Savage Comes To Life!
Previous. Right, after dithering around about whether it was worth trying to fix the damaged Savage 21, I've finally had a go, and I've met with more success than I'd hoped for.
I was always worried about the engine, as that would be the most expensive part to replace, so I tested that first. Taking the glow plug out and putting it into a starter, it glowed hot & bright. Now I only had 16% fuel from my RS4's, so I put half a tank of that in.
Priming the fuel tank, attaching the glow starter, and the 21bb engine started on the third pull! It stalled after a few seconds, so I opened the idle valve up slightly and it ticked over nicely. After putting the rest of the tank through at idle revs (the engine hadn't been used for over a year) it was time to let it cool down and have a go at fixing that broken front suspension.
Matching the broken parts together I found that they fitted perfectly, so I mixed up some Araldite Rapid and stuck the bits together, then held them in place with a couple of cable ties. I left the car over-night, then cut the cable-ties off to find that the suspension seemed to hold together very nicely.
Unfortunately the steering servo didn't seem to be working properly. Despite having a fresh set of batteries the wheels weren't turning properly, even when off the ground. After waggling the steering a few times the servo stopped working altogether. Flipping the truck upside down I removed the front skid-plate to get at the steering servo. Undoing the steering attachment the servo still wouldn't work. I tried spraying some Nitro cleaner on it to see if it was seized, but nothing happened.
Luckily I still have the Tamiya Touring Car I bought before last Christmas (which I still haven't fixed the spur gear on), so I took the Acoms steering servo out if it and carefully put it inside the Savage. Hey presto, the steering now worked, if a little sluggish. I think a heavy duty steering servo is what is really needed here.
Buoyed on by my success, I put the Savage 21 into my car and headed down to the nearest piece of scrub-land. The Savage started first time, but was running very rough. I played around with the carb settings and managed to get better performance, but the engine wouldn't run smooth and kick out enough power to make the 2 speed transmission work.
Everything else seemed to be working ok, and near the end of half hour even the engine seemed to come on song, and amazed me with the sheer presence that a huge 1/8th Monster Truck has barreling along a woodland path. It didn't turn well (that weedy servo probably), but it looked and sounded good.
Learning's? I've got to try the 21 with the 20% fuel it really needs, and get instructions for tuning the 21bb engine and the two speed transmission.
The fuel will have to wait for next pay day, so let's look at the engine & transmission.
Rather than repeat what the experts have already said, I've cut and pasted the relevant bits from the 21bb user guide & manual:
Phew! Sounds complicated, but should be ok, once I've got the proper fuel.
Next up is the 2 speed transmission.
One more thing, the Savage kept on stalling after half a tank of fuel, and I couldn't start it again until I filled up the tank. Apparently this is a well known problem with Monster Trucks of many persuasions and is referred to as the half tank lean out problem. The most common solution seems to be to fit a newer style tank from a Savage 25, where the fuel pipe comes out of the top and not the bottom.
There we are, how to set up the transmission and engine on a HPI Savage 21. I can't wait to get the 20% fuel & really get stuck in!
Pictures of the partly repaired Savage...
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