Polyurethane Handlebar Dampers ("Space Capsules") | Honda CB175 / CB350 / CB360 / CB450
The rubber handlebar dampers on your vintage Honda twin dry out, compress flat, and crack over the decades — leaving the handlebars loose in the upper triple tree with noticeable play in the steering. These made-in-USA polyurethane replacements are firmer and longer-lasting than the original rubber.
Why You Need This
Honda's inline twins — the CB175, CB350, CB360, and CB450 families — vibrate by nature. The 180-degree crankshaft design is inherently vibration-prone. Honda dealt with this by rubber-mounting the handlebars to the upper triple tree through cone-shaped dampers in each handlebar clamp. Two dampers per clamp (one upper, one lower) isolate the bars from the frame and fork assembly.
When those rubber dampers deteriorate, the fit between the handlebars and triple tree becomes sloppy and loose. This translates to weird handling and feel when turning your bike. The handlebars may also shift or rattle under braking or over bumps.
We call these "Space Capsules" — they look like a Mercury space capsule. Made from 80-durometer polyurethane right here in the USA, they're stiffer than the original rubber, won't degrade and squish the way rubber does, and hold their shape over time.
Specifications
| Spec | Detail |
|---|
| Replaces OEM Parts | 53133-237-680, 53133-237-000, 53133-303-000 |
| Fits Models | CB175 (1968–1973), CL175 (1968–1973), SL175 (1970–1972), CB200 (1973–1976), CL200 (1974), CB350 (1968–1973), CL350 (1968–1973), SL350 (1969–1973), CB360G/T (1974–1976), CL360 (1974–1975), CJ360 (1976–1977), CB450 (1965–1974), CL450 (1967–1974), CB500T (1975–1976) |
| Material | Polyurethane — 80 durometer, made in USA |
| Sold As | Set of 4 (2 upper, 2 lower — enough for both handlebar clamps) |
CB500T owners: Honda changed the taper diameter on the CB500T triple tree compared to the CB450. The dampers sit further down in the triple tree, and the threads may bottom out before the retaining nut fully tightens. Add a few M12 washers on top and/or bottom of the handlebar riser to compensate. See our CB500T fitment article for details.
Installation
Install the upper polyurethane dampers on the stems of the handlebar clamps first. Then install the stems into the triple tree and seat the lower polyurethane damper and retaining nut.
Frequently Asked Questions
Why polyurethane instead of rubber?
Polyurethane at 80 durometer is firmer than the original rubber Honda used, which means tighter handlebar feel and less play in the steering. It won't degrade and squish the way rubber does — the original rubber dampers crack, compress flat, and fall apart after decades of exposure to UV, ozone, and oil.
How many do I need?
Each handlebar mounting clamp uses two dampers — one upper and one lower. This kit includes all four (two uppers and two lowers), enough to do both handlebar clamps.
My upper triple tree is cracked — will new dampers fix that?
No. Cracked upper triple trees are extremely common on the CB350 K4/K5/G, CB360, and CB450 K3–K7 — Honda's original castings were crack-prone. If the triple tree is cracked, new dampers won't fix the problem. We sell replacement upper triple trees for the 350/360 and the 450 that include a set of Space Capsule dampers and new hardware.
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Last updated: March 2026
