How do I know if it needs a top end?

Lost compression, increased oil consumption on a four-stroke, a rattle or knock that was not there before, or a noticeable drop in power are the usual signs — but the honest answer is a compression and leak-down check, not a guess from symptoms alone. Hours since the last top-end rebuild matter too, especially on a bike ridden hard.

That decision gets made from what the inspection finds, not assumed going in. A top end with a scored cylinder and a tired piston might only need those two parts; a bottom end with worn bearings and a damaged crank might call for a fuller rebuild. Findings get discussed with you before the call is made either way.

Do you build custom motors?

Yes. Custom motor builds are scoped around what you actually want from the bike — more top-end pull, a broader spread of power, or durability for long off-road hours — not a generic performance package.

Service 05

Inside the motor, on purpose.

Opening a motor is not the default answer to a running problem — it is what happens once an inspection has confirmed that is where the problem actually lives. Top-end work, bottom-end and full rebuilds, and custom motor builds all start from the same place: find out what is actually true about the engine before deciding what to do about it.

Top-end work

What wear looks like, what hours suggest, what an inspection settles.

A top end wears predictably with hours, but "predictably" still varies a lot with how a bike is ridden — a two-stroke run lean or a four-stroke run past its oil-change interval both shorten that window. Symptoms like lost compression, a rattle under load, or rising oil consumption point at the top end, but they do not confirm it on their own.

A top-end rebuild in Colorado also has to account for altitude — jetting, compression, and how hard an engine works to make power up here all shift what "normal" wear looks like compared to sea level. The inspection accounts for that rather than applying a sea-level assumption to a Front Range bike.

Bottom-end and full rebuilds

A decision made with the rider, not for them.

A bottom-end or full dirt bike engine rebuild is warranted when the inspection finds bearing wear, crank runout, or transmission damage that a top-end service will not touch — not on a fixed hour interval and not because a top end is already open. Plenty of top-end jobs stay top-end jobs because the bottom end checks out clean.

When a bottom end is warranted, what that means in scope and what it does not fix gets laid out before the work starts. The goal is a motor that matches what was actually found, not a rebuild sold on the assumption that bigger is safer.

Custom motor builds

Built around what you actually want from the bike.

A custom motor build starts with what you want changed — how the power comes on, where the bike pulls hardest, how it holds up over long off-road hours — and works backward from there, rather than starting from a parts list and hoping it adds up to a goal. Displacement, compression, cam timing, porting, and internals all get chosen against that goal, not in isolation.

A custom motor build is one piece of changing how a bike performs. Where that gets combined with mapping and suspension work is covered under performance & custom.

How an evaluation works

Inspection first. Then the work.

Every engine job — top end, bottom end, or custom build — starts with the same sequence.

Inspection

Compression, leak-down where it applies, and a look at what hours and symptoms suggest before anything is opened up. Two-strokes and four-strokes wear differently, and the inspection is built around which one is on the bench.

Findings, discussed

What the inspection turns up gets discussed with you before it becomes work on the bill — what is worn, what is marginal, and what is fine. A part with life left in it stays on the bike.

The work

Scoped to what was actually found and agreed to, not to a generic rebuild checklist. Top-end and bottom-end work both happen at this stage, at whatever depth the findings call for.

Routine wear items caught before they become an internal engine problem — fluids, filters, and the checks that catch trouble early — continue to fall under maintenance & service.

Start a service request

FAQ

Engine and motor questions

How do I know if it needs a top end?: Lost compression, increased oil consumption on a four-stroke, a rattle or knock that was not there before, or a noticeable drop in power are the usual signs — but the honest answer is a compression and leak-down check, not a guess from symptoms alone. Hours since the last top-end rebuild matter too, especially on a bike ridden hard.
Rebuild or replace?: That decision gets made from what the inspection finds, not assumed going in. A top end with a scored cylinder and a tired piston might only need those two parts; a bottom end with worn bearings and a damaged crank might call for a fuller rebuild. Findings get discussed with you before the call is made either way.
Do you build custom motors?: Yes. Custom motor builds are scoped around what you actually want from the bike — more top-end pull, a broader spread of power, or durability for long off-road hours — not a generic performance package.