כל עוד בולם הזעזועים והרגלית תקינים, המחיר סביר.

כל עוד means as long as, so long as, or provided that.

In this sentence, it introduces a condition:

כל עוד בולם הזעזועים והרגלית תקינים, המחיר סביר.
= As long as the shock absorber and the kickstand are in good condition, the price is reasonable.

It is stronger and more specific than just if. It suggests: this statement is true under this condition.

In the present tense, Hebrew usually does not use a separate word for is / are.

So:

• המחיר סביר = The price is reasonable
• בולם הזעזועים והרגלית תקינים = The shock absorber and the kickstand are in good condition / are functional

This is completely normal Hebrew.
If you wanted past or future, then Hebrew would use forms of להיות (to be), but not usually in the present.

Because it describes two nouns together:

• בולם הזעזועים — masculine singular
• הרגלית — feminine singular

When Hebrew has a mixed-gender plural group, the adjective normally takes the masculine plural form.

So:

• masculine singular: תקין
• feminine singular: תקינה
• masculine plural: תקינים
• feminine plural: תקינות

Since the two things together are mixed gender, תקינים is the correct form.

בולם הזעזועים is a construct phrase (called smikhut in grammar).

Literally, it is:

• בולם = absorber
• הזעזועים = the shocks / the jolts

Together: shock absorber

So Hebrew builds this idea as absorber of the shocks.

A key point: in this kind of construct phrase, the first noun often does not get ה־, even when the whole phrase is definite. The definiteness comes from the second noun:

• בולם זעזועים = a shock absorber
• בולם הזעזועים = the shock absorber

So even though בולם has no ה־, the whole phrase is definite because הזעזועים is definite.

Because Hebrew commonly says shock absorber as absorber of shocks:

• זעזוע = shock / jolt
• זעזועים = shocks / jolts

So בולם הזעזועים literally means the absorber of the shocks.

This is just the normal Hebrew term for the part.

ה־ is the definite article, meaning the.

So:

• רגלית = a kickstand / small leg-support
• הרגלית = the kickstand

In the sentence, both items are definite:

• בולם הזעזועים = the shock absorber
• הרגלית = the kickstand

That is why the sentence sounds like it is talking about specific parts of a specific vehicle or item.

Because מחיר (price) is a masculine singular noun.

The adjective has to agree with it:

• מחיר סביר = a reasonable price
• המחיר סביר = the price is reasonable

If the noun were feminine singular, you would use סבירה instead.

Sometimes, but the meaning changes a little.

• אם = if
• כל עוד = as long as / provided that

So:

• אם בולם הזעזועים והרגלית תקינים, המחיר סביר
  = If the shock absorber and the kickstand are in good condition, the price is reasonable

• כל עוד בולם הזעזועים והרגלית תקינים, המחיר סביר
  = As long as the shock absorber and the kickstand are in good condition, the price is reasonable

כל עוד sounds more like a standing condition or requirement.
It fits very naturally in this kind of sentence.

Yes. Hebrew can also say:

המחיר סביר כל עוד בולם הזעזועים והרגלית תקינים.

This means the same thing:
The price is reasonable as long as the shock absorber and the kickstand are in good condition.

Putting כל עוד... first gives the condition first.
Putting המחיר סביר first gives the main statement first.

Both are natural.

תקין / תקינים can mean:

• in good condition
• functional
• proper
• working properly
• not defective

So in this sentence, it does not only mean physically unbroken. It can also imply that the parts are working as they should.

That is why תקינים is a very natural word in contexts involving machines, vehicles, equipment, and parts.

Not always in every context, but very often that is what it means in vehicle-related contexts.

Literally, רגלית comes from רגל (leg), and it can refer to a small leg-like support. Depending on the object, translations may vary slightly, but kickstand is a very natural translation here.

So a learner should mainly understand it as a support part that stands like a small leg.