GB400 cam chain help

**mark247** · 26th March 2007, 18:54

My GB has a bit of a rattly camchain and im thinking i should probably replace it sometime soon. I know a bit about engines but im no pro. But i would like to save money and do it myself. Are the parts hard to get and how much do they cost? And how long does it take for a mechanic to replace the camchain? Oh yeah, and should i get the tensioner done at the same time? Or possibly just do the tensioner?

Thanks in advance.

**xwhatsit** · 26th March 2007, 23:04

No idea how much it would cost for a mechanic to do, but I did my camchain when I was fixing the engine and it was not really that difficult.

My bike has a very similar engine to yours, so I assume most of what I know applies. Parts, get them from Econohonda (http://www.econohonda.co.nz/), they are very cheap, and they will definitely have everything you need. Camchain for my 250 was $~70 or something. Tensioner is probably a good idea, but if it's not showing huge amounts of wear then it should be fine, or so I'm told. Definitely replace the camchain though, because not only do you have to worry about the tension on the chain (a combination of chain and tensioner), you also have to worry about the chain being so stretched it'll get your timing out.

If your engine's like mine, you need to take off the crankcase side cover, which will mean a new gasket, and a new rocker cover gasket too if you have one. It's all very cheap to do, less than $120 or so in parts. Definitely do it or have it done, don't muck around with camchain, very expensive if it fails you.

**What?** · 27th March 2007, 06:28

I strongly advise replacing the tensioner and guide when replacing the cam chain. Failure to do so will result in a short life for the new chain.
Give Ian a ring at The Motorbike Shop for a quote on labour-only replacement of parts; you might find it not worth the hassle of doing it yourself. The trick to an easy replacement is to break the new chain, break the old chain, tie the two together, then pull the new one through and re-join. This means you don't have to split the crank case.
Malcolm at Econohonda in Te Aroha is the man for parts.

**mark247** · 27th March 2007, 08:29

Originally Posted by What?

Give Ian a ring at The Motorbike Shop

What motorbike shop are you talking about?

**mark247** · 27th March 2007, 08:33

Oh and also, how do i know exactly when i should replace my cam chain? My bike is making a bit of cam chain noise but not heaps, it has always made it since i got the bike now that i think about it. Does it get louder when it wears a bit?

Cheers.

**vifferman** · 27th March 2007, 08:48

Originally Posted by mark247

Oh and also, how do i know exactly when i should replace my cam chain? My bike is making a bit of cam chain noise but not heaps, it has always made it since i got the bike now that i think about it. Does it get louder when it wears a bit?

Yes, it does get louder. But unless the tensioner goes, it will get louder so gradually you may not notice it. Replacing the camchain would be best done in conjunction with some other major engine work, but given that the camchain/tensioner is really the only weak part on most Honda engines, 'major engine work' may never eventuate.

On many bikes (VFR800 VTec, VTR1000, CBRs, etc), the tensioner and/or guides will need replacing before the chain. However, if the tensioner fails and some 'catastrophic interference' occurs, shops will usually replace everything while they have it apart, as the parts aren't a huge part of the cost.

My first bike (CB175) had so much wear and slop in the camdrive that the chain had eaten a big chunk out of the engine casings. The thing still ran, but probably lost some guts. However, on some bikes (VTR1000, VFR800) if there's too much slop, the chain can jump the cam sprockets, despite there being provision to stop them doing that, and they'll clatter to a halt. I think whether really bad things happen or not is perhaps due to the camchain length.

**mark247** · 27th March 2007, 08:57

Well it seems like a wise idea to get that done sometime then. I'll certainly price it all up, and then if the chain gets louder and ill get done pronto.