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Cb400f primary chain noise after big bore kit install

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Doom64:
Hello, I have just put a 466cc big bore kit in about 500 miles ago, the primary chain seems to be a lot noisier now for some reason.
When the standard pistons were in it it could tick over at 1200rpm and there would be a slight knock but nothing really loud, but now with the 466cc kit in when it ticks over at 1200rpm there Is a very loud clunking sound and when you bring it up to 1800rpm it quietens but you can still hear it.
Pretty sure it is the primary because when you put it in gear on the center stand and put the back break on it goes quite.
I have not touched the bottom end the only thing I did was take the sump off and wiggle the primary and the sprocket.
I have balanced the carbs but there was a couple of kinks in the hoses, so I will get some new ones and do it again.(although I used the same set when it had standard pistons and it was fine)
Does anyone have any idea as to why it would suddenly go loud when I haven't even done anything else apart from change the pistons?
Thanks in advance.

TrickyMicky:
Hi, I'm no expert having never ventured any lower than the cylinder barrel, but bear in mind that even when it's in gear with clutch disengaged and brake applied, the primary chain is still moving. I think I would start with the easier task first and have another go at the carbs. Be lucky.

hairygit:
At 500 miles it's not really properly run in yet. If you balanced the carbs before fitting the big bore kit, or done them staright after fitting it, they will almost certainly be a major factor in the noise you are getting. What worked for the original barrels will probably be way out on an engine that's still running in, and balancing carbs before the new pistons are run in properly will also have been a waste of effort. I'd keep using it until it's done at least 1000 miles and you are happy to ride it a full throttle, then try balancing the carbs again (After doing all other service items first, (tappets, timing, camchain, oil and filter change, and correct oil level) as what was okay on the original pistons which were matched to the bores, or what seemed okay with the (Tight) new pistons will almost certainly be different to how it needs to be when properly run in. 

hairygit:

--- Quote from: Oddjob on June 26, 2018, 12:33:01 PM ---Also might be the damping rubbers on the clutch basket not the primary chain, quite common to hear of those starting to go after so long. There was someone who could supply new rubbers for the basket but not heard of them for a bit.

--- End quote ---
That crossed my mind, and I recall it was TTR400 the member that had some made. But I discounted that probability as all he did was fit the big bore, left the bottom end untouched.

Sent from my X6pro using Tapatalk

Doom64:
Thanks for the replies some handy info there.
I balanced the carbs again today it quietened a bit but is still noisy, I will wait until I do 1000 miles until I set it all up again as mentioned.
You can hear the rattle from both sides but it is louder on the left side.
The standard pistons and rings where put in new about a year ago, just wanted a bit more power so I put the 466 in.
Does anybody know where else sells the damping rubbers or other rubbers that fit?
When will it be safe to start giving it some harder acceleration? Kept it under 6000rpm for the first 250ish miles and slowly started increasing revs. now done 550ish miles. 
Thanks.

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