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wr-426

just rebuilt, engine noises

9 posts in this topic

i have just put my 426 back together after 3rd gear let go, the bike is running fine, but i am worried that it is rather loud, i am concerned about it being a little end knock except it didn't have a knock there before i pulled it apart, i have installed a new wiseco piston and gudgeon pin and a second hand but in good condition barrel. i am waiting on a shim kit before i can shim the valves perfectly, at the moment i have made do with what i had and got them close enough that i don't think it should be a problem. the bike is particularly loud at idle. I'm hoping i am just paranoid, but if anyone can ease my mind or tell me what to check to ease my mind that would be greatly appreciated,

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i have just put my 426 back together after 3rd gear let go, the bike is running fine, but i am worried that it is rather loud, i am concerned about it being a little end knock except it didn't have a knock there before i pulled it apart, i have installed a new wiseco piston and gudgeon pin and a second hand but in good condition barrel. i am waiting on a shim kit before i can shim the valves perfectly, at the moment i have made do with what i had and got them close enough that i don't think it should be a problem. the bike is particularly loud at idle. I'm hoping i am just paranoid, but if anyone can ease my mind or tell me what to check to ease my mind that would be greatly appreciated,

How much piston-cylinder clearance did you have with the used cylinder?

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How much piston-cylinder clearance did you have with the used cylinder?

i cannot remember exactly, but i remember measuring the clearance between the skirt and the barrel and it being quite alright. The nikasil on the barrel was in quite good nick with the cross hatch from it's previous life still showing nicely. and again my old barrel and piston was a lot more worn beforehand and it didn't sound like this before.

what do these bike sound like when their valve clearances are too large, i am familiar with the sound of loose tappets but that of large clearances in a bucket and shim setup?,

the only person i could get to listen to it and tell me whether to be worried or not is away for another few weeks :smirk:

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I really couldn't tell you what they sound like with valve clearance over spec. That's generally not the condition. How far over the limit are the valves right now?

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I really couldn't tell you what they sound like with valve clearance over spec. That's generally not the condition. How far over the limit are the valves right now?

only a couple of thou, max. i am beginning to think i maybe just a bit paranoid. maybe tomorrow i'll go listen to a friends 03 450 that has just had a 490 kit put in it. i remember it being a noisy bike maybe that will help me gauge whether mine is a problem or not.

i did notice today that the clutch cover seems to act as a bit of a resonator for sound, if i put my palm on it, it takes away a little bit of the sound. anyone else ever come across that?

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They rattle like hell! when the valve clearance is too large more of a loud ticking noise. did you install a hot cam? the narrow lobes on the hot cam make the feeler gauges feel different

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If your a couple of thousands off it isnt that much of a difference, but you will know for sure when they are way out. The make a loud rattle comming on the power. Im always paranoid every time a build one also its natural. "I HOPE". I have been building engines for years and always hear noises. Hope it helps.

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being a 426 and having built it on quite a budget, there are still some old parts that are a bit on the worn side, the clutch basket does have some dips showing up in it's sides and i didn't have the cash for hot cams or to put in a new rod and crank, but i think i'll just take it for a few gentle rides and see how it progresses, i will be doing those clearances properly as soon as i get those shims, (i live on a little island where postage takes weeks and there isn't a bike shop for a few thousand k's).

I'll be back if i have more questions or news,

Cheers,

Jesse

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