AMC twin rebuild

Information relating to the Matchless G9 or AJS Model 20 500cc twin
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AMC twin rebuild

Postby Floydella » Wed Mar 14, 2018 8:42 pm

I read an article in the Jampot sometime last year regarding a club member who rebuilds twins. I have since mislaid the article! My G9 is exceptionally noisy and I suspect it may be camshaft/cam follower wear. I would like the gentleman in question to perhaps contact me with a view to discussing the problem. I have a couple of videos of the engine running which I can send via an email address? Thanks in advance!

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Re: AMC twin rebuild

Postby clive » Thu Mar 15, 2018 8:09 am

Dave I think the difficulty is that although you are a member you are not logged into the site as a member. This means the message facility for him to contact you may not work. Regards
clive
if it ain't broke don't fix

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Re: AMC twin rebuild

Postby Floydella » Thu Mar 15, 2018 10:50 pm

Hi Clive sorry for confusion regards my user name. I was under the impression that I had to change my username to post on the forum. I would prefer to use my original name of Floydella to receive replies? Can you arrange this please? Regards Dave Moeser

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Re: AMC twin rebuild

Postby g5wqian » Fri Mar 16, 2018 6:56 am

hi dave ;
i have a 600 twin , the tappets tend to be quiet after theyve been adjusted and then over time the noise seems to increase and i need to adjust them again .

mine made a knocking noise when i bought it some years ago and it turned out to be a previous owners rebore that was at fault , it had been finished too tight with little or no clearance for the pistons and subsequently had a partial seizeure at rear of nearside piston , which made it have a knocking noise at lower revs .

mine is now honed out with plenty of clearance and its nice and loose , it makes more noise when cold for a few miles but when warmed up is quiet .

they do tend to whine when ticking over , ie the timing gears but thats a pleasant noise to me .

what you dont want is for the engine to seize up on you , if it makes some noises many of them are normal .

the tappet clearance at .006" is tight and fiddly to get it smack on so i doubt youll ever have it at .006" for long other than immediately after its been set .

mine is usually between .006 and .008" after running for 1500miles but at .008 it will make more noise , i am not really bothered with it until i think its got too noisey for my liking .

i can work on my engine and do the tappets easily but it is still a fiddly job to do , i do it when i feel the need , my bike is reliable and i do many 100 mile runs each year on it no problem .

cheers
ian

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Re: AMC twin rebuild

Postby clive » Fri Mar 16, 2018 9:27 am

Dave the bass wrote:Hi Clive sorry for confusion regards my user name. I was under the impression that I had to change my username to post on the forum. I would prefer to use my original name of Floydella to receive replies? Can you arrange this please? Regards Dave Moeser

Way outside my volunteer jd I am afraid. You will have to email Eamonn on webmaster@jampot.com
Regards Clive
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Re: AMC twin rebuild

Postby les ward » Fri Mar 16, 2018 5:22 pm

Might be Ian Farrington from West Sussex, who has rebuilt many twin engines. His own bike is a 600cc twin, so he knows them well. You should find his advert in the Jampot magazine, but if you can't find the advert I could give you his contact details.

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Re: AMC twin rebuild

Postby raffles » Fri Mar 16, 2018 6:46 pm

Take a look at recommendations you will find all sorts of people who may be of help in you rebuild but for a twin engine
I would go to JOHN BOLTON of Workshop 14. Find his details in the adverts in the JAMPOT MAGAZINE.
Tony

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Re: AMC twin rebuild

Postby leswaller » Fri Mar 16, 2018 8:54 pm

I used John Bolton to rebuild my G9. Excellent job. :D
Les
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Re: AMC twin rebuild

Postby Floydella » Fri Mar 16, 2018 10:40 pm

Thank you chaps for your wise words! I will initially try resetting the tappets but having run the bike back in the early '70's the bike was quieter then... the noise I have described seems too 'heavy' for it to be the tappets and it doesn't get any quieter once it's at running temperature. If any of you would be interested in hearing it and have an email address I can send a short video of it running?

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Re: AMC twin rebuild

Postby Duncan » Fri Mar 16, 2018 11:06 pm

Hi Dave, have you tried listening at different parts of the engine with a long screwdriver "stethoscope" to narrow down the location?

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