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NH350 exhaust rocker box wanted

Posted: Tue Jul 15, 2025 4:28 pm
by JohnH
Hi all. I'm brand new to the forum, and also new to old bikes. Been around them forever due to my dad having many, including a lovely 1955 NH350 that I'm enjoying getting on the road and using. Just discovered that the thread on the exhaust rocker box/valve lifter is stripped so trying to find a replacement.

Many thanks.

Re: NH350 exhaust rocker box wanted

Posted: Tue Jul 15, 2025 4:41 pm
by dave.owen
Draganfly had some made a few years ago. The only problem the inspection cap is a metric thread but I believe drags have suitable caps for the replacement rocker box.

Davr

Re: NH350 exhaust rocker box wanted

Posted: Tue Jul 15, 2025 7:36 pm
by JohnH
Oh really.. I'll contact them to check if they still have any. Many thanks

Re: NH350 exhaust rocker box wanted

Posted: Tue Jul 15, 2025 8:29 pm
by dave.owen
Screenshot_20250715_202823_Chrome.jpg
Looks like they have sold out

Re: NH350 exhaust rocker box wanted

Posted: Wed Jul 16, 2025 4:23 pm
by JohnnyBeckett
hi ,and welcome to to the forum , if no one comes up with one you can try EBAY under Ariel parts i have got a lot parts over the years off ebay last month i got a complete NH engine to send to someone

Re: NH350 exhaust rocker box wanted

Posted: Wed Jul 16, 2025 7:53 pm
by JohnnyBeckett
hi, their is someone on eBay selling a NH engine in parts you maybe able to buy the rockerboxs off Him the eBay number is 167516028563 and you use can find is phone number

Re: NH350 exhaust rocker box wanted

Posted: Wed Jul 16, 2025 11:11 pm
by Simon.Gardiner
Might be worth considering a thread repair (helicoil type).
Kits are fairly widely available online, you might even be able to source something locally.
The kits seem to be quite pricey (especially if only used for one job!) - cheaper than a new rockerbox though!

Another source might be Seb Mciver, if you can track him down. He seems to be fairly active on Facebook but that's not a place I'm very familiar with.

SG

Re: NH350 exhaust rocker box wanted

Posted: Thu Jul 17, 2025 10:58 am
by JohnnyBeckett
hi my experience with old Ariel casings when you tap it to fit a recoil you may find the threads you tap to fit the insert break up or taps oversize the last one i done on the gearbox level plug i had to use jb weld with the insert to hold it in and i used a smaller tapping drill like they recommend , its maybe ok if its a deep thread but if you are going to do the
tappet adjusting cap i would not try there is not enough threads

Re: NH350 exhaust rocker box wanted

Posted: Fri Jul 18, 2025 3:27 am
by nevhunter
Agree Johnnie. It's too fiddly and there's not enough metal to play with. Perhaps tap it (Fine thread) a bit oversize and make another Cap. nev

Re: NH350 exhaust rocker box wanted

Posted: Fri Jul 18, 2025 11:43 pm
by Simon.Gardiner
It's the exhaust lifter thread, not any of the caps.

SG