G67HP-6 Primary chains on large displacement motors, some feedback please.

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edwardmorris

New member
Hello, I'm new to this forum and I apologize as this question isn't technically isn't about the Laverda.

I was looking into some good primary chain alternatives for a 915cc Honda engine with a hot cam. From some of the reading I've been doing, the Laverda folks seem to be very happy with either the merc duplex chains or the G67HP simplex chain. In my case, the duplex isn't really an option so I would like to know if any of you who have used them in a larger than the stock 750cc capacity have some feedback to share. Is it a viable option for a torquey 915cc application? Thanks for any input.
 
Andy Chains is the bloke to speak to, out of the UK. Haven't seen a post from him for a while though.Andy supplies all sorts of oddball chains for all sorts of bikes.
http://www.laverdaforum.com/forum/index.php?action=profile;u=330
 
Thanks for the reply Vince! I will reach out to Andy for sure, but I would like to hear from people who have actually run this chain and how its been holding up especially on the bored out engines. Any feedback would be appreciated.
 
USMorris said:
Thanks for the reply Vince! I will reach out to Andy for sure, but I would like to hear from people who have actually run this chain and how its been holding up especially on the bored out engines. Any feedback would be appreciated.
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Andychain does have a wealth of experience of chains - he probably dreams about them.
Make him your first port of call.

For the avoidance of any doubt, many, many people here have his chains and no complaints from a single person to my knowledge.
 
G'day USMorris

I presume you're talking about a SOHC Honda 750 derived special (you said a cam, not cams, as in DOHC). Rummaging around the memory cells, I think they have 2 x simplex chains. The sprocket spacing for 2 x simplex won't suit a duplex, so you can cross a Merc duplex off your shopping list.

As others have said, talk to Andy andy@the-chain-man.co.uk
He will be able to recommend, and probably sell you a suitable pair of simplex chains.
 
SimonR501 said:
Andychain does have a wealth of experience of chains - he probably dreams about them.
Make him your first port of call.

For the avoidance of any doubt, many, many people here have his chains and no complaints from a single person to my knowledge.
Click to expand...

Thanks, I've emailed Andy but haven't heard back yet. There is little doubt about using them with a 750, however for peace of mind, it would be great to know if someone has used them on larger engine without issue. The current build is 915cc, but I'm hoping my next build will be 1000cc and I'll be back to square one on finding out what chains to go with.
 
Dellortoman said:
G'day USMorris

I presume you're talking about a SOHC Honda 750 derived special (you said a cam, not cams, as in DOHC). Rummaging around the memory cells, I think they have 2 x simplex chains. The sprocket spacing for 2 x simplex won't suit a duplex, so you can cross a Merc duplex off your shopping list.

As others have said, talk to Andy andy@the-chain-man.co.uk
He will be able to recommend, and probably sell you a suitable pair of simplex chains.
Click to expand...

Indeed it is! And yes, the duplex is not an option for me (see first post) for the reasons you've described. I'll wait to hear from Andy, but again, it would be really nice to hear from someone running these chains on a larger displacement engine than the 750cc.

Thanks for the replies guys, I appreciate it.
 
The RGS, SFC 1000 and Corsa use 2 x Simplex primary chains and churn out more power than a 750/4, up to 95bhp as standard.
Andy said once thatvAston Martin used 1 x Simplex chain to time their engines.
 
Late Laverda triples use two 06B-1 (3/8 x 7/32) simplex chains for the primary drive.  These superceded the 06B-3 triplex type. 

G67 is the Iwis designation for the 06B-1 norm/trade designation.  Cannot find any reference to what "HP" stands for.  Andy??

I'd imagine a Honda SOHC 4 would need at least forced induction to come anywhere near the torque figures a Laverda triple can churn out, no matter how far the thing is bored out. :D

piet
 
Sounds to me like you're trying to re-invent the wheel. There must be heaps of bored out, hotted up Honda 4 engines getting around with reliable primary drive chains in them. They're all over the classic race scene. Maybe you should talk to someone like Rex Wolfenden (T-Rex Racing Australia) who has been building them for donkey's years. I can't find an email address for T-Rex, but here's their address and phone number. http://www.ozebook.com/cr750_files/trex.htm
 
Grant/Piet, thanks for the info, that helps. And I agree with you Piet on the torque ;) IINM, the HP stands for High Performance, at least that's my guess based on their catalog.

Dellortoman, perhaps some context will help. There are indeed many big dog Honda fours being built and raced over here, and almost all of them use one of the only two HD chain suppliers available. Neither of them is cheap (price range in $250-$300+ US). Recently, it was uncoverd that these two suppliers were allegedly just resizing IWIS and Febi Bilstein chains and selling them. In that discussion, the Breganzane blog came up where the G67HP chain was mentioned as a popular choice for the Laverdas. After purchasing a set and comparing to the stock RK chains in the 750, it turned out that the IWIS chains have much better pin diameter, but thin (REALLY thin, 1.4mm) side plates, and the tensile strength was rated lower as well. These factors cast some doubt as to whether the G67HP would make a good choice for large displacement engines that will be raced (both drag and track/road-race). From the responses above, if the much beefier triples run a set without issue, then they should be more than enough for the little 750 ;)

Thanks again guys, for helping out a (as of yet) non Laverda owner ;)
 
I recall a comment from Andy saying something about pin size and tensile strength. If I remember correctly pin size and fit was more critical than side plate tensile strength. I'm sure someone will be along in a minute to correct me if I'm wrong.
 
Grant said:
I recall a comment from Andy saying something about pin size and tensile strength. If I remember correctly pin size and fit was more critical than side plate tensile strength. I'm sure someone will be along in a minute to correct me if I'm wrong.
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I did some more searching based on that and found this post by Andy

http://www.laverdaforum.com/forum/index.php/topic,80345.msg129570.html#msg129570

There was another thread I found here where a member has used two G67s on his Jota, so I believe that there isn't ANY more doubt that they will be more than enough for the 915cc with a JMR S4 ported head (still under 90HP but getting up there ;)).

Again, thanks for the input gents, I wish Andy had stopped by too, but I can imagine him being super busy. I've read through a lot of his posts and they're all pretty informative!
 
Couple pix "borrowed" from the 750 folks for reference...
 

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Grant said:
The RGS, SFC 1000 and Corsa use 2 x Simplex primary chains and churn out more power than a 750/4, up to 95bhp as standard.
Andy said once thatvAston Martin used 1 x Simplex chain to time their engines.
Click to expand...

Seeing this reminds me that the '60's SAAB 900's including the 16 valve turbo used two single row chains connecting the fore-and-aft engine to the front wheel transmission, 180bhp in the case of the turbo. Never heard of any failures.
 
Wow, so the IWIS G67 has been around since that long? Nice. 

So does the chains in the pix above look the same as what you guys have been using on the primaries?
 
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