Hi,
Sorry for offending the purists but, i have a project which is putting a 930 Hilman Imp engine in a 99 Special R14 87889 for which i do not have he original engine!
i read the "Hole story" some years ago!
I have bought an Internal kit from RGM, without the Fork slides £360 ish and the oil holes in the alloy dampers have been relocated higher up, to avoid I presume the Forks bottoming out, whilst searching through products, later on I noticed that they offer a Covenant Conversion and extended length fork bushes to stop topping out! Are these modifications really necessary?
Any thoughts would be appreciated!
Cheers
John
The bottoming out fix is w…
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Thanks for your thoughts;…
Thanks for your thoughts;
I am not really sure, but I suspect the Imp engine is slightly heavier than the Norton lump, but not by much, so I was trying to cover all bases and have a the best/ strongest but well-damped front suspension! On the rear I have a Terry Mead, Swinging Arm extended by 1 inch above standard in 17 gauge T45 and of a construction like the Norton one with closed loop BSA Gold Star type ends.
Just me personally, but I never liked the Clevis U-type open-ended Swinging-arm Rear-wheel spindle fixing!
Cheers
John
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In my experience some owne…
In my experience some owners are unaware that there is slightly more total movement in the fork tube/ fork bottom than there is in the oil damper assembly and forks bottom out on the damper assembly. There is something like 1/16-1/8 less total movement in the damper assembly and you set up the damper rod in the top nut to ensure the damper assembly never makes a mechanical end stop. Took me a few years to learn that lesson. But such ignorance keeps some people making money flogging bits.........
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Hi, Is the Covenant kit no…
Hi,
Is the Covenant kit not necessary with fine adjustment then?
There are claims that even ignoring damage potential almost an inch is lost off the Fork travel with the standard set-up!
Cheers
John
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You have done the most hel…
You have done the most helpful bit yourself, so in my opinion you do not need the rest of the kit as it can be achieved in different and cheaper ways. It is the Covenant kit that loses you the extra inch of travel due to the sleeve put under the top bush limiting travel (a longer bush does exactly the same) it does not give you that inch back, If you do nothing the most annoying thing will be a clunk as you put the bike on the center stand, as you are building a special and will be changing the weight distribution if nothing else then careful setting up of the front fork spring pre load and maybe slightly stronger springs with longer rods would fix that issue and be more helpful handling wise.
I have CBR600RR cartridge inserts in my Commando forks, it has a simple top out spring in the top and the compression bump stop is the std profile in the bottom with the holes high up, I have adjustable low speed rebound and compression damping with shim stacks for mid and high speed damping. I have 3 spring rates to choose from and adjustable preload for setting the ride height. Compared to this mod the covenant mod is tinkering at the edges.
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The bottoming out fix is worth it and part 1 of the Covenant kit so you have that covered, the topping out is not critical, really depends if hearing a clunking sound as the forks extend to full extension as you pull it onto your center stand grates with you or not. Topping out riding can be cured by playing around with oil viscosity and spring pre load. Also I thought the topping out was Commando only, as they messed up the rod damper length so the valve on the end of the rod hits the top of the damper body before the std length bush covers the oil holes in the stanchion trapping oil between the bushes to give a proper topping bump stop. I just made the rod longer and got more travel.