Hitchcocks Forum

I was giving my conti gt535 a check and clean this past Sunday and I found that the rear lower edge of the petrol tank next to the front of seat was bolted down hard on to the frame, This must be a cause of vibration through the bike, I removed the rear tank bolts and put washers under the mounts and now when bolted down the tank is clear of the frame, On a run today I am reasonably certain that vibration in the mirrors has decreased, at 70 mph I can see behind quite clearly so I am sure this has made a difference, I need to do a few more miles to be sure, I would be interested to hear from other conti gt535 owners on this subject, anybody got any tips on this.

Why isn’t the tank rubber mounted? That’s one more mystery I can’t fathom!

Our hosts do a rubber pad thingy for this; apparently the vibration can hole the tank. If I had a CGT I'd probably buy a set. The earlier Bullets and C5s are not much better. In mid 2015 the C5 tank mount was changed so that it sits on rubber buffers front and rear and doesn't have the horrible- looking flange at each side of the tank at the front.

In Answer to PRESTOS (Is the tank rubber mounted then yes it is) The front of the tank slots onto rubber mounts and the rear is fixed down on two rubber vibration mounts, but they sit too low and allow the flange on the tank to contact the frame, I have raised my mounts by 3 mm and its now clear of the frame so its an assembly problem not component.

Hagis - the actual cause of the vibration is the engine, not the tank! All big singles vibrate, even my F650 which had a balancer shaft was not immune from the problem. The EFI 499cc engine is a lot better than the 535, but even that is not perfect. My Conti vibrates like a hammer drill at around 2,800 rpm but lower and higher up the rev range it smooths out - by 3,250 the mirrors are clear and the vibes are reduced to just a tingle through the bars. However, thats not to say it can be ignored and my suggestion would be to put some closed cell foam where the tank meets the frame. Also its most important to wash and polish on a regular basis as that is the way you pick up any loose fasteners. I've found one of the horn brackets on the last few threads and a loose spoke in the rr wheel together with the exhaust heat shield nearly off - now all Loctited in place. I've also replaced quite a few of the cycle part fasteners with nylocks - including the M16x1.5 rear wheel spindle nut (just like the front wheel spindle) with a nylock (about £3.50 for 4 on ebay - note the fine, NOT the coarse thread M16).

Hagis - I've been out to the garage and noticed the same thing on my Conti. I've realised the tank off the frame rails by 4mm - two hard rubber 25mm dia flat washers, drill a 7mm hole (careful or you'll loose digits on this operation!) and insert under the tank mountings. Tighten the fittings (10mm spanner) back down and the tank is raised up 4mm. It doesn't interfere with the seat at all and seems the best (engineering) solution to the problem. If you want a picture then go on this Facebook group Royal Enfield Owners UK (note this is not Royal Enfield Owners Club and is free to all and all are welcome!).

NIGELPHOTO is correct in saying all big singles vibrate, this is part of their charm, I have ridden big singles most of my life including BSA victor, Husqvarna 510 and 610tc off road, Aerial red hunter, Velo mac, Bsa c10L and c11g,Norton 500 and a few more that I rode to death on the fields in my younger days so I have had a life long affair with thumpers, nothing better. My RE 500 bullet Electra has just completed 10,000 miles touring around the Glens and mountains of Scotland and has been a pleasure to ride, My Conti gt535 is a step up from the Electra in that its quicker, nimbler but is still a pleasure to ride I had a choice this PM fix the sticking brakes on the Citroen c5 or take the gt535 for a run you can guess which won so after 50 miles I am now convinced that lifting the rear of the tank off the frame has made an improvement to the vibration on this machine, when running the spanners over this machine I have found nothing loose and apart from adjusting the clutch and throttle cables all is fine, I suspect that the rear top engine mount from the cylinder head to the frame would be a source of vibration through this machine so I will give some thought to modifying this mounting with rubber bushes or isolastic mounts to improve things, I don't if this is possible so may have live with things as they are.

Can I ask how you find the bars? I test rode one two years ago and felt that they were far too wide. Much wider than my Velo clubman (27 ins). If there was a fix to instal narrow bars, I might be interested. The engine performance was also turgid, admittedly it was a new bike.

The front tank mount on my C5 which left the factory late November 2014 is rubber mounted but the rear bolt is also the cylinder head stay. The front mount is a tube through rubber bushes on the frame. The rear is a lug welded to the frame. As the rear is the head-stay which has to be solid, I'm not sure how it can be rubber mounted. I have stuck car-sill rubber to the top of the tube under the tank, it does not touch the tank but does damp vibration there.



Looking at the specs, the EFI-500 and the CGT-535 are virtually identical apart from the bore and very marginally wider ports.



The CGT bars are just clip-ons, you can change their angle until they hit the tank, or change them for shorter ones. You could even saw the ends off but they have to be long enough to fit the switches and hydraulics. All Enfields vibrate like the devil and feel turgid until they're well run-in. Compared to a Velo (nice), you've got less horses but more torque, and probably under-geared, but you do have brakes and real lights to see with.

I have not had a problem with the bars at 30 inches, they are 1 inch narrower than the bullet Electra I have been used too, There is on the market now a billet conversion that allows you to fit standard bars of any shape, This bike was an awkward stiff machine until it had done 1200 miles after that it loosened up and using the engine between 3500 and 5000 revs brings it into its own.