Starting my Thundercat

Hi all,

This is my first posting on this site and I am hope for some advise.

I have recently got back intro motorbikes after a 20 year break (house, mortgage, children, etc).  My last bike was an FZR600R, so the Thundercat was a natural choice. I have bought myself a little project for the winter months, a 1998 Thundercat that has been sitting for about four years, in theory it just needs a new battery and some fresh petrol in it to get it started.

Dose anyone have any suggestions on anything else I should do before I try to start it.

I'd like to think what you've said might be all that you need.
Mine normally needs a few attempts of bump starting after a very long break but is fine after that.
Maybe a real expert will be along shortly.
Good Luck & keep us posted.

Cheers
Rosco

Engine-wise, personally I'd change the oil before trying to start it - unless it's been in a nice warm garage, water may have condensed in the sump. Just put some very cheap car oil in and run it for a few tens of miles gently to flush out any rubbish, then do a proper oil and filter change.

Also, before trying to start it, take the plugs out (not easy, unless you have tiny hands!) and put a teaspoon of oil in each cylinder, then crank it over for a few seconds with the plugs out, and some rag over the holes to catch the spray, so as to lube the bores under no-load conditions. Probably worth fitting new plugs while you have them out, unless the old ones look in really good nick.

You may find it's reluctant to fire up, or run smoothly without choke. Possibly this may be due to gummed-up pilot jets. They may clear of their own accord after a couple of miles, and adding some IPA or Silkolene FST to your fresh fill of petrol may help. If not, you'll have to take the float chamber covers off to get at the jets - the holes are quite tiny - and blow them through with carb cleaner or similar solvent. If you do have to do that, you'll need a good-fitting x-point driver to get the screws out, and it's worth replacing them with Allen screws in case it ever needs doing again. Also a good-fitting flat driver to get the jets themselves out.

The brakes are the other area that may need immediate attention, though you need to make a judgement on this, depending on their condition and whether they seem to function correctly and free off easily. If nothing else, change the fluid and clean the pistons by pumping them out a way - they can be pumped out to maybe 5mm short of half-way across the gap before you run the danger of them popping out of the seals Obviously this has to be done with the calipers of the bike and the pads removed. Then clean the pistons off with something like plastic pallet strapping and give them a smear of red rubber grease before pushing them back in again. It may seem self-evident, but don't push the pistons back into the bores until they're nice and clean, otherwise they may damage the seals. If they won't pump out and push back fairly easily (thumb pressure) you may need to strip the calipers and clean out the seal grooves, and possibly fit new seals if the old ones show any signs of deterioration. Old OEM pads can lose their bite, so new HH pads are recommended.

Obviously lube everything that can be lubed easily - cables, pedal/lever pivots etc. and particularly the chain - check for corrosion and tight links. Personally I'd use plenty of engine oil on the chain to start with, to get rid of any corrosion and to penetrate into the rollers etc. Check the condition of the sprockets, too.

In the longer term the grease in the steering head and rear suspension bearings may have hardened up and need re-greasing. While you have the swing arm off to grease the pivot bearings, check the arm itself for corrosion and re-finish (e.g. powder coat) if necessary. Also the fork oil will probably need changing sometime soon.

Good luck, and welcome to Thundercat-dom!

Wow, thank you for your very detailed response, this is all good stuff to know, I have already changed the oil and put on the new battery. It turns over really well, so I will check the plug, add a drop of oil in the cylinders and go from there. If it ever stops raining today I will get some fresh petrol and some carb cleaner and go for it.

Once this is done I will then start a full service and clean it (it looks like it hasn't been cleaned for many years).
Then start the preparation for a re-spray.

Lots to do but this was always going to be project for me, hopefully I will have it on the road for early summer.

I keep you updated with the progress.

If possible, try to remove each of the nuts on the exhaust manifold, one by one. Refit with copper grease on the threads + torque up.

If they look rusted or corroded, then I wouldn't bother - it can be the opening of pandoras box - but if you can do this, it will save a huge amount of trouble later on!

Might be worth giving them a good dousing with penetrating oil over a week first.
As Tom said, they do have a habit of shearing the studs.

If you have stainless downpipes though, they may last longer than the bike.

Finally I got it running, this is going to be the longest project in history. It got a nice sports exhaust on it which sound great, although I not so sure my neighbours think the same.