Scottie mailed me the other day to tell me of a rather nice SRAD track day weapon he had acquired. It was a none runner, somebody had taken it off the road to spam it up and had not been able to get it running when it all went back together. It looked a tidy enough thing, had a really nice paint job and enough parts to get my money back if it all went wrong. You never know what you might find when what you are essentially buying is somebody’s story, the only verifiable fact was that it didn’t run.
Right up my alley, really, I love a challenge and I have never laid hands on a SRAD before so a deal was done and the beast was loaded in the van for the short hop up the A16.
First thing was to whip off the seats and the tank and have a general look around, the battery was a bit flat so I put some volts in it, turned on the ignition and everything lit up. No whirring noise from the pump though. I am unfamiliar with these so don’t know if the pump runs until pressure is achieved or whether the engine needs to be running for the CDI to send pulses – I will find out soon enough.
As there didn’t seem to be any fuel flowing I thought I would see if there was any in the carb bowls. The thoughtful chaps that designed the carbs built drain screws in to the bowls so it was easy to verify that apart from some thick green piss like fluid the carbs were indeed empty. Just for a laugh I used my usual method of filling carbs – an outboard engine priming bulb to get some fuel where it needed to be and tried again. No joy – they are clearly gummed up, when I lifted the needles they each had thick deposits that were more than enough to restrict fuel flow – if they are that bad the idle jets and main jets are bound to be the same. I squirted in some easy start to see if there were any signs of life and it briefly burst in to life for the first time in many years.
It’s not worth going any further now without whipping off the carbs and giving them a proper clean, I suspect that will be all they need, I will of course then have to investigate why the fuel pump doesn’t run, I don’t expect it to be a difficult fix.
I couldn’t see at first how to get the carbs off – they don’t have the usual jubilee clips holding them on to the rubber inlets. What they have is a long screw for each pair of carbs, access holes are provided in each side of the frame so you can get a long screw driver in there to loosen the carbs and whip them off. Nice little design touch, that one.
Another thing that may not be immediately obvious is the tickover adjuster, which also has to come off with the carbs. It has a small bracket that is fastened to the frame with the same bolt that holds on the rear of the coolant overflow tank. You need an open ended 10mm spanner to get at it, it’s a bit fiddly with the fairing in place but removing the fairing is a lot of hassle so I did it without.
The rest of the removal is straightforward, remember to undo the electrical connectors to the carb heaters.
As expected the carbs were quite gummed up, especially three of the idle jets, two of which ended up in the bin as no amount of soaking, poking and air blowing seemed to clear them. Fortunately I had a couple in stock so rather than stressing about it I put new ones in.
The fuelling isn’t right on it though – the standard jets are 12.5 on the idle, which is what is in there and the mains should be 125 on the inner two cylinders and 127.5 on the outer two – mine has 122.5 on all four. As it has a K+N air filter and a rather racey pipe I would expect something like 15 idles and 130 mains to be more in the ballpark. I will play with that later.
So with the carbs stripped, cleaned, blown through and generally looking splendid I popped them back on the bike. Handy couple of hints here – the rubbers are usually really tight, especially on older bikes. Before I bust a blood vessel and throw things across the workshop I do 2 things. The first is to wind out the clamps as far as they will go – the rubbers have to expand a long way and if the rubbers are not really loose they will stop you from getting the carbs back on. The next thing is lube. I use tyre fitting soap but WD40 will do the job nearly as well and leaves no residue that has to be wiped off. It makes a huge difference to the success of the mission.
Join me next time when I will see if my efforts have been wasted or not. Dave.
Article provided by David Powell of Boston Bike Bits.
