I finally got down to removing and starting to strip down the engine now on my 2007 TKR today. I knew that the bike had been 'Barried' and bodged somewhat when I got it and I had to do some remedial repair work on it when my son had it. I also knew that my scooter has a Dellorto CDI unit with the electrical oil pump as I had seen those while doing repairs before, so I was shocked when I found ANOTHER Dellorto mechanical oil pump bolted to the front of the engine, being driven by a cam on the crankshaft! This one:- One hose was just dangling down below the bike, the other was cable tied to the frame but didn't appear to go anywhere. This is a Speedfight 50 oil pump from a quick Google search and it's not mentioned in the Haynes PDF manual that is doing the rounds. My TKR also has this Dellorton Electrical pump bolted to it that was connected to the oil tank and carb. So, it appears that I might have an engine that is a mix of Speedfight 50 and Trekker 50 with two oil pumps, one mechanical, one electrical, or has something been missed here with someone's previous bodging on the bike? Is the mechanical pump redundant, or should it be pumping oil to boost the pressure to the electrical one that runs from the CDI? Can I blank off the mechanical one's mounting hole and just run from the electrical one alone, as this is what the bike appears to be doing at the moment? It's also possible that a replacement Speedfight engine has been fitted to the TKR and whoever fitted the engine stuck with the Trekker's electrical pump. Either way, it seems to be a weird hybrid. The Haynes Manual is no help about this, as it references Mikuni and Gurtner oil pumps and I am dealing with Dellorto units. Has anyone got a picture of an original Speedfight engine setup using the Dellorto mechanical pump, so I can compare it with how things were set up on my bike?
I've found another link that says that this unit is an exhaust recirculation valve - is this correct? This is what the engine looks like from the front (this us not my engine, but looks identical). As my machine has a tuned pipe with no recirculation branch fitted, it appears that this is redundant if it is an exhaust gas recirculation pump, so I can probably make a plate to blank this off as long as someone confirms that this is indeed what it is.
Could be that the mechanical pump packed up and somebody fitted the electrical pump as a cheaper option and made the other redundant. What about running it on pre-mix whilst leaving the oil pumps attached but with the hoses open to see which one, or indeed, if both work?
It's been fine with the Dellorto electrical pump to be honest, but I wasn't expecting to see this other Dellorto unit on the front of the engine, especially as it's apparently not connected to anything. I can't say that the Dellorto electrical one is a cheaper option as you need the matching CDI unit. Maybe the CDI and electrical pump were an upgrade or a retrofit to this machine, I'm really not sure as to if it's an oil pump or an EGR pump.
With some help from my son, we finally got the crankcases split today. The crank definitely has no drive for a mechanical oil pump so the electrical one is probably original, as long as the engine is also original. I've decided that I'm going to blank off this 'EGR pump' hole with a blanking plate made from some 3mm aluminium sheet I have spare. I'll make a gasket to suit as the original pump used an O-ring to seal itself. The barrel was moderately scored on the exhaust port side, as was the piston and the main bearings seem a little 'rattly' and noisy compared to new ones, so they are getting binned off too. The other shocking things was that there was no head gasket under the head. The cylinder head will be cleaned and lapped, to ensure that it's flat and a new head gasket will be fitted during the rebuild. New bearings, crank seals, gaskets and cylinder/barrel should have the internals as good as new again. I now need to thoroughly clean the crankcases, measure the crank seal depths, remove the seals then heat them up, to remove the bearings. I also have to extract the remains of a snapped stud on the transmission side of the crankcase. I'll need to order some new rubber bushes for the engine mounting, as the ones on the engine are knackered. I'll run a chaser tap through all of the threads to make sure that they are OK and Lumiweld those that are suspect and re-tap them, to make them good again. Then there's a new rear brake cable to buy, as the old one has just about had it. The cases are badly pitted and oxidised and I'm torn as to if I should acid pickle them to remove the oxidation, or take it off with silicon carbide glasspaper. Either way, the cases are getting etch primed and painted with silver lacquer before re-assembly. I'm going to take my time with this engine restore and the results should be brilliant.
Thanks for the reply. I'll leave it off and blank the hole off with an alloy plate then; with the tuned pipe being fitted on the bike, the air pump is doing nothing useful, unless it can be used to inflate the tyres!
