998 Compression
Showoff!! :-)
How did it end up?
Well, on pulling out the engine, and extracting the pistons, the compression rings on number 1 were broken into 21 separate pieces! Luckily all the fragments had remained within the ring grooves, and not fallen out and scored the bores... number 4 was just as bad, but both pistons were trashed... the lower ring groove had a sharp burr on the bottom edge, and the top edge of the top ring grooves were kind of wavy in appearance!
We were faced with a dilemma: try and source 2 new pistons, and take a gamble as to whether the bore had been "ovalled"... but we could only find one supplier of flat top standard pistons, and they were at a cost of UK£57+VAT each... ouch!
We made a few phone calls, and found a 1098cc complete engine & gearbox for £70... again, it was a gamble, as the guy that owned the breakers yard had not heard the engine run....
The intention was, to strip the 1098 down, and install the new piston rings that we had got for the 998... but I stripped it down and had a quick look (ie head off), and it appears to have been recently rebuilt, with shiny silver rocker gear & valve springs, and nice clean pistons, and hone marks visible on the bore walls.... we didnt bother with the rings, and just put on a fresh copper head gasket, and dropped it in!
We also converted the clutch from the old B&B to the newer Verto, so that we could use the existing pre engaged starter... as the new engine was an A and not an A+!
It has been done 3 weeks now, and is running quite well... especially now we have the correct needle in the carb, and i have "sort of" got it set up... although a friend has a commercial CO/HC analyser and is going to come over with his gas analyser and strobe light one evening next week, to do the job properly.
It's a proper little rocket now, and as Chris Barron did comment, the difference between a sick 998 and a good 1098 is quite noticeable!
Yesterday I noticed quite a bit of blue smoke blowing from the exhaust on stationary revving..... does not do it when cold, and the 20w50 is nice and thick, so I am hoping that it is nothing more sinister then the valve stems/guides need "proper" seals installing, as opposed to those silly little rubber rings. Hell, a friend has a hydraulic press, so I may even splash out a new set of valve guides too! :-)
Will keep you all posted!
James
Posted: Aug 25, 2006 03:02 PM