The thought of owning a turbo powered JZR was sufficient reason enough to make the long trek to Stafford on a freezing winters days in 2007. Despite the shortest of test drives on an icy driveway, the heart instantly won over common sense and a deal was agreed. After a few entertaining trips "feeling my way" and some longer trips I began to enjoy the turbo's very rapid performance. After a while I began to suspect that the turbo was not functioning as it should - sometimes the expected power wasn't delivered so I guessed it might be a wastegate problem. Eventually, the turbo effect had disappeared completely so the time had come to get it repaired. What a naive statement that turned out to be. It didn't take long to discover that the IHI turbo was made specifically for the Honda CX 500/650 turbo bikes and that not only were reconditioned or new units unavailable, but that spares were unobtainable too. Calls to various turbo reconditioning companies produced a number of "can't help" responses, but one said they could help if I paid them nearly £900. That seemed rather a lot so the hunt continued.
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Eventually I found another reputable company who suggested a more realistic figure of £450 but with no guarantees. To carry out the work they would require the failed turbo and the spare that I had (the spare had rather worn bearings). The reconditioned unit duly arrived back and was fitted - great - back to the expected (exciting) performance. Sadly my euphoria lasted for about 400 miles before one brief spell of acceleration was accompanied by an alarming screeching sound. I backed off and accelerated again. Once again above 3500 revs. I was rewarded with a cacophony of noise akin to ball bearings in an empty bean can, and this horrible screeching. Obviously something was seriously wrong with the turbo so my journey home from Silverstone was very tame at sub 3000 revs. Being a cautious fellow I had snapped up a spare turbo from a reliable source some months back, but like my original "spare" the bearings didn't seem too good either. However, I removed the "reconditioned" unit and fitted the spare. A trip up the road suggested that all was fine; 2 miles - OK; 3 miles OK. Looks like it is working well. No - after 3.5 miles a whistling developed and a slight drop in power. A check of the installation found nothing untoward. Another test run produced similar results - OK for a couple of miles and then noises. I drove back home and wrote off the following day's run to Silverstone which would have started with a couple of laps of the circuit as part of the Historic Weekend's Retro Run - DAM!
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What to do now - that was the question. In the time I had owned the car I had experienced more "repair time" than running time. I really wanted to drive the little car and not spend time gazing at it in its undressed state. What about a 650 engine then - not as powerful but nevertheless it would pull the JZR along at a good rate. I called Sam Day - the Honda CX guru - and after a discussion about the relative merits we decided that a CX500 with modified heads would be the best compromise. Sam explained that whilst 500 parts were not as readily available as they used to be, 650 parts were very scarce indeed. I didn't want a "turbo" scenario all over again so agreed with Sam's suggestion.
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The scene was set - I just needed a CX500 engine now Ebay was an obvious possible source but very much a case of "caveat emptor". A call to Brian Lofty seemed a logical step and he said he would ask around. However, Sam quickly came up trumps with news of an engine for sale from Tony Simpson (Zipper). This was duly purchased, collected by Sam and taken back to Sam's workshop for inspection and rebuild.
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The story that follows is the account of what started as an engine swap and became something more involved.
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Roger
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