Shed Time

After my ride in March where a very terminal sounding rattle developed during the day, I have been on the fix-it trail with a few wrong turns. Fearing that I would find some serious damage on opening the R1 engine I used Find a Part and got about 5 emails with R1 engines for sale. Prices ranged from $3000 to $1250. I took a punt on the $1250 unit and paid $80 to have it shipped from Newcastle NSW. The engine is a 2001 unit and came complete except for carbs and starter motor.  

With some mods due to changes in the gear change shaft length and one of the mounting bolts having a smaller diameter, the engine went in using a trolley jack and started OK after a spray with ether.  I tapped and fitted cap screws to the AIS system ports and returned to standard jetting on the replacement set of carburetors that I had sourced from the US in the hope that I could regain some better fuel use. Too much fiddling with jet kits and ignition advancers. I must stop kidding myself that I know more than the Yamaha people. A bad habit I picked up living for too long with Yamaha 2 strokes. 

Some drilling and tapping has an oil temperature sender fitted to the oil/water heat exchanger and a drilling into the main oil gallery allows remote fitting of a pressure sender for an oil pressure gauge. They did not perform well on the Anzac Day ride but are okay now as I have remounted them in rubber and improved the power and earth wiring.

Once the 2001 motor was in, I pulled the `98 unit down looking for the "knock".  All seemed well apart from a small piece of the intake piston skirt on number four missing.  The crown of 4 also showed much more carbon build up than the other three pistons. A solvent leak test on the intake and exhaust ports cleared the head of having a problem.

Quotes from local Yamaha dealer had me on the web and onto a couple of Yamaha dealers in the US with much more reasonable pricing for OEM parts. I ordered most of the stuff including gaskets but misread the system thinking you could only buy 4 pistons and rings so did not order the piston.  Each shipment from the US cost $80US for FedEx or UPS. No cheaper options. Couple of days later I checked and found you could order as many or as few a number of items as you needed so ordered a piston, rings and clips from a different dealer and paid another $80 shipping fee.  Bugger.

Both shipments arrived as promised so I fitted the new piston and put the bottom end of the motor back together. Once the clutch was fitted and I rotated the unit there was still a knock-type-feeling when 1 and 4 came to top dead centre. I had not fitted the head at this stage.   Pulled off the clutch and the knock went away.   Bearings ordered with another $80 ship fee; good grief.  The engine is now together with replaced main and big end bearings. There is no sign of the knock on rotation. I will keep it until the new unit has some more kays on it and if all goes well I will do the EBay thing to recover some of the costs that Val has noted.

Some serious time has been spent but there are no longer any R1 engine mysteries to discover. Strip down and rebuild went well except for breaking a 6mm thread bolt with a 12mm hex head instead of the normal 10mm hex head.  I used the 12mm hex torque reading, should have read the manual better. I ordered a replacement with the bearing shells.

The big mystery is still what caused the "rattle". I did have problems with the bike running on three cylinders at times, notably after Ron's funeral when it stayed on three all the way to Gisborne and would only fire on 4 after replacing the plug.  This happened soon after fitting what I thought were standard carbs. Main jets were 138 instead of 130 but the main offender may have been the pilot jets that had no numbers.  The 1998 engine standard in Australia is 17.5 but 15 is the US with 4 turns out on the mixture screws instead of 2.5 turns out with the 17.5 jets.

On the Buninyong Tower ride I was running 130 mains with 17.5 pilots but the damage may have been done. Bearing damage may have been the result of raw fuel causing pressure on the bearings of number four. I guess I will never know. I need a fuel injected bike but then what would I do in the shed?

Geoff Jones