FZR400 winter overhaul | Page 3 | GTAMotorcycle.com

FZR400 winter overhaul

Brian P

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I'm getting some pictures sent to my phone showing some parts ready to be picked up ... Road trip to Niagara Falls in the next day or two, and then I can start getting the chassis put back together.

Also, Pro 6 should be done rebuilding the shock, and de-glazing the cylinders, later this week.
Still waiting for fork rebuild parts and some OEM internal engine parts from the dealer.

No decision yet on bodywork or wheels. I know what I want to do, but some accounts need to move from "receivable" to "paid" in order to make it happen ...
 

Brian P

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Whew ... Long day. After work, first to St Catharines to www.cryo-ice.net and dropped off the transmission for cryo treatment, then to carboncat's shop (Reflections Auto Refinishing) in Niagara Falls to pick up painted parts. I can get some assembly done ... but it's been a long day, so it's not happening now.
 

Brian P

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Rainy day update - re-assembly has begun. I didn't take these pics until the end, but it went pretty much as follows.

Easy first task was to re-install various rubber grommets onto the frame and subframe, then I hung the front of the frame from above.

Lower triple and steering head bearings into the bare frame, set the preload on the bearings. I used the lower triple from the spare-parts stash hoping that it wasn't bent. Ignition switch bolts to the bottom of the upper triple and I set it in place and test fitted the fork tubes. Perfect alignment! And the steering turns smoothly from side to side.



Next ... Greased all the suspension pivots. Assembled the chain guide, suspension links, and stand spools (using the old ones for now) onto the swingarm, hung the chain around the swingarm, bolted that into the main frame.

Next ... Assembled the subframe onto the main frame, then the left footpeg and shift linkage.



Then ... Right footpeg, rear master cylinder, rear brake switch, brake pedal return spring, guide for the brake hose. The bracket for the brake caliper looked like crap - took that off and painted it myself, then reassembled it - rear brake is done.



And that is how it sits - hanging from the ceiling. Waiting for front fork rebuild/upgrade parts to show up in the mail - should arrive any time. Pro 6 Cycle is tracking down rebuild parts for the WP shock ... everyone has Ohlins stuff nowadays, but no such luck for older bikes. Waiting for engine parts (main and rod bearings, piston rings, and a few seals) from the dealer. Waiting for the transmission to come back from cryo treatment - but it's not scheduled until next weekend.
 

FiReSTaRT

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Nice.. Lovin' the Fizzer-porn.. Keep'em coming :)
 

Brian P

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Front end parts came in from Race Tech. First task is to estimate the length of preload spacers required (with a new tape measure!)



For a rough first guess, the length of the combined spring, spacer, and new damping valve should be the same as the length of the original spring and spacer. Original (top), and new (bottom). The spacer is made of PVC pipe. Race Tech supplied a piece of it but it was nowhere near long enough ... I had some in stock so I used mine.



Next is to drill out the stock compression damping holes. The stock damper rod forks use a fixed orifice. The new compression damping valve uses a small orifice with a spring-loaded-closed valve that opens when there is a lot of flow through them. To make this work, the stock damping holes have to not function any more. Stock holes:



Drilled out as specified by Race Tech:



This is the fork parts laid out with the new guide bushings installed. (the damping valves are upside down here ... fixed this later)

 

Brian P

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With the parts put together, this bolt holds the bottom of the damping rod in. The damping rod wants to spin ... I got the screw started by hand and used the air impact on low pressure to tighten it.



Fork seal installation tool - a piece of PVC pipe. First the outer guide bushing - pressed in place using the old guide bushing and the spacer that sits above it, then remove the old guide bushing and put in the spacer, then push the new seal in using the old seal. When the clip pops into its groove, it's done.



Easiest way to set the fork oil level is on the bike.



Now for some math. With the fork cap, spacer, washer etc in place and the fork extended, there is 35mm between where the fork cap seats, and the top of the fork. Question is, how much to shorten the spacer?



We know that the bike weighs about 180 kg with fuel, deduct the unsprung weight (wheels, brakes, etc) and the sprung weight is likely around 160 kg, about half of which is on the front end - 80 kg. I weigh about 100 kg, about a third of which is on the front, so 33 kg. Total front sprung weight should be around 133 kg. Half of that - 67 kg - is on each fork.

The spring rate is 0.95 kg/mm so that means, with the sprung weight including me on it, the spring will be compressed 70.5mm from its free length. That includes the rider-aboard sag which we want to be around 35mm for a street bike. The rest of it is the amount that the spring has to be preloaded. So the 35mm measured before, ought to be pretty close. In reality it won't be exactly this, partly because the fork is at an angle to the load, partly because the top-out spring will have some effect, partly because the weights are estimates. But ... Should be close enough.

I misplaced the 27mm socket that I need for tightening the steering stem. I'll finish this job tomorrow after I find it.
 
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RockerGuy

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You need some form of sheet metal as walls for your "shop"
 

Brian P

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The good: picked up all the new parts to build the engine from Brampton Powersports today. Still have to wait for the cryo-treatment job to get done but I won't be able to pick that up until a week from now. Then I can put the engine back together.

The bad: Since KTM bought out WP Suspension, parts for everything that WP made before the buyout are discontinued, and that shock uses an oddball piston seal. Pro 6 is looking for new-old-stock parts. Apparently some flat-trackers are still using the same style of shock, but getting someone to part with one of their stash of rebuild parts might not be so easy. May have to take the plunge and buy a new Penske shock - they build shocks to whatever specs you want. That wasn't in the budget, but there was some allowance for things-gone-wrong, and I'm not exactly opposed to the idea of having good suspension ...

I found an old stock shock in my own parts bin but it's only good for holding the bike off the ground. It will do for now.
 

Brian P

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Crankshaft bearings are in.



Crankshaft and timing chain are in the upper case, with a drop of oil on each journal.



Test-fit for crankshaft rotation - all OK.



Con-rods and pistons are on. Loose carbon has been cleaned off the pistons and the new piston rings are on.



Waiting for transmission to come back from cryo treatment, also waiting for Woodcraft handlebars and a set of ignition wires - and, figuring out what to do with the shock.

I'll let Pro 6 continue looking for a seal kit for my shock, then pursue other options after that.
 
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architect

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Awesome thread. Thanks, Brian. Subscribed.
 

Brian P

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Update - at last!

After another week-long business trip, I picked up the transmission from cryo treatment.

First step: swap in the lower-mileage and now cryo-treated shift forks and shift drum. This mechanism is filled with finicky little bits and the orientation matters.



But, once together, you can test the mechanism with the shift forks roughly in line with the shaft to make sure the orientation is right. The little spring-loaded roller is what holds the shift drum in each gear.



Now, something that I do to all of these engines - raise the oil pressure a bit, as a countermeasure to a tendency of these engines to run a little shy on oil delivery at high revs. This is the relief valve - remove this pin with your fingers over the valve to catch the spring-loaded bits inside:



Here are the innards of the relief valve - a simple spring-loaded plunger that vents oil out the holes in the side of the housing when oil pressure pushes it back against the spring. It's held together with that pin above, and a projection on the oil pan holds the valve itself in place against the crankcase.



Here it is, back together, with a couple of washers between the spring seat and the pin, to preload the spring a bit more. It won't give a large increase in oil pressure, but more is better than less as long as it isn't too much.



Now, the transmission itself goes in - making sure all the bearings, seals, thrust washers, locating pins and rings, and the jet for the oil feed are in place. You can test the whole transmission at this point to make sure it goes through all six gears and has neutral, and has a little clearance between the gears when it is in between gears.

 

Brian P

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Then, there's a big step that I don't have pictures of, because it has to be completed before the sealant sets.

A bead of black RTV sealant is applied around the outer perimeter of the crankcase wherever there is oil on one side and outside air on the other side. This has to be a thin bead. You do not want excessive silicone inside the engine; it has a way of getting into the worst possible places if too much is used. I always apply the bead of sealant towards the outside of the mating surfaces to encourage it to squeeze to the outside of the engine rather than the inside.

Then the cases go together. The transmission is already together in the lower case, and the crankshaft, timing chain, crank oil seal, and pistons and rods are already assembled in the upper case. To do this, I lift the upper case by lifting the timing chain and hanging the crankshaft below it and then flipping the upper case over - this way the crank doesn't fall out of the upper case when you flip it over. The rear guide for the timing chain has to be carefully guided through, and the drain hose for the crankcase vent has to go through a guide hole in the lower case. It is a finicky operation. Once everything aligns, the upper case drops in place. The bolts from the bottom have to be tightened first but you don't want the cases falling apart when you flip them over again, so I insert one of the upper bolts into its hole and snug it before flipping the cases upside down.

Then, the main cap bolts go in and are torqued to specs. Yamaha casts the tightening order numbers into the cases, making that part easy. The bolts along the front of the crankcase also go in from the bottom, and there is one bolt covered by the oil pump that goes in from the bottom, all torqued to specs.

It's easier to put the oil pan on before flipping the engine rightside up again and doing the top bolts - but before that, I install the oil filter, I put the oil pump in, torque its bolts to specs, pour a bit of oil into the intake screen, and spin the oil pump in the forward direction to prime it. Then the new pan gasket goes on ...



Then the oil pan goes on and bolts are torqued to spec. Then the engine can be flipped rightside up, and all the case bolts that go in from the top can be installed and torqued, taking care to install a couple of cable guides that belong on a few of these bolts. One of the bolts along the back of the engine only gets threaded in a couple of turns at this point - because later on, when the engine goes into the bike, that's where the chassis ground strap (to the battery) connects to.

Then ... Starter reduction gear, starter gear cover with a new gasket, starter motor, water pump, a holder for the rear main seal and clutch pushrod seal can all go in, and the cylinder base gasket can go on, and here is how it sits.

 

XenoVibe

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1989 was the year I was made :D Love Yamahas. Is that the one with the double circular frog eyes or the single brick headlight?
 

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