Project Linkins 3LN6 - The Pink Lady

https://dan-moto.com/en-au/collections/fzr250_fzr400/products/lciexsr-ya0502-r5-2

Looks like they dropped the price, I think I paid more.

I got my brake caliper overhaul kits from Wemoto.

2x Front kits (eight pistons): https://www.wemoto.com.au/bike/yama...ake-piston-seal-and-dust-seal-front-brake-oem

2x Rear kits (two pistons): https://www.wemoto.com.au/bike/yamaha/fzr/250/1993/13093/brake-piston-seal-and-dust-seal-rear-brake

Master cylinder overhaul kits. I got the front from ebay (from the UK): https://www.ebay.com.au/itm/305249816925

The rear kit was an all balls kit, but was not correct (suits 2KR/3HX).

The only correct kit I can find for the 3LN rear master cylinder is the OEM one: part number 3LN-W0042-50

 

Tiny little air jets, these are also apparently used as a fuel jet on some jet skis.

 

Behold, aftermarket air filters for FZR250 3LN models.

I have used unifilters on a ZXR250 with keihins, same as the standard filter. We shall see how the Mikunis play with this.

 

Today I got highly motivated and rode to work in the pouring rain to get stuck into Pinky.

Compressed air is a lovely tool for drying off sopping wet bikes before you work on them.




First order of business, get the carbs properly sorted, because I was in a hurry to get it registered before. I checked all the fuel jets, float heights etc and all was good.

I replaced the last float needle and got all the main air jets out (lost one old one), they were all clear but new ones are good. I finally cleared the fixed pilot air jet on #1 too. A bit of gunk came out of the passageway.




Next item was the about-to-break choke actuator that the cable hooks into. I managed to find a new old stock one on ebay. Rare as rocking horse ****, very lucky to have got it. Of course, I have kept the old one in the hope of 3D scanning it and 3D printing replacements for everyone else.






I thought the pilot jet on #1 carb was a problem because adjusting the mixture screw was having no effect on the miss and cold exhaust on #1. The head on the jet is stripped so I've never been able to remove it, but as it turns out I had forgotten that I have a vacuum fuel tap now. Left the vacuum line open after removing the fuel tank. Blocked it off and it started running right. Got me worried for a bit.

While I was chasing that, I quickly did a compression test on #1 and got 150psi which is good enough, I'll have to recheck the specs though. We also checked the spark strength which was very good, about 1" of spark with the plug cap removed and nice strong blue colour.

Nice brown/tan colour on #1 plug




I was still chasing the ticky/rattly noise, until my boss jumped in and took the cap off the cam chain tensioner and forced it down one click. The engine is nice and quiet now. Balance was left alone as I did it after the new manifolds and haven't done very much riding since.




I got the new Unifilter fitted, but the fitment is not perfect. The filter is slightly oversized. It works and you could squeeze it in so it conforms to the airbox, but I had the airbox bottom fitted to to the bike and so access is a bit poorer around the front side. It still seals but looks ugly. There is a fairly stiff plastic insert throughout the filter, so it's not just two pieces of foam. The OEM filter is of course a perfect fit. They are no longer available and rare to find, so I will of course keep the original in the hopes of getting HiFloFiltro or DNA to make an OEM replacement.








The next item was the speedo and why it isn't working. I disconnected the cable from the dash, got the front wheel in the air and spun it, which confirmed my fear that the problem lies within the speedo unit itself. But all was not lost, because the problem is still external to the speedo unit internals.

There is a 90 degree spiral gear set, made of plastic, that bolts onto the back of the speedo housing. When I opened it, it was full of green fuzz. After emptying it out, I eyeballed the gear and saw that the teeth are partially stripped. The fuzz was the gear shredding itself to pieces. Thankfully, the matching gear inside the speedo is fine.




I have already bought a donor 3LN6/7 dash on ebay and it will arrive next week, hopefully I can just steal the 90 degree bit, bolt it on and have a working speedo.

While I had the dash out of the bike, I pulled it apart to replace some globes and clean up the connections. I replaced the 3 12v3watt globes with 12v4watt as that's what we had. I did not have the tiny little Toshiba 12v1.7watt globe sadly.

The wiring harness connectors all got inox'd as well.






Since I had the speedo out anyway, I did the speed limiter removal modification. I used my snap-on ziptie cutters are they are small enough for job.

 

By my eye the filtration area extends to the very edge of the filter

 

Got my ebay dash today, used to fix the speedo on my original one.

On the back of the speedo there is a right angle block where the cable threads on. Inside there are two spiral gears. The one in the cable end was partially stripped and was full of green fuzz when I opened it.

The matching gear on the speedo needle shaft was loose on the shaft, I checked it against the donor which was tight.

So I took the gear off the spare speedo, just a circlip and a pin in the shaft, and fitted them to my original. Then bolted the spare cable block and gear to my original.

Hey presto speedo fixed. The original would click and the needle would dip down when it clicked. This is the gears separating and the needle speed dropping down. Every time this happens the gear is damaged a little bit more. When I went on my joyride, I was doing higher speeds, after which the needle stopped working and the green fuzz was generated.

After all that, then the tacho stopped working... disconnected the electrical blocks and cleaned out some of the inox I put in there, plug it back in, and it works once more.

I also gave it a cold start this morning, it was 8 degrees and windy. I gave it half choke no throttle and hit the button. It immediately fired but didn't catch. Went full choke no throttle and it roared into life. With a noticeable complete lack of cam chain ticking, and no exhaust leaks. The motor on this one now sounds really quiet, insteading of matching the open pipe for noise.

This weekend I'll take it for a burn and test out the tune job and new air filter. Then I might stick it on a dyno and see what she makes.

I've got just a few little odds and ends to order and I won't have to touch it again for a while. Needs cush drives, lid for the coolant bottle and drain hose.

 

How's this for a cold start

 

Speedo limiter mod no good I think I cut too much off it or have otherwise upset something in the circuit. I am hitting a limiter at 14,000 in gear, in neutral is fine.

Tomorrow I will go and change out the speedo for the spare - I love doing the same job twice!

Last items to do are cush drives and coolant bottle cap and drain hose, as I am getting coolant spill out onto the rear tyre. Items are on order.

I think I will order some Alpha 14's in 110/70 and 140/70 for a track day at the least, sadly I am not a fan of the Rosso Sports but they are the correct size. Just riding around on the street I am already very close to the edge of both tyres, and I'm not being a street rossi either. The suspension adjustments and raising the forks have affected things I think.

 

Swapped speedo no difference, looks like I need jetting with new air filter and open pipe, good excuse to get it on the dyno

 

I had Metzeler M7RR on my R6, they were the only tyre I've used that don't suffer road camber wear on the right hand side of the front tyre, even after a year of daily usage. They went surprisingly well on the track, the only time they were unhappy was when I cooked the left hand edge going a bit hard one lap at eastern creek, even then, just a little squirm and it didn't give out.

I got to the very edge of both front and rear without getting knee down, the R6 was a weapon on the track







Will look at them for my next set of road tyres, but for the track I'd take the Alpha's

 

I got a delivery of bits today - New cush drives and coolant bottle cap and overflow hose.

Got those fitted up and also put the standard air filter back in. Hey presto it runs so much better. So the Unifilter needs further testing. I will save it for later.

Coolant bottle cap and overflow hose fitted and routed correctly, no more coolant on my back tyre thank you. Made turning right at roundabouts a bit hairy, no longer.

Cush drives are a must, so much less bucking of the bike.

 

I just checked and it shows out of production

EDIT: Found it on part number search, it is indeed available.