FZR250 Questions and Looking for parts

For anyone in Sydney - I just found the perfect place for bearings and associated parts.

ABC bearings - There's a branch down in Brookvale, not far from me. They've also got branches in Silverwater and Smithfield.

www.abcbearings.com.au

I'm going to work my way through the bike bearings and seals wise- so there's possibly front and rear wheel bearings, swingarm bearings, steering stem bearings and fork seals and dust caps. Now I may not replace many of these as I service them, but I will get part specifications as I check everything and post them up so that way everyone has a reference to work from.

peace out

Glenn

 

good to know the place, in newcastle i find bearing dynamics at wickham very good.

 

Has anyone else rebuilt the full carb set?
I know from some of the screws these carbs have been apart before so -
Got two questions:
1 - the two centre butterfly shafts only had fibreglass shims on one side over the shaft seals - however when fully tightened there's room for two - one on each end of the shaft - parts diagrams are difficult decipher for this.

2 - the actual shaft seals are too loose, they're not cracked or brittle, just hardened.
I can just envisage them not giving a good airtight seal - does anyone know of a source for these?
Different search strings are yielding poor results. Though I may just replace them with square o-rings if I strike out trying to find them...

I've finished cleaning the carbs and will make a detailed howto as I re-assemble them.

peace out

Glenn

 

Thanks Grey - champion reply as I kept coming up empty via google.

I'll put together the howto in the coming days

 

Juts briefly on the topic of the butterfly screws - there was a video I scanned through briefly on youtube - the guy on there used a dremel to take the backsides off of the screws as they have been peened to mutilate the threads to stop them ever coming out and going through the engine.

On mine they came out relatively easily so have been removed previously, but the ends hadn't been ground down.

BTW I put the existing butterfly shaft seals into automatic transmission fluid to soak - so we'll see if that improves their elasticity and makes them swell a little. It was either that or brake fluid, I had the trans fluid to hand...

peace out

Glenn

 

A little bit of heat can always be used to good effect as sometimes just the heating then cooling can do wonders - one of the little hobby style butane torches to heat each screw.
They are small enough to get into the carb throat and their flame is very small and precise and most importantly not too hot, expect though that the heating of the butterfly shaft will necessitate replacing the seals.

But I consider their replacement mandatory if you're rebuilding the carbs, cleaning everything and replacing all of the other seals already

BTW the litetek seals kit is great, one catch is that there are eight main jet square o-rings, I didn't have any reference material to hand and spent ages puzzling where the second one went - till I checked and realised there were four spares.
Huge lightbulb moment for me!!

Also there is a washer below the spring and above the o-ring for the pilot screw, the o-ring will likely be stuck in the orifice with the washer stuck to it. I managed to lose one washer and had to manufacture a replacement.

Also getting the main jet o-ring out was a pain, but as I was battling an enormous amount of built up varnish and crud I soaked that carb part in methylene chloride before it made it to the Ultrasonic cleaner.
Then I used a sewing needle to clear the passage between the central tube and the jet housing.

Methylene chloride is downright nasty, but destroys pretty much anything - rubber included. It was the fastest way to remove the crud from the jets and jet housing.
Don't get it anywhere near plastics of any kind.

I've also gone one step further and removed the float bowl plug which seals the low speed (starter?) jet circuit to check the cavity.
It's the one with four holes forwardmost in the carb throat. I'll report back what size square o-ring I get to replace them. They take some effort to remove using flat blade screwdrivers and gentle twists around the circumference, but they do come out.

 

AAH YES the spare o-rings -blonde moment - who says being blonde is more fun, it must be hell for them on a long term basis

 

OK here's a simple PDF document with a table and headings to keep track of shim values - it's a very easy process but I think the best way to get good access is to take the little extra time and remove the engine entirely to get clean & clear access and avoid any dirt or debris falling into the engine

peace out

 

I've revised the above PDF a little make the listing of shims you already have and cross referencing to produce a list of those required simpler

also the clearance range with the <x< is meant to mean greater than and less than because precise measurement with feeler gauges limits to about 0.02mm - 0.03mm with combinations of various thicknesses

 

OK let start by saying that any trepidation that you may have about doing the valve clearances iscompletely unnecessary.

Just be methodical and double check everything.

I'll write out a howto once my shims arrive and I can take some photos as I re-assemble.

You may need either some vernier calipers or a 0-25mm micrometer. Two of my shims were with the thickness etching facing down and they were worn over the etching and were illegible.
So I had to put the micrometer on them.

It's much easier to do with the engine out, plus you get access to nooks and crannies behind and around the engine to get them clean.

On the carb jets:
The pilot jets are non bleed - if you have any difficulty un-screwing them as they're soft brass, put the jet housing in hot water to get the aluminium to expand and try removing them whilst it's still hot. Gloves are essential.

I've got a specs sheet which has the numbers for the jets, however I noticed it's printed in '96 and I've got 102.5 mains - 1&4 100 - 2&3 - the spec sheet agrees
37.5 starter (spec sheet says 42.5) and the pilot jet is a 30 (spec sheet says 80) I thought the 30 was improperly stamped 80, however all 4 are the same.

hope this helps

peace out

Glenn

 

This is the specs sheet I found here: http://my-x15.net/fzr250/FZR250 specs.pdf

peace out

 

That's great news Blair - count me in for the butterfly seals once they arrive. I've already got the viton kit from you fitted which was such a blessing having everything in one kit.

I haven't recorded the jet numbers, but as I've been working on other parts, the carbs are only partially assembled, so I'll get all of the numbers you're after.

Mine is a 3LN1 - for reference.

My carbs seems to be stock and the only reason I can fathom for yours having been re-jetted would be likely a different fuel level/float height.

Grey, I'll do the howto on the valve clearances over the weekend, my shims arrived today - overnight from precision shims. I ordered yesterday and had them today - sensational service so they get my unconditional recommendation.

Anyway I started cleaning all of the brake calipers not anticipating the shims would arrive so quickly. Once they're done I'll do the shims/vavle clearances.

One tip for anyone looking for cheap paddock stands - go to Aldi I picked up two, originally 49.95 - they were down to 19.95 when I got mine. If they've got any left at a local store they may be even cheaper now.

I used the two of them and a milk crate to remove the engine - it worked well.

peace out

Glenn

 

OK here's my Carburettor specs - I wrote the main air jet type from the pic on the mikunioz page
Bike Model FZR250 3ln1

I.D Mark 3ln 00

Jet needles - all carbs #5CT7
Needle Jet - all carbs #N8 - 625 Series

Main Jets: 1&4 #102.5, 2&3 #100
Main Air Jet - all carbs - #30 (non bleed type - Mikuni N151-067)

Starter Jet - all carbs #37.5

Pilot Air Jet - all carbs #105

Butterfly - all carbs #125

The only difference I can see from the 3ln supplement is, and I don't read Japanese - the #130 I suspect is for the butterfly, whereas mine are #125.

Hope this helps

peace out

Glenn