Greetings from new FZR250 owner in Australia

Welcome mate, few of us around here with dead FZR's... (actually, i think pretty much everyone who owns one has either had it dead or has another dead one haha)

 

welcome

 

welcome to the beginning of your voyage - all the information you require will be here and for whatever you can't find just ask

 

welcome to the forum mate, Just for a heads up if you haven't seen the posting on it yet.... If you would like to see the manuals and all the tech stuff on your bike, becoming a contributing member which helps with maintenance of the site so we can keep helping people who love their 250's.

https://www.2fiftycc.com/index.php?resources/categories/fzr250.25/

Cheers,
Tm

 

Welcome!

If compression is low, there are a few further things to do before pulling it apart.

First thing is repeat the compression test and make sure that the throttle is wide open for an accurate reading. Second is to put some oil into the cylinders, repeat the test & see if the reading improves. If it does then the rings are worn out. If not, and the reading is still low but consistent across all cylinders, the valve clearances will be too tight.

To do valve clearances you need feeler gauges (in metric) and a shim kit (or order specific shims after you have it all apart), it involves taking the timing tensioner and camshafts out. Underneath are the lifters (also known as buckets). FZR250's are a shim under bucket design. When installing replacement shims, the numbers should face up on these bikes. Lube them with a bit of oil or moly grease.

Clearances for FZR250's are:

Intake: 0.11mm to 0.20mm
Exhaust: 0.21mm to 0.30mm

In the resources section there is a sheet you can print out and use to record your measurements. It's dead simple once you've done it once.

 

Aboard

 

Also if it turns out you need engine bits, you can get top end kits (rings, pistons, wristpins and circlips), main bearings and rod bearings from aliexpress. So as long as your crank isn't stuffed you can rebuild the motor.

But for low compression due to worn out rings, all you have to do is take the head and barrels off. Thankfully on this series of motor, the barrels are separate to the top crankcase half, so you don't have to pull the whole motor apart just for a top end freshen up.

main crank bearings https://www.aliexpress.com/item/12p...-1HX-2KR-STD-Main-Crankshaft/32704769982.html

conrod bearings https://www.aliexpress.com/item/8pc...0-RR-ZEAL-250-FZ250-DELTRBOX/32281393624.html

pistons & rings https://www.aliexpress.com/item/4-S...-FZ250-FZR250-1HX-Piston-and/32734549504.html

I've used these bits from AHL (but for 3LN series motors) in the past with no issues. Someone in China seems to have bought the molds for the pistons - the set I received were marked YAMAHA 3LN on the underside of the pistons - exactly the same as the OEM part. The 3LN pistons use a smaller oil control ring to the earlier 2KR/1HX motors, so be aware if ordering.

If you're not comfortable doing the work yourself, or don't have the tools, find a good engine rebuilder. The trouble with the FZR250's is that the service manuals are only available in Japanese. However you can use the FZR400 manual, which you can get in english, for a lot of things on the 250.

 

just an FYI the compression test needs to be done with the throttle held open and the slides propped up also

 

Re popping up the slides, on CV carbs there are slides above the throttle butterfly. Like the name says, they slide up. Have to be fully open for the compression test.