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This is my bike a little before the rebuild. Years of oil, road salt and grime has taken its toll and when a headgasket 'O' ring popped and I finally got a garage all to myself I decided to do an engine rebuild and give the bike a good clean.

This is my little workshop. It has a light, 2 power sockets and a leaking roof.

I carefully removed the fairings tank and pipes. Then drained the water which came out brown. Not a good sign.

Removed the 2 stroke bottle airbox and left cylinder head to see if it was the cause of the problem. It was.

The inner 'O' ring had popped meaning water got into the engine. Leaving it in my brothers garage for a year afterwards didn't help either. The piston rings were now rusted solid in the barrel.

With the radiator removed and the cover of the water pump removed, you can see that at 1 there's rust in the water system. At 2 there's white deposits on the rubber hose. I think this happens from using tap water instead of distilled water you can buy from Halfords or other car shops.

With the metal parts now removed from the bike I sat and scrubbed them with a degreaser called 'Gunk' which costs about £5 for a litre at halfords. Don't use steel wool as bits of it dig into the aluminuim and turns rusty and it's very harsh on aluminium.

I used a brass bristle brush which doesn't scratch aluminium and scotchbrite type pads which can scratch aluminium but works well on steel parts and a toothbrush for a hard to get to places.

Gunk stinks and is the sort of stuff that would sting like mad if you get it in your eyes. So wearing eye protecting is a must and gloves are optional but if you want to avoid oily handmarks all over the house resulting in one very angry wife, I'd go with the gloves.

I didn't scrub on the machined side of the cylinder head and barrels to avoid scratching and causing leaks when reassembled.

(Yeah, I know stupid haircut, double chin.)

Cylinder heads and barrels

The right hand barrel was removed with no problems and was pretty filthy. I took the power valve assembly out and put them in a sealable plastic bag ready for cleaning.

To get the barrel and pistons off remove exhausts, spark plugs and 4 nuts at the base of the barrels. Slide them off making sure the piston and conrods don't whack against the crank cases. Stuff CLEAN oily rags around the conrods to keep the damp out and make sure the bike is not in gear. If it is in gear and you wheel the bike around you'll break something expensive.

To remove the piston. Put your goggles on. There's a spring clip (Number 29 in pic below) that can be a bugger to get out. One of them shot out and hit me in the goggles so they do save a one eyed drive to the hospital and sitting for 5 hours next to a drunk covered in vomit. Use long nosed pliers to remove it. Then push the gudgeon pin out(number 28) from the other side with your finger. Pull the piston off and throw away the small end bearing (number 30) cos they should only cost about £3. Although I've been quoted £12 before. Also buy new spring clips cos they'll be bent afterwards and they're cheap.

After mad scrubbing with the brass bristle brush, toothbrush, Gunk and whilst drinking beer, here it is. Pretty good eh!?

The power valve assembly picture is before the clean. I bought new springs as the above ones were a bit bent but I also noticed the new ones were about 5mm longer than the old ones. The guilotines were very difficult to clean as the brass bristle brush couldn't shift the carbon deposits. I used a bit of wood to scrape the deposits away instead.

Removing the front sprocket

t's probably easier to remove the front sprocket than trying to wiggle the chain around the side of the sprocket. There is an allen bolt that needs undoing and it may be very tight as mine was. I sprayed loads of WD40 and carb cleaner on it the day before trying to shift it.

With the back wheel still tightened up, I got my brother to hold the back wheel still while I fitted an allen extension peice in my ratchet. This meat I could get a lot more leverage and less likely to slip than with a normal allen key. Don't try getting a spanner on the castellated metal piece and try holding it still while using the allen key on the bolt as you'll snap one of the 4 castellated bits off as you can see in the picture below. I think this piece is important for the speedo so I'll have to get it replaced for the bike to be road legal.

*NOTE:18/5/05 When I rode the bike round the block after the rebuild I noticed the speedo was way out. I had a look in the parts book for the part number and it wasn't listed. Fingers crossed it'll get through the MOT without the man noticing.

When the allen bolt is out. Hook something behind the castellated metal peice to get it off. After that use circlip pliers on the circlip holding the sprocket in place. Loosen off the back wheel so the chain becomes slack and pull off the sprocket.

After 18000 km this sprocket is only just starting to hook on the teeth. It must be down to the light weight of the bike, good chain oil and correct chain adjustment (most of the time). It certainly wasn't down to riding like a pansy or only in the dry. The new Renthal front sprocket felt lighter too.

When refitting the sprocket. Make sure the allen bolt is tightened to 13 N.M of torque.

Dropping the engine out

The left hand piston was stuck solid in the barrel. I had to drop the engine out of the bike before trying to get it out. I labelled the wires, and all the little 2 stroke oil tubes before disconnecting them so I could put it all back together again afterwards. Old coffee jars were used to hold all the bolts that were being removed from the bike.

When I'd removed the carbs, reed valve covers and oil pump I was ready to drop the engine. Taking the oil pump off is pretty important too. It has tiny brass tubes on it and they're bound to get snapped off lugging the engine round.

Oil pump

My brother came round to help remove the engine. There's 2 massive long bolts at the back of the engine and 4 smaller ones. The engine weighs about 30kg's

so it was possible for him to hold the engine while I undid it, then dropping it gently onto a biscuit tin. I suppose a trolley jack was probably the best tool to use for lowering the engine but I don't have one and my brother needs the exercise.

Stuck piston

Although the work is not pictured here the way weremoved the stuck left hand cylinder barrel was to bolt a flywheel puller to the cylinder head studs. Resting on top of the stuck piston we put a small socket and slowly tightened the the nuts on the flywheel. This put the pressure on the socket, onto the piston top and slowly pushed the piston out. Spraying loads of WD40 and carb cleaner helped too.

Removing the top part of the crank case.

Below are the bolts that need removing (M6 and M8 type bolts) but you also have to remove the flywheel. Behind the flywheel are 3 more bolts that need removing to get the top of the crankcase off too.

Removing the flywheel

To undo the bolt marked at 7 you need a flywheel holder. They're about £45 from the Honda dealership round the corner so I opted to make one myself.

It's not pretty but it did cost £5 for about 5 feet of steel bar at the hardware store. The swivel piece is about 6 inches long. Care must be taken using this. If the bolts are too long in the end pieces they may damage the coil behind the flywheel. The Flywheel bolt needs 80Newton metres to release it so if you have someone else there to hold the engine or turn the spanner it would make things a lot easier.

When all the bolts are removed from the top crankcase piece, the crank can be split by tightening an M6 bolt at 1 into and M6 nut at 2 at a housing on the front and back of the engine. Try not to lever at the gap with a screwdriver as you may crack the crankcases.

Before and after

The top crank case was scrubbed with brass bristled brush, toothbrush and 'Gunk'. Care was taken on the machined faces not to scrub with anything that could scratch them.

At 1 is a brown plastic seal that I've read on other sites breaks and has to be replaced. I've never had a problem with it though and it looked in pretty good condition.

At 2 I found a little puddle of oily water, it had bits of grit and there was a little amount of surface rust on the left hand bearing, but other than that the crank seemed as good as new. And it should do as it had only done less than 2000miles from the rebuild Crescent Suzuki did

A test to see if the conrod bearing are worn are to grab the con rod ends and wiggle them to see if there's any play. These were fine.

I cleaned out the oily water below the left side of the crank by shoving cotton buds in the gaps and wiping with clean clothes. Rubbed off as much surface rust from the left side bearing then poured 2 stroke oil on the bearings. Rotated the crank a few times checking for any roughness in the turning, then made sure everything on the crank was covered in 2 stroke oil

If I had to remove the crank I would've had to take the gearbox off on the right hand side but as it was fine I put the top crankcase cover back on and tightened the M8 bolts to 28N.M (Newton Metres) with a torque wrench and the M6 bolts to 10N.M

After getting the top crankcase back on give it loads of Gunk, beer and scrubbing with brass bristled brush and it looks pretty shiny. Making sure no gunk got inside the engine of course.

Pistons

Look nice don't they? They didn't look that good when they came out.

On top of each piston is either an L or and R. and an arrow pointing to the front of the bike. Left piston for left side of bike. Right for right side.

When you get a packet of piston rings you may notice the side profile of them is different. Although I couldn't see any difference but you'll notice when fitting the rings the fatter diameter ring won't fit in the top slot. See pic below. Number 3 is the top piston ring. Number 2 is the bottom ring and number 3 is a corregated type spring that is never pictured in the workshop manual and pushes out the lower ring.

In the slots for piston rings are little pegs, which you can see on the pistons above. The ring ends butt up to these pegs.

Rings are supposed to snap easily although I've been lucky so far. My way is to hook the middle bit of the ring and splay the ring outwards and push down when it's spread far enough.

Shining a piston is supposed to give more power. Polish as illustrated in the above picture. Up and down then side to side. Don't rub too hard. To polish the pistons and removing very light scratches the manual says to use 400 grit paper. I thought this was a bit harsh so used 600 grit to start with then changed to 800 grit paper and finally buffed with a Dremel and white, slightly fluffy buffing attachment. I've also heard that you're not supposed to polish above the bottom piston ring. Of course, I read this after doing it.

If you're keeping the pistons you've taken out of the bike you can scrape the piston tops of carbon deposit making sure not to scratch it. I found Gunk and a piece of wood worked. Use a toothbrush and Gunk to clean out the piston ring slots too.

If you need to rebore your barrels the info below is straight out of the workshop manual. I don't know what the writing means but the bore diameter is 54.08mm.

When I had the 4 rebores on my left hand barrel it was the 3rd attempt I decided to ask the people doing the reboring if they knew the correct bore diameter. They didn't. Welcome to the wonderful world of grey imports.

Fitting the pistons

Fit new small end bearing covered in 2 stroke oil.Put on goggles. Fit one spring clip to piston. Put piston in place. Slide in oil covered gudgeon pin. Fit other spring clip. Done!

Fitting the pistons in the barrels.

Fit a metal base gasket correctly with the word 'up' at 2 cut out of it pointing up as indicated in the pic. Make sure you have the little positioning cylinders in place around the bottom 2 studs indicated below at 1

Smear 2 stroke oil in the bore of the barrel then smear oil down the sides of the piston. make sure you're using the correct barrel for the side of the engine. The left barrel will have an Lon the side. The right an R.

Squeeze the top piston ring with your fingers and slide the bore onto the top of the piston and over the ring. Then squeeze the lower ring with your fingers and slide the barrel right down onto the studs at the bottom. Tighten M8 bolts to 25N.M with a torque wrench in the order indicated in the picture.

Fitting the cylinder heads

Smear a little 2 stroke oil to the head gaskets and fit them in the grooves. Take your time making sure they fit well as all my trouble with the burst gasket could've been because I didn't take my time fitting it correctly. Check which way the water pipe needs to face.

Use copper washers and dome head nuts as normal nuts will leak water and tighten in the indicated order below to 25N.M

Putting the engine back

Don't do it this way as you won't be able to bolt the back of the engine in to the frame as there's a bit of frame in the way. The lowest bolt at the back needs to be the first bolt fitted. Then swing the engine up and fit the rest.

When you've got the main engine bolts in, reconnect the 2 stroke pipes. Here's a daigram from the manual. The japanese writing near the top of the picture indicates this pipe goes to the left carb. The japanese writing near the bottom of the picture indicates the pipe goes to the right carb.

Make sure the earth strap near the back of the engine gets bolted back on.

Powervalve controllers

When I dropped the engine from the bike I left the cables, cable holders and funny shaped wheel hanging freely as I didn't want to have to readjust them again. The picture above from the workshop manual should give all the information needed to adjust them though. The hexagon nut at the top of the picture shows the orientation it should be at with the engine off.

The four cables in the picture don't seem to last very long and as they quite cheap it's worth replacing them every few thousand miles.

I'll buy a few sets hopefully soon and put them on sale on the VJ23 shop

Hoses

Before fitting the hoses back on I cleaned them inside and out. Making sure there weren't any deposit inside. I fitted them back on using new Jubilee clips from Halfords. They're heavier than the Suzuki ones but are a lot tougher built. The radiator went on after putting a hose in one end and blasting water through for a few minutes to get rid of any deposits and dirt.

I may buy a load of titanium hose clamps. I'd have to order in bulk. They'll be 40% lighter than steel hose clamps, stronger and corrosion proof

If you're interested mail me suggesting an interest and I'll buy some in

Oil

The grade of oil is SAE 10W40 and the bike needs 700ml

It needs changeing every 6000km

I use Castrol TTS for my 2 stroke oil. It's about a tenner a litre and seems to work very well.

Water

I used distilled water after tightening all the jubilee clips on the hoses, pouring in half a litre expecting water to come gushing out. when it didn't I filled it up. There are a couple of water traps on the bike. One is at the water pump and you have to undo the bolt in the picture. I found I also had to push the bike forward when it was in gear too so the pump turned round and squirted out some air.

On the back of the barrels there are bolts that can be undone to release air too.

1 stroke pump

with the 2 stroke oil tank connected undo the bolt indicated in the pic below and wait for some oil to ooze out. Then tighten.

I think the manual also suggested filling the little tubes with oil too. I couldn't quite tell as it is in Japanese. I bought and eye dropper(pippet) in the hope of filling these small tubes but found they were full of oil anyway.

Sugaya race pipes

My Sugaya race pipes have been covered in old engine oil for a couple of years. I did it on purpose as they're made of mild steel and would rust like mad in a damp garage. I cleaned them by covering with degreaser Gunk and scrubbing with a brass bristled brush. I cut off the lockwire that holds on the end cans and the metal pieces that butt up to the barrels and cleaned them separately. When the pipes were dry I used 400 grit paper and scotchbrite scouring pads to try and remove the flakey lacquer and rust. This took a lot of work and it still doesn't look like I've done anything. Then I brushed off all the rusty dust and used a hight temperature exhaust lacquer called Cif (below) to hopefully prevent them rusting. I found it online at a scooter shop. I bought 2 cans but one can was enough. It was about £4.

I have actually phoned around to get a set of these copied in titanium, and I've found a man who can do it. Obviously I'd have to talk it through with the man, because these pipes are very well shaped and not like those lobster shell style

If anyone is interested in titanium race pipes, send me a mail and I'll phone around. Maybe I can get the price down by ordering quite a few. I think there's up to a kilo weight saving through using titanium. It'll probably be grade2 titanium, which is quite grey in colour, but it'll never rust, ever!

Who knows, maybe I could supply titanium expansion pipes for all sorts of 2 stroke bikes. I pity the poor metal worker who has to make them though. They're such a complex shape. :)

They still look a bit minging but at least they'll hold off the rust.

This is how it looks with the cleaned pipes on. I've stuffed tissuen in the end of the cans as the shed is damp so I want as little moisture near my bike as possible.

Relay fix

When we tried to start the bike in (2003) and used jump leads from my brothers car a puff of smoke rose from the relay

I think looking back, the starter motor was worn out and that caused the relay to break. The relay cost £25

Looking at the white plastic block the relay goes into revealed the plastic had melted a bit and the spade connector inside needed replacing. As the plasic block is part of the loom I had to be very careful fixing it.

It may be possible to get a replacement connector from vehicle wiring products or Car Builder Solutions

Vehicle wiring products

Car Builder Solutions

I cut down either side of the part of the block the spade connector was in and pulled the connector out with long nose pliers. I carefully undid the connector attached to the wire. Then attached a 10mm spade connector. I'd rather an 8mm as the connector out of the relay is 8mm wide but for some reason they've not got an 8mm in Halfords.

I tried the starter and the starter motor turned intermitently. Poo! Off down Halfords and got some of that really thick red amp cable just in case the existing cable to the starter from the relay got fried. It can take something like 60Amps so it'll easily handle whatever the tiny battery can send through it.

Fitted the thick red cable, connectors tightly on the spades,tried turning the starter over. Same intermittent turning over.

I took starter motor off and looked inside. It was broken! A copper wire to the brush was burnt out. I tried to repair by soldering but I needed a new starter motor.

CDI Check

To check the CDI you need these diagrames and a voltmeter.

Voltmeter cost about £15 from a car spares shop. A Draper one is more robust than the one pictured.

Here is a link to a youtube video I did showing how to test a CDI.

How to test an RGV250SP CDI

The numbered diagramme may look back to front but that's the way it appears in the workshop manual.

When testing with a voltmeter the readings will be similar but will rarely be exactly like the readings in the diagrammes. If a reading comes out as zero, then something is wrong.

The pencilled settings on the diagramme are my readings when I tested my CDI. Notice they're different from the values in the daigramme but it's ok. That's just the way it is.

Getting the bike going

It took a while to get the bike running but I'll make a section on how to start a difficult to start 2 stroke. I let the bike tick over till it got to about 45*C and couldn't resist a ride around the block. I read somewhere that you're only supposed to do no more than 5000revs for the first 20miles so I took it easy. I noticed after my 5 mile ride that there was a little bit of a 2 stroke leak from somewhere on the engine casing. This may be down to me not using any sealant on the 2 crank halves. I'll have a look next winter at sorting that.

Here's a new side plastic I bought along with the starter motor. It was about £200 which isn't so bad considering it came with all the stickers on. I thought it would come blank so spent about £60 on stickers that were'nt needed. DOH! Still I may sell them on ebay sometime.

Conclusion

After riding the bike for several years now, I think the above engine rebuild turned out quite well. I've had little things go wrong over the years, like when switching to the reserve tank and little bits of rust blocked the hole. The 2 stroke leak on the crankcases stopped. The Sugaya pipes melt the undertray, which is a pain, and starting the bike is still a pain in the arse.

Thanks for reading