Learning about two strokes [Archive]

WRT

17th January 2006, 08:38

I've learnt a lot about two strokes since getting the CR. I've learnt they are noisey, smokey, and shake like a crack whore with the DT's. I've learnt that they are a lot of fun to ride hard, and with a powerband comes on like a lovetap from a sledgehammer coupled with a throttle like a light switch, that they demand respect from the rider.

Last Saturday I learnt a few more things about them. I learnt that if they start sounding like an Italian tank running sans oil, then best hope your not too far from home. And that you cant believe the advertising propaganda - if you want to know how much your bike really weighs, try pushing it over a sand dune.

Also worthy of mention is that after pushing said bike over said sand dune, dont go playing paintball. You will be too tired to make rational decisions as to what constitutes a safe barrier to hide behind and will wind up copping some bruises as a result. See evidence attached.

So last night I thought I would learn some more. I had my first attempt at stripping down an engine in quite some time - my last effort was a rebuild of Morrie Minor thou engine, about a dozen years ago or more, and I gotta tell ya - this is a whole other kettle of fish. First impressions were good, two strokes are simple engines and very easy to disassemble. To the stage in the photos took an hour, and that included me finding my way, and cleaning all the bits that normally get missed while the bike is in one peice.

Looking a bit closer at the damage to the internals, my original hope that I might be able to get away with stripping the engine down in place proved somewhat diminished. Little chunks of metal are spread throughout the engine, through the chamber and into the exhaust. The piston is well shot, but thats not too upsetting, it was getting time for a rebuild anyways. However, the piston wasnt stuck to the bore (which, surprisingly enough, looks completely unscored), instead something down within the crank case seems to have been the bit that let go.

So possibly looking at a big end or something like that. I called it quits at the stage you can see in the photos, and it will be Wednesday night before I will have chance to do any more work on it. At that point I am going to pull the rest of the engine out of the frame, and strip it down good and proper. Meanwhile, I am going to head out to grab some lube for when the bill comes in for the parts.

Still, at least I'm learning something from it all I guess.

k14

17th January 2006, 10:00

Piston doesnt look too bad. As long as the barrel is alright you should be able to get away with a new piston and rod kit. I assume you can get a new rod and big end put onto the crank etc. If you can I think it should be less than $500 to get it up and going again.

What is this "sans" oil you are talking about? I'd recommend shell advance racing, never had any problems in my rs and the engines aren't too dissimilar.

WRT

17th January 2006, 10:08

The barrel seems to be ok, was pretty nervous about it after reading in the manual about how the coating on it means its a throw away job if you get it scratched. But it seems mint.

Still got to get into the bottom of the engine to check the big end and crank etc, but there were some fairly chunky bits in amoungst the detritus scattered around the engine (see the cup in the middle of the parts, those were just some of the bits I pulled out). Dreading to think what the damage might be down there, but I'm keeping my fingers crossed.

And by "sans", I was meaning without. She was making some almighty rattling noises. As soon as I heard them I pulled the clutch in and hit the kill switch. After that she was a no-go, first thing I checked was if she would turn over, but she was seized up tight as a drum.

sAsLEX

17th January 2006, 10:08

What is this "sans" oil you are talking about?

You never did pay attention in Latin did you, Mrs Atkinson would be most dissapointed

sans Pronunciation (snz, sä)
prep.
Without.
[Middle English, from Old French, blend of Latin sine, without and absenti, in the absence of, ablative of absentia, absence, from absns, absent-, present participle of abesse, to be away; see absent.]

WRT

17th January 2006, 10:10

Ixion

17th January 2006, 10:54

Nope, if it's a coated bore and no visible damage it's almost certainly good to go.

Piston's obviously a goner. You may or may not need to replace the big end, might just be bits of ally got into it and jamming.

Replace the crank seals as a matter of course, and the little end if it has a roller gudgeon. And make sure that you get ALL the little bits out of the bottom end AND the zorst, cos they can come back upstream and bite y'.

I've learnt they are noisey, smokey, and shake like a crack whore with the DT's. I've learnt that they are a lot of fun to ride hard,

Yep, that's two smokers !

and with a powerband comes on like a lovetap from a sledgehammer coupled with a throttle like a light switch,

Not all two strokes. Petal pulls like a train from 1500 rpm (about 55kph in top) , and the power is progressive all the way to peak - no discernable power band (that's the CV carbs, the earlier ones had more of a power band effect, still nothing to speak of)

cheese

17th January 2006, 11:04

ah if it's got mo major scores you'll be fine.

have fun splitting teh crank!!

guess you don't want to come out to woodhill this weekend then....... unless you manage to get it all doen really quickly......

BTW, your engine is so similar looking to my RM's it's not funny.

WRT

17th January 2006, 11:05

Thanks for that Ixion, funnily enough I'm actually looking forward to Wednesday night when I pull it all apart, just for the learning curve and also to see exactly what has gone wrong. Will definately check out all parts while I have it stripped down that far, may take me a little while to put it all back together because I am just working it all out as I go along.

Thing is (and this is a little too coincidental for my liking), the last ride I went out on the airfilter fell off somewhere along the way. Naturally, I only realised this when I get home and pull it apart to clean the sand and crap out of it. I suspect that the sand has gotten in there and really messed something up. Lesson learnt from that too - always make sure your filter is done up tight.

And the CR has only a tiny amount of power down low, but when that powerband comes on, make sure you got a good grip on the 'bars . . . the combo of 60 odd hp and around 90kg makes for a wild ride over rough terrain. God I love it . . .

k14

17th January 2006, 11:07

Hard to make out from this, but the barrel is nice and shiney, and seems to be scratch free. The surface is smooth as. Is there anything I need to do to it to check it other than just running my finger over it?
Yeah looks pretty sweet. The plating on them is nikasil, you can get them replated but you have to send it over to the UK somewere and the process isn't bulletproof, alot of the 125 guys just buy a new barrel when it wears out.

You should get a new little end etc with the piston kit. Do you know how long it has done on that piston and crank?

WRT

17th January 2006, 11:08

guess you don't want to come out to woodhill this weekend then....... unless you manage to get it all doen really quickly......

Yeah, I wouldnt hold my breath if I was you! I'm going to do my best, but havent even got to the "ordering parts" bit yet, so will have to see how things go. Plus have two weddings to go to this weekend, but if the bike was running rest assured I would be trying to slot a ride in there somewhere.

Be real keen to meet you up there for a blast one weekend tho. Been on a few road rides with KBer's before, but no off road ones yet.

WRT

17th January 2006, 11:11

Bang on there, K14. The barrel is coated with Nikasil, and the manual reckons its a throwaway if you scratch it, so I breathed a sigh of relief when I saw it looked pretty intact. Supposedly (if I can believe the previous owner) it should be sitting on around 50hrs on the piston now, but no idea about anything else in there. I'm thinking I might do a few bits on it while I am at it, like the reeds etc. Like I said, its all a learning curve for me, but still, good fun and I'm really getting to know the bike now!

Plus its a great time to clean all those hard to get to places! ;)

k14

17th January 2006, 11:20

You never did pay attention in Latin did you, Mrs Atkinson would be most dissapointed

sans Pronunciation (snz, sä)
prep.
Without.
[Middle English, from Old French, blend of Latin sine, without and absenti, in the absence of, ablative of absentia, absence, from absns, absent-, present participle of abesse, to be away; see absent.]
Shut up, didn't learn anything in that stupid class anyway :motu:

Motu

17th January 2006, 11:47

Sounds like a bearing has gone somewhere....little end,big end or mains,I'd say big end at a guess.Do them all anyway,they are fairly cheap,although there are gearbox bearings to factor into it when you strip it completely.I hope you can buy a big end - Honda has a habit of supplying ''crankshaft assemblies'',but being a supposedly race bike big end seperatly should be available.Good luck with the rebuild - and keep it clean please.

WRT

17th January 2006, 11:50

Cheers Motu, will be doing my best to keep it clean, and keep the sand on the outside from here on in.

At least once this is all done, I will know everything is right on the bike. And that if anything does go wrong that I can fix it myself.

Brian d marge

17th January 2006, 13:37

Hi there
Well I am on my 5th big end right now , Excuses ranging from crap oil to heavy right hand.
Hondas crank ...hmmmmm Hate them , they CAN be rebuilt , BUT you need a jig to assemble them as they have a tinny plate to take up the volume which is easy to destroy ,
Over here they just replace the crank assembly , Pro X do a reasonable Rod bearing assembly, If you can find a place that will rebuild a Honda crank,
( Me I am either going to ship the cranks to a place that will rebuild them Or make a jig myself and rebuild them Myself, - most likely this is the way I will go as I want to be self supporting by next year -

The power delivery can be made smoother by the use of a flywheel wieght. I made my own as the american one were expensive, I made my own for about 150 NZ, It really helps the power delivery in the tight stuff.

When rebuilding . BE CAREFUL with the power valves they are a PAIN to time ....The engine will run but it will make NO power , I have the earlier engine ( sticking with that cos its and sleeve not plated , and my are the slide type power valves , and they will open and close with gas pressure , making you think its timed correctly when it isnt !!!

When refitting the barrel DONT FORCE it , its real easy to bend things

If it is the crank let me know how you get on .

Ixons post is spot on , replace those crank seals as a matter of course , they are asy and cheap to do , Oh and the main bearings if you budget can stretch , the CR ones arent much cop.

Me ...I would like to put my 91 engine into the newer 2005 chassis ....anyone have a 2005 chassithey want to sell????

Stephen

WRT

17th January 2006, 13:43

Cheers Stephen, will be taking my time with it all, thats for sure. Not fussed about adding weight to the flywheel, I've come to love the way that thing makes power!

Sounds like the general consensus is to just get stuck in and replace as many of the bearings and seals as I can spring for. Will do guys, cheers for the tips.

cheese

17th January 2006, 15:53

yeah, I just went to get my tyre changed and I had to get a new wheel lock, thingy that goes over the spokes and new bearings and seals.

$200 thank you very much.

WRT

18th January 2006, 07:29

What tyre did you go for? I'm going to need a new set sometime soon. Got a lagoona cross thingy on the back, and its pretty damn naff.

cheese

18th January 2006, 07:59

I got a a second hand tyre, a M2 or something....

so that $200 wasn't including the tyre!!!!!!!

WRT

18th January 2006, 08:02

Ouch . . .

cheese

20th January 2006, 08:22

How is the bike looking? what is the damage?

WRT

20th January 2006, 08:31

Well, its been a bit of a saga, nothing too major, but will have some pics to show the damage shortly. Doesnt look as bad as I first thought, now that I finally have the engine out (the rear mount runs through the swing arm, and it was stuck in there good . . . finally got it out last night).

Looks like it was the piston skirt (if that is the right name for it) that broke. Only round the back, so that was why the engine was able to keep running despite the noises. Still havent got the crank case in peices yet, hoping to do that tonight. Will post up a more complete story shortly with a pic showing the damage.

WRT

20th January 2006, 09:14

Ok, so Wednesday night I get stuck into it again. I start seperating the engine from the frame. All goes well until I get to the mounting point right at the back, where it also seems to be the main pivot for the swingarm. The nut comes off without any trouble, but the bolt wont shift. I'm stood there swearing and cursing and generally beating the crap out of the thing and it just wont budge.

So I called it quits (had to go out for a friends going-away drinks), and just left it there with half a can of CRC sprayed down its throat. Yesterday I caught up with a mechanic mate and got a copper mallet (one of the ones with copper on one end and some other soft matterial at the other) and a punch like metal thing to knock it out. Only had half an hour to spend on it last night, but that was enough. Managed to get the bolt out and remove the engine.

Now that I have the engine out I can see everything a bit clearer, and round the back of the piston, the skirt (I think thats the name for it) has just shattered. I think what happened was some of the bits dropped down and got wedged in around the crank, and thats whats locking it up. When it happened, I was going round a berm, and just as I rolled on the gas this clattering noise started, so I yanked in the clutch, coasted to a halt and hit the kill switch.

When I had done a quick visual on it to make sure nothing was hanging off, I pulled the kickstart out to see if the engine had seized or not. And it seemed to have as it wouldnt budge. But I'm starting to think that it was just that some bits had fallen down and jammed everything up.

I spoke to Botany Honda yesterday, and the piston kit is going to be around $230-250, depending on what type of piston it is (apparently there is an A and a B model). A pair of main bearings is around $50 for the pair, and the seals are around $20 for the pair. Gasket kit around $100, again depending on what ones are needed. If the big end had gone, then apparently its "big biccies". So fingers crossed on that one.

So now the plan is to finish stripping it all down sometime this weekend, and then if its all as simple as its starting to look, then I might get away with just the piston kit and some gaskets. Give it a good clean and off she goes.

But what do you guys reckon, should I replace the main bearings/seals even if they seem ok? Would that be the wise thing to do? And what about the swingarm bearings, should I chuck a new set in there while I'm at it? They appear ok at the moment, but I'm wondering if it would be the logical thing to do while I have everything in peices (especially given the effort required to get the buggers out in the first place). Bearing in mind (ba dum chish!) that I'm not overly flush for cash at the mo, but also that if its going to save me time and money in the long run then I'm prepared to bite the bullet.

And one other thing, in the picture you can see corrosion around the studs, is this normal (for an '01 that gets ridden at Woodhill a fair bit admittedly)?

Cheers guys for all your help and advice.

- Walter

Motu

20th January 2006, 09:35

Whoa! Catastrophic piston failure I reckon....wonder what caused that? I've done collapsed pistons just by giving the crankcase a very,very,very good flush out,so long as it hasn't run for too long it won't have damaged the bearings,the alloy piston material is softer than hardend ball bearings.

But,though it's more work and money,personaly I'd strip it and mains and seals all through,and check gearbox brgs.Check your suspn linkage bushes too....never ends eh?

WRT

20th January 2006, 09:44

Cheers Motu. Could it be caused by sand getting in when the air filter fell off? I'm starting to have doubts about that now. Or is it more likely to be that the guy before me replaced it with an el-cheapo kit? Or maybe not at all???

I will be pulling it apart to see how things look on the inside. I did think about just flushing it out, but I just wouldnt trust it to get everything out, and plus I'm keen to make sure that there is no other damage in there.

On the flip side, I'm a bit nervous about pulling it all apart, incase the gearbox goes "sproing . . . " and I'm left with a mess I've got no chance of putting back together. While the manual has been brilliant so far, I am just learning all this as I go along . . .

On initial inspection the suspension bushes seemed ok last night, but I was in a hurry and I might just give them a closer inspection to double check. If they are cheap enough (and in stock) then maybe it would pay to do them at the same time.

Still, its all good fun and I am learning heaps about the bike as I go. Next time its due for a piston and rings, its gonna be a walk in the park!

Ixion

20th January 2006, 12:49

Gearbox should be straight forward- only thing that typically is a pain is the kickstarter spring. having said that, I don't know your bike. But two strokes are pretty simple. You may have some probs with the big nuts around the clutch area.

Is the broken skirt on the exhaust port side. I saw a piston shatter a bit like that once when the bike pulled a big gobbet of cold water back up through the zorst .

Definately replace the seals, main bearings is a bit more of a judgement call if cash is tight. Depends on how they feel (any clickiness, roughness , junk 'em) and how long they've run. Mains on a two stroke can run very long hours .

cheese

20th January 2006, 13:00

yeah next time don't bother taking the top of the cyclinder. You can leave it on and save yourself a head gasket ($20.00).

I'd just grease the rear swingarm to shit. Unless it has some play in it don't replace them. It's EXPENSIVE!! around $200. And you can always do it later. I just had a bearing collapse in my swing arm. Luckily it didn't get completely rooted adn it's still ok.

with the A and B pistons, they are for if your cyclinder is a bit worn (as I was told) the b is slightly larger (as I was told, may be wrong).

If you think that you can get all the bits of piston out with out spliting the case, might be ok, but could be a bit of a risk. I guess you could get a can of degreaser adn blast it in there while holding it upside down, but it's a bit of a risk..... if it was me I'd split it and make sure it was clean as a clean thing on clean day otherwise you may have to push your bike at woodhill again (and that sounds like fun.......)

Have you got a bearing puller? or would you just get the shop to do that bit? make sure you don't drop the crank either!!! a "mate" of mine did that to my old IT175 adn rooted it!! I've got one if you want to borrow it. it's just a $30 super cheap one, but does the trick.

That was odd how your piston shat itself. you are SOOOOO lucky it didn't bugger your liner comletely. Soooooo lucky!!

oh and get a price on a wiseco piston. they are normally a bit cheaper (and stronger!!!)

oh adn while i'm at it. I found that sometimes your engine mounts need to be loosened jut a little bit to help the swingarm bolt come out. Same with putting it back in. Made life a heap easier on my RM.

WRT

20th January 2006, 13:25

Thanks Ixion and Cheese, good info in there for a newb such as me (or anyone else that comes along in the future). Ixion - the piston broke on the back, away from the exhaust port. At a guess, if it had broken on the front it probably would have conked out from lack of compression? Dunno . . . but I will do the seals for sure, for $20 its probably a pretty wise thing to do!

Cheese - I dont have a bearing puller, but if they are just $30 from Supercheap then I might shoot down tomorrow and pick one up, handy to have in my arsenal of tools. Cheers heaps for the offer tho. And will make sure I am damned careful with that crank! Interesting about the A and B sizes, hopefully if I just go the same as what is in there then all should be sweet. With the swing arm, I'd removed all the engine mounts except for one a the front, which had the nut off but the bolt left in, just to support it, and still the little bugger wouldnt shift. I gave it a light grease and reinserted it again to let me wheel the bike out of the middle of the garage, and even then it was hard to get back in again. The bearings did look ok, will give a thorough inspection and as you mentioned, just pack it all up with grease. Sounds like it should be ok.

Just a quick question tho (and sorry if I sound like a complete novice with this - but hey, I am!). With the gaskets, if they come off and are intact, do they need to be replaced? The two I have removed so far, have both come out in one peice with very little resistance, like they haven't been cemented in place. So the question is two-fold, can I reuse intact gaskets, and should I be cementing them as I reassemble?

Cheers heaps for your help guys, much appreciated!

Brian d marge

20th January 2006, 13:36

Well it wasnt a crank then!!! ,
Starting from the swing arm . Make sure the pivot is ok they can bell out if you use a drift to remove them. Not for no reason people recommend greasing the linkages. ( I have a price list round here for a 2001 I think, I will look up the bits later on )

Cylinder head gaskets, I dont use one . I lapp the head to the barrel anduse a small amount of Loctight 577 master gasket just between the cylinder and the water Jacket.

Sorry I am rushing here as the wife is telling me to get out of bed !!

When splitting the crankcase YOU Need TO USE THE PULLER The cases are very soft and you WILL damage them if you try any other way.

Main bearings will drop out when the assembly is heated properly inthe oven .the will require very liitle help when the case is up to temp.

Pro x do a rod kit which WAS cheap , I dont know about now , BUT as Motu say alluminium is softer than the needle bearings of the crank so you could split the cases , do the mains , and flush the crank ( it hasa wee window inthe rod and you can seethe surface of the needle bearings , check for flaking and excessive wear)

Crank seal are compulsory ,,,

The big nut on the clutch is easier to do with an air gun , but failing that , jam the clutch drum with a rag, use a LARGE socket 1/2 inch drive ...with a Longish handle (put a bit of Strong pipe over handle ) then with a Heavy mallet belt the end of the handle ...Large leverage sudden shock .....that nut can be tight
I awlays do that nut while engine is in frame ,,,but sometimes I foget .....

Anyway glad to see it wasnt terminal !!!!

BTW Cr pistons crack on the thrust face ...due to excessive clearance , and a repeated shock , from where I havent found out yet ,,,,,,I have had 2 pistons with cracks in same place !

Stephen

cheese

20th January 2006, 13:47

you can reuse gaskets, but for teh $20 I'd just get new ones. outer cases are ok, but the main one the runs down the middle of the engine and the bottom of the cyclinder isn't worth the hassle of a leak. I reused the one around my kick starter, but then it leaked, was a wanker!! so I used some gasket goo. no leak now!!

oh and I'd just take the split case in to get the main bearings fitted in the shop. save you alot of hassle.

the other day when I pulled my engine out, I got two big bits of polystrene, threw a thowel of the lot and rested the engine on that . makes a nice easy place for it to sit. Oh and even after you have drained the gearbox oil, you still have more oil inside. So be prepared!!! messy messy.

you will have to take the cluch off too and the magneto, so you will definately need a bearing puller. They are a little wanker to get off, you have to hold it still while you undo the nut!!! little fucker!!! and then be careful of the keyway when putting it back on. If you have a manual it will be sweat. oh and take note of where the two lines mark up for the timing. otherwise bike will run like a bag of shite.

oh and another good tip, get a few boxes, adn put all your left hand side bits in one and all the right in another. it make it easier to put back together.

do you feel like you have opened a big old can of worms?

Motu

20th January 2006, 14:10

I don't know what sort of puller you need for the flywheel,I have some here....but a cheap trick with Honda's was to use the rear axle,it had the same thread.Most gaskets have a thermo setting sealer impregnated into the material,so even if they look perfect,they aren't.But if you are real skint a high quality silicon could be used....I'd be inclined to use something pretty good on the base gasket,you'll have more compresion with the new piston - what most don't realise is that you also will have far more crankcase compression,and I've seen just new rings blow out base gaskets.

Oh,the corrision around the studs is fairly normal,but not perfect - use anti corrosion grease on them.

WRT

20th January 2006, 14:15

Thanks guys for all the advice. Will be working on it again over the weekend and will report back with a progress update and maybe some more piccies.

Fingers crossed it will all go smoothly and I'll have it back together shortly!

cheese

20th January 2006, 14:38

yes then you can come practice falling off at woodhill with me.

Brian d marge

20th January 2006, 15:45

Just a thought
I have a good few CR engines around the places, 5 crank shaft assemblys crankcases , gearboxes etc ..and a digital camera ....
If you need any clear photos or more detail ,,,Just ask ...easy as
Even I ,,the Master of all cheap baskets ( I even make my own gaskets !! ) ..went out and bought the flywheel puller ..

When reassembling the flywheel, The KEy is only there to locate the flywheel , you need to lapp the taper with fine grinding paste as its the Taper that does the holding NOT the nut ,,IF you dont it WILL come loose ...( dont ask me how I know !)

I have parts books right through to the Me 03 19 heisei 8 which would be the 98 model ,

the prices havent change that much !!!!

can scan if reguired ?

Stephen My cr at the moment is a frame ..,,I have reshimed the Rebound Stacks in the front fork, for the heaviest springs 0.42kg/mm that Honda do ( would like 0.44)
Shortened the swingarm by 5mm Used a 125 one

Overhauled the rear shock ,,,twas Shagged !! ,,,So now its clean up time and back together ...

Stephen

cheese

20th January 2006, 16:01

Why shorten the swingarm?

Brian d marge

20th January 2006, 16:19

Our tracks are real tight and twisty you hardly can get into second gear ...I wouldnt call them MX tracks more like Supercross tracks

Stephen

Brian d marge

20th January 2006, 19:03

Just a thought while I was sitting here at work,,,eerrrrrr working The cranks on Honda CR The only reason they are diffiicult to rebuild is that there is a thin disk on the Crank Flywheels To take up the volume of the crankcase, and If I remember My BSA bantams the Horse shoe collar crankcase stuffers were all the rage and didnt really work.
I wonder how or what effect it would have If I removed said disk, Then I could freely rebuild the cranks.
I could imagine a little bit of throttle response, ( turbulance reduced , A slight loss in Hp ,,,Doesnt worry me )
I have an rooted crank round some where I will rip it apart and see......Then I could buy a stack of rod kits and Jet so lean it hurts baby !!!!:wari::innocent:

Just a thought

Stephen

cheese

23rd January 2006, 08:02

Oh god I was riding out on that RMCC farm ride and my crank seals wnet adn I was the local smoke machine! So I'm now going to give mine a go and split the case and shit.

Man the wife is PISSED at my bike cause it keeps breaking down!!! Rm means

Regularly munted
repair monthly
etc etc

dam money hole!!!

WRT

23rd January 2006, 10:27

Cheese - damn, sorry to hear about that mate, not good. Was that just this weekend?

Meanwhile, I went to Super Cheap on Sat morning, got myself a gear puller to remove the flywheel. The smallest they had was a 3" one, took it home and whaddya know - fidnt dit. The arms are just too big. So I shot over to the old mans place and had a go on his grinder for a bit (nothing like buying a brand new tool and feeding it into the grinder less than an hour later - but that's what you get for buying cheap tools, eh?). Took it home, still too big. Back to Dad's (he lives about a 25min drive away, dammit) ground it down some more. Took it back home, and bingo! The arms now will fit under the flywheel.

So, should all be plain sailing now, right? Not likely . . . now when I reassembled the arms back onto the triangular bracket at the top of the puller, the bracket pushes the arms too far apart. So now I need to go back to Dads, use his grinder again (this time on the bracket) just so I can get this bloody flywheel off.

So, no progress to report . . . and I'm not doing another special trip over to the old mans to use his grinder, I'm over his way on Tuesday after work so will do it then. Probably best that the engine and I have a little cooling down period anyway, I was about ready to start disassembling it with a hammer!

cheese

23rd January 2006, 10:50

LOL I know that feeling.

I'm going to try to do just the seals and see how it goes.

little fucker.....

cheese

23rd January 2006, 12:37

Hey WRT, we could both do the 4 hour with RMCC and at least one of our bikes would finish.... LOL

http://www.rmcc.co.nz/event.php?id=70

WRT

26th January 2006, 09:37

Ok, so after much wailing and gnashing of teeth, I managed to get the flywheel off last night. Now I've just got to find a way to hold the drive sprocket while I undo it, and I should have the case cracked (badum-chish!). Its been no small job for a simple fella such as myself.

Unfortunately thats all the time I've got to spend on it this week as I've got the day off tomorrow to head down the line for the long weekend. Roll on next week, will keep you all posted as the saga continues . . .

cheese

26th January 2006, 10:21

lol I tried to see if my 3 inch bearing puller would fit last night and guess what???? Just fits!!!

No grinding for me!

WRT

26th January 2006, 10:37

Thats a shame, cause after all the practice I got making my puller fit, I'm now the Grinding Master!

cheese

26th January 2006, 10:59

I may have to take of the timing dooflicky though.

apparently the easy way to get those nuts off is with an air tool..... I don't have one though...

Kickaha

26th January 2006, 17:42

Now I've just got to find a way to hold the drive sprocket while I undo it, .

Engine still in the frame it is easy, put it in gear and have someone hold the rear brake on, while you undo it

out of the frame, shoot down to the local tyre store and get them to undo it with an impact gun or wrap the chain around the spocket and clap visegrips onto the chain just behind the sprocket to hold it while you undo it

cheese

26th January 2006, 20:37

Oh!!! So easy!

Legend!

k14

26th January 2006, 20:58

Could try an impact driver too. That worked to get the impeller for the water pump on my rs off. Thats geared straight off the crank so was impossible to stop spinning when i tried to undo it.

WRT

31st January 2006, 07:40

Two steps forward, one step back . . .

Ok, didnt get much time over the weekend as I went away on Friday and only got back last night. Still, on Thursday night I managed to get the sprocket off, I used a large pair of slipjaws to hold it while I removed the bolt. Kickaha - that first method to remove it while still in the frame is a good 'un, thanks for that - I'll add it to my list of things to do before removing the engine from the frame in case I ever have to do this again.

So now that's off, I undo all the crank case bolts, then get out my nice new puller from Super Cheap, and whaddya know - the bolts dont fit into the crankcase. I looked at using the bolts from the engine, but the heads on them are too small and the puller wont hold them. So now I've got to track down another, smaller, puller. Will be off to 'Rip Every Poor C*nt Off' tonight to see what they have.

Still, goes to show how hard these little jobs can be when you dont have all the tools. At least by the time I have finished I'll have a decent tool box kitted out!

Sketchy_Racer

31st January 2006, 08:34

WOw!!!!!1

this sounds serious!!!!

Im gonna be pulling my KDX apart soon i can tell. The amount of engine noise is outta this world!! (me thinks its shagged Mains)

luckily, i now know what to undo with the engine in the frame ;)

good luck with it

-RG

cheese

31st January 2006, 14:46

Don't ask me about shagged main bearings!! Grrrrrr

WRT

31st January 2006, 15:30

Mate, you are having as bad a run as I am. Hope you get it sorted.

WRT

1st February 2006, 10:34

Success! Got the case apart, after some gentle persuasion with a hammer. Cranked it up with the case puller, then a few small love taps and it all came apart.

Couple of questions tho. I want to give it all a good hosing out in there to make sure all the little bits are gone - whats good to use for that? Would CRC do the job?

Also, I'm told that there should be an A or a B on the underside of the piston - but there aint, if there was then it must have been stamped on the bit that broke off. How do I know what piston kit to order?

And finally, I'm thinking of getting a wiseco kit as many riders have recommended them to me. Where's a good place to source them locally?

As always, thanks for your help guys!!

- Walter

Sketchy_Racer

1st February 2006, 13:35

nice,

IMHO

get a wisco piston kit.

they are better than Oem and can actually cost less.

WRT

1st February 2006, 13:53

Sweet, thanks for that, any idea where I can score one from? Gonna start ringing round a few places in a couple of hours, do Motomail, AMPS or Cycletreads sell them?

Brian d marge

1st February 2006, 14:02

They look the same as my 91 cases , You have an 01 ????

anyway that simple green or washing up liquid an for the ulitmate , simmer in large pan with washing up liquid ..

the dry ( in oven very low heat ) spray wit crc to stop corrosion

failing that kero ( I use gasoline then kero as Gas cleans easier than kero )

Look on the top of the piston for the A or B ... but std pistons Someimes dont have the mark ( mine dont )

I have always measured mine and selected the best fit ..

Stephen

WRT

1st February 2006, 14:07

Thanks for that Brian, no mark on the top, so might have to measure it. Might give the gas then kero trick a go, sounds like me (have got plenty of both of those at home) then follow up with a dosing of CRC like you mentioned.

Kickaha

1st February 2006, 17:02

Also, I'm told that there should be an A or a B on the underside of the piston - but there aint, if there was then it must have been stamped on the bit that broke off. How do I know what piston kit to order?
- Walter

If you wont to do it properly first get the bore measured and work out what piston size you need off that

WRT

2nd February 2006, 07:26

Righteo - found the answer. For anyone else that has trouble working out which type they have, the model is actually stamped on the outside of the cylinder casing, as it happens mine is an 'A'.

Also, phoned round some places yesterday afternoon to try and track down a wiseco piston kit, and had limited success. Motomail and AMPS dont stock piston kits full stop, while the guy at Cycletreads was quite helpfull and while they dont stock them, he said he can get a wiseco kit in for me and will be phoning me back this morning with a price. I also spoke to Botany Honda (they are the ones that suggested to look on the cylinder casing, so big ups to them) who originally priced up the OEM kit for me as being between $235 and $250, depending on which type it was. When I asked about wiseco ones, they said that they can get them in, but that they are "way" more expensive than the OEM ones. Which seems strange to me, as everyone else seems to think that they should be cheaper and they are available brand new on eBay for around $130 NZD plus freight.

I'm kinda hoping to get one locally, even if it does cost a little more (so long as its not double the price, in which case I'll buy online instead) so will have to wait and see what price Cycletreads comes back with. Will keep you all posted.

cheese

2nd February 2006, 08:35

was there many bits of crap in the bottom of the case?

WRT

2nd February 2006, 10:08

Yeah, there were a few! Not enough to make up the full missing peice of skirt, but enough to cause serious headaches. I'm also going to have to give the expansion chamber a damn good clean out as Ixion mentioned, as I suspect there are a few bits still down inside that.

Oh joy . . . would be nice if I could find more than an hour at a time to spend on it too, I reckon (aside from waiting for parts and having to manufacture the tools to do the job) I could have had the entire job done in less than a day.

Brian d marge

2nd February 2006, 13:57

The entire bike takes 8 hours from bare frame and diassembled Engine.

Thanks for finding out whhere the stamp mark is ( Ill still measure though !)

Interexting note , The Pro X rod kits are about 210 NZ ( 1600 yen ) but the complete crank assembly is 20 000 yen ,, will find out in a few min when I go to bike shop

Well your nearly there ...good luck , keep exercising or it will hurt the next morning on that first ride !!

Stephen

F5 Dave

2nd February 2006, 14:46

Think Northern or Whites are the Wiseco distributors

Just got a 125 piston & it was , erm, maybe $130, heck can't remember, but something like that, but it was old stock. Just on the wiseco site today looking for when I will do the GasGas as they are std. Think that was $130US

try http://www.wiseco.com can order on line or just get an idea.

There you go $120.87US say worse case $30 shipping, to NZ at .68 that's $220.

Brian d marge

2nd February 2006, 15:36

Sorry folks your goin to hate this ...New fork springs, new chain, 1 almost new rear sprocket and new front sprocket

all up 100 NZ ....man the original honda spares can be a bargain sometimes !!!

A very happy Stephen

WRT

2nd February 2006, 16:02

Man what a mission. Ok, Whites are distributors only, so cant purchase through them. Northern arent stockists, but they put me onto Power Sports (good on them for suggesting someone who could help me with something that they couldnt). Power Sports again are distributors, but they quoted me a price that I should be able to get through any of the local retailers - they suggested Spectrum. Apparently regardless of A and B models, Wiseco just do the one kit, called the 702, priced at $221 incl. GST.

However, on trying to get hold of Spectrum, their number just comes up engaged, so will just have to keep trying. Meantime I'm still waiting for Cycletreads to get back to me, I spoke to Mike there this morning who has been quite helpful, he quoted $243 for the Wiseco kit but when I asked if that was A or B he said he'd have to go check and he hasnt gotten back to me yet. Will try to get hold of both Spectrum and Cycletreads tomorrow, but I have to admit that I am tempted by eBay, seeing as its only half the price I could also order a few other bits like reid valves and so on, and get way more for my buck.

Which brings me to my next point, how often should the reid valves be replaced? Should I be doing them at the same time?

And F5 Dave, thanks for the pointers, you got me heading on the right track with that info.

F5 Dave

2nd February 2006, 16:09

Carefully inspect the reed valves. Any damage, fraying or delaminating will be obvious. They should lie flat on the valve housing.

Brian d marge

2nd February 2006, 16:27

My parts catalogue for the ME03 19 ( 1996 ) shows

Crankshaft ass at 25000 yen ( 325 NZ )

piston complete ( 5000 Yen A or B NZ 65 )

reeds 500 yen each x 2 13 NZ total

Now this catalogue is a few years old , but the prices havent risen by that much 30 percent is my guess

ie the springs I bought this morning were 2150 yen catalogue and I paid 3150 yen

This probably doesnt help , but might give an indication to the cost of Genuine spares ...

Stephen

cheese

2nd February 2006, 21:48

Teh guys at Spectrum are hell busy fixing my RM. LOL BUt they are flat out. Try in the morning.

Go for eBay! Wiseco or ProX.

WRT

10th February 2006, 09:54

Ok, got some parts on order, they should be here on Monday arvo. I did go through Spectrum for them, $220 for the wiseco piston kit, $110 for the full gasket set and $25 for the seals. Bearings were going to be $40 apeice tho, so have flagged that and will try to source my own ones seperately. Worst case scenario, the current ones actually arent in bad condition so might leave them in.

And a little plug for Spectrum because they have been most helpful and on the ball - call Grant on 489 5355.

F5 Dave

10th February 2006, 09:59

I'd leave the gearbox bearings alone if they seem fine. Output (by sprocket) can get a hard time if chain too tight but usually last ok if oil ok.

The mains always need replacing if you have puled them out + 250s will kill them (can't remember all the thread) & they are big so get expensive, bought some yesterday ~ $25ea from Serco or any decent brg shop. C3 clearance.

WRT

10th February 2006, 10:05

Cool, thanks for the advice Dave. I'm going to do a run around and see if I can pick up some, I've got a mate who's a car mechanic so I'm going to lean on him to see if he can source some for me. Fingers crossed. Just have to get the numbers off the old ones when I get home tonight.

F5 Dave

10th February 2006, 10:11

Often they are cheaper with the dust seals fitted, but you just flick those out & wash the grease away with kero.

To insert throw brgs in the freezer for an hour or so. Heat cases. Push in with press or tap in with hammer carefully & always use a big socket or something to press only on the brg outer. Seals go in last.

Cases can be pulled together using longer bolts gradually pulling cases in. Crank will be pulled to one side & needs a smack (nut over thread to protect end) to centralise & free, will make a crack noise often. Check gearbox operation before & during pull together. Sometimes need a turn to change gear. Detent star & follower will need to be fitted.

cheese

24th February 2006, 09:38

Come on WRT, sort that bike out! LOL

WRT

27th February 2006, 12:55

Well, a bit of an update for ya. After I managed to get it all back together the weekend before last (working till about 11pm on the Sat night to try to get out for Sundays ride), the engine fired up first kick (very first kick, was stoked at that) but the gearbox seized up during the "test" ride down the driveway. Fortunately I was at very low speed, and just skidded to a halt. Couldnt get it out of gear, so had to carry the back end of the bike all the way down the drive to get it back into the garage to work on.

That was where my problems started. Had to mess around for a while getting the chain off because the joiner was in behind the frame. However, all up, it only took me around an hour on the Sunday morning to get the engine out of the frame and stripped down to the point where the crank case can be split. The next three hours were spent coaxing, begging, pleading, smashing, bashing and crashing at the casing trying to get it apart. It would appear that the 'box had selected two gears at once, which caused it to twist up and grab the casing. After the three hours I only had the casing split less than half an inch apart, so before I wound up smashing it to peices I put it on one side and called it quits.

Was away from Thursday to yesterday, but I did get a mechanic mate of mine to take the engine and I got a txt of him just about half an hour ago saying hes managed to get it split. Turns out that I missed a thrust washer out somewhere along the way.

At least now I know what needs to be done, and it shouldnt take too long (assuming I can find the missing washer . . .) to get it all back together.

Sketchy_Racer

27th February 2006, 14:29

bugger,

well at least you know it goes ????

This has been a bit of a learning curve for you eh ;)

WRT

27th February 2006, 14:30

Its taught me an amazing amount about anger management, thats for sure!

Sketchy_Racer

27th February 2006, 15:10

lol,

yes im sure it has.......

I know from doing my CBR about patience now........and a little bit of anger management.

still good fun tho IMO

WRT

27th February 2006, 15:17

Yeah, will be glad when its all back together (again . . .). Getting to know more than I ever thought I would about two strokes!

cheese

27th February 2006, 15:39

LOL for sure!

Then we can go for a ride at woodhill (when it opens again) I'll take a tow rope....

WRT

27th February 2006, 15:43

LOL - sounds like a plan. Hopefully we wont need it tho . . . after all this time, energy and money, I'm kinda hoping it might just run ok for a while!

cheese

27th February 2006, 15:48

same with the RM!!

Fucking two strokes.....

Wellyman

27th February 2006, 15:53

Two strokes are intresting thats for sure. just be easy while rebuilding it and you should be fine. make sure you put in plenty of oil again after the rebuild. and if using forged pistons rember to run in as per the instruction manuals
WM

Motu

27th February 2006, 16:02

Doesn't really matter if it's 2 or 4 stroke as far as the gearbox is concerned,any engine with a vertical split case is the same - put them together,and then wonder where the hell all the bits left over go.First thing I do when the cases are together is check selection of all gears.

WRT

27th February 2006, 16:36

Funny thing was it was working to begin with. Then it found 1st by itself while I was pushing it, and when I took it for a test ride I managed to go 1st-2nd-3rd-2nd and it was when I went back down in to first that it locked up. Think I must have wound up with both 1st and 2nd for a bit there. Still, at least it didnt happen while I was in third! Might-a made a few bits go crunch then . . .

Ixion

27th February 2006, 16:54

Second thing . First thing is check rotation of crankshaft !

WRT

27th February 2006, 18:29

Just been looking at it all, and 1st gear has dropped a tooth. Dont suppose anyone has a spare first gear for a 96-01 CR250?? Just need the gear off the countershaft, the one on the main shaft looks ok.

Bugger . . .

Speaking of which, what do you guys reckon, could I get away with a second hand one from a wreckers, or should I buy new? I'm a bit nervous about how much this might cost, and what other parts I may have to buy along with it. Will be phoning around the dealers getting prices tomorrow.

Motu

27th February 2006, 19:08

Second thing . First thing is check rotation of crankshaft !

Hah! I was actualy going to put that,but it didn't seem to find it's way onto my post,I suppose I was thinking gearbox at the time.

I'd preferably go for a new 1st gear - 1st gets the biggest punishment on a dirt bike,slamming down without the clutch into those tight turns you overshot.It'd have to be a minta if second hand.

cheese

27th February 2006, 20:19

Oooh bugger...

you don't do things by halfs at all do you. piston in pieces, loosing teeth...

WRT

28th February 2006, 07:12

Oh yeah, I just seem to love making work for myself! Ah well, needed a good project anyways. Gonna phone around a few places today and get some prices.

cheese

28th February 2006, 07:24

see what wellyman can do for you and there is a wrecker in tauranga that has lots of MX bits.

cheese

28th February 2006, 07:27

Sorry I just found them, Bailey motorcycles and dismantlers 06 278 4726 - in hawera.

WRT

28th February 2006, 07:28

Cheers mate, and Wellyman - are you out there?

WRT

1st March 2006, 14:11

Dammit, this isnt looking good. Spectrum priced it at $233 for the cog (ouch) and it has to be ordered from Japan - it could be here in three weeks, thanks very much. Botany Honda didnt sound too confident on getting the right part, and I had to fax through a copy of the manual showing which part it is. Even then, they still wanted me to count the number of teeth (should be 27, mines only got 26 tho - hence the problem), which I did last night and advised them this morning. Still waiting to hear back from them with a price.

Baileys and Atomic have not wrecked a CR, so there goes that idea. No sign on ebay (US or UK), and trademe decided to tease me by having a whole YZ250 gearbox for $150. Nothing for a CR tho . . .

Anyone got any bright ideas? Any other places I could look? Better yet, do any of you guys have a spare CR gearbox floating round somewhere?? Brian d'marge? Anyone?

Failing that, I've got the "spare" tooth, would there be anyone that could tack it back on? Call me cynical, but somehow I doubt a spot of superglue is going to do the trick this time. Never the less, I'm getting desperate.

WRT

1st March 2006, 14:59

Alright, got some good news to report - MattyC suggested takanini wreckers, who hadnt wrecked a CR before, but he told me to ring EconoHonda in Tauranga - $148 later and I should have it tomorrow morning. Cant wait, all going well I can start assembling again tomorrow!

cheese

1st March 2006, 15:18

I forgot about them!!

Go CR go!

Brian d marge

1st March 2006, 16:48

WRT

2nd March 2006, 07:32

Maybe I should have been more patient! Ah well, not to worry - I've got that one coming from Econohonda now, also had a PM from Wellyman offering to track one down for me, but cheers heaps for the offer anyway Stephen, its awesome the way KBer's all help each other out like that.

On ya guys, bling coming your way!

cheese

3rd March 2006, 14:56

Ha ha tell us what happened now!

WRT

3rd March 2006, 15:09

Alright, just for your amusement . . .

The part arrived from Econohonda (big ups to those guys, great service and price) I started to put it all back together, didnt I? Got as far as putting the clutch housing back together when I managed to twist the head off one of the bolts that hold the springs in place.

Good-oh.

So now I'll have to remove the clutch basket and take it in to someone to have the remains of the bolt drilled out - anyone able to recommend somewhere?

I guess I just wasnt cut out to be a mechanic.

cheese

3rd March 2006, 20:20

you can always laugh when it's not you though....

Sketchy_Racer

3rd March 2006, 20:25

Man this is going from bad to worse.

Just keep hanging on. It will work out.

This reminds me alot about what i had to do on my CBR when i got it.

The_Dover

3rd March 2006, 20:26

I can manage in two strokes.

I just have to abstain for a a few weeks.

cheese

3rd March 2006, 21:02

Fuck mate that pic has got to be teh fattest ass ever!!

WRT

6th March 2006, 12:29

Well, some success over the weekend. I finished assembling the bike on Friday, and on Saturday I got a mate to give me a hand and with a bit of persuasion the snapped off bolt came out. After a bit of testing up and down the driveway, all appeared to be alright.

On Sunday I went up to the WMCC Riverhead trail ride, and met up with Cheese up there (good to finally meet you mate). The bike made it through the day without leaving me stranded anywhere, seemed to be starting fine and was for the most part running really well.

The only thing is, every now and again, it was like the bike didnt want to run up into powerband. The midrange would still pull well, but at the point where the powerband normally kicks in, it was like the bike just ran out of revs. Kick it up a gear, and it would surge forward again, but felt like it was running up against a wall just as where it would normally come on song.

But this wasnt all the time. Sometimes, it would run fine, I had some faster runs on some of the straights where it was going beautifully, but then other times it would stop revving just short of powerband.

So tonight I'm going to look at the powervalve, I gave it a good clean while the engine was stripped down (it was covered in gunk) so I'm going to make sure its not sticking or something.

Its been a fair old mission, but god it was good to get out for a ride yesterday . . .

k14

6th March 2006, 17:22

The powerband running like that could mean its too rich in the carb. Did you clean that out while the engine was out? Could be the float sticking or something like that.

Oscar

6th March 2006, 18:04

WRT

7th March 2006, 07:29

Brian d marge

8th March 2006, 15:30

Thanks k14 and Oscar, actually I didnt clean the carb while it was out, if it aint broke and all that. Might look into it though, will check to see if the float is sticking.

Am tending towards the powervalve theory at this stage, but didnt get chance to look at it last night as I got called back into work.

I have no experience of stuffing up the later engines such as yours BUT I HAVE stuffed up mine a few times, My one has the gilllotine type power valves and they can be a pain to put back together, They will LOOK like they are working but actually that is the gas pressure opening and closing them ( If I remember it also ran flat like yours ,,but that was a long time ago and my memory plays tricks )

Stephen