89 Cagiva WMX 250 2 stroke rebuild

[ononewheel]

My piston is burnt and my cyliner lightly scratched what should i do???


I have heard that a YZ piston will go straigth in and are a lot easier to get hold of is it true and what years yz's?


Also is the cylinder nikasil plated??

How much roughly does it cost a shop to replace gaskets, piston, rings, and hone or bore the cyliner or plate it???

Luke

 

[Timr]

Hey, my buddy used to have one of these bikes, it was kept in my garage so it was practically mine.

Anyway, this bike came back to the US in 1990 rebadged as a Husky. So, to get parts, you need to search for WMX 250 Husky parts at large Husky dealers. Many still have the old parts sitting on thier shelfs. The last part I purchased was a clutch cable from a dealer in Atlanta. This guy had tons of used an new parts.

Search for Husky groups, there are some on the internet, and they can help you out. They know where all the parts are.

Good luck.

 

[ononewheel]

Yeah, will do. Thanks!!

Do you know how to find out what age it is at all????

 

[TM-Frank]

I have a 89 Husqvarna WRK. When Cagiva bought Husky they planned to sell their 2-stroke MX bikes as Cagivas and the Enduros as Huskies, because the swedish 2-stroke line was outdated. They differed in plastics and the Huskies had a rear drum brake while the Cagiva WMX had a disk.

Piston seizes for the engine were (according to workshop manual):

A: 69,945 mm - 69,950 mm

B: 69,950 mm - 69,955 mm

C: 69,955 mm - 69,960 mm

D: 69,960 mm - 69,965 mm

E: 69,965 mm - 69,970 mm

F: 69,970 mm - 69,975 mm

But when I remember correctly the larger seizes (E & F) were impossible to find even back the. But maybe these data helps finding your Yamaha piston.
Cylinder is plated.
I could give you the vehicle ident. numbers for the Husky WRK models, but I doubt that they will help you to determine the model year of your WMX.

 

[ononewheel]

Is A the standard size, and b the 1 oversize, and c the 2 oversize???

Ive got a problem at the moment with getting the barrel off. There are two nuts that you have to undo on the outside of the cyliner and two inside the watercooling part of the cylinder. One i have undone but the other one is rouded off (worn) , Ive banging on a smaller socket, as only sockets can reach it yolu cant get a pair of stillsons on it. But the socket always slip, how can i get the nut off?

Help very much appreciated.


P.S just remembered that plated cylinders dont have oversize pistons. What are all the pistons?

 

[ononewheel]

PS my bike (89 i think) has a rear drum, but is a cagiva. hAS CAGIVA WRITTEN ALL OVER IT.

 

[TM-Frank]

Di I understand your profile correctly? You have already sold the bike or what?

Nevermind, the different piston sizes are needed because when they get their cylinders from their supplier thes are not all exactly of the same size. One may be 70,00 mm and another one is 69,99 or so. Therefore they have different piston sizes too, so they can equip each cylinder with a piston that gives the correct clearance.

When one of the cylinder nuts in the coolant cavity is rounded then you have a problem. I don't have any idea how you could get it off then. I always used a 14mm socket on which I reduced the outer diameter with a grinder, so that it fitted into the coolant cavity.

 

[ononewheel]

I was about to sell it i got the cheques through the post, and they were ****ing fake!!

My bank acocunt was closed and everything!!

If I can I would like to sell it because it would be easier for me to get some money for it and add some money and get a newer bike. What I ideally want is a newer 250 or something bigger (fav bikes CR500 and YZ 426), I want a two stroke preferably.

I just aint got the money to go and buy another bike, without selling mine.


Anyways while I have the bike im gonna do it up, make it run sweet, and look SWEET!

Yeah, the nut in my coolant chamber that keeps my cylinder on is round as a roundabout now!!

As people have tried putting littler sockets on it to grip it which have just slipped and worn away.

I need help!!!!

 

[TM-Frank]

Only solution I can think of at the moment is to drill out the bolt. That is really the worst place you could find for a worn out nut, man!

 

[ononewheel]

Tell me about it, if it was any where else Id whack a set of stillsons on. Ive seen some special sockets on the internet that apparently drip rounded nuts but they are like 30£, which would prob be the same price a motorbike shop would charge.

Dont know weather to get the special sockets and try.

I sprayed loads of penetrating spray on it so it would undo easily but this was after it was quite rounded.

Can the bolt that this nut goes on be undone from the bottom of the engine???

Ive also seen the gator grip sockets (with the pins in universal size) are they any good??

I need my bike working man!!

 

[TM-Frank]

I did a search on google for these gator grip things you mentioned. Saw them once in TV. Besides that I am a bit sceptical about them your problem will be that they dont fit into the water jacket.
You can't reach the bolt from below. First of all it is in a hole that is not drilled through (don't know the right english word - blind hole?!) and second - as long as the cylinder is still on the crankcase you can't split the case.

 

[ononewheel]

So I take it the only thing I can do is buy the special socket set for like 30£,

look at the website below please and tell me if these sort of tools will be any good.
http://www.koken-tool.co.jp/en/novelty/twist.html

Also, im gonna try using my impact wrench (manual hammer one), on one of these sockets if i get them as they are supposed to loosen them very well.

The last option will be to probally send it to a bike shop, I probally wont have the guts to drill the nut off.

Any other ideas at all?

 

[TM-Frank]

Hmmm, maybe it works, maybe not. Never had one of those and therefore can't judge them.
I would ask around in your local workshops first. Maybe someone has a tool to remove it or an idea how to do it.

 

[ononewheel]

I am gonnaphone some garages quick the only other thing i can think of ISSSSSS, get MR LOCTITE out, and loctite a socket to the nut but making sure not to touch the bolt. Would that work???

 

[Timr]

On One Wheel,

If your bike has a rear drum brake, then it's probably an '88 model, not an '89. I remember that this was the main distinguishing feature between the two model years. I'm not positive, but a lot of parts were interchangable from the '88 to the '89.

 

[ononewheel]

Wohoo, I got the nut off.

Still got a problem though.

My engine has got a latex glove in it.

Must of fell in over night. Because it was covering the cylinder and reed up. Its wedged between the cylinder and piston. Ive tried to pull the cylinder off but its stuck to the piston.

You can see a bit of the latex glove on the inside of the piston and in the intake.

What can I do to unseize it and get the glove out.

 

[TM-Frank]

To loose a latex glove in a narrow orifice can definetely be a problem! LOL

Try to tap the cylinder sides with a platic or rubber hammer. When you tap on the side in an upward angle it should come loose sooner or later. Probably just sticking on the gasket or maybe a bit of oxidation around the studs.

 

[ononewheel]

To loose a latex glove in a narrow orifice can definetely be a problem! LOL

Try to tap the cylinder sides with a platic or rubber hammer. When you tap on the side in an upward angle it should come loose sooner or later. Probably just sticking on the gasket or maybe a bit of oxidation around the studs.

The cylinder has already been lifted off about four inches. But as the piston is stuck in it, it only goes up till the piston is at Top Dead Centre.

Have tried pulling Hard, Harder, and even harder at the cylinder but that did not work. The glove goes from the reed to the inside of the piston.

Have also tried spraying loads of penetrating oil, lubricant and even 2 stroke premix oil on the top and bottom of piston and through the intake but this has done no good.

HELP!

Any ideas??

I expect that no one has got a glove stuck in their engine before but people must have had a broken circlip, broken rings stuck between the cylinder and piston before.

 

[ononewheel]

PS, the way i got the rounded off but out was with a "flute" snap-on socket that worked first time.

When i got the but out i noticed that it is actually round now with no angle or sides on at all lol.

Gonna frame it or sumit. lol only jk

 

[TM-Frank]

Hmmm, does the piston have a window on its intake side? Can't remember. Has the glove entered through that window and is now stuck in the upper rod bearing or what?
Have you tried to cut the glove with scissors or a sharp knife?
Next thing I can think of is burning the latex with a propane torch (make sure there is no fuel left).

 

[ononewheel]

Yes you are right!!! I. can actually see the whole now that it is covered by the glove. But I can see a little of the glove in the reed intake, and in the middle of my piston. As I have half pulled the cylinder but cant get it off.

So there must be a window that the glove goes through the intake into the middle of the piston(where the middle is cut out at the bottom)

Thats the thought I had, to burn it off.

I have tried pulling as much out as i can, maybe can get a little more out.

I have heard that getting the burnt rubber off the cylinder and piston will be a disaster, apparently yuou have to use fine grade emery cloth, wet and dry et cetera.

My idea, was to set it alight, pull the cylinder off. Blow out if it has not gone out yet.

Then wipe off as much as I can with a cloth whgile the rubber is soft.

Does that sound ok to you?

 

[ononewheel]

WOOOOOOOHOOOOOOO!!!!!!!!!

The engine is stripped!!!!!!


Now i need a new engine replate or rebore or overbore. I need a new piston kit aswell, whats the ama limit for boring 250's as i want to be able to race this.


I cant find a piston kit any where can anyone help.


How much does it cost for new piston, and rebore, basically a rebuild.

 

[TexKDX]

Getting the nuts off - might have to resort to a dremel, hammer, and chisel to cut the nut off. Try to keep from tearing up the stud threads in the process.

 

[ononewheel]

Getting the nuts off - might have to resort to a dremel, hammer, and chisel to cut the nut off. Try to keep from tearing up the stud threads in the process.

I have got the nut off. But where can I get a replacement nut? Also need a new engine mount bolt.

 

[TM-Frank]

Any Husqvarna dealer should be able to get a piston and all other parts for that engine.
The nut is a metric fine thread (M10x1.25 or so, I think) and should be available at any good equipped hardware store (or at the Husky dealer), same for the engine mount bolt.