KLX250 Needs rebore

[PBMGold]

Looking for recomendation of best value and quality work to have KLX250 barrel rebored, new piston and rings. Currently has 30 psi compression. Been quoted about $520 from Team Moto to have barrel re-sleeved and supply piston and rings. Labour to dissasemble and then reassemble will be extra.

Also not sure to take it out to 280cc overbore as I understand they are almost powerful then, although I do understand this may put pressure on gearbox and at this stage I have no idea of the condition of the gearbox.

Lastly, the head spark plug has been stripped and I had been told that inserting a helicoil is not the best practice but insert a sleeve that is welded in is a more permanent fix.

All comments gratefully accepted....except for the ones that say get rid of the KLX and get something that has power in the first place.

[Davey Crocket]

A time sert is what you need for the stripped plug hole thread. You may find you will need to do some work on the head as well, minimum a valve grind [if possible] and new valve seals. It would be cheaper just to rebore it to a bigger oversize. You wont know what size until you strip it. If the motor doesn't run [and you haven't had it running] you could be in for a world if hurt with the condition of the rest of it.

[GMC]

Resleeve the barrel?
Is it past it's last oversize?
If so then you should probably look at the 270 kit as (if my memory is correct) I think it can be bored to this from the stock liner.
Someone else may remember better than me.

The pressure from the power pulses (cough cough) of the big bore on the gearbox will depend on hard hard you ride it.

[sleepy]

What year KLX do you have?

[Simo63]

Resleeve the barrel?
Is it past it's last oversize?
If so then you should probably look at the 270 kit as (if my memory is correct) I think it can be bored to this from the stock liner.
Someone else may remember better than me.

The pressure from the power pulses (cough cough) of the big bore on the gearbox will depend on hard hard you ride it.

Good point Geoff.  Some say that with the 270 kit fitted, the horsepower output of the KLX250 reaches into the double digits ... as high as 12 hp at times ...

[CRTAD313]

You could try the guys at Serco in Bris. Team Moto are probably sending it there anyway.

[matcho mick]

http://forum.ozvmx.com/index.php?topic=102.0

[sleepy]

If yours is as Matcho Mick last post link you may want to get back onto Team Moto as I think they are quoting you on the piston and sleeve for the 1990 model bike.
I had a quick look through the common sources and can't find a listing for the older motor, could take a bit of searching to find an oversize piston. I would guess it would have a cast bore which can be bored if you can find a piston. You would need to now what size it is now before looking.

[PBMGold]

Thanks Sleepy. Team Moto think they have an original standard piston and rings still in stock and if they pull it down will then discover the extent of work required. I might get away with just a hone. Guess I was thinking worst case scenario that if the bore is scored and it was appealing to increase the capacity. I did think 12 horsepower was a bit harsh. Don't lawnmowers have more than that?

Well picked CRTAD313 about Serco doing the work. Yep Team Moto were just going to ship it out.

Latest quote is if re-sleeve up to $1000.

Just not sure if that is a reasonable price. I'm no mechanic, total numpty with a spanner so would prefer to have an expert do the work.

[GMC]

Don't understand why the talk of such big dollars, the 81 KLX is basically the same as the KL 250 motor which are dime a dozen
They had a steel sleeve and oversize pistons

They were originally a 70mm bore
Serco list pistons at 70, 71, 72, 73, & 76 (not sure if they have all in stock)
check under KZ100
The 73 makes 268cc
the 76 makes 290cc

The 76 piston will require a bigger sleeve and the cases machined out to accept the bigger sleeve which will be dollars.
Can't remember for sure about the 73 piston but I thought it could be bored with the original sleeve.
If your bore is that stuffed it will be way cheaper to find another barrel and just go a straight rebore, as I said the KL barrels were the same.

Part # = 11006-1002
Part Description = CYLINDER ASSEMBLY,FLAT BLACK
Model Count = 6
KLT250-A1 82 250 KLT250 UTILITY 3 WHEEL ATV
KLX250-A1 79 250 KLX250 OFF ROAD
KLX250-A2 80 250 KLX250 OFF ROAD
KL250-A3 80 250 KL250 DUAL PURPOSE
KL250-A4 81 250 KL250 DUAL PURPOSE
KL250-A5 82 250 KL250 DUAL PURPOSE


Part # = 13001-1005
Part Description = PISTON,STD
Model Count = 24
KLX250-A1 79 250 KLX250 OFF ROAD
KLX250-A2 80 250 KLX250 OFF ROAD
KL250-A1 78 250 KL250 DUAL PURPOSE
KL250-A1A 78 250 KL250 DUAL PURPOSE
KL250-A2 79 250 KL250 DUAL PURPOSE
KZ1000-C4A 81 1000 POLICE 1000 POLICE
KZ1000-A1 77 1000 KZ1000 STREET
KZ1000-A2 78 1000 KZ1000 STREET
KZ1000-A2A 78 1000 KZ1000 STREET
KZ1000-A3A 79 1000 KZ1000 MKII STREET
KZ1000-A4 80 1000 KZ1000 MKII STREET
KZ1000-B1 77 1000 KZ1000 LTD SPORTBIKE
KZ1000-B2 78 1000 KZ1000 LTD SPORTBIKE
KZ1000-B3 79 1000 KZ1000 LTD LTD STREET
KZ1000-B4 80 1000 KZ1000 LTD LTD STREET
KZ1000-C1 78 1000 POLICE 1000 POLICE
KZ1000-C1A 78 1000 POLICE 1000 POLICE
KZ1000-C2 79 1000 POLICE 1000 POLICE
KZ1000-C3 80 1000 POLICE 1000 POLICE
KZ1000-D1 78 1000 Z1-R STREET
KZ1000-D3 80 1000 Z1-R STREET
KZ1000-E1 79 1000 KZ1000 ST STREET
KZ1000-E2 80 1000 KZ1000 SHAFT STREET
KZ1000-G1 80 1000 Z1 CLASSIC STREET

[Nathan S]

You could buy a whole KL for less than the cost of a resleeve...

[sleepy]

Don't understand why the talk of such big dollars, the 81 KLX is basically the same as the KL 250 motor which are dime a dozen
They had a steel sleeve and oversize pistons

They were originally a 70mm bore
Serco list pistons at 70, 71, 72, 73, & 76 (not sure if they have all in stock)
check under KZ100
The 73 makes 268cc
the 76 makes 290cc

The 76 piston will require a bigger sleeve and the cases machined out to accept the bigger sleeve which will be dollars.
Can't remember for sure about the 73 piston but I thought it could be bored with the original sleeve.
If your bore is that stuffed it will be way cheaper to find another barrel and just go a straight rebore, as I said the KL barrels were the same.

Part # = 11006-1002
Part Description = CYLINDER ASSEMBLY,FLAT BLACK
Model Count = 6
KLT250-A1 82 250 KLT250 UTILITY 3 WHEEL ATV
KLX250-A1 79 250 KLX250 OFF ROAD
KLX250-A2 80 250 KLX250 OFF ROAD
KL250-A3 80 250 KL250 DUAL PURPOSE
KL250-A4 81 250 KL250 DUAL PURPOSE
KL250-A5 82 250 KL250 DUAL PURPOSE


Part # = 13001-1005
Part Description = PISTON,STD
Model Count = 24
KLX250-A1 79 250 KLX250 OFF ROAD
KLX250-A2 80 250 KLX250 OFF ROAD
KL250-A1 78 250 KL250 DUAL PURPOSE
KL250-A1A 78 250 KL250 DUAL PURPOSE
KL250-A2 79 250 KL250 DUAL PURPOSE
KZ1000-C4A 81 1000 POLICE 1000 POLICE
KZ1000-A1 77 1000 KZ1000 STREET
KZ1000-A2 78 1000 KZ1000 STREET
KZ1000-A2A 78 1000 KZ1000 STREET
KZ1000-A3A 79 1000 KZ1000 MKII STREET
KZ1000-A4 80 1000 KZ1000 MKII STREET
KZ1000-B1 77 1000 KZ1000 LTD SPORTBIKE
KZ1000-B2 78 1000 KZ1000 LTD SPORTBIKE
KZ1000-B3 79 1000 KZ1000 LTD LTD STREET
KZ1000-B4 80 1000 KZ1000 LTD LTD STREET
KZ1000-C1 78 1000 POLICE 1000 POLICE
KZ1000-C1A 78 1000 POLICE 1000 POLICE
KZ1000-C2 79 1000 POLICE 1000 POLICE
KZ1000-C3 80 1000 POLICE 1000 POLICE
KZ1000-D1 78 1000 Z1-R STREET
KZ1000-D3 80 1000 Z1-R STREET
KZ1000-E1 79 1000 KZ1000 ST STREET
KZ1000-E2 80 1000 KZ1000 SHAFT STREET
KZ1000-G1 80 1000 Z1 CLASSIC STREET

Handy info there. Same piston as the Z1000. Serco may have a single piston in one of the sizes in stock.

PBMGold if you like I can PM you a phone number of someone to talk to.

[JohnnyO]

I had a new klx250 in 1980 and fitted a big bore 300 kit that was part of a 1200cc kit for a Z1000, it was a sleeve and piston.
There was also a 272 kit available which was the piston from a 1100 kit to suit Z1000.
I bought the kit from Phase 4 in Brisbane,  doubt whether they're still around..

[Momus]

I put a second oversize (73 mm) Z1100 piston in an otherwise healthy KL in 1984 to get 268 cc. Cosways supplied the piston, Small Bore bored the standard cylinder out with no worries.

All up I think it cost me about 100 bucks.

Gave a better than pro rata increase in power, probably because of the increased comp.

[PBMGold]

GMC - Fantastic information, thanks. You didn't swallow a micro-fiche viewer or something did you?

I'll ring Serco today and see what they have.