GZ 125 with 250 engine

[SimonLee]

Hi everone im on here because you will know best. I have a 2000 GZ 125 and recentley bought a 2002 250 engine for it, what i wanna know is has anyone done this already? will i need to up jet? my carb or get a 250 one? will i need to adjust the airflow and can my generator fit it or will i need a 250 one




any advice help is appreciated good bad a jokes cos i expect it im not a teenager :rawk:

[jonathan180iq]

That's a pretty wicked looking bike. You can tell it's being ridden and that's what motorcycles are for.

AFAIK, it should just mate right up. We don't have a 125 service manual, but we do have one for the 250, which you can download here:

SERVICE MANUAL:
viewtopic.php?f=7&t=2158

Check the serial number on the carb that you currently have on the bike. If it matches one of the ones in the front of the service manual, then you won't need to change anything out. There are only 2 types of carbs on these things, so you'll either have one of those 2 or you won't. If you don't, I would wait until you see how it runs with the 125 carb and then determine if adjusting the jetting is something you want to do. It can be done, but it's not something you can knock out in 2 easy steps. It takes some trial and error. Because of that, some people prefer to just buy new parts. You'll have to make that choice.

I think only our fellow rider, RYNR, has really good info on the 125 and what you need to do during the swap. He has a pretty big thread about rebuild a 125 if you search for his name.

[SimonLee]

Thankyou Jonathan Morrigan gets ridden loads lately than is to the sun finally making an appearance. I have a manual and thancks for the info on the carb numbers ill check and keep you posted

[alantf]

Hi there Simon.

Lovely to have another Yorkshireman aboard! Born in Sheffield, lived most of my life in Rotherham, then a few years in Donny. Worked most of my life as an electrician, but when there was no work around, I drove buses. Used to come into Barnsley when I drove for Trackie. :2tup:

BTW, I'm coming over to my daughter's in Maltby, for a couple of weeks, in June. I won't have transport, but if you get the bike running, maybe you can get to Maltby, & we can go out for a pint.

[SimonLee]

Hi Alan glad to see a white rose too my bike is running now it's just 125 I'm waiting to be sure it will all go in before it gets a beefy stuck in. I would very happily come for a pint or you could come meet us at the marr lodge in Doncaster that's where our mcc meets

[alantf]

Hi Simon,

Two things:- Firstly, I've PM'd you about the Marr Lodge - I'll be there, it's only 14 miles from Maltby. Secondly, don't forget that the American carbs are set up weaker than ours, to comply with their emmission regs, so any info might be slightly misleading. :2tup:

[jonathan180iq]

IIRC, the service manual has a reference to the differences of the Euro carb. I haven't read that thing in a long time, but I am certain hat it's in there.

[SimonLee]

ok thankyou jonathan180iq
i guess the next thing is where do i get pipes from as mine is a single one and 250 is a twin

[alantf]

Wish I could get 'em in my suitcase. Got a full exhaust in my garage, with just a scratch. Insurance replaced the exhaust (among other things) when a 4x4 I was overtaking turned left without signalling, & the bike went down. The bike shop guy didn't want the old ones, so he gave 'em to me.