Any one put RG150 chamber on a GP125?

[bucketracer]

Team ESE did run some std GP rods for a while, they were spinning them up to 10-11,000 and they lasted pretty well, and now Suzuki have a universal rod kit for all the 125 motors that is good enough to be used in the early RM's so that could be the go. TZ went to RGV250 rods for the 16mm pin and the better/easier range of pistons available with the bigger pin.

[koba]

Your talking about your bike I presume? See you down there mate.

Thanks for the inspiration TZ.
Picked up the RGV rolling frame tonight, looks like a bargain and not as heavy as I thought it might be. Should keep me out of trouble over winter.

A question for the wise
What sort of revs can I safely(ish) go to to with a stock GP125 bottom end, I know redline is 8K but this one seems to be making good power well past that.
Am I asking for trouble going past 8K without improving the rods, bearings etc?

Cheers
Red

More than 8 will be fine, to a point. Where that point is will be better answerd by TZ.
The main condition to this is the condition of the parts.
If they have sat about and have a bit of rust formed on the big-end pin/rollers it will fall to pieces very rapidly.
It's a really good idea to put a new rod-kit in it before you use it as a race machine. The up-front cost of doing so may look steep but it is money well spent;you should get reliability and piece of mind.
The ESE guys run a different setup, I'm sure TZ will elaborate. You will have to decide to go straight to something different or retain the stock setup to start with.

[F5 Dave]

+1. Learnt the hard way several times I used to buy old engines for my race 50s, but they always used to do big ends. Until I rebuilt the crank with new bits.

[koba]

+1. Learnt the hard way several times I used to buy old engines for my race 50s, but they always used to do big ends. Until I rebuilt the crank with new bits.

Your experience is where that comes from, although I've had a brush with it myself when I pulled my motor apart to find a blued rod. Damn lucky I got to that in time.

[Buckets4Me]

A question for the wise
What sort of revs can I safely(ish) go to to with a stock GP125 bottom end, I know redline is 8K but this one seems to be making good power well past that.
Am I asking for trouble going past 8K without improving the rods, bearings etc?

Cheers
Red

Have you thought about the ignition as the standard gp125 is very big and heavy
that was one of the first things changed on the early TZ bikes before Team E.S.E was around


mx type (kx80 ?) then the igniteck after

[Triplenut]

Thanks Gents,
I checked the rod when I had the barrel off, Not properly but it all looked to be fairly new with no obvious slop.
I'll run it as is with a little care for now and plan on finding one of those suzuki rod kits as soon as I can so I can rev it out properly.

Cheers
Red

[Triplenut]

Have you thought about the ignition as the standard gp125 is very big and heavy
that was one of the first things changed on the early TZ bikes before Team E.S.E was around


mx type (kx80 ?) then the igniteck after

I haven't done anything to the ignition other than clean and time it to stock.
Keen to upgrade but my electrical skills are fairly suspect.
How hard is it to updrade to the KX80?

[TZ350]

The Kawasaki KX80 ignitions, pretty much go straight in if you get this kind. The flyweel bolts straight on and the timing marks even line up, the only trick is to use a piece of welding wire bent into a circle and laid in the stator recess to centralise the stator plate. You may be able to see the small packers in the picture, a piece of welding wire is easier.

[Triplenut]

The Kawasaki KX80 ignitions, pretty much go straight in if you get this kind. The flyweel bolts straight on and the timing marks even line up, the only trick is to use a piece of welding wire bent into a circle and laid in the stator recess to centralise the stator plate. You may be able to see the small packers in the picture, a piece of welding wire is easier.

Cheers, to reasy even for my muppet electrimacal skills.

I'll keep an eye out for one, any ideas what year KX ?

[TZ350]

I'll keep an eye out for one, any ideas what year KX ?

No I don't know what years, but its the shape of the stator thats important, the fully round stator needs some machining to make it fit and the CDI for the round stator has a retard curve that does not suit the GP.

[saxet]

A few pics for triplenut to give some idea as to how I put aGP125 motor into a RGV250 frame.
The funny looking bracket by the wood pile is the front hanger I made up minus the actual engine mount brackets which got cannabilised for another project.

[Triplenut]

A few pics for triplenut to give some idea as to how I put aGP125 motor into a RGV250 frame.
The funny looking bracket by the wood pile is the front hanger I made up minus the actual engine mount brackets which got cannabilised for another project.

Thanks once again Tex, much appreciated.
Gives me some ideas for a starting point.

I was initially thinking maybe I could get away without the front mount if the upper and lower rears were stong enough. Its hard to know until you try.

I take it there were no ill affects from tilting the engine forward ? like bearings/gears running out of oil etc.

Cheers
Red

[saxet]

No prolems at all with tilting the engine, even the carb seemed fine in my experience.
I had to hoist the front of the bike up when changing the oil to get the engine level so I could fill it accurately.
Only the lower rear engine mount was solid, the upper rear wasn't that resistant to flex.
I took the cheap option for the upper mount as I was paying someone two weld it.

[jasonu]

+1. Learnt the hard way several times I used to buy old engines for my race 50s, but they always used to do big ends. Until I rebuilt the crank with new bits.

Yep I blew 2 TF125 big ends in a weekend using old crap. Speedpro still brings it up every now and again. Rebuilt cranks are the only way to go.

[Triplenut]

You'll probably piss yourselves but I've managed to convince myself its done in the true spirit of bucket racing.
Need to save $ for a crank rebuild.

Was trying to stiffin the front end as my rebuilt brakes are causing the front end to all but bottom out.
Decided to fit a rear shock spring to the forks, that was to stiff and a bit like a pogo stick on rebound.
So I removed the fork springs added some heavy oil to give it a chance of some damping and bolted the shortened spring in place.

I know its primitive, ugly and not even vaguely technically correct but the net result is significantly stiffer forks that act mostly like forks should, well old shitty forks.

Have balanced it out with stiffer rear shocks and I figure it'll only feel hinged in the middle not both ends.
Find out this weekend at Methven Street races

Cheers
Red