Scooter boy
I was wondering whether a tf125 engine would work with regards to the electrics in a GP100. And as I would like to keep it road legal for now while also getting it ready to bucket race, would VTNZ cry to much about the 25cc increase? As long as the engine mounts aren't mucked around with too much? Would they even notice?
Tyres down.. Porting, chamber, piston, carb, experience riding, etc still to go!
Norf Welly Massif
They probably wouldn't notice. Not to sure about the electrics though.
If you do the transplant, you're going to have a spare GP100 motor...have you got plans for it?
The Unknown Rider
Scooter boy
Not really, interested? If the transplant works, i might indeed have an extra engine!
Tyres down.. Porting, chamber, piston, carb, experience riding, etc still to go!
No8 Wire Extraordinaire
Read up on the LTSA website carefully. If you want to keep it legal there may be some fish hooks. Certainly my RG50 with TS125 never cut the mustard. You can do engine swaps (they are largely thinking cars) & there are some regulations about power output changes. You may squeak in with this.
Or you may find that no one wants to WOF it as they aren't sure. In which case it's $400 for an LVV inspection/certificate (if it passes) & possibly a re-VIN if they get silly on its current status. Obviously not worth it.
Think about how much to repair the GP engine or find a GP125, now that they would never notice & likely not to care. Further the airbox/exhaust/electrics etc would all line up ok. The details are what makes swaps difficult & I've done a few now.
Don't you look at my accountant.
He's the only one I've got.
Scooter boy
Just for interest sake... Does anyone race rm125 engines in buckets? And for the moment, would an rm125 engine support the electrics? Anyone have any Suzi 125 engines lying around the place that they don't want, preferably ones that dont need a complete rebuild and that run... new piston I can do... tf motor fell through...
Tyres down.. Porting, chamber, piston, carb, experience riding, etc still to go!
125GP!!!
RM engine's not allowed, as they are motocross engines.Originally Posted by richiewendt
Sorry slingshot for asking this but
What would the point be surely the TF engine doesn't put out that much more power than the GP (if less) and the gearbox's wouldn't be suited for on road as well (But may well rock at the bucket track!)
Scooter boy
SO anything that is competition not allowed? SO what would be a good and common 125 engine be then?
Tyres down.. Porting, chamber, piston, carb, experience riding, etc still to go!
MotoFXR's will rule the world!
Most 125's are bored out 100's, MB,GP,etc. Yamaha do a RH125 and as F5 said Suzuki do a GP125. The old 2 strokers are becomming rear now due to 30 years of bucket racing sucking them up.......Is your 100 dead or are after more power. If your not going to bucket race it and are hell bent on a putting a MX motor in it you will be forever throwing money at it in the way of piston and rings, not to mention rear tyres......be bloody cool though.
Its harder to lose weight than gain horsepower.
No8 Wire Extraordinaire
The general idea was to make the racing competitive but cheap. If they allowed MX engines people would turn up with increasingly new engines (can't buy an MX engine by itself usually, have to buy a whole bike as usually its the engine that gives up first). Then some people would buy a brand new one & no one else would be competitive. MX or other competition engine would roast everything else,but than again would be expensive to run in comparison, especially as they age. On the road they would be very short lived.
100s are allowed any size carb & watercooling mods. 125s must be aircooled & 24mm carb max.
Back to the original engine, 2 strokes are cheap to rebuild, unless it's carved in half.
Don't you look at my accountant.
He's the only one I've got.
Scooter boy
Na, I do want to race it, there's no doubt about that, but I am poor and so for the mean time I want something that is still relatively road legal... I would chuck some decent tyres on and rip the lights off every few weekends and take her out... Am in the process of selling my RG150 and have dosh to burn (not too much though)
So, could I buy a 125cc piston and bore the barel out, or is that too much of an increase? I want a 125 so I could use it for a bit of highway use, not long distance though, and also I have little experience in tuning (none at all really) so I reckon it would be easier to just get a 125cc and play around within the restrictions, a lot safer than tuning up a 100 to get the same/more power than a 125 and stuffing it up. You're right, the engines are getting rare as I've found out!! Hence I don't want to learn the hard way and destroy an engine!!
Tyres down.. Porting, chamber, piston, carb, experience riding, etc still to go!
Who You Calling a Pig
125 air cooled is the largest two stroke you can have in F4
For the record Qkkid was in my bed, not the other way round
Scooter boy
yeah, but I mean can you bore a 100cc barrel out to a 125cc, is it physically possible, or is that asking too much... 100-125cc is quite an increase...
I've been doing my research and the stroke for each bike is the same, but the bore is 50mm in the 100 and 56 in the 125. is a 6mm difference quite big, esp when the barrel is quite small? thats 3mm ring bored and honed out...
Tyres down.. Porting, chamber, piston, carb, experience riding, etc still to go!
2 smoke lover
In short No, There is not nuff meat in the barrel. If you want a 125cc you gotta get a 125 barrel and head.
Compare Pornography now to 50 years ago.
Then extrapolate 50 years into the future.
. . . That shit's Nasty.
Scooter boy
So do GP100 and GP125s have the same bottom end? And is there enough space under the engine side cover where the carb is located to fit say a 28 mm flat slide carb in? And where do you get these odd litle bits and pieces anyway?
Tyres down.. Porting, chamber, piston, carb, experience riding, etc still to go!
Forum whore
you need a piston and barrel off a gp125 and that is all
but the timing will be different and not quite as fast as a compleat 125 engine
i dout you will notice the difference
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