Legality of swapping engines? Certification process?

[iranana]

I have an RD250 and I've been thinking of converting it to a 350, or putting in a whole 350 engine. The bike is already road legal, but I'm guessing I'd need to get to get some kind of certification (I've been on the NZTA website and they call it an LVV Plate or whatever). How does one go about getting a bike with a modified engine road legal? I've thought about just putting on the 350 heads and barrels and not telling anyone... but that doesn't seem like the brightest idea. Cheers!

[F5 Dave]

That totally seems like the brightest idea. Not that my 350B had 250 stickers on it when I was a learner. . . But that was a few years ago. Back when your rego sticker had an 'L' on it if you were a learner.

The rules are I think, you can only go for a 15% increase in power or cc without a LVV cert. On my 500 Yamagama (RZ350 with 500cc aftermarket racekit in an RG/RGV250 chassis) I needed to get a chap to certify it & then get a plate the size of your outstretched hand riveted to it (under the seat pan). Cost a fair whack, but it was pretty obvious.

Plenty have done the 350 conversion (heck I have a 250 with one in my lockup stored for a freind). Aircooled RD site will probably tell you how to alter the carb settings & possibly the oil pump, but I'd rely on better modern oil being sufficient.

[iranana]

Hmm interesting, I've seen different figures for how much HP the 250 puts out, but I *think* the '78 250 was meant to make around 32-34HP. The 350 is said to make about 40, so that's kinda close to 15%. So... If I was to convert the top end and not tell anyone, would I be in the shit if I got caught or would my insurance be nullified? The only way you'd be able to tell is by looking at the cylinders... so the average person probably wouldn't have a clue. Was thinking of just pulling the clutch, oil pump, heads and cylinders from a complete 350 engine and chucking em in there.

[98tls]

I certainly wouldnt bother with certing etc,ive a complete later model GSXR front end on my old S and never a problem with wofs.Cant imagine anyone would notice anything on the RD.Great idea,do it.

[F5 Dave]

If some Kneedit got wiped over the '347cc' cast into the cylinders & blacked over then no one could tell. I did my 500 as it was just a bit obvious. see left, but I didn't do anything about the YZFSP which had R1 callipers as they came like that on that model, prove it otherwise. Bodywork was none of their biz. I certainly wouldn't tell anyone about the 810cc big bore I was considering if I'd got it (they had too many leak problems with the kits).


There have to be some controls as you get numpties taking the suspension out of their cars so they ride low yet bounce uncontrolably when they hit bumps & in the same breath people will fit front ends on bikes that don't have lockstops that meet anything solid or queer up the geometry to be unstable.

[98tls]

If some Kneedit got wiped over the '347cc' cast into the cylinders & blacked over then no one could tell. I did my 500 as it was just a bit obvious. see left, but I didn't do anything about the YZFSP which had R1 callipers as they came like that on that model, prove it otherwise. Bodywork was none of their biz. I certainly wouldn't tell anyone about the 810cc big bore I was considering if I'd got it (they had too many leak problems with the kits).


There have to be some controls as you get numpties taking the suspension out of their cars so they ride low yet bounce uncontrolably when they hit bumps & in the same breath people will fit front ends on bikes that don't have lockstops that meet anything solid or queer up the geometry to be unstable.

Nice those Dave.

[Grumph]

If some Kneedit got wiped over the '347cc' cast into the cylinders & blacked over then no one could tell

Back in the day it was Dymo tape - right size and font too. i know of one 250 prod title won using that tuning aid....

[F5 Dave]

Hahaha, hmm wonder if my parents still have theirs?


Owwh Naughty proddie racer. Actually that's a bit of an arse to cheat like that.

[skippa1]

Hmm interesting, I've seen different figures for how much HP the 250 puts out, but I *think* the '78 250 was meant to make around 32-34HP. The 350 is said to make about 40, so that's kinda close to 15%. So... If I was to convert the top end and not tell anyone, would I be in the shit if I got caught or would my insurance be nullified? The only way you'd be able to tell is by looking at the cylinders... so the average person probably wouldn't have a clue. Was thinking of just pulling the clutch, oil pump, heads and cylinders from a complete 350 engine and chucking em in there.

Who do ya reckon is going to look that closely?

[The Reibz]

While we are on the subject, will a wof guy notice a GT30r sized garrett bolted on to a busa or should I just go and get it certed? Churr

[AllanB]

Just do it.

[baffa]

Keep in mind if you plan on insuring it, that wont fly in an accident.

[jolly_26]

While we are on the subject, will a wof guy notice a GT30r sized garrett bolted on to a busa or should I just go and get it certed? Churr

"This model was factory turbo. Honest, it's for fuel efficiency or something like that."

[Samm]

What's the legality of swapping an identical engine? I had no issues getting a WoF after a frame swap, but was wondering if what I did was legal(wasn't going to bring it up with the mechanic!).

[the oldstuff]

I think those swaps are perfectly legal as long as you document the number changes. As for 350ing a 250 secretly, have an accident and you are fucked.