Hey guys.. I'm vignesh from coimbatore, tamilnadu.. This is my first post in XBHP.. i too own a Fiero(suzuki 2001 model), which i use it for dirt racing.. i also prepare dirt spec bikes as a hobby for my friends.. I've been working on Fieros for more than 4 years now and also specialize in performance modifications for all bikes.. I make Free Flow Exhausts and expansion chambers with some help from my friend.. i'd like to share and gain knowledge through this forum..

Welcome to Xbhp & the fiero thread..

Do share your knowledge here, we are a small group & share more than biking more often than normal..

Thanks bro,i was saved by lady luck
Well,loosing control of the bike is surely a scary thing and your reflexes will be already preparing the body for the fall even at such short notice.But when you somehow manage to come out of the tank-slapper induced wild ride without taking a fall/getting hit,you really feel it was a shear miracle.
The bike came out with nothing more than a dent to the center stand mount.All thanks to the speed i was travelling at, which ensured that the stone moved on impact,which also ensured that there was enough momentum to keep the bike moving and hence ensuring i had a chance to keep it upright.
Never experienced burst tyre till date.That should have been a similar experience i guess.Frankly i'm scared of riding bikes with high handle bars really.
Reminds me of Laurel and Hardy movies that would literally be like a revolving door to the underworld!

There are quite a few fieros here which have been hot-rodded ,so it would be interesting to know what kinda modifications you've done on the fiero platform till now.Do let us know about em.

Thanks buddy.. I appreciate your warm welcome..

@gixx
My fiero runs a 190 cc high compression bore(cbz piston 0.25 piston +1mm cylinder phasing).. compression is way too high that i had do stick the gasket to the head with araldite(anabond 666t and 3bond were of no use)..
RTR 180 cylinder, head, cam, rocker arms,etc
Yamaha RXG vm24 carb running 115 jet,
Drilled out stock air filter assembly*
Custom made 30'degree inclined FFE(Without noise suppressor )
All resonators removed(Does make a difference)
Extra steel plate added to the clutch assembly**
RTR 180 TCI unit with Thunderbird's high tension coil.
Bigger Exhaust port***
Custom wound high tension valve spring
stock valves and cam shaft,****
Dirt trim and 100% off road tires...


*-K&N filters did not help much..
**-More explanations given on demand..
***-DO NOT port the inlet valves.. the stock port size of RTR can easily feed bore sizes upto 70mm..
****- High lift cam affects the torque at low revs which is a disaster for 4 stroke dirt bikes..(the only way by which we can screw RX guys) Engine stopping power will also be affected(This is the reason for me to choose a 4stroke)
My cylinder



Valve grooves and piston outer leveling,


At TDC

Hi V1gnesh,

Welcome to the forum. You'll fit right in. That's an impressive set-up you're running. Cheers

That's impressive indeed.Now,when you say Resonantors ? which ones are you talking about here?Do you mean to say that you're using RTR air-filter box with resonator and the bend-pipe of a RTR(which used to come with a resonator)?What affect have you seen with and without those ,in terms of performance?
I've removed the baffle of the stock megaphonic silencer.Which dia bend-pipe are you using?
Since you've mentioned it clearly that you want low-down torque,hence you're using vm24 and stock cam of the RTR.So i assume you wouldn't have opted for a bigger dia bend-pipe.
Custom made valve springs is indeed impressive,mind telling us more about it?as to how and where you fabricated those?
The sleeve looks stock,is that the case?

Thanks buddy..

The resonator is the one which comes in the RTR head, connecting the intake port and small hole present below the exhaust port on the cylinder.. The resonators are used for fuel efficiency.. Due to high compression, these resonators result in negative efffects..

I'm using stock Fiero air filter box with holes made on the front of the box.. Without the holes, my engine did not rev much..

Custom bend pipe to match the exhaust port.. having a bend pipe more than the dia of the port decreases bottom end torque and less than port dia decreases peak rpm and power at higher rpm will be way less than stock..

There are two springs supporting each valve in the head(Spring In Spring). I went to a local spring manufacturer along with the dimensions of the stock spring. Just increased 2.5 mm of the spring length of both the springs. So more torque.. My fiero power wheelies everytime i shift to 2nd from 1st between 4000-5000rpm.. Stock Sprockets and 18' wheels.. There are a lot of spring manufacturers in Patel road, Coimbatore..

Yes.. It is a stock sleeve of RTR cylinder..it can be bored till 70mm i guess.. I know a guy who runs his fiero with Daewoo matiz's 68.75 mm piston running stock sleeve on the dirt track.. His Fiero doesn't have that much bottom end like mine, but its a screamer.. In stretches, his bike is a monster.. But corners matter in a dirt race..

The resonator you're talking about is the SAI i guess,the secondary air induction system to meet emission norms.Good thing you got rid of it.
My bike's having:-

1. ZMA piston kit.It's a flat top piston and not the stock one .To increase the compression.
2. Ported stock head,it's more as dynamic compression increase can be felt.
3. RTR180 intake manifold.
4. 29mm p180 carb.
5.RTR 180 TCI with ignition coil.
6 Iridium spark plug NGK CR7E IX.
7.Stock silencer with baffle removed with a bigger dia straight end-pipe.
8. Oil-cooler of P220 FI/200
9. std Bullet's handle put USD with custom made rear-sets.
10. Pulsar disc-brake assembly.
11. 14T gb sprocket.

I'm thinking of going for RTR 160 swing-arm,any idea about it?

Thats a great setup.. how much top speed did u get?? 140+?? thats around 200 cc rite??

Mine is a RTR 180 manifold which is bored to match the mikuni..

Iridium plugs are a great boon for TCI setup.. i heard iridium plugs for cdi doesn't make quite a difference.. If u know why, pls throw some light..

where did u install the oil cooler?? In the oil pump tube??

what does USD stand for??

I'd recommend you to go for the ZMA bend pipe if port size matches..

Regarding the swing arm change, it depends on how u ride the bike.. I guess RTR swing arm is a bit lengthy and wheel base will increase.. This causes loss in flickability(Fiero's speaciality) and increase in handling and stability at high speeds(Fiero's weakness)..

Some pics of my Suzuki Fiero Dirt bike...

Well the bike's top-end has gone up,she revs easily to 12k+ rpm and i had it ported for top-end only.But i haven't checked it accurately though.Yes, she's 195cc's now with the bore size being 65.5mm.The cylinder's stock fiero one bored-out and sleeved for it.

The reason could be because of IDI having a longer duration spark with lower temperature were as CDI has a shorter spark duration with higher temperature.Since Iridium has lower resistance maybe it works better with IDI.

There's a oil-cooler provision designed into the fiero engine.We also have checked the oil flow pressure and it's excellent.I'll show the pic with inner oil flow circuit in the next post.

USD means up-side-down That is the handle has been put upside down to make the riding position sporty.

The bend pipe is not an issue, what's needed is 29mm one and a guy makes it here on order.

Yes i want more WB,the thing i wanted to know was whether the rear axle bolt and the swing-arm pivot bolt needs to be changed or not.I guess it needs to be changed.

How much did the valve springs cost?So it has increased bottom-end by some margin then?

Thats great.. I'd like to know more about the oil cooler(My bike boils if ridden in the track for more than 30 mins)

Does sleeves last longer?? Did you get original ZMA sleeve or any other OE??

hope you have the RTR footrest saddles..

Thats something to note on iridium plugs.. Mine is bosch twin electrode(60rs ) my plug wears quite soon due to high compression..

I guess axle and axle bolts must be changed.. You better go for the unicorn's swingarm and mono.. have to elongate the chain and rear mudguard...

Yes.. the valve springs have dramatically increased bottom end
( to 2 strokers).. But as a fact, it should wear out the cams quick(more stress on the cam lobes).. This won't help much for your application i guess.. I spent 800rs on 4 valve springs..

Good pics and your bike sure looks battle hardened.That's the thing about fiero isn't it?the damn engine can be used for any purpose,street,track, or dirt and drag.

Yes,your bike can use a oil cooler for sure then.I'll post the links to my previous posts on it here.

About the sleeve,i've no idea how long it'll last,if it's a ZMA one then it will last as long as the lathe guy mentioned.

The rear-sets are custom made,they in combination with the handle will make the RTR feel like that of an arm-chair if you know what i mean.

What your bike needs is NGK R CR9E spark plugs.Trust me on that,with higher compression that plug is a must!The CR7E is looking pale on my bike because of higher compression.

Yeah i'm no racer,so i guess the valve springs aren't for me.