Gz250 Hp Increase Tips?

[Jaseman]

i reply to your exhaust pipe question, search google for this part number EXUSL24. That is what i put on my GZ250. at low to mid RPM you it very hard to work out that its only 250. But it is much louder than i was expecting.

[Jordan310]

Hey!

Can anyone tell me what K&N filter will fit on this carb?

[Aussie Steve]

Holy crap wish I had that much room around my motor!

[Bigiron472]

There is not a lot you could do for lil Suzi. A one cylinder 250 is not much to work with. You can open up the air flow with exhaust tricks and a high flow Air filter. If you do that, you'll need a wizard to work over your carb. Even so you are taking your chances. Modified carbs can become a real pain.

A windscreen can help. I can duck down behind it and gain a little speed because of the decreased wind resistance.

The oil you use can help. I personally do NOT recommend the fruit punch the dealer uses. I use Castrol GTX 10W40 in mine with great results and zero consumption. Lil Suzi drank an oil change with the Suzuki stuff and I might have blown 'er up if I hadn't noticed. By the way, your first indication that she's low is that she gets sluggish. The little eye makes it easy to check so you can avoid that trouble. Don't assume that because your GZ is new, it won't use oil. Mine most certainly did!

You will find that the 5,000 mile mark is when you'll probably notice increased pep. I hold that as the true break in point.

Understanding the machine's design and capability is the key to getting the most out of the GZ250... both miles and performance. Lil Suzi is geared like a farm truck. It can do 75mph because it has one more gear than a 53 Chevrolet truck. I do not recommend you try it. The engine is screaming and the bike is just too light for that. If you use the KPH scale on your speedo to shift; 20 in first, 40 in second and so on, you'll have the revs where you want 'em for a lively getaway. The bike is made to run it's best at speeds between 45 and 55 mph.

I bought a heavier cruiser bike for highway riding. I keep Suzi for the back roads and in town. I am tempted to tweak Suzi but I'm reminded that I got her to have fun and save money, not get aggravated and spend money.

[Mydlyfkryzis]

Those holes look more like 3/8th inch. 1/8th is a lot smaller than that.

Can you confirm the drill size?

[Easy Rider]

Originally Posted by joesuzuki

Today I drilled ( 1/4" holes in the back of the Exhaust pipe and ripped off the inlet air diverter on the air cleaner. Man, what a difference!!!!!!! The bike doesn't run like my 1100, but it sure does run a hell of alot better. Joe

Don't know where Joe is located or what year bike he has but nobody I have been able to locate in the US or Canada has been able to replicate his results. Others have found that opening up the intake results in a WAY lean condition and crappy performance........with our without decreased restriction in the exhaust.

Others have reported slightly better performance if they up the main jet and the needle along with air cleaner and exhaust.

[Easy Rider]

Originally Posted by Bigiron472

I bought a heavier cruiser bike for highway riding. I keep Suzi for the back roads and in town. I am tempted to tweak Suzi but I'm reminded that I got her to have fun and save money, not get aggravated and spend money.

Sounds like you would be a perfect candidate for a 16T front sprocket.

Not recommended for anyone who carries a HEAVY load, does a lot of highway riding or climbs a lot of steep hills but it is ideal for puttering around town and cruizing at 60 or less. It will easily run 65 in 4th (but I wouldn't hold it there too long!) and 5th is pretty much like overdrive.

The down side is you lose a bit on the top end (70 instead of 75) but downhill or with a tail wind, it runs like a scared rabbit!

[mtalicarox]

Originally Posted by inspiron

Not necessarily ... my GSX 1400 is designed for touring, so even with 1402 ccm displacement, I have just 106 hp. A GSX-R 750 has about half the displacement, but is tuned to deliver 148 hp.

Incorrect sir Weights and Measurements - Sport Bike Data - Sport Rider

The 06 GSXR 750 is 129.1 HP.. where on earth did you get 148?

[Bigiron472]

2 quick questions; What constitutes a heavy load for the 16T front sprocket for lil' Suzi... I'm 200 lbs. Is there way to recalibrate the speedo?

[Easy Rider]

Originally Posted by Bigiron472

2 quick questions; What constitutes a heavy load for the 16T front sprocket for lil' Suzi... I'm 200 lbs. Is there way to recalibrate the speedo?

The speedo is driven off the front wheel. Changing the drive sprockets will NOT affect that.

You should be OK. Add a passenger or lots of gear ~150 lbs. and it might be a strain.

[Bigiron472]

The question I have is one of legality. I found this silencer in England and Russia but none in the USA. I have to wonder if this pipe is legal to use here or drilling holes in the stock silencer. The chance of getting caught out by Big Brother isn't very likely I expect but I wonder if there's some bloody law against messing about with the cheesy GZ. It seems there's a lot of different pipes available for every other bike out there. Does anyone know?

[Bigiron472]

Right! so where does one obtain this larger front sprocket?

[Bigiron472]

Is there a powerplant/trans unit that can replace the 250 on the GZ frame. Is the frame stout enough to support the power increase? How involved would the necessary mods to the frame be? Anyone know?

[Aussie Steve]

Generally in the past it was common to fit up to a 350 into a similar frame. This was in the past though and frame technology has moved on since then.

My burning question would be why bother? Sell the quarter litre and buy a 500four or more. The money you will spend trying to increase the output of this model will not be worth the effort IMO.

[Bigiron472]

The question of a larger powerplant is against the day when the little scrapper gives up the ghost. Instead of sending her to the bone yard, I might want to make a hobby horse of her. I did learn the craft on her while the free (from my brother) BSA was costing me 2 grand to make roadworthy. It could make a fun toy after it's 250 life is over.

[Aussie Steve]

I had a 66 Lightning and it cost considerably more than $2000 to get up and running so I would consider myself lucky if I were you. As regards the 250 I guess a 350 motor should be reasonably priced and should fit straight in.

Good luck with both!

[revelation]

I have noticed the drill holes look far bigger that 1/8". I drilled 8 at a 1/4" in on mine and the holes on the pic look bigger than mine. Am I missing something. My motorbike sounds better but I don't think it's helped in performance.

[Easy Rider]

Originally Posted by revelation

I drilled 8 at a 1/4" in on mine and the holes on the pic look bigger than mine. Am I missing something. My motorbike sounds better but I don't think it's helped in performance.

Me too (4X1/4") and me neither (no performance change).
Some folks have done 1/2" holes but I think that would be too obvious AND too difficult to plug reliably, should the need arise.

[tdawg]

Can someone who has drilled the holes in the exhaust send me a picture. I am interested in doing it. I know you guys were talking about it not improving the performance but making it louder, are you guys glad you did it?

[Easy Rider]

Originally Posted by tdawg

I am interested in doing it. I know you guys were talking about it not improving the performance but making it louder, are you guys glad you did it?

NO. It sounds different alright but not "good" different. What we have, after all, is pretty much a large lawn mower engine. Putting holes in the muffler makes it sound like.........a lawn mower with a blown muffler. NOT impressive.

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