Setting up a GN250 to suck less and some other general questions

[TehPoopsmith]

Geeze its been a long time since I posted on this forum. Anyways after getting out of moto completely for a long while I have ended up with a GN250 in my possession. I am on the whole pretty happy with with it actually but I do have a few setup issues/minor problems that I would like some advice on from people who have more experience than myself.

First. I feel that the weight distribution of the bike is a bit off. It seems to have quite a weight bias towards the rear wheel which results in the front wheel feeling skittish of bumps at 100km/h. I was thinking of possibly lowering the front fork a touch, and putting lower/flatter handlebars to make it a bit easier to weight the front end. Also a new tyre that doesn't suck would probably help a lot (got a brand/model recommendation for me?)

Second. It has a new battery but it just doesn't seem to have to oomph to spin the engine over from cold fast enough to reliably start it. Put a jumper on and it starts mint, just too much compression and not enough voltage I think. Its a Yuasa standard acid/plate battery but I know there are agm and lithium and a whole bunch of other options out there now. Do any of the other options put out more CCA per size? Would be good to get something to fit the same hole that can get the bike started.

I am aware that any mods are turd polishing but I actually quite like the bike, and I don't feel the need for speed at the grizzled old age of 34. Its actually just nice to get out there and get that feeling of surfing the corners again after so long.

[Kickaha]

Lower, flatter bars and a decent front tyre will transform it, see if you can get the Bridgestone BT46 or Pirelli Sport Demon or any decent brand

[1/32 man]

Some years ago, many actually, the stepson and his mate bought bikes. The mates ride was the GN and it was fitted with low flat bars. I never rode it but it didn’t look too bad, better than stock bars that’s for sure.

[F5 Dave]

That's a very hard mission as GNs suck very hard.

An ex GF had one. Put lower bars on it, I should mention in the late 80s as a riding instructor we had half the class on GNs. They all struggled. Put this cute young lass on my 550, and after a single loop of the carpark on it she then went through the S obstacle she couldn't on the GN.

So I rode it a little. It was dreadful. But some of us have been broke and needs must.

Low bars. Put some more oil in the forks. Drop them down a bit. If you're handy, cut the springs and make up the space.

Save up and don't give up. Motorbikes are the best decision in your life.

She did put me on the path of red heads from that point pretty much.. so it's not all bad. Even if they have no souls.

[TehPoopsmith]

That's a very hard mission as GNs suck very hard.

An ex GF had one. Put lower bars on it, I should mention in the late 80s as a riding instructor we had half the class on GNs. They all struggled. Put this cute young lass on my 550, and after a single loop of the carpark on it she then went through the S obstacle she couldn't on the GN.

So I rode it a little. It was dreadful. But some of us have been broke and needs must.

Low bars. Put some more oil in the forks. Drop them down a bit. If you're handy, cut the springs and make up the space.

Save up and don't give up. Motorbikes are the best decision in your life.

She did put me on the path of red heads from that point pretty much.. so it's not all bad. Even if they have no souls.

Haha that's a great yarn. Yeah it likes to self steer/dive at low speed, I think the head tube angle (is it rake in motorbike land?) is a bit slack. Would make life difficult around the cones. I have a lathe so I can machine up some spacers no worries. Stock fork oil is 10w, do you recon I should go up a bit? Damping seems somewhat lacking.

RE: Povo bikes, this one was offered to me for $300 dereg, I said sure thing why not. Got it running put it in the shed with no plans to do anything further. About a year later my brother needed a commuter so he asked if he could borrow it. He got it all legal, rode it around for a year then upgraded and gave it back. So it really was just a chance thing that I ended up with it hahaha. For now it does the job, I usually just take it up some of the windy road out the back of Pirongia.

[release_the_bees]

I used to have a GN250. My main memories of it were having to lay down flat on the tank to maintain 100 km/h up even the slightest of hills.

My other main memory was of the rear suspension overheating, causing the rear to step out on pretty much every corner going through the Manawatu Gorge.

The GS500 that I replaced it with seemed one heck of an upgrade at the time!

Sent from my SM-S901E using Tapatalk

[F5 Dave]

Yeah sorry if I was a little harsh, was a few drinks in. Actually they are not bad bikes apart from the chassis and engine. Which pretty much leaves the front brake, which when new is good. Good enough to squash the forks flat for second until they pogo back.

So maybe 15w, but going too heavy has other very undesirable effects. Read up about how to shorten springs if you are handy. They need to be bent and ground flat on the ends like properly square. Cut the close together coils if it is progressively wound. You the have to make up the space you've removed.

Banging spacers in without cutting the springs will increase the preload but not the spring rate. It will seem like a great improvement bouncing on them, but will still dive just now not react over stutter bumps. Well, it's worth a small improvement say adding 1cm, but after that the above will apply.

You could shorten the travel by making spacers on the damper rods, so it was ,less like a chopper . But they are low enough to scrape, so maybe longer rear shocks, but. . .

My gf also traded to a GS500 as an incredible improvement. Be hard to find a good one now, but a thought.

[husaberg]

It might be a bit extreme but i have a pair of Clip on that are GN250 sized 33mm.
Ace bars or blats might be more livable.
Like Dave said the geometry and ground clearance sucks.
They need the front dropped stiffened and the rear end raised. Do as Dave says it will only cost time.
Any shocks that are 10-30mm longer will be better.
Pretty sure they had a silly size rear wheel. As well. Yip google says its a fat 16 inch.
If you have a early drum front one i have great a later wheel and caliper MC i will swap for the Drum set up.
For the rear wheel a X7 or GSX250 from early 80's looks likeit will work if you have mags if spoked look for a tu250 rear wheel.

for the front end its 33mm so look at
33 Suzuki GN-250 Z/D (82-83)
33 Suzuki GS-250 TT/TX (80-81)
33 Suzuki GT-250 K/L/M/A/B "Hustler" (73-77)
33 Suzuki GS-300 LZ/LD (82-83)
33 Suzuki GT-380 J/K "Sebring" (72-73)
33 Suzuki GT-380 L/M/A/B "Sebring" (74-77)
33 Suzuki GS-400 B/XB (77)
33 Suzuki GS-400 C/XC (78)
33 Suzuki GS-425 N/EN (79)
33 Suzuki GS-450 ET/ST/EX/SX/EZ/ED (80-83)
33 Suzuki GS-450 GAZ/GAD (82-83)
33 Suzuki GS-450 LT/LX/LZ (80-82)
33 Suzuki GS-450 TX/TZ/TXZ/TXD(81-8

most of these must have had better wider front wheels the GN was pretty skinny 1.6? i doubt it was 1.85.

The CB250RS and the CB400NT had 33mm forks as well