Row sound GN250

transporter · Two Stroke Sniffer Joined: 21 Oct 2009 Karma :

Hi there,quite new to the forum but wondered if anyone could help me with a strange noise coming from my Suzuki GN250. Its kind of higher pitched metallic tick noise that develops in to a kind of row row row sound when revved (revved it 3 times there Smile

). Theres no undue smoke coming from the exhaust but it does smell a bit (strong fumes). apologies for all the technical terms LOL but im quite new to bikes as well as this forum. I think the sound may becoming from the cylinder head. Can anyone offer any ideas,all the best,Rich

Cigaro · World Chat Champion Joined: 28 Mar 2007 Karma :

Check the tappet adjustments. Failing that it could be the valve seats.

If your exhaust smells it might be burning oil, what are the oil levels like? These engines are very sensitive to being run out of oil, so keep an eye on it.

I have a similar problem with mine (see the link in my sig for a project log), I'll be stripping the motor down in a few weeks. Nice to see a fellow GN owner Thumbs Up

transporter · Two Stroke Sniffer Joined: 21 Oct 2009 Karma :

Thanks for the info,i will get a feeler gauge and check the clearances,do i need a special tool to adjust the tappets or valves ?.My GN is the same colour as yours on a 93 plate,cosmetics are just about sorted now,swapped the original bars for some flat drag bars,got the chrome luggage rack and engine bars on it and also a slash cut Harley silencer but not fitted that yet. Painted the engine in black and highlighted the top few fins of the cylinder in silver like on the Triumph bonneville,looks nice. Also like you im toying with the idea of painting the tank a different colour as i find th gold on black looks a bit dowdy,i may possibly paint the fork legs black and put some black gators on too.Anyhow,thanks again for the info,will keep an eye on your build and post a picture of my GN when i get on my other PC,Rich

steo · Nova Slayer Joined: 08 Jun 2009 Karma :

The GN have a very soft camshaft, cam followers & cylinder head. As mentioned in a previous post, if the bike is let run low on oil, it completely buggers up the top end.
I can't see by adjusting the tappets that it will make a blind bit of difference if the engine is as noisy as you say. I would be more inclined to pull the rocker cover off & look for wear on the camshaft lobes & cam followers (tappets). Also check for wear on the cylinder head & rocker cover recesses where the camshaft rotates on.

Noxious89123 · World Chat Champion Joined: 10 Jun 2007 Karma :

ms51ves3 · Super Spammer Joined: 07 Jun 2007 Karma :

prawny1 · World Chat Champion Joined: 28 Jun 2005 Karma :

Cigaro · World Chat Champion Joined: 28 Mar 2007 Karma :

transporter · Two Stroke Sniffer Joined: 21 Oct 2009 Karma :

Yeah thats how mine sounds,wish you would have revved it a bit to see if you got that same sound as mine,bit like a cross between a scream and a Row sound Confused

But the rattle is a lot like mine. Can i buy the bits to fix it then, any ideas where i would get them from ,local bike shop, net ???

steo · Nova Slayer Joined: 08 Jun 2009 Karma :

If you did your tappet adjustments & the engine is still rattly, check for wear in the cam chain. If you take the spring out of the tensioner before you remove it from the barrel, you can get an idea of how much adjustment is left in the chain.
If that's okay then take the rocker cover off to assess any wear in the top end components before you go and buy the parts.
You may be able to source the bits from fleabay or your local breakers but if not, you'll have go to your Suzuki dealer as I wouldn't imagine an ordinary bike shop stocking these parts.
Hope this helps...

transporter · Two Stroke Sniffer Joined: 21 Oct 2009 Karma :

Thanks for the info. I think what im going to have to do here is get my head burried in to the workshop manual and see how the engine comes apart. I will check the valve adjustments to see if they are OK, am i right in thinking i need a special tool for adjusting the valve clearances ? are they bike specific or does 1 tool do all ?

steo · Nova Slayer Joined: 08 Jun 2009 Karma :

Standard set of feeler gauges will do as long as you know the right tappet gaps (service manual), probably around .10mm exhaust & .05mm inlet but I'm not 100% sure. Basically if your feeler gauge blade placed in the appropriate tappet at the proper timing mark feels too loose or too tight then you know it's outta sync.
The rocker cover comes off handy enough, around a half a dozen size 10mm socket bolts, take the fuel tank off for better access. Just be careful when removing them that you remember where you took the bolts outta, some are longer than others.
Consult your manual for proper instruction coz my post is just a general guide as I'm browned off with the usual knit pickers & (you know who you are) who just brow beat a lot of the posts on this forum....

Cigaro · World Chat Champion Joined: 28 Mar 2007 Karma :

Inlet should be 0.03-0.08mm, exhaust 0.08-0.13mm.

PM me your email address and I'll send you a copy of the service manual Thumbs Up

transporter · Two Stroke Sniffer Joined: 21 Oct 2009 Karma :

Thanks again for the information,i already have a copy of the workshop manual for the GN so i will have a browse through that and see if i can quieten the bike down a bit. I will let you know how i get on as soon as ive had a pop at it,speak soon,Rich