Time to pull the motor...

[slow_heavy_750]

Well..its getting to be about that time where I have to pull the motor out of the bike and see why its burning a bunch of oil (anyone who has ridden/driven behind me can tell you the bike burns ALOT of oil...lol)


I think the problem is valve seals, but im not positive. With the head coming off im definetly gonna do new rings, and depending on the condition of the pistons, maybe pistons too.


While im in there I figure id might as well make it worthwhile and do something performance oriented also. The bike already has pod filters and a 4-1 exhaust, so i was thinking of possibly doing a cam, P&P, and shaving the head.

I was looking at the web cam 118 grind, which says its good for stock motors, since everything else they offer for the 2 valve is for big bore or race etc.


So my question is, how much should I shave the head to bump the compression to a still streetable level (I have no problem with running 93 octane), and will the cam/P&P offer a worthy performance gain? I know wiseco has the big bore kit...anyone have that installed and can say how big of a difference that makes?


Thanks in advance guys...and im also very open to opinions

[robertob]

Why don't you find a GS1000 engine and do a swap?

[Kris V]

Don`t shave the head it is not required to make big power gains,get the cams that you want and degree them. You will make great power gains with just that. What size is the engine?

[Steve]

What size is the engine?

Well, let's see...his user name is "slow_heavy_750", and his signature says "1977 Suzuki GS 750", so it might be ... hmmm ... maybe ... 750? 8-[


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[slow_heavy_750]

Its a 1977 750. Id like to keep the 750 motor in it instead of swapping....thats the easy way out [-(

[justin caise]

I'm no motorhead (read: Don't know my way around a cam) but I'd like to help.
PM sent.

[Kris V]

Steve,Yes I know it is a 750 DDuuhh:roll: what I meant to say is what "CC" is the engine. Working in a bike shop for a while I have seen people who did not know that their bike had oversize pistons or bigger rings in it especially when they buy it used.:shock:

[slow_heavy_750]

Steve,Yes I know it is a 750 DDuuhh:roll: what I meant to say is what "CC" is the engine. Working in a bike shop for a while I have seen people who did not know that their bike had oversize pistons or bigger rings in it especially when they buy it used.:shock:

Its still at stock bore...I hear ya on the working in a bike shop thing...id say 60% of the people who bring their bikes in dont even know what year and model the bike is...lol

[rapidray]

I am ALWAYS for bigger motors as I just think stock SUCKS! If you go the 844 kit I think it is, with smaller cams (as in smaller of the BIG ones), & 29 smoothbores, I would do a .030 cut on the head to true it up & bump the compression about a quarter of a point. The 2 valve heads require a MUCH bigger cut to bring compression up than the 4 valvers do due to the depth & size of the combustion chamber. Good luck whatever you decide but pistons & cams all cost the same no matter how big the engine is. If it were me, I would go 1000 motor or, better yet, a 4 valve 1100 motor. Ray.

[Steve]

Just out of curiosity here...what does a .030 cut on the head do to valve timing? :shock:

I am thinking it would retard the cams a bit, but how much?


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[Ironriot]

Milling the heads is more trouble than its worth IMO. Steve brings up a good point. You're gonna screw with the timing. Which is a headache in itself. Unless you got a few years screwing with timing, then by all means....

[Nicholaschase29]

are you sure that going to change the timing?

[robertob]

are you sure that going to change the timing?

Always does. If you change the distance between the centerline of the cams and the centerline of the engine, you add slack in the timing chain that the tensioner pulls back in. That retards the cam timing relative to the crank.

[Nicholaschase29]

That makes sense because it only puts tension on one side of the chain now that you mention that.. If he does get the after market cams they would be slotted though so that he would be able to degree them anyway though right?