Has anyone tried porting the intake? I am new to the GS500, but I know that some Japanese intake ports need help. For example, the Yamaha xs650 ports are too big, and the Yamaha SR500 intake is too low. When I raised the intake port on my SR, the bike ran better all around--including gas mileage.
No, i havent ported my gs but i am wanting to this winter. I am just going to open them up slightly to increase flow. Im also going to polish the exhaust port and change the merge collector to a better flowing design. Im trying to get 50hp out of this engine lol. It puts out 43hp atm so im not sure if these mods will give me another 7hp, maybe two or three. I need to learn the ins and outs of porting before i attempt this though. Thank god for the internet. :technical:
I have (actually my boss did it for me), but I also did it along side a valve job, exhaust, intake, and rejet, and never put the bike on a dyno so I have no idea what it did.
I worked at a machine shop at the time and was doing an engine rebuild so we had a little fun with the head while it was apart.
Ran very well all said and done. I'm trying to remember how it was compared to the bone stock GS I owned afterward, though I was a very different rider from one to the other and this was 4 bikes ago...
I'm sure it had more top end power, my second GS (stock) could barely get me up to 100 while my modded one could make it over.
I've been doing some reading on this subject and it seems alot of people are filling the radius around the valve stem with JB weld and shaping it all up nicely trying to increase air/fuel velocity. They are using it to raise the floor of the ports too. It's not specific to the GS500 but it's interesting none the less. I'm not sure its the way i want to go, anyone have ant thoughts on this practice?
Johno
Yeah.....I am thinking what happens if that lump of JB weld or a piece of it comes loose??? :cookoo:
Quote from: sledge on May 30, 2017, 02:22:01 PM
Yeah.....I am thinking what happens if that lump of JB weld or a piece of it comes loose??? :cookoo:
if its applied correctly, the whole lump would have to come off to be an issue.. not saying JB weld is the way, but lots of epoxy's have come a long way.
I have used high-temp epoxy on a couple of SR 500 heads. I have not had any problems with chunks breaking off. What has happened is some erosion after 1,000 or more miles that puts deposits on the intake valves and may have contributed to a burned exhaust valve. I think that the ethanol and other additives in the gasoline may be at fault. If I do it again, I'll try J-B Weld, which may be more resistant.