cam timing

[Katzukes]

Hi, I have a GS1100 motor that I'm rebuilding. So far I have a 1325 F.B.G big block, mild port job on 1100 head, gsxr750 dot cams and rs36 carbs. My questions are, what should the cams be degreed to and where should I start with the carb settings, main, needles etc. It's not a drag bike, just street, with the occasional stop light blast.

 

[Guest]

For what you want to do I would put the cams at 107 exhaust and 105 intake where you jet the carbs at will bet deturmand by the build and compression on your motor and you elavation you live at. Just start out with the Mukuni factory setting as most suggest. But I have found that they run better jetted richer than the factory settings.

 

[Guest]

I have a similar engine that I race. 1327 with 10.5 to 1 compression. rs 38's needle in the middle. 125 mains. Cam Motion G7 intake and G4 exhaust. Middle of the road porting. With the cams degreed to 107 for both, the builder got 180hp...Of course, he was a very knowledgeable engine builder...
https://www.youtube.com/watch?v=WndH55dZqsY
Curt

 

[rapidray]

gsxr750 dot cams

Mae SURE you check where the cams land in all the journals. You will have to grind the cams where they aren't ground where they land in one of the journals in the head. Also, with the intake cam at 105 make sure you have enough piston to valve clearance. I like .100 on the exhaust side & .070 on the intake side on a street motor. On race engines I will run them as tight as .080 & .050 if I know the rider is good with their parts & how they run. When I check piston to valve clearance, I do it with a dial indicator on the retainer & check at 8 degrees before & after TDC on the cams. This tells you the TRUE piston to valve clearances. It will be a FUN street motor but make SURE you have a big oil cooler on it. I consider the next parts necessary on a high performance engine also: 750 oil pump gears, top end oiler, welded crank, welded heavy duty clutch hub, & cylinder & case studs. After about 180 hp, even on a street bike, you will need to go to a straight cut gear set on the crank & clutch hub. Feel free to call me at 714--356--7845 if you have questions or need help.
Ray.

 

[rapidray]

You also won't have a tach drive anymore with the GSXR exhaust cam. Keep that in mind if you are planning on using the stock cable drive tach.
Ray.

 

[Katzukes]

Thanks for the replies, I have the factory welded crank, welded angled gear hub, 750 oil pump gears, 1150 oil cooler and cover, APE studs, case and cylinder also a top end oiler. I am putting it in a 82 Katana so I dont need the tach drive. Rapidray, it's coming together slowly but if I run into any problems I will get in touch and thanks. I'm gathering 130 mains and the needle in the middle is a good start for the RS36 carb.