74 RD350 - Anything more than 2 strokes is a waste
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Re: 74 RD250...is now a 350 - Anything more than 2 strokes is a waste
Yep. Got a box of those. Looks like that head is pretty disasterized without the crack! (got a box of those too) Still trying to figure out why I keep them. You should be able to find good ones for reasonable. The later year heads are stronger having a complete last fin on the inside and crack far less often, so are a better replacement. Look for those. Some other things to consider since you have an issue and are going to need cylinder work: 350's have trouble with the head gaskets. Bone stock they are marginally ok, but add any extra pressure they leak. Common solution is to mill the cylinders flat at the gasket surface and use RD400 gaskets - giant improvement, but the combustion chamber needs to be adjusted to compensate for the thinner gasket. Cutting an o-ring groove in the cylinder is even better, but results in zero gasket thickness and combustion chamber compensation. Adding a step in the head to center it in the gasket recess of the cylinder, cutting a groove for an o-ring in the head, and adjusting the combustion chamber accordingly is the optimum solution and does not require altering the cylinders. A bolt on solution are the new Ottoco DG replica heads which also solve this problem with an o-ring seal, but need careful re-torquing to stay tight. You lose the stock look of the engine and they are pricey, but bolt on to stock cylinders and solve all the problems. There is power and reliability to be had fussing with the heads and is well worth the trouble.
Yep. Got a box of those. Looks like that head is pretty disasterized without the crack! (got a box of those too) Still trying to figure out why I keep them. You should be able to find good ones for reasonable. The later year heads are stronger having a complete last fin on the inside and crack far less often, so are a better replacement. Look for those. Some other things to consider since you have an issue and are going to need cylinder work: 350's have trouble with the head gaskets. Bone stock they are marginally ok, but add any extra pressure they leak. Common solution is to mill the cylinders flat at the gasket surface and use RD400 gaskets - giant improvement, but the combustion chamber needs to be adjusted to compensate for the thinner gasket. Cutting an o-ring groove in the cylinder is even better, but results in zero gasket thickness and combustion chamber compensation. Adding a step in the head to center it in the gasket recess of the cylinder, cutting a groove for an o-ring in the head, and adjusting the combustion chamber accordingly is the optimum solution and does not require altering the cylinders. A bolt on solution are the new Ottoco DG replica heads which also solve this problem with an o-ring seal, but need careful re-torquing to stay tight. You lose the stock look of the engine and they are pricey, but bolt on to stock cylinders and solve all the problems. There is power and reliability to be had fussing with the heads and is well worth the trouble.
jchek779
Leave the gun. Take the cannoli.
Re: 74 RD250...is now a 350 - Anything more than 2 strokes is a waste
Here's a question that some of you guys can hopefully answer. I've been on the hunt for a 3/8 or 10mm offset front sprocket for a 520 chain that guys the spline. I've called around to the known sprocket shops with no luck. I came across a thread in a google search that said the K0-K6 Gsxr 1000's have the same spline pattern and a 3/8 offset in stock configuration. Do any of you guys have first hand knowledge with the GSXR setup to verify if the sprocket is in fact offset? Thanks in advance for any help or leads.
Here's a question that some of you guys can hopefully answer. I've been on the hunt for a 3/8 or 10mm offset front sprocket for a 520 chain that guys the spline. I've called around to the known sprocket shops with no luck. I came across a thread in a google search that said the K0-K6 Gsxr 1000's have the same spline pattern and a 3/8 offset in stock configuration. Do any of you guys have first hand knowledge with the GSXR setup to verify if the sprocket is in fact offset? Thanks in advance for any help or leads.
Re: 74 RD250...is now a 350 - Anything more than 2 strokes is a waste
If you can't find what you need, you could always turn down the stock 530 sprocket and weld it to the new 520. Then machine out the center of the 520 and there you are. Not a big project if you have an output shaft to align them for welding and can use your friends lathe again. Of course, better if you can just buy one but it's an option if you can't.
If you can't find what you need, you could always turn down the stock 530 sprocket and weld it to the new 520. Then machine out the center of the 520 and there you are. Not a big project if you have an output shaft to align them for welding and can use your friends lathe again. Of course, better if you can just buy one but it's an option if you can't.
jchek779
Leave the gun. Take the cannoli.
Re: 74 RD250...is now a 350 - Anything more than 2 strokes is a waste
Thanks for the response. That's definitely on the list as an option. I saw that in JohnU's Suzuki build. I'll have to bring the front sprocket into work to check the hardness of it. I'm not sure a carbide cutting bit would touch it, but I guess we'll see. Going to have the local bike shop order me a gixxer front to see it first hand.jpmobius said:
jchek779
Leave the gun. Take the cannoli.
Re: 74 RD250...is now a 350 - Anything more than 2 strokes is a waste
Thank you. That 450 still blows me away with how well it came out. The "thumbs up" that accompany riding that bike make the 25 hours in front of the buffing wheel worth the time invested.DV2000NJ said:
jchek779
Leave the gun. Take the cannoli.
Re: 74 RD250...is now a 350 - Anything more than 2 strokes is a waste
Part I - Brake caliper adapter. I spent last weekend creating cardboard mock-ups of front and rear brake caliper adapters. I'm running a KX450F front brake/master cyl combo. On the rear, a 2009-2012 Ninja 250 setup to work with the swingarm but needed some new mounting holes to work with the braking rear rotor and Excel hub. I turned the cardboard into Solidworks and then printed them in plastic. I want to make all of my mistakes in $7 plastic before having them cut on the waterjet. As it turns out, I made a huge mistake with the front adapter and sent the CAD model to the printer (and the waterjet for quote...). Glad I made that mistake. I was able to drill and tap the rear pieces and get them mounted on the bike. Good news - it fits. We'll try the front again this week.
I ordered a 520 conversion 03 GSXR 1000 Sun Star front sprocket after having read in a google search that the 01-06 1000's came stock with a 10mm offset front sprocket. Picked it up today to find that it had zero offset. Still screwed. I'm going to try to find somewhere locally to figure out how to fabricate an offet sprocket with the 530 stocker and the 520 conversion. I can say for sure that the stocker is HARD.
I also laid some black paint on the recessed portions of the side covers and finished adding the grain to the aluminum. The side covers didn't come out perfect, but my 40 year old bike isn't perfect either.
Part I - Brake caliper adapter. I spent last weekend creating cardboard mock-ups of front and rear brake caliper adapters. I'm running a KX450F front brake/master cyl combo. On the rear, a 2009-2012 Ninja 250 setup to work with the swingarm but needed some new mounting holes to work with the braking rear rotor and Excel hub. I turned the cardboard into Solidworks and then printed them in plastic. I want to make all of my mistakes in $7 plastic before having them cut on the waterjet. As it turns out, I made a huge mistake with the front adapter and sent the CAD model to the printer (and the waterjet for quote...). Glad I made that mistake. I was able to drill and tap the rear pieces and get them mounted on the bike. Good news - it fits. We'll try the front again this week.
I ordered a 520 conversion 03 GSXR 1000 Sun Star front sprocket after having read in a google search that the 01-06 1000's came stock with a 10mm offset front sprocket. Picked it up today to find that it had zero offset. Still screwed. I'm going to try to find somewhere locally to figure out how to fabricate an offet sprocket with the 530 stocker and the 520 conversion. I can say for sure that the stocker is HARD.
I also laid some black paint on the recessed portions of the side covers and finished adding the grain to the aluminum. The side covers didn't come out perfect, but my 40 year old bike isn't perfect either.
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jchek779
Leave the gun. Take the cannoli.
Re: 74 RD250...is now a 350 - Anything more than 2 strokes is a waste
Just found a place in Japan that makes RZ250/RZ350 front sprockets in 520 with a 10mm offset. I thought I had read somewhere that the RZ output shaft spline in different from the RD250/350 - can anyone confirm/deny that the RZ and RD share the same output shaft spline geometry?
http://xam-japan.co.jp/en/sprocket5.html
Just found a place in Japan that makes RZ250/RZ350 front sprockets in 520 with a 10mm offset. I thought I had read somewhere that the RZ output shaft spline in different from the RD250/350 - can anyone confirm/deny that the RZ and RD share the same output shaft spline geometry?
http://xam-japan.co.jp/en/sprocket5.html
Re: 74 RD250...is now a 350 - Anything more than 2 strokes is a waste
Man I'm not 100% sure but at least 99.99% that they are different. There is a place in Australia that makes the offset RZ so I contacted them and they said no dice. I was able to turn down a 530 offset front sprocket on a lathe. It was hard but once it started cutting it was on. I think that I may have mentioned before to jcheck out PBI sprockets. They do the offsets.
Don't worry about the side covers, as trick as those wheels look most people may not notice that there is an engine in there.
Man I'm not 100% sure but at least 99.99% that they are different. There is a place in Australia that makes the offset RZ so I contacted them and they said no dice. I was able to turn down a 530 offset front sprocket on a lathe. It was hard but once it started cutting it was on. I think that I may have mentioned before to jcheck out PBI sprockets. They do the offsets.
Don't worry about the side covers, as trick as those wheels look most people may not notice that there is an engine in there.
Re: 74 RD250...is now a 350 - Anything more than 2 strokes is a waste
http://www.shop.pbisprockets.com/media/PBI%20Catalog%20Complete(1).pdf
Everything (Front) that starts with 776 is 530 with the same countershaft as the RD350. 456 part number is the 520 conversion.
http://www.shop.pbisprockets.com/media/PBI%20Catalog%20Complete(1).pdf
Everything (Front) that starts with 776 is 530 with the same countershaft as the RD350. 456 part number is the 520 conversion.
jchek779
Leave the gun. Take the cannoli.
Re: 74 RD250...is now a 350 - Anything more than 2 strokes is a waste
I had called around to a number of different places looking for a 520 offset in that spline - PBI, JT, Sprocket Specialists but had no luck. I ended up ordering a PBI 530 in a 3/8" offset that I'll have to turn down.
clem said:
I had called around to a number of different places looking for a 520 offset in that spline - PBI, JT, Sprocket Specialists but had no luck. I ended up ordering a PBI 530 in a 3/8" offset that I'll have to turn down.
Re: 74 RD250...is now a 350 - Anything more than 2 strokes is a waste
Looks like you have the skills to get it done. To me it seemed lot easier than welding two sprockets together. You would still have to put the inside one on a lathe to turn it down past the teeth so either way you would be on a lathe.
Looks like you have the skills to get it done. To me it seemed lot easier than welding two sprockets together. You would still have to put the inside one on a lathe to turn it down past the teeth so either way you would be on a lathe.
Re: 74 RD250...is now a 350 - Anything more than 2 strokes is a waste
I had a friend of mine who is a machinist do it for me. I would have hurt myself. He turned it down flat then put a little taper on the teeth.
He also did my rear drive hub to get everything to line up.
I had a friend of mine who is a machinist do it for me. I would have hurt myself. He turned it down flat then put a little taper on the teeth.
He also did my rear drive hub to get everything to line up.
jchek779
Leave the gun. Take the cannoli.
Re: 74 RD250...is now a 350 - Anything more than 2 strokes is a waste
It's much more cost effective to make all of your mistakes in printed plastic. Unfortunately, it takes some time to get things printed as I have to leave work during business hours to head to the coworking place where the printer is located, load the files, then head back the next day to pick them up. My first mock up was with a cut up cereal box. It was kinda flimsy so my hole locations were slightly off. Then I realized that the caliper needed more room from the rotor OD. I've revised my 3D model again but don't want to wait for the plastic to be printed. I may go the route of doing it in MDF. First world problems right?
It's much more cost effective to make all of your mistakes in printed plastic. Unfortunately, it takes some time to get things printed as I have to leave work during business hours to head to the coworking place where the printer is located, load the files, then head back the next day to pick them up. My first mock up was with a cut up cereal box. It was kinda flimsy so my hole locations were slightly off. Then I realized that the caliper needed more room from the rotor OD. I've revised my 3D model again but don't want to wait for the plastic to be printed. I may go the route of doing it in MDF. First world problems right?
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Habanero52
The Race......is only with yourself!
Re: 74 RD250...is now a 350 - Anything more than 2 strokes is a waste
Very cool.
jchek779 said:
Very cool.
jchek779
Leave the gun. Take the cannoli.
Re: 74 RD250...is now a 350 - Anything more than 2 strokes is a waste
I did't want to burn the time to have another iteration of the front brake caliper adapter 3D printed in plastic, so I went the pre-technology route and made one out of wood. I printed my 2D adapter drawing to scale and used it as the template for my wood mock up. I think I've got this close enough to turn over to the laser cutter. I also found out that you can tap threads into wood.
I did't want to burn the time to have another iteration of the front brake caliper adapter 3D printed in plastic, so I went the pre-technology route and made one out of wood. I printed my 2D adapter drawing to scale and used it as the template for my wood mock up. I think I've got this close enough to turn over to the laser cutter. I also found out that you can tap threads into wood.
