I'd pull plug, rotate motor over in gear making sure exhaust valves are closed. Then gently push a rag into the exhaust runner port. Then I suggest a peanut grinder or dremel tool. Then use vacuum then pull rag out, then roll bike to open exhaust valves then stick vacuum in exhaust port air will flow through spark plug hole through exhaust valves making absolutely sure you don't get metal shavings into the cylinder.
There is a lot of metal that can come out of the exhaust port. I was surprised. The bike really rips after doing the GSXR muff, grinding out the welds and removing some of the material in the port. Thanks for watching.
Hello, I have a question about your video on YT, where you enlarged the cylinder head exhaust opening, did your Dr lose any torque at low and medium revs after this modernization?
Hi, no I haven’t noticed any loss. The bike pulls hard from idle to upper rpms. But I did make several changes at once. The muffler, grind the welds at the header, jetting and air box. I’ll be putting a DRZ400 pumper on in the next few month, I heard that will make a big difference. Thanks for watching.
That had to have helped flow immensely.being a performance car qnd bike guy im always on the lookout for free hp ...crappy casting and porting or gasket matching has always yeilded gauns for me ..i bet a bit of blending and knife edging and youd really help the upper rpms .. I wonder how the valve seat and pocket ride looks ..as im sure you knkw thats where the big porting gains generally are.great vid brother.enjoy the bike
Your welcome, A lot sometimes gets lost from the engineering drawings to the cast product. Thank You for watching. Enjoy the DR650 they are wonderful bikes.
I have no Idea, because I made a bunch of changes at the same time? If the pipe is off again I would like to clean up the port a bit more.Thank you for watching.
Let me know what you find out when you do, At some point I would like to remove the exhaust header pipe and finish blending the exhaust port to the copper gasket all the way around, I left a lot that can be cleaned out. I need a smaller half round bastard file. I know the bike really rips with the GSXR muffler and the header/port mod. Haven't touched the airbox or carb yet.
@@sumpoiler Thanks, That would be a good problem to have. I have read guys getting better mileage do the the efficiency of the FCR39 carby too, plus instant power down low. Looks like I have my summer project! take care.
Good vid. Am planning to file header pipe lip only. Can you or anybody else advise if doing this will impact on Mikuni carby needle or jet settings in any way Thks
It shouldn’t , just by grinding the lip in the header pipe. Had the header pipe off the DRZ250 and someone already ground the header pipe, but I stuffed an oily paper towel in the exhaust port and with the Dremel matched the entire port to the exhaust crush washer. Removed about an 1/8 inch all the way around. Hoping that makes a difference?? I’ll have a video on that soon. Next time the exhaust is off the DR650 I’ll do the same to it. Can’t hurt, I’m just matching the port to the gasket. Thanks for the comment.
You know, everything worked out great, The bike haul ass, I did the Procycle mid pipe kit, the GSXR muffler and ground down the bumps in the exhaust all at the same time, so I can't tell you how each one worked, but together it Rips!! Thank You.
Regarding the exh ports. What you are doing is the least of your problems. In fact you may be making things worse as you are removing a potential reversion lip.
Actually bike runs great, factory castings leave a lot to be desired, matching the ports or blue printing has been done for years by many including me. I am not oversizing the port I am bringing it to where it should have been from the factory. I also removed the restrictive welds in the header pipeand matched the exhaust port to the gasket size. No harm was done and the performance of the bike was greatly enhanced.Castings rarely come from the factory as the designers intended. Thank you
Maybe even 6% ha ha probably 0% not sure? I had my DRZ250 exhaust header off a few days ago to grind the welds, and there was a 1/8 inch lip all the way around the crush gasket in the cylinder. I stuffed an oily rag in the exhaust port and Blended the port to the size of the crush washer for the exhaust header. It came out nice and I will do that next time the DR header pipe comes off. Not doing anything crazy just opening it to the size of the pipe for a smooth flow. Ill post that video too.
Spray shavings cream into ports , use dreamell and then shop vac
That's a great idea, next time the exhaust is off I'll try that, and blend in the exhaust port.
I packed the valve seat ports with cotton wool balls covered in vaseline and just pulled them out when finished.
Thank you, next time the pipe is off I'll finish cleaning up the ports with the dremel, and stuffing the area behind where grinding.
I'd pull plug, rotate motor over in gear making sure exhaust valves are closed. Then gently push a rag into the exhaust runner port. Then I suggest a peanut grinder or dremel tool. Then use vacuum then pull rag out, then roll bike to open exhaust valves then stick vacuum in exhaust port air will flow through spark plug hole through exhaust valves making absolutely sure you don't get metal shavings into the cylinder.
Great point!
Hmm, good stuff. "Thumbs up" from this Kentucky boy.
There is a lot of metal that can come out of the exhaust port. I was surprised. The bike really rips after doing the GSXR muff, grinding out the welds and removing some of the material in the port. Thanks for watching.
Hello, I have a question about your video on YT, where you enlarged the cylinder head exhaust opening, did your Dr lose any torque at low and medium revs after this modernization?
Hi, no I haven’t noticed any loss. The bike pulls hard from idle to upper rpms. But I did make several changes at once. The muffler, grind the welds at the header, jetting and air box.
I’ll be putting a DRZ400 pumper on in the next few month, I heard that will make a big difference.
Thanks for watching.
@@verbalwidget7267
Gday mate
How’d ya go with the pumper?
Did ya find one?
Cheers
That had to have helped flow immensely.being a performance car qnd bike guy im always on the lookout for free hp ...crappy casting and porting or gasket matching has always yeilded gauns for me ..i bet a bit of blending and knife edging and youd really help the upper rpms .. I wonder how the valve seat and pocket ride looks ..as im sure you knkw thats where the big porting gains generally are.great vid brother.enjoy the bike
Your welcome, A lot sometimes gets lost from the engineering drawings to the cast product. Thank You for watching. Enjoy the DR650 they are wonderful bikes.
How big of a difference does it make filing it off
I have no Idea, because I made a bunch of changes at the same time? If the pipe is off again I would like to clean up the port a bit more.Thank you for watching.
I only did the header pipe file , may have to check the head after seeing this
Let me know what you find out when you do, At some point I would like to remove the exhaust header pipe and finish blending the exhaust port to the copper gasket all the way around, I left a lot that can be cleaned out. I need a smaller half round bastard file. I know the bike really rips with the GSXR muffler and the header/port mod. Haven't touched the airbox or carb yet.
@@verbalwidget7267 When You Do The Carby And Air Box Mods You Have Trouble Keeping The front wheel Down
@@sumpoiler Thanks, That would be a good problem to have. I have read guys getting better mileage do the the efficiency of the FCR39 carby too, plus instant power down low. Looks like I have my summer project! take care.
Good vid. Am planning to file header pipe lip only. Can you or anybody else advise if doing this will impact on Mikuni carby needle or jet settings in any way Thks
It shouldn’t , just by grinding the lip in the header pipe.
Had the header pipe off the DRZ250 and someone already ground the header pipe, but I stuffed an oily paper towel in the exhaust port and with the Dremel matched the entire port to the exhaust crush washer. Removed about an 1/8 inch all the way around.
Hoping that makes a difference??
I’ll have a video on that soon.
Next time the exhaust is off the DR650 I’ll do the same to it.
Can’t hurt, I’m just matching the port to the gasket.
Thanks for the comment.
How did it work out?
You know, everything worked out great, The bike haul ass, I did the Procycle mid pipe kit, the GSXR muffler and ground down the bumps in the exhaust all at the same time, so I can't tell you how each one worked, but together it Rips!! Thank You.
Regarding the exh ports. What you are doing is the least of your problems. In fact you may be making things worse as you are removing a potential reversion lip.
Actually bike runs great, factory castings leave a lot to be desired, matching the ports or blue printing has been done for years by many including me. I am not oversizing the port I am bringing it to where it should have been from the factory. I also removed the restrictive welds in the header pipeand matched the exhaust port to the gasket size. No harm was done and the performance of the bike was greatly enhanced.Castings rarely come from the factory as the designers intended. Thank you
5% more horse power!
Maybe even 6% ha ha probably 0% not sure? I had my DRZ250 exhaust header off a few days ago to grind the welds, and there was a 1/8 inch lip all the way around the crush gasket in the cylinder. I stuffed an oily rag in the exhaust port and Blended the port to the size of the crush washer for the exhaust header. It came out nice and I will do that next time the DR header pipe comes off. Not doing anything crazy just opening it to the size of the pipe for a smooth flow. Ill post that video too.
Huge lip!
Flow wise it is a good size hump. I got a little bit of it out. Next time I will be ready for it. Thank you for watching
@@verbalwidget7267 Thanks for the vid