R5 Autopsy

[Jspooner]

At 6k RPM without fail this thing just starts bogging and running like crap. It can sort of "clean out" for a bit and sort of buck and make power but then even if I close throttle it will die..... Definitely not a throttle position thing it is at 6k every time.
I'm freaking lost again.

If you can't tell if its lean or rich do this, while you are riding it and it is doing what you say at said RPM just open the choke and see if it gets better of worse, if it gets better that means you are lean, if it gets worse that means you are rich, if it doesn't change anything then you could have another problem or you are waaaaayyyy lean. What do your plugs look like? 

[teazer]

It sounds like an ignition issue - which usually means it's actually carbs.

I'd suggest removing the carbs and clean out all the passages and particularly the main air jet passage. If that's blocked, the fuel is drawn in in big lumps and they don't burn well.  Fuel droplets are actually liquid and it's the vapor around the droplet that burns. Air through the main air jet helps to break large droplets down to smaller ones and that provides more surface area and more complete burning.  With poor atomization you can have raw fuel in the exhaust and a mixture that reads lean.  That apparent dichotomy is because not much fuel is burning.

Those carbs should just have a drilling IIRC without an actual air jet, so it should be easy to see if they are clean once the needle jets are removed.

[2 Stroke Jamoke]

I would say to check your ignition system carefully.  Go through it all, set the timing for 1.9btdc check your point gap new plugs and check that plug gap! I can tell you from direct experience if your ignition is off in any way you will have problems! The fact that it is rpm related leads me to think it's a plug or timing problem.  Chuck helped me at the gap this year with my "jetting". Turns out it was everything but jetting! Timing was way off dropped the plug range by one and switched to pump gas. Night and day difference (I was at 0 timng) so def check that stuff off first then move to jetting cheers-Ian

[Czakky]

I appreciate all the advice!

I checked and double checked timing. That won't stop me from triple checking though.

I like Teazer's suggestion of checking the air jet. I just had the carbs apart but I didn't remove the needle jet.

After checking the timing... again, I will try your suggestion JSpooner. I think I tried that already but that might've been a few jets ago.

[quocle603]

I would clean with an ultrasonic cleaner. I got one off Ebay for 20 bucks and it's great.

[Czakky]

I've got another rebuilt oil injector now with fresh check valve springs. Seems to work just fine.

My running issues continue. Fresh plugs, no change. The old plugs were pretty black with a good amount of oil.
I tried Jspooner's suggestion and hit the choke when I'm having issues and it definitely didn't help.

I'm going to try fresh(er) condensers and see if that helps.

Any recommendations on R5 condensers?

[quocle603]

I've got another rebuilt oil injector now with fresh check valve springs. Seems to work just fine.

My running issues continue. Fresh plugs, no change. The old plugs were pretty black with a good amount of oil.
I tried Jspooner's suggestion and hit the choke when I'm having issues and it definitely didn't help.

I'm going to try fresh(er) condensers and see if that helps.

Any recommendations on R5 condensers?

Go to your auto parts store and just get cheap 2 dollar condensors. They will work fine.

https://m.advanceautoparts.com/p/bwd-distributor-condenser-g635/3031810-P?fbclid=IwAR2RbdPQkpH00CJrQNmPYsDw4RYsXTeS12EdJrrfPmYiTKvUEYdJ27ifyCk

http://m.oreillyauto.com/h5/r/www.oreillyauto.com/site/c/detail/BWD0/G635/03461.oap?year=1976&make=MG&model=MGB&vi=1204816&ck=Search_03461_1204816_-1&pt=03461&ppt=C0330&fbclid=IwAR0Vb_mlbHjM7HOqVUhmN6y93NUq5qnH1L3iyYGYkNtjsMROsrlueXUGCrs

[bracket maker]

I've got another rebuilt oil injector now with fresh check valve springs. Seems to work just fine.

My running issues continue. Fresh plugs, no change. The old plugs were pretty black with a good amount of oil.
I tried Jspooner's suggestion and hit the choke when I'm having issues and it definitely didn't help.

I'm going to try fresh(er) condensers and see if that helps.

Any recommendations on R5 condensers?

Go to your auto parts store and just get cheap 2 dollar condensors. They will work fine.

https://m.advanceautoparts.com/p/bwd-distributor-condenser-g635/3031810-P?fbclid=IwAR2RbdPQkpH00CJrQNmPYsDw4RYsXTeS12EdJrrfPmYiTKvUEYdJ27ifyCk

http://m.oreillyauto.com/h5/r/www.oreillyauto.com/site/c/detail/BWD0/G635/03461.oap?year=1976&make=MG&model=MGB&vi=1204816&ck=Search_03461_1204816_-1&pt=03461&ppt=C0330&fbclid=IwAR0Vb_mlbHjM7HOqVUhmN6y93NUq5qnH1L3iyYGYkNtjsMROsrlueXUGCrs

+1 they will work fine. ford tractor works too.

[teazer]

Are the jets new genuine Mikuni or used and maybe worn out.  How does a jet get worn out? By owners sticking drill bits and wires through them to get the clean.  And dirty jets need more vigorous "cleaning".  In other words they are now too large.

Jets are cheap and life is short. 

[Czakky]

What an awesome forum! Two people reached out to me to try and help.

@Teazer All the brass is new as of 1.5 years ago installed by me. The bike has ran great until recently.

After chatting with Quocle yesterday I think we decided the best next step is to do a real deep clean on the carbs. Then try the new condensers. After that I will try my old coils one at a time.

Stay posted. Thanks again for the support.

[Czakky]

Oil pump not working.... It's got to be a restriction at the tank at this point.

[Striker1423]

Oil pump not working.... It's got to be a restriction at the tank at this point.

Mine flows about that much...

[Czakky]

Thanks Striker

[teazer]

Try removing the filler cap and see if it flows.  If so you need a breather hole in the cap.

[Czakky]

R5s have a separate breather tube, mine is and was clear. Good idea though.