sfdownhill

Agreed. Thought I was out of the woods three years ago when I installed the 847 reg/rect with fat cables and filled up all the tubular wire connectors with solder. Wishful thinking on one of these old bikes. Just learned that last week they installed a CA ECU for the dyno runs [And my track days - crap!]. They didn't want to use the 49 state ECU I provided because of how/where the wires on the original wire harness were melted - this is the second 49 state ECU that has become suspect. Puzzling but intriguing.

Agreed - I will reserve judgement until I get a chance to ride it, but am very happy with the appearance of the torque curve.

Quick update to demonstrate that I’m not one of those guys who posts up a big conundrum then vanishes. We installed an all-new used wiring harness and a VFRness subharness to beef-up the vulnerable main fuse circuit. This solved the electrical problem and the bike is running great on the dyno and the street/freeway, though only James has ridden it - I won’t get to ride it until a friend of James’s brings it out to the track this weekend. The dyno chart is off-topic for this electrical thread, but I’ll include it, just cuz. The bike did one hp less on the recent dyno pulls than it did on the Attack Performance dyno in 2019, but we’ve come to learn that the Attack dyno is notoriously generous. And why not? It’s gotta be good for business to have a dyno that skews a little high.

Thanks capn - once we get the electrical sorted, Ill gather all the photos and write up the mods.

Too much of an attention getter! I did a good job of installing the awesome 847 reg/rect and thought I'd be able to sit on the sidelines eating popcorn while watching all the other electrical gremlins get chased by other guys...

At the FunTrackDayz event last week, Duc2V4 and I were cracking up at the way the announcer on the PA would add a hooting "HOOOWEEEE!" after every grid announcement.

Thanks RC1237V and DannoXYZ! We will incorporate both your wise words as we undertake the hopefully-final trouble shooting and possibly harness swap this weekend. I found a clean looking harness from a 2000 VFR and have it on the way. Forensic examination of the old harness is definitely in order. We’ll have CSIVFR do the lab work.

Thanks Grum and Cogswell! I’ll incorporate your suggestions as we proceed with fact-checking. BTW, the current ECU in the problem bike is the good A01 from the bunch of four ECUs we used to test. I pulled the good A01 from another 2001 and so am shopping for an ECU to replace it. The ‘bad’ A01 may deserve another round of testing on the other non-problematic 5 gen.

Hello VFRers - The ECU on my 5 gen doesn’t pass ground to the fuel pump, so I would like to purchase a replacement OEM ECU for a 2000-2001 5th gen VFR. Here is the part number of the ECU I’m looking for (part number is printed on all ECUs): 38770-MBG-A01 If anyone has a spare ECU with this part number or knows of someone who might have one, please let me know - I’ll be very grateful. I can also be reached by text/phone at 415-699-2805 Cheers, Lance

Thanks raYzerman - if the harness matches the ECU in that ad, it’s a 98/99 harness like the ones we already have. In the US, 5 gen ECUs w part numbers ending in 671 (49 state) and 771 (California) are all 98/99. I’ll check with the seller.

Tirso - thanks for letting me know you had the main fuse B problem too. Yep, I’ll do a ‘look what I done’ thread on the mods.

Thanks for the responses guys - we’ll check the main fuse B and its wiring. I do have a VFRness mini harness on hand, so can and will replace any wires that appear to have been overheated or damaged.

First please allow me to shoot a super huge metric ton of thanks to VFRD member Mohawk! He talked me through some of the finer points of his Yoshi-style dual velocity stacks and big airbox mod. As with the header project, couldn't have done it without him Problem in a nutshell: -Grounding problem rears its ugly head at higher rpms - engine cuts out then comes back on, rinse repeat a dozen times or so until it quits for good. -The last time it died for good and coasted to a stop, a few wisps of smoke came out from under the dash and it smelled of very hot wiring insulation. -Three hours later at lunch break the crash truck brings the poor VFR back to the pits - all the way to my pit, which is more than really needed. Thanks FunTrackDayz crew! Fuel pump wouldn't prime, pulled fuel pump connector and tested - no voltage. Tested across the FI/IGN/PUMP fuse - no voltage. -12 hours later and fully cooled down, the bike started up, idled, and ran, though the tach remained inoperative, pegged at zero. -The professional mechanic who is working hard to solve the problem wants to install an entire new [used] wire harness. -We have found two 1998/1999 harnesses, both in great shape. But 1998/1999 VFR's don't have a catalytic converter or O2 sensors - mine is a 2001, so it has a cat converter and two O2 sensors. -QUESTION: Can a 1998/1999 VFR wire harness [and 1998/1999 ECU if necessary] be installed and work well on a 2000/2001 VFR? Longer version: [1] Almost 3 years ago, my 60k mile 2001 would start and idle, but died immediately when rev'd over 2500rpm. The exhaust smelled very rich, so I thought an injector or two were stuck, and I got all involved with a new V4 mistress. Mistress shown here: November 2021 I moved to a new city for a new job, and along the way, lucked into a relationship with a certified Ohlins suspension tech named James who also happened to make custom captive axle spacers for race bikes. One thing led to another, and we did a bunch of mods barely touched on in the photos at the end of this post. The engine got a valve adjustment, starter valves synched, new AS3 silicon coolant hoses, thermostat, coolant, oil, filter, double velocity stacks, and a Rapid Bike Race with My Tuning Bike autotune module. [2] During static engine test runs at the craftsman's shop after the mechanical work, the engine would sometimes cut out - die. James and his partner Mike worked very hard to find what appeared to be a problematic ground on one of the bike's circuits. James thought it might be a bad ECU, so superstar VFRD member Duc2V4 went through his VFR inventory, came up with three different 5 gen ECUs, and ran them over to James's shop for testing. They ended up with a good 49-state 2000/2001 ECU. Mike noticed that sometimes raising the tank would cause the pump to stop while priming. They couldn't find a broken/failed ground wire in the harness, so they added new ground wires to the suspected circuits. It seemed fixed. The dyno James usually uses wasn't available due to the tragic death of young MotoAmercia racer Jason Aguilar - his family owns the dyno. James couldn't street test the 5 gen because I had been silly and distracted enough to forget to give him the current California tags. [3] I took the bike from James's shop, picked up Duc2V4 and his 5 gen, and headed to the track. Toward the end of the first lap of the first session, the bike started cutting out for around 1/2 second, recurring maybe every 15-20 seconds - randomly stopping running under acceleration around 8000rpm, then it would run again. I thought the cutting out was the autotune working on the fuel map, but as I started the second lap, the engine cut out and the tach dropped to zero, then the engine started back up again. Tach stayed on zero.. A few turns later, the sad VFR quit running all together and we coasted to a stop on a safe bypass road. A few wisps of smoke came out from under the dash and I smelled hot electrical wiring or components. The motorcycle cranked over but would not fire. [4] Later at lunch break the crash truck brings the poor VFR back to the pits. Fuel pump wouldn't prime, so Duc2V4 borrowed a multimeter from Thomas the guy pitted next to us, and checked for voltage. He, pulled fuel pump connector and tested - no voltage. Tested across the FI/IGN/PUMP fuse - no voltage. It must be said that James is beyond competent as a mechanic, machinist, and as a track day promoter. I trust him completely and he felt terrible about my VFR quitting at the track. We got back from the track day at 9:30 that night. James met us at his shop to take the bike back in and figure out the problem. The engine started and idled, rev'd a little, but the tach was still sitting at zero. If it ends up that a complete wire harness swap is needed, the question remains: "Can a 1998/1999 VFR wire harness [and 1998/1999 ECU if necessary] be installed and work well on a 2000/2001 VFR? Here's the stuff that went on w my 5 gen [Scarlet]:

Hey guys - sorry for not being present on this thread for a while. Duc2V4 and I have been struggling with our VFRs and not getting around to checking here. His 108k mile 6 gen was using a lot of coolant, so he decided to put a 5 gen engine into the 6 gen chassis - cool beans. My 5 gen hadn't run for 2 years [Bad motorcycle owner...bad], and when I finally got it running and out to the track, it quit after a lap and a half. I'm about to start a thread on the intermittent electrical problem. Note: intermittent is the most loathed word in all the troubleshooting universe. We'll probably be able to be back here after mid-April.

Hi Cornpo. There is not a formal list for another round of headers, but don't write it off. There are about 5 people interested in headers, and that's taken 6-8 months to gather. The minimum order is 15 units, so it's possible that - over a fair amount of time - we'll be able to put together an order.

Hip hip hooray for hoarded parts! Let us pay tribute to our racks and stacks of parts...they'll all be put to porper use in good time. Seb, yes there are maps for 5 gen [PC3, can be converted to PCV], 6 gen [PCV], and 8 gen [PCV]. Paypal $50 to vfrheaders@gmail.com and let us know which map you'd like.

Hi sfdownhill, Thank you for your donation of 25.00 USD. We look forward to improving the forums with your donation. Thanks VFRDiscussion

Oy! I completely neglected to check your geographic location! Happy hunting on your 5 gen search.

Even with 6 x $ you’d have a hard time finding someone who’s installed these headers with the listed items and a good tune who wouldn’t do it all again...I’m getting pissed at myself for not sorting my 5 gen’s injectors so I can get back on the road with it. Not to mention that the Rapid Bike Race with My Tuning Bike autotune will probably benefit from a track day or two...as will I.

Hey Skids - not to hijack the header thread, but since you’re looking for a 5 gen to put headers on, I can justify proceeding! I have a 2001 with less than 10,000 miles that will be for sale in two months (maybe sooner). It’s all stock except upgraded regulator/rectifier, never crashed or dropped, in pristine condition. PM me if you’d like to continue this conversation.

Thanks for this, Dano, it’s very helpful. We’ve expanded 5 or 6 midpipes now, always done by Wade (the guy who makes our headers) in his shop, and have not had any splits. The commercially manufactured midpipes - Staintune and Yoshimura - had 3 or 4 slots where they fit over the headers. Wade cut slots into the custom midpipes too, and none of them split - not sure if it was the slots, technique, or materials that helped us avoid splits.

Mohawk, that looks like about the lightest sprocket carrier/cush drive I've ever seen. It looks like there's a JT logo on your carrier - is this correct? I'm used to seeing Ducati drive assemblies with an outer flange covering the cush bobbins, with bolts from the bobbins coming through the outer flange and nuts on the bolts holding the outer flange [see vfrcapn's post/photo above yours]. I love your safety wire loop [very tidy] and it appears that the cush bobbins on your assembly have female hex fittings, so I assume they thread into something that transfers drive forces to the carrier, yes? It would be very interesting if you could shed some light. Thanks!

So glad they finally made it Francisco! What an ordeal it was getting USPS and Portuguese customs to coordinate...whew. Keep us apprised of your install and tuning. Cheers! Hi zinsern - there is no telling if it will happen, but will let you know if it does.

Beautiful work, Capn. Not only a goer, but also a shower. Bet it sounds schweet.

Thanks for that info Cogswell. And yikes - my headers don’t have bungs for the OEM O2 sensors. Plus they’re already ceramic coated. Dang. Well, it’s just another of those puzzles we solve when modding our VFRs.