[GSS]

This is probably very simple. My interceptor had this same vibration above 50 mph and it was clear that there was a fine bounce in the front wheel. Took the wheel to Marty at GoMoto in Minneapolis and within 5 minutes he confirmed that the tire was slightly out of round. Replacement tire solved the problem immediately.

This does not sound like wobble….only the early C5s with the 18” front wheel had a life on edge, impressively head bobbing wobble at 60+ mph…..every Bullet fan should experience that once 

[iblastoff]

OK, this is probably not complicated enough but has anyone checked; 1. wheel balance  2. concentric run out of the wheels and tires??

i'll ask about this when i drop off my bike for 500km service this thursday!

[fireypete]

Get the front wheel off the deck, centre stand and a Jack maybe.  Turn the wheel and tap each spoke and listen, hopefully they all sound the same, if one sounds "dull"'may need a tighten   If the wheel has been "out of true" for a while the tyre itself maybe stuffed now so even fixing any rim issue may not solve the wobble.  This remedy was found on YouTube, Indian bloke posted it. Couldn't understand the lingo but could see what he did to fix his issue.

[Dutch Rider]

i'll ask about this when i drop off my bike for 500km service this thursday!

Mine is going to the dealer thursday as well for it's first service!

[Jared_Lee]

Sorry, I meant to also add that no way, no how is 3,500 rpm in 6th lugging the engine if the engine is running properly. Literally zero chance. 3,500 rpm is this motor's sweetest, smoothest spot. Takes more to go highway speeds, but it'll get buzzier above 4,000.

[JesusA]

As discussed here in your other thread…….

https://forum.classicmotorworks.com/index.php?topic=31105.0

……My bike handled as smooth as silk until I had new tyres fitted. Then the bobbing started.
It was fixed by fitting a new tyre and wheel by the dealer, but only after weeks and weeks of chasing the cause.

My advice to you and iblastoff is to go to a specialist motorbike tyre business - hopefully you have a reputable business within reach - explain the issue and see what they come up with. With any luck, they might save a lot of time and angst.

HTHs

Thanks Spicyred, since business here in august is not at 100%, I will run a bit more and in september, if issue persist, probably I will try to find and contact one specialist as you recomend.

[NVDucati]

For folks with the bounce issue and it is because the tire itself is out of round (not the rim / not a mounting issue).
Tire shaving is a thing. We used to do it a lot (before radial tires). There was a time when we would strongly advocate for Continental tires because they were the most round. Now-a-days, it is Avons which seem to hold that distinction. (they don't outsource their top line tires)

Still, we would check all the tires on our personal bikes and our race bikes. And for customers who had been lucky enough to get a stinker. We used a shop made roller bearing mounted on a spring tensioned arm. Like a big dial-indicator to test. The actual shaving was done on the centerline of the tread with a Shur-form (grater).
It just removes a tiny bit to get it round. And you are suffering waiting for your sucky tire to wear out anyway.

Not rocket surgery. You don't really even need to take the wheel off. No need to over think it. Round is round, unround is not. Just say'n ...
https://www.amazon.com/s?k=shurform+blade&crid=GN8OYQGX0BET&sprefix=shurform+%2Cautomotive%2C240&ref=nb_sb_ss_fb_1_9_ts-doa-p
https://www.amazon.com/Tire-Grinding-Disc-4-Inch/dp/B01MTDAF96

[zimmemr]

For folks with the bounce issue and it is because the tire itself is out of round (not the rim / not a mounting issue).
Tire shaving is a thing. We used to do it a lot (before radial tires). There was a time when we would strongly advocate for Continental tires because they were the most round. Now-a-days, it is Avons which seem to hold that distinction. (they don't outsource their top line tires)

Still, we would check all the tires on our personal bikes and our race bikes. And for customers who had been lucky enough to get a stinker. We used a shop made roller bearing mounted on a spring tensioned arm. Like a big dial-indicator to test. The actual shaving was done on the centerline of the tread with a Shur-form (grater).
It just removes a tiny bit to get it round. And you are suffering waiting for your sucky tire to wear out anyway.

Not rocket surgery. You don't really even need to take the wheel off. No need to over think it. Round is round, unround is not. Just say'n ...
https://www.amazon.com/s?k=shurform+blade&crid=GN8OYQGX0BET&sprefix=shurform+%2Cautomotive%2C240&ref=nb_sb_ss_fb_1_9_ts-doa-p
https://www.amazon.com/Tire-Grinding-Disc-4-Inch/dp/B01MTDAF96

I've cut a lot of tires with a shurform.  But as far as tire truing, we ran a lot of recaps on our trucks and not all of them were round. When we got a real clanger we'd send it back to the tire shop and they'd true it on thier lathe. I was involved with an SCCA showroom stock car effort at one time and we'd send the tire over to be cut and trued as well. If you have a truck tire shop or a tire shop that sells race tires in your area it might be worthwhile asking them if they can mount up and true the tire for you.

But like NV say: it ain't rocket science, if it were mine I'd spin the tire, if it has a high spot that I couldn't shave off, I'd just replace it with a new Bridgestone or whatever.