I fell off my XS650 'Fat Cast Brat' and I'd like your opinion.

[thrilla]

Hi all!

So I picked up my first 1978 XS650 last month from the 2nd owner since its restoration. I had it delivered from south England to my house in Yorkshire, I was blind buying but I've been obsessed with XS650's for a few years and when this bike, built by Kuna Customs, came up for sale, I had to have it.

When it was delivered I was blown away, the bike is tremendous - a dream, really. I took it out that night and had a blast winding it round the country roads near my house.

Nothing seemed wrong with it, it felt solid, impressive pull and power, the only thing I would say is it's certainly not smooth, maybe a volatile mix, crappy oil, custom exhaust, or just the age of the bike. I expected it to have some beef, so I wasn't disappointed in the slightest. Another thing is that I have to keep one of the chokes on to keep it idle, which is fine but, I knew the carburettors needed seeing to. The pictures attached show the brakes and brake disks, to put it simply, they are bad. Spongy, squeaky, unpredictable... 'Whatever' I thought, I wanted to change the brakes, no dramas.

Last week, the night was nice, I wanted to ride to a nearby village which has a big bike scene. I hopped on the bike and rode steady. As I proceeded down a tight and narrow lane, (a road that I drive my car down all the time) a few cars passed me no problem. Towards the bottom a car appeared out of nowhere, and almost obviously made no attempt to slow down or move over, I'm not blaming them but after I passed them, I went too far over to the left (UK) and slid on some dry dirt.. Ouch.

I was fine, I got on my feet, quickly picked my bike up and pushed it into the driveway a few feet away. A few cuts on my hands from where the brake/clutch levers smashed my knuckles, a grazed leg and a scratched helmet. I was fine. The bike, to my surprise also seemed fine, I was expecting more damage, although I slipped at about 20mph after passing the car. The rear brake was scratched up, clutch lever, a few bolts, and most annoyingly, the tank has a dent in it from where the forks impacted it. That hurt, but whatever it all seems minor.

After about 10 minutes, once I'd composed myself and tested the bike, I jumped back on. The bars had bent or misaligned with the front wheel, so I'm steering at an angle but again nothing major. Once I got about half way home I realised that my rear brake was non existent, just nothing there, and 1st and 2nd gear were jolting, struggling, not sure how to explain but they felt very very broken haha (sorry) 3rd+ was fine.

When I got back I was pissed, my dream bike, damaged with no other excuse than stupid reactions and probably the huge tyres, look cool though.

I just wanted to post this and get the opinion of the reader as to help me figure out why 1st and 2nd feel horrendous, and what kind of modifications I should make to it, to make it smoother, and are the carburettors the reason I need to keep 1 choke on, even when its warm.

Description of the bikes restoration, photos and video: https://www.kunacustoms.com/product/yamaha-xs650-fat-cast-brat/

Photos of damage attached.

 

[gggGary]

Sorry to hear about the sudden interruption to your most excellent adventure. 1st clutch lever/cable binding can mess with shifting. Then remove LH cover check for bent shift shaft. After that linkage inside rh cover in back of the clutch.
Forks you will need to look for bent tubes then lower triple.

 

[jetmechmarty]

There is a tab on the front of the frame neck, or should be. With a stock neck and stock lower triple clamp, the assembly can not contact the tank unless the tab on the frame got bent (most likely), or the stop on the lower tree broke off. Shit happens! We learn and move on. Your bike will live on.

Your carburetors are likely not clean. Running choke on is a sign the pilot circuit is clogged. Once timing is correct and carburetors are functioning as designed, you'll find most of the vibration can be tuned out of the 360 degree engine until the upper RPM range.

Best wishes!

Me, in 2016. I lived!

 

[5twins]

You look to have those aftermarket Chinese Keihin copy carbs, by most reports very troublesome. Good luck with those, lol.

 

[grizld1]

+1 to that! Those bored out knockoffs of the Keihin PWK28 are good for nothing but satisfying masochists who get off on frustration. They might make decent paperweights if you don't mind ugly. Your best course would to have real carbs mounted. Best to buy them from a shop that can do more than paint and sell bling and knows the XS650. Those tires are too wide for the rims they're on, enough so to be dangerous. Good luck to you.

 

[Jan_P]

Stiff Honest Worlds from the worlds most experienced men here on carburetors
Commands respect.
just break down and then continue again

Se if we can get you back on the road again
A clutch adjustment is the first please google how it is done
The dent probably a professional can pull out. Without damaging the paint
I can only see pictures off the right side and that is nothing major .. Would be very surprised if that has caused any major problems
Please provide the left side and front pictures
The tires looks " Different "
Especially the front ... Perhaps a smaller there can be in the pipeline

To rub salt in the wound the kick starter seem soft .. Perhaps low compression ..
Or you have much stronger legs than myself.

 

[WideAWAKE]

In the video the guy has to keep it at a high rev and pulls off and you can hear the bike stumble.

Also, those forks look like they only have 3” of travel??? Idk. Maybe it’s just me, but they looks strange.

If it didn’t run right and the brakes were terrible, I’d contact the builder you bought it from.

 

[Raymond]

Hi Thrilla, sorry to hear about your incident. Bars and front wheel mis-aligned - in a low-speed accident, that's often all it is and they can be re-aligned by loosening off the pinch bolts on top and bottom yokes and twisting it all straight. Don't forget to tighten up afterwards, obviously. Pump the forks up and down to make sure they rebound freely and aren't sticking. If there is real doubt about whether the forks might be bent, they need to be dismantled and the stanchions rolled along a flat table or sheet of glass but not very likely from the 'off' you've had.

Gears playing up is very likely to be clutch adjustment as the others have said. Sounds like the carbs need some work, cleaned and tuned correctly or replaced.

Nothing that can't be fixed - hope you're feeling better and not lost too much confidence. Cheers, Raymond

 

[gggGary]

You might want to confirm neither tire hits other bike parts at full compression of the suspension.

 

[thrilla]

There is a tab on the front of the frame neck, or should be. With a stock neck and stock lower triple clamp, the assembly can not contact the tank unless the tab on the frame got bent (most likely), or the stop on the lower tree broke off. Shit happens! We learn and move on. Your bike will live on.

Your carburetors are likely not clean. Running choke on is a sign the pilot circuit is clogged. Once timing is correct and carburetors are functioning as designed, you'll find most of the vibration can be tuned out of the 360 degree engine until the upper RPM range.

Best wishes!

View attachment 214139
Me, in 2016. I lived!

Oh wow thats a nasty accident, glad you survived it! Thank you for the advise, and no my carbs certainly aren't clean and will be opting for a much better replacement. Thanks!

 

[thrilla]

+1 to that! Those bored out knockoffs of the Keihin PWK28 are good for nothing but satisfying masochists who get off on frustration. They might make decent paperweights if you don't mind ugly. Your best course would to have real carbs mounted. Best to buy them from a shop that can do more than paint and sell bling and knows the XS650. Those tires are too wide for the rims they're on, enough so to be dangerous. Good luck to you.

haha yes the carbs are horrendous, I'll be opting for the stock / better replacement. And yes tires will be replaced with on/off road tires, that was the first think I was going to do before the accident. Thanks

 

[thrilla]

In the video the guy has to keep it at a high rev and pulls off and you can hear the bike stumble.

Also, those forks look like they only have 3” of travel??? Idk. Maybe it’s just me, but they looks strange.

If it didn’t run right and the brakes were terrible, I’d contact the builder you bought it from.

Hi I have contacted the builder, awaiting his reply, I've mentioned what you've said, thanks

 

[thrilla]

Hi Thrilla, sorry to hear about your incident. Bars and front wheel mis-aligned - in a low-speed accident, that's often all it is and they can be re-aligned by loosening off the pinch bolts on top and bottom yokes and twisting it all straight. Don't forget to tighten up afterwards, obviously. Pump the forks up and down to make sure they rebound freely and aren't sticking. If there is real doubt about whether the forks might be bent, they need to be dismantled and the stanchions rolled along a flat table or sheet of glass but not very likely from the 'off' you've had.

Gears playing up is very likely to be clutch adjustment as the others have said. Sounds like the carbs need some work, cleaned and tuned correctly or replaced.

Nothing that can't be fixed - hope you're feeling better and not lost too much confidence. Cheers, Raymond

Hi Raymond, I'll be having a full examination of the bike with a veteran retro bike owner, I'll go though all the points you've mentioned and thank you for the kind words. I've not lost much confidence ive had crashes before on my MX bikes but just a bummer that it happened to my dream bike. Thanks again

 

[grizld1]

"Motocross: a series of controlled crashes." Can't recall who came up with that definition way back when. Anyway, it'll take a lot more than a 20 mph involuntary get off to intimidate a motocross rider. You'll get that scoot sorted, thrilla; looks like you have the patience, resilience, and right attitude for the job.

 

[thrilla]

"Motocross: a series of controlled crashes." Can't recall who came up with that definition way back when. Anyway, it'll take a lot more than a 20 mph involuntary get off to intimidate a motocross rider. You'll get that scoot sorted, thrilla; looks like you have the patience, resilience, and right attitude for the job.

Haha! You got that right. Thanks for your kind words mate!

 

[londoncabby]

GPZ500 carbs are a good alternative.

 

[Raymond]

Took a look at UK ebay an there's a few sets of GPZ500 carbs on there, about £60 ish.

 

[Hudriwudri]

My short opinion without getting into too.much depth:
Get the awfully square rear tire off and get a real tire even in bigger dimension like eg BT45, and get some work Hy carburetors eg like some dell'orto 34 pumpers, of everything else is stock on the sled.

Kind regards Christian

 

[Grimly]

Get rid of that fat front tyre. It caused horrible understeer, which might have contributed to your off.

 

[Splodge]

I think I remember that bike from ebay a few weeks ago, I remembered it particularly because it looked like it had a back wheel on the front.
ebay auction link
I hope you get it fixed up soon mate.