Author Topic: Cb500 Street "Race" bike refresh  (Read 12781 times)

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Offline Korven

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Re: Cb500 Street "Race" bike refresh
« Reply #25 on: January 16, 2019, 12:15:58 pm »


One thing i noticed while timing the cam is that the inlet valve is begining to open at 49-50 btdc, Thats where the cam card says ill want ignition.

did you measure that with 0 lash or at running clearance?

It was measured with the same specs as the cam was graded, at .40 clearance. Aint running clearance be close, but not at 0? ie hot engine.

Wasnt sure if there were supposed to be copper washers on here.
easy to remember: if there is oil underneath the bolts, use a sealing washer. meaning, one from a soft metal like copper or alu.

Noted. I guess that means the only ones that need it is the one under and above the bracket.


Covers on just for "feeling" Not sure what i am gonna do with them.
that breather cover is on backwards ;)

Haha, Yeah i saw that aswell. Is it suppose to vent into the air filters or just onto the ground? Diffrent manufacturers seem to do diffrence things with it.

I ended up rebuilding the master cylinder. It was on the bike when i bought it but seemed to be leaking. Is the original master cylinder fine with dual discs or is it a big no-no?
it's a matter of preference. there are people who use the stock size, and others who prefer a bit larger. mine is 16mm and i'm happy with it. at the same amount of lever travel, a larger one moves more liquid. so it's a compromise between those things the downside being that you can loose "feel" if the cylinder is too large.
all in all, with dual disc i'd say 14mm or larger would be best.

What size is the original piston?

Thanks for all the great advice!

Offline MRieck

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Re: Cb500 Street "Race" bike refresh
« Reply #26 on: January 16, 2019, 12:21:40 pm »
Big update!

I had some trouble fitting the chain to my sprocket but removed the rubber (was told this was a stupid thing to do, but cant really see any problem with it except it might be noisy.) the chain just wasnt seating properly with it. It was needed to come of anyways if the sprocket needed to be machined for the cam adjustment (it didnt)
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Offline flatlander

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Re: Cb500 Street "Race" bike refresh
« Reply #27 on: January 16, 2019, 01:05:48 pm »
One thing i noticed while timing the cam is that the inlet valve is begining to open at 49-50 btdc, Thats where the cam card says ill want ignition.

did you measure that with 0 lash or at running clearance?

It was measured with the same specs as the cam was graded, at .40 clearance. Aint running clearance be close, but not at 0? ie hot engine.

huh? the cam card in your picture earlier in the thread wants .006" valve clearance (or lash or tappet clearance - means all the same). that's your running clearance.

and the opening/closing numbers it provides, should be measured at .04" valve lift. it doesn't say at what clearance that is measured at but normally, it would be at 0 clearance. measured at running clearance, the numbers would be lower.

that's why i was asking, because depending at what valve clearance you measure at, the opening/closing numbers are different.
anyway, if you're sure the cam is degreed in correctly, i'd follow the cam card advice for setting the ignition.

Covers on just for "feeling" Not sure what i am gonna do with them.
that breather cover is on backwards ;)

Haha, Yeah i saw that aswell. Is it suppose to vent into the air filters or just onto the ground? Diffrent manufacturers seem to do diffrence things with it.

not directly into the air filter, it would dirty it. on the 550 they routed the breather tube into the air filter housing, then a foam filter to catch the dirt before the gases would go via a tube into the air filter.
but the 500 did not have that as far as i know. you can just attach a tube and route it down towards the ground.

I ended up rebuilding the master cylinder. It was on the bike when i bought it but seemed to be leaking. Is the original master cylinder fine with dual discs or is it a big no-no?
it's a matter of preference. there are people who use the stock size, and others who prefer a bit larger. mine is 16mm and i'm happy with it. at the same amount of lever travel, a larger one moves more liquid. so it's a compromise between those things the downside being that you can loose "feel" if the cylinder is too large.
all in all, with dual disc i'd say 14mm or larger would be best.

What size is the original piston?
12mm if i remember right.



Offline flatlander

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Re: Cb500 Street "Race" bike refresh
« Reply #28 on: January 16, 2019, 01:07:52 pm »
Big update!

I had some trouble fitting the chain to my sprocket but removed the rubber (was told this was a stupid thing to do, but cant really see any problem with it except it might be noisy.) the chain just wasnt seating properly with it. It was needed to come of anyways if the sprocket needed to be machined for the cam adjustment (it didnt)
Who said it was stupid?

it's not a problem.

Offline Korven

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Re: Cb500 Street "Race" bike refresh
« Reply #29 on: January 16, 2019, 02:29:53 pm »
Big update!

I had some trouble fitting the chain to my sprocket but removed the rubber (was told this was a stupid thing to do, but cant really see any problem with it except it might be noisy.) the chain just wasnt seating properly with it. It was needed to come of anyways if the sprocket needed to be machined for the cam adjustment (it didnt)
Who said it was stupid?

I posted the problem in a thread in the sohc/4 section, maybe I misunderstood what he meant, my English ain't the best.

One thing i noticed while timing the cam is that the inlet valve is begining to open at 49-50 btdc, Thats where the cam card says ill want ignition.

did you measure that with 0 lash or at running clearance?

It was measured with the same specs as the cam was graded, at .40 clearance. Aint running clearance be close, but not at 0? ie hot engine.

huh? the cam card in your picture earlier in the thread wants .006" valve clearance (or lash or tappet clearance - means all the same). that's your running clearance.

and the opening/closing numbers it provides, should be measured at .04" valve lift. it doesn't say at what clearance that is measured at but normally, it would be at 0 clearance. measured at running clearance, the numbers would be lower.

that's why i was asking, because depending at what valve clearance you measure at, the opening/closing numbers are different.
anyway, if you're sure the cam is degreed in correctly, i'd follow the cam card advice for setting the ignition.

I checked it at .006 tappet adjustment. I checked the grading when the valves were lifted .04

If i would do it with 0 valve lash. All values would show be earlier?

Again sorry English is not my best.

Offline scottly

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Re: Cb500 Street "Race" bike refresh
« Reply #30 on: January 16, 2019, 08:45:45 pm »

12mm if i remember right.
The original MC is 14mm, and works well with two 38mm calipers.
Don't fix it if it ain't broke!
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Offline flatlander

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Re: Cb500 Street "Race" bike refresh
« Reply #31 on: January 16, 2019, 11:02:36 pm »


I checked it at .006 tappet adjustment. I checked the grading when the valves were lifted .04

If i would do it with 0 valve lash. All values would show be earlier?

Again sorry English is not my best.

yes. anyway, your opening/closing numbers were as good as they can be so i'd stick to the advice on the cam card for the ignition as well.

your english is fine.
korven... are you a sausage by any chance? a swedish sausage?

Offline Korven

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Re: Cb500 Street "Race" bike refresh
« Reply #32 on: January 17, 2019, 12:34:35 am »


I checked it at .006 tappet adjustment. I checked the grading when the valves were lifted .04

If i would do it with 0 valve lash. All values would show be earlier?

Again sorry English is not my best.

yes. anyway, your opening/closing numbers were as good as they can be so i'd stick to the advice on the cam card for the ignition as well.

your english is fine.
korven... are you a sausage by any chance? a swedish sausage?

hm. If i were to buy a webcam, they have information on their site saying that one should use 0 lash when grading their cams. only way to find out about this cam is getting hold of a 70's yoshi cataloge. But the numbers do match (with some small error) so i think i did the correct thing, else it should have been included on the cam card. i've contacted some other members with the same cam and they seemed to just drop it in and time it like the original cam and they seem to be good to go. I know i dont have much experience with engine building, less so off high performance upgrades. I tied a contact with a local guy racing a 350, maybe he knows something.

Yeah i am a swedish sausage (suited in gothenburg). I registred with "brown" infront as a joke but didnt wanna come off as unserious so i removed it. But hey life should be lived with humor in it, hehe.

About the timing. I have been thinking, maybe its not a bad idea to invest in a dyna S. There was a cheaper european version that you could use with a magnet pickup. Maybe this is something ill do later on. Not sure if the bike would be really hard to start with the advancement on the timing or if it would wanna kick me in the leg like the old high/low ignition solution motorcylces had. I've bought the hondaman ignition aswell but might give that to my original instead. With the bike i got a ignition system with a shark on its logo. its still within its sealed package. not sure what it is, dont think its dynamic though. ill post a pic of it later on.
« Last Edit: January 17, 2019, 12:43:06 am by Korven »

Offline flatlander

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Re: Cb500 Street "Race" bike refresh
« Reply #33 on: January 17, 2019, 04:25:08 am »
exactly, your numbers look spot on so i wouldn't worry about it. it's normal to have slight variation to the published numbers. there's manufacturing tolerances, measuring tolerances... as you're within 1 or 2 degrees, you're pretty good! which is actually astounding considering that you directly use the stock sprocket holes. i guess those yoshi guys knew what they were doing!

personally, i use running lash to degree the cam. 0 lash is a bit theoretical as you won't use that anyway, and you want the timing to be right in real-life use, not under lab conditions.

i lived in gothenbug  for a bit over a year during my studies. nice place! the cops are probably still searching for me but that's another story...  ;D
jag pratar bara lite svenska. var vinns det öl??

ignition discussions are a bit like oil threads. i think it's best to first look at the few basic types and when you've decided on one, look within that category for what's on offer.
- fully mechanical: stock stetup for our bikes, with points etc.
- hondaman: in its own category, being a transistorised version that otherwise leaves the stock items in place
- electronic with mechanical advance unit: stock advancer, and electronic spark timing
- fully electronic: advance is also electronically controlled. there are different varieties, some with a fixed advance curve, some where you can select it. some where you can choose the rev limit, some where you can't. most are magnetically triggered, there is also one that's optically triggered.

there are pros and cons to everythings. search this forum for info, or start a separate thread to get advice and opinions.
i myself went for a boyer bransden which is fully electronic with a CDI box. advance curve is pre-set and rev limit can only be set by the manufacturer. so pretty no frills but has been working flawlessly so far.

about the amount of advance, you might want to ask in the hi po part of the forum. guys there can probably point you in the right direction.

Offline Korven

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Re: Cb500 Street "Race" bike refresh
« Reply #34 on: January 17, 2019, 10:44:10 am »
exactly, your numbers look spot on so i wouldn't worry about it. it's normal to have slight variation to the published numbers. there's manufacturing tolerances, measuring tolerances... as you're within 1 or 2 degrees, you're pretty good! which is actually astounding considering that you directly use the stock sprocket holes. i guess those yoshi guys knew what they were doing!

personally, i use running lash to degree the cam. 0 lash is a bit theoretical as you won't use that anyway, and you want the timing to be right in real-life use, not under lab conditions.

i lived in gothenbug  for a bit over a year during my studies. nice place! the cops are probably still searching for me but that's another story...  ;D
jag pratar bara lite svenska. var vinns det öl??

ignition discussions are a bit like oil threads. i think it's best to first look at the few basic types and when you've decided on one, look within that category for what's on offer.
- fully mechanical: stock stetup for our bikes, with points etc.
- hondaman: in its own category, being a transistorised version that otherwise leaves the stock items in place
- electronic with mechanical advance unit: stock advancer, and electronic spark timing
- fully electronic: advance is also electronically controlled. there are different varieties, some with a fixed advance curve, some where you can select it. some where you can choose the rev limit, some where you can't. most are magnetically triggered, there is also one that's optically triggered.

there are pros and cons to everythings. search this forum for info, or start a separate thread to get advice and opinions.
i myself went for a boyer bransden which is fully electronic with a CDI box. advance curve is pre-set and rev limit can only be set by the manufacturer. so pretty no frills but has been working flawlessly so far.

about the amount of advance, you might want to ask in the hi po part of the forum. guys there can probably point you in the right direction.

What did you study and where? Chalmers or at Gothenburg university?

I saw your thread on your 500 (or was it a 550) and you mention some of these changes:


"fork rebuilt with wilbers progressive springs and seals
t-kat forkbrace

conical headset bearings

new wheel bearings

swingarm bushings replaced with roller bearings"


What is the diffrence between wilber springs and the stock?
What about the Swingarm bushings. The stock one is just Metal sliding against metal as far as i can tell from the parts list, does this make a diffrence? Enlighten me please!



Offline flatlander

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Re: Cb500 Street "Race" bike refresh
« Reply #35 on: January 17, 2019, 11:07:49 pm »
it was at goteborgs universiteit. law and photography. odd combination. so i stopped with the law to appear more normal  ;)

the main difference with the springs is that the original ones were 40 years old, had about 60k km on them and had sagged. the wilbers on the other hand, brand new. in europe there's mainly two aftermarket makers of springs for these bikes, wurth and wilbers. both german companies. wurth is usually more comfort oriented, wilbers more performance oriented. they also make oem materials for bmw. i think currently they make 2 different springs for these bikes, one a bit heavier than the other.
you can get cheaper springs from the far east but then quality is uncertain.

and the swingarm bushings... well metal against metal will have more friction than a roller bearing so with the rollers, the arm should move more easily and be more responsive. modern bikes also use them, for a reason.

Offline Korven

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Re: Cb500 Street "Race" bike refresh
« Reply #36 on: January 19, 2019, 09:40:02 am »
Im going with the stock swingarm setting, atleast this time around. I pushed some new grease in and it seemed kind of happy.

Got my new tire fitted. I just heated it alot until the rubber was soft and it was on in about 10 minutes! The valves that i purchased was a perfect fit! Started building a tire balancing rig. It needs some cutting, then its just to bold the thing together. Its nice what you can make from some "scraps" layin around.






Once i get the rear end all sorted out i can start removing the front end. It just feels better to have the frame sitting on two points. Also its nice to not have parts everywhere.

Offline Korven

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Re: Cb500 Street "Race" bike refresh
« Reply #37 on: January 27, 2019, 05:58:04 am »
Made a bit of progress. Rear Wheel all done and balanced. fitted onto bike. did alot of buffing. especially on the front shock for the clear coat. I spent all friday niht and saturday morning buffin them. They became a little "dull" and pale with the clearcoat. i didnt get the result i hoped for. I clearcoated the clutch cover and it looks kinda "brushed and uneven" I later discovered that was due using two diffrent polishing brushes. If it wouldnt look so uneven it would be cool with that "brushed" look. Ill stick with it for now. Not clearcoating anything else right now. Clear coat i used was Eastwood brand. Also had alot of pizzas and beer this weekend, how many are too much?







Offline seanbarney41

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Re: Cb500 Street "Race" bike refresh
« Reply #38 on: January 27, 2019, 07:12:59 am »
Too much is never enough.
If it works good, it looks good...

Offline Korven

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Re: Cb500 Street "Race" bike refresh
« Reply #39 on: January 27, 2019, 11:21:36 am »
Some more pics. That Timing cover needs some more work.





Offline Korven

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Re: Cb500 Street "Race" bike refresh
« Reply #40 on: February 01, 2019, 06:40:10 am »
Second tire is on. I heated it to 70 degrees with a heating gun for about 30minutes on the low setting then put a hair dryer inside the tire. It litteraly took me 2 minutes to press the tire onto the rim with just some washer soap. this time i didnt even use the tire irons. Heating when doing tires is king. Hooked it up in my balancing rig and did the rest.

Did some work on the timing cover. Its made by a local firm that did (and does) performance brake parts among other things back in the day. http://www.isrbrakes.se/ It had some damage to it since the oring is so flat the metal contacts the engine, it was just prone to breaking off. needed to replace that oring but decided to remove it all together since i had 8.5mm clearance (the original chrome one has 2.5mm) Did 2 hours of manual filing (phew) but became pretty nice without any mistakes. Its a little more slim now.





Offline Korven

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Re: Cb500 Street "Race" bike refresh
« Reply #41 on: February 05, 2019, 11:47:31 pm »
Oilpump in. Ignition cover repaired, removed the oring track and going with the orignal gasket, bit slimmer now. repainted it with enamel paint, turned out great.
made some brackets for the brakehoses. Could have used those plumbing brackets with rubber but made my own from things i had laying around. Shouldnt hit the wheel now. Mounted the restored master cylinder. Needed to work it a bit with Compressed air pressing it back to open position. works like a charm now. Meters got a new powdercoated bracket. Replaced some of the wires. Engine is almost done its only tappet clearance and ignition timing left. Maybe i can get it mounted in the frame next week. Self-amalgamating tape on the frame prepped for mounting. Started to replace the ignition coil cables aswell, well see how that turns out.

One thing that popped up! The front tire had instructions what way it should be mounted if it were a front or rear tire, i guess this is for not spraying your motor with dirt and for getting all of it into the rear fender when mounted as a rear tire. Couldnt think of any other reason really.





« Last Edit: February 05, 2019, 11:51:30 pm by Korven »

Offline flatlander

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Re: Cb500 Street "Race" bike refresh
« Reply #42 on: February 06, 2019, 01:39:13 am »
looks  all very shiney there  8)

One thing that popped up! The front tire had instructions what way it should be mounted if it were a front or rear tire, i guess this is for not spraying your motor with dirt and for getting all of it into the rear fender when mounted as a rear tire. Couldnt think of any other reason really.

the real reason is are how forces are applied via the tyre to the road surface. the front tyre needs traction mainly during breaking i.e. against direction of travel, the rear one mainly needs to grip in direction of travel.

Offline SF

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Re: Cb500 Street "Race" bike refresh
« Reply #43 on: February 06, 2019, 05:17:55 am »
Beautiful looking engine


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Offline SOHC4 Cafe Racer Fan

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Re: Cb500 Street "Race" bike refresh
« Reply #44 on: February 06, 2019, 08:49:04 am »
That's a shiny motor!
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold

Offline Korven

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Re: Cb500 Street "Race" bike refresh
« Reply #45 on: February 12, 2019, 12:54:01 pm »
Last weeks progress. engine in frame





Offline Korven

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Re: Cb500 Street "Race" bike refresh
« Reply #46 on: February 16, 2019, 02:12:44 pm »
Slow but steady progress this week. Rearset levers are probs a bit too low but fine adjustments like that will have to wait until sadle is in place. Those braided oilhoses look neat for now, hope they wont be too much of a dirt magnet. Started working on refining my mirror mount that had some clearance issues. Carbs are going on next, they were rebuilt last year so this time they are just bolt on.


Offline seanbarney41

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Re: Cb500 Street "Race" bike refresh
« Reply #47 on: February 16, 2019, 02:49:38 pm »
This is coming out spectacular...wish there was more folks doing like you!
If it works good, it looks good...

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Re: Cb500 Street "Race" bike refresh
« Reply #48 on: February 17, 2019, 10:55:29 am »
Are you sticking with the yellow or going for a color change?
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold

Offline Korven

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Re: Cb500 Street "Race" bike refresh
« Reply #49 on: February 17, 2019, 01:43:02 pm »
Are you sticking with the yellow or going for a color change?

Its a hard one. For me what makes a Honda cb a honda cb is the colorful and deep metallic stock Color. But, The Parts are just in so excellent condition it would be a shame to redo them. It's a time capsule after all. the only part that has some flaws is the front fender, Its also the only part im not 100% convinced of using. its not entirely round, placed it on the tire. and does it look like a banana in your eyes? (haha)




What are these two holes for? they are threaded.



Last three pics are all just about seats. I will prob go with the old handmade seat. Still couldnt let the thought about a cowl though. took my vfr cowl and placed on my stock bike (dont look too close) but it didnt give me the feeling i was looking for.



« Last Edit: February 17, 2019, 10:25:03 pm by Korven »