Some advice required?

[nuggets]

Originally Posted by geode

can you define "poor" with more specifics?

As it's a kids bike, and it'll get used off-road, any coating will be vulnerable to chipping / scratches / getting dinged. At least with rattlecan you can do quick easy touch-ups as needed.

I find getting a good primercoat on is the key.

poor means that the paint scratches easily. I use primer, then top coat.

[sakurama]

Hammerite would actually be a very good solution for you. It has a distinctive mottled appearance which makes it very forgiving of application (can be done with a brush) can be painted over light rust (but it's better if you sand it and wipe down with alcohol) and is extremely durable. I've painted a lot of studio set carts and shop cabinets with it and it's held up well for 15 years now.

G

[nuggets]

Originally Posted by sakurama

Hammerite would actually be a very good solution for you. It has a distinctive mottled appearance which makes it very forgiving of application (can be done with a brush) can be painted over light rust (but it's better if you sand it and wipe down with alcohol) and is extremely durable. I've painted a lot of studio set carts and shop cabinets with it and it's held up well for 15 years now.

G

Thank you. That seems like it should work nicely for me.

[ed mocz]

Bedliner in a spray can should work. I've even used it on a pressed paper display at work.

[jwalters]

I got another question for thecosman and the other thread listeners. This one is more opinion than procedural, but I think this thread's audience could have some great input.

I'm seeing a demand for Do-It-Yourself CDI/EFI electronic systems to retro fit early 80s-90s era motorcycles that may have failing/broken CDI units. Shelf life of these electronic black boxes isn't as long as a set of Amal carbs. As "vintage" bikes start to include EFI machines, it is going to be very difficult for a restorer to find working NOS EFI and CDI units for each make/model of bike. Bike enthusiasts such as Zeeltronic, MegaSquirt and others have made some great electronic boxes to retro fit certain motorcycles with modern CDI/YPVS/EFI alternatives.

As a bike nut and electrical engineer, I'm curious if any of you see a demand for other electronic systems for various make/models of vintage bikes (like suspension data loggers). I have a full electronics lab at my garage, and am searching for a project that may be of use for the community. Any ideas?

[ben2go]

Originally Posted by jwalters

I got another question for thecosman and the other thread listeners. This one is more opinion than procedural, but I think this thread's audience could have some great input.

I'm seeing a demand for Do-It-Yourself CDI/EFI electronic systems to retro fit early 80s-90s era motorcycles that may have failing/broken CDI units. Shelf life of these electronic black boxes isn't as long as a set of Amal carbs. As "vintage" bikes start to include EFI machines, it is going to be very difficult for a restorer to find working NOS EFI and CDI units for each make/model of bike. Bike enthusiasts such as Zeeltronic, MegaSquirt and others have made some great electronic boxes to retro fit certain motorcycles with modern CDI/YPVS/EFI alternatives.

As a bike nut and electrical engineer, I'm curious if any of you see a demand for other electronic systems for various make/models of vintage bikes (like suspension data loggers). I have a full electronics lab at my garage, and am searching for a project that may be of use for the community. Any ideas?

If you are interested in EFI.look into microsquirt.I have it planned for my GS500.It was designed specifically for smaller engines.It's a spin off of megasquirt.If you know the engine you want to convert it can be done cheaply,excluding the FI unit.Another feature of microsquirt is it's ability to control the ignition timing.This feature along with efi can really wake up a stock motor and bring out it's full potential.

http://www.microsquirt.com/

http://www.microsquirt.info/uswiring.htm

http://www.diyautotune.com/catalog/m...11b3eab96d7202

[disston]

I looked at a bunch of that stuff from Micro Squirt and the other one. The other one seemed to be a lot of car stuff. The Micro Squirt seemed doable for somebody that wants to learn the lingo and learn to design their own system. I did not see an out of the box unit that would put EFI on my Airhead motorcycle. Why don't you make this doable. Is it already? Just how much of this stuff do I have to digest in order to do it?

I wouldn't think electronic handling would be a big seller to the Airhead community. We already have out of the box Electronic ignition and I think EFI would sell.

[ivantheterrible]

I want to follow up on a question I asked, and got a answer to, then ask another.
Earlier in this thread I asked about changing from a 16'' rear rim to a 18''. After getting some good advice here I decided to go for it. I contacted woody's wheel works and after a few emails were exchanged, I sent them a rear hub for the model bike i have, and a few weeks later they sent me back a 18'' rim. They were great to work with and very patient. Anyway, it's on the bike (cb250) and i really like it. I was somewhat concerned about how it would effect the handling, but if anything it feels much more planted and stable.

My new question. -I want to change out the front fender. but I'm wondering about how big a roll the front fender plays as a fork brace. I don't know the terms for the different styles of fender bracing, but what's on it now is a single piece that is part of the fender and what i want to put on is more like brackets that suspend the fender above the wheel, but look to offer little support. Sorry, i know that's very vague.

[DaBit]

OK, let's try this one.

I still have an SV650 build going on. One of the latest (OK, already a couple of months ago) additions is a pair of DR-Z400E cartridge forks with triples. Since the DR-Z aluminium lower triple is far more voluminous than the steel one I used before, the OEM radiator was in the way and it could not be moved backwards enough.

Because the OEM radiator is also wider than the frame, and thus a source of problems during a dropoff, I decided to tackle this problem the hard way and replace the radiator.

Now, I could not find anything to my liking; either too big, too expensive, too restrictive (most oil coolers), too hard to mount, etcetera. And since I also wanted some real practice with aluminium-TIG I went to the local scrap heap, got myself two full aluminium car heater cores (Hyundai H200 and Ford Ka) for $20, cut them to the size I needed them to be, and used the welder to close them again and add hose connections and mounting tabs. I also made the distribution of coolant to the 3 radiator cores (they are in parallel) out of aluminium tubing since fitting 8 hoses in the space where there were only two did not allow the use of standard T-fittings. I sure am a lot better at welding aluminium than I was before, even with my homegrown aluminium-TIG-welder which lacks all the controls a modern TIG-machine offers.

Older picture of the first cooling system test run:


Now, these three radiator cores are just hanging in the air. To me, this seems a less than optimal situation. Incoming air just 'hits the wall', so to speak.

I have heard that proper shrouding behind the radiator could increase the efficiency of the radiator cores tremendously by increasing the amount of air that passes through. I can visualise the shroud creating a local vacuum behind the radiator which causes a pressure difference that pulls air through.

But how would one design the shrouding? what are the do's and dont's?

Cooling performance of the current setup is more than adequate by the way, but if it can be improved I will. Radiators get clogged with mud, I might break one in the middle of nowhere, take it off and continue with 2 radiators, etcetera.

[DaBit]

You mean this or this? Worth a study..

[subybaja]

Rat.pilot, look up POR-15. Great DIY stuff and cheaper than powder coating.

DaBit, are you sure you're not thinking of automotive fan shrouds? Sealing the fan to the rad makes a big difference there...

Thecosman, speaking of minor wheel mods...what's your opinion of using a stock 17" KLR rear hoop on the front, for the high-flotation "TW look"? Woody's said it was tried and no one liked the 17, but the 18 works OK. I have yet to hear from anyone with the big tire up front who didn't love it. I just can't see, aside from perhaps tire availability, why a 17 wouldn't be as good as an 18?

[sakurama]

Originally Posted by subybaja

Thecosman, speaking of minor wheel mods...what's your opinion of using a stock 17" KLR rear hoop on the front, for the high-flotation "TW look"? Woody's said it was tried and no one liked the 17, but the 18 works OK. I have yet to hear from anyone with the big tire up front who didn't love it. I just can't see, aside from perhaps tire availability, why a 17 wouldn't be as good as an 18?

Please don't do this. Why the idea of a big front wheel for "floatation" or "more rubber" on the ground continues to stay alive is beyond me. The giant rear tires of the choppers at least echo the big tires of a dragster so they have at least a visual reason for ruining the handling.

So, here's the deal: a 17" front wheel (of the typical street width) will ruin the handling of your bike off road. It might float but it will also not steer. At all. I've personally known about 4 people who've tried this and every one has done one ride and promptly pulled the wheel. The TRW has geometry to mitigate (but not cure) the horrible handling of the giant front tire. It's heavy, it resists turning and it has LESS traction on dirt and sand. Ask yourself when was the last time you saw someone race a TRW? It's a bike made to crawl around camp and it's not really good at that.

Personally I have experience with this as well. I have a KTM 950 with two sets of wheels: 21" front for dirt and a 19" one for mixed use. I once made the mistake of using the 19 for some off road stuff and it was pretty bad - the bike was vague and wouldn't track and in sand it was unrideable. A friend who was learning to ride off road took a supermoto into the sand and after he was exhausted I had to ride it out. There was no way you could. A 17" wide supermoto front tire has zero connection to the sand - knobs or not.

You need a big and narrow front hoop for off road. MX bikes experimented with 20" front wheels for the improved turning on hard pack conditions but it didn't last. Don't buck convention here - 21" is the correct front wheels size for true off road and 19" will work in limited situations but not on sand.

Gregor

[offalot22]

Hello, great thread and thanks for the selfless sharing of knowledge.
I am building a little street tracker out of an old Yamaha SR185 I need some direction to go with the exhaust. Is there some basic science to exhaust/muffler design. I made a full exhaust for my KLR and was lucky enough for it to have worked pretty good but every little horsepower counts on this little bike so I would like to put a little more thought into it. Thanks.

[dentvet]

I have one of the many rat bikes described in this forum. Its a ninja 650 dualsport with a dirt front end grafted on. My rake angle is about 33 degrees and my trail is 5 1/4 inches. Do you see anything inherently wrong with those values? The bike seems to perform ok for me offroad but i haven't really pushed it either. Fire and ATV roads are the goal.

I read Foale's article on trail experiments where is was said that 27 degrees rake and 3 1/2 inches trail was the norm but not necessarily written in stone.

I like the 21 inch front tire but i could reduce the rake a bit if i dropped the triple clamps down the fork.

Other possibilities are finding forks with more spindle offset to reduce the trail.

[Wadester]

Originally Posted by dentvet

I have one of the many rat bikes described in this forum. Its a ninja 650 dualsport with a dirt front end grafted on. My rake angle is about 33 degrees and my trail is 5 1/4 inches. Do you see anything inherently wrong with those values? The bike seems to perform ok for me offroad but i haven't really pushed it either. Fire and ATV roads are the goal.

I read Foale's article on trail experiments where is was said that 27 degrees rake and 3 1/2 inches trail was the norm but not necessarily written in stone.

I like the 21 inch front tire but i could reduce the rake a bit if i dropped the triple clamps down the fork.

Other possibilities are finding forks with more spindle offset to reduce the trail.

More trail just translates to more stability - to the point of reducing maneuverability if you get crazy. Head angle/rake doesn't act quite the same, but it's still a "whatever feels right" as long as you have matching trail. Your setup isn't really radically different.