Another crack at making a DOHC "cool"

Cool looking bike! Nice job on the paint and styling.

Not trying to bash the tire decision, but I did some tire research, specifically in regards to rain riding AFTER purchasing tires almost identical to yours last year for my KZ400. The results that I found stated that in any case (wet or dry), more rubber on the road at any given time is best. With knobbies you have a handful of knobs touching the ground with pointless space/gaps between them. With a standard tire, pretty much any all season even performance tire, you have about twice as much rubber in contact with the ground at any given time (especially when leaning) than with knobbies. Again, bike looks cool, just sharing some of the research I did FWIW.

Also, nice to see yet another vintage bike guy in the area. I'm in Hood River now but spend a bit of time in PDX.

Thanks for the feedback!

The progressive springs are from Dime City. The reason I can't use standard non-air assisted fork caps is I have 37mm forks. All the forks witt the standard caps I'm aware of are 33mm and 35mm - if anyone knows of something I'm missing, please let me know.

About the tire - I found a good deal on a Metzler Tourance so I picked it up and threw it on. I'm going to keep the knobby and try it out after I put some miles on the bike.

A view over the bars



Been working on the electrical so I haven't had a ton to update the last few days.

Stripped down my factory harness and started working on minimizing it.

The wrap on the factory harness was nasty! It was peeling off, dirty and almost gooey.



After asking many questions in the electronics section I got to this point.



I used cloth friction tape for a retro touch



On my turn signal switch I weatherized it a bit and soldered the signal leads.



Then heat shrink on the switch body



Installed my tail light which has integrated turn signals (don't mind the seat gap, it's not bolted down in the pic).



Got the ignition switch mounted up and wired



Air filters mounted



Installed a new petcock and braided fuel hose



Any idea if routing the hose out of the petcock and upward to allow this guy to fit, then to the carbs would be OK? I'm concerned about the upward hose hindering fuel flow.



Couldn't handle going back to wiring so I worked on a few other odds and ends then started shaping my seat pad. I used the seat to get a rough shape, but I will have a seat pan that the padding and cover mount to.

Roughed out







Starting some shaping





Edges angled in



I'm going to have to go back to working on the electrical but it's getting close. I just have to get the brake light switches, neutral light and the oil pressure light and I think the wiring will be done.

treitz said:

Cool looking bike! Nice job on the paint and styling.

Not trying to bash the tire decision, but I did some tire research, specifically in regards to rain riding AFTER purchasing tires almost identical to yours last year for my KZ400. The results that I found stated that in any case (wet or dry), more rubber on the road at any given time is best. With knobbies you have a handful of knobs touching the ground with pointless space/gaps between them. With a standard tire, pretty much any all season even performance tire, you have about twice as much rubber in contact with the ground at any given time (especially when leaning) than with knobbies. Again, bike looks cool, just sharing some of the research I did FWIW.

Also, nice to see yet another vintage bike guy in the area. I'm in Hood River now but spend a bit of time in PDX.

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I haven't met many other older bike owners in the area either surprisingly.

Just checked out your site - next time I'm in the Gorge I'll look you up.

I'm down in Albany. About 80 miles south of Stumptown.

We have a pretty big group of vintage riders in Portland. We organize on Faceook, so let me know if you need an invite.

Re: Another crack at making a DOHC "cool"

You probably should find somewhere better to mount that battery I use that same vintage glass fuel filter and it's fine running "upward" your fuel supply is always higher than the carbs.


Yeah Son!

Sonreir said:

I'm down in Albany. About 80 miles south of Stumptown.

We have a pretty big group of vintage riders in Portland. We organize on Faceook, so let me know if you need an invite.

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I'm one of those oddities who doesn't have facebook but I appreciate the offer and would be interested in meeting up with you guys.

Texting is about as cutting edge as I get with my non-face-to-face communication - I'll message you my number.

Re: Another crack at making a DOHC "cool"

Loctite77 said:

You probably should find somewhere better to mount that battery I use that same vintage glass fuel filter and it's fine running "upward" your fuel supply is always higher than the carbs.

Yeah Son!

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I'll give it a go and see if I can get it to fit. The DOHC carbs look like they give a little less free space.

Your fuel line will be fine. The only thing that could hinder flow is if it were kinked/pinched.

I'm happy to report a first start!

My idle is high (I estimate around 2000) and isn't dropping after getting to operating temps so I'm going to check cable tension and air leaks before I start making carb adjustments.
The filters and carb boots are both new though so I'm hoping there's no cracks - possibly not seated correctly, but hopefully no cracks.
Now I wish I would have wired in my tachometer before starting it.

Unfortunately, the stock DOHC carbs are not fond of pod filters. It going to get a lot of tinkering to get it to run OK and running well may be a bridge too far.

Re: Another crack at making a DOHC "cool"

Loctite77 said:

it's fine running "upward" your fuel supply is always higher than the carbs.

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Well not always, but if it isn't you've got a lot more to worry about.

ArBrnSnpr said:

About the tire - I found a good deal on a Metzler Tourance so I picked it up and threw it on.

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Yay. Excellent tire for your application.

ArBrnSnpr said:

I'm going to keep the knobby and try it out after I put some miles on the bike.

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Boo. It will fold your bike while in a corner someday. I'm not talking knee down, I'm talking too much front brake any time and down you go. This is not speculation, I have scars.

I really like this build, looking forward to the final product.

ArBrnSnpr said:

I haven't met many other older bike owners in the area either surprisingly.

Just checked out your site - next time I'm in the Gorge I'll look you up.

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For sure! Shoot me a private message if you're headed out this way.

bike is really coming along nicely! Nice job on the wiring.

ArBrnSnpr said:

About the tire - I found a good deal on a Metzler Tourance so I picked it up and threw it on. I'm going to keep the knobby and try it out after I put some miles on the bike.

Click to expand...

That metzler looks like a good choice. I think you would be much happier (and safer) if you found a matching one of those for the back and sold off the knobbies.

treitz said:

That metzler looks like a good choice. I think you would be much happier (and safer) if you found a matching one of those for the back and sold off the knobbies.

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I looked into a matching rear but apparently they only make 17's so I'm looking into something similar from another brand.

Sonreir said:

Unfortunately, the stock DOHC carbs are not fond of pod filters. It going to get a lot of tinkering to get it to run OK and running well may be a bridge too far.

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I've read of guys having better luck getting these 2 to 1 K&N filters to work on DOHC bikes than they do with single pod K&N's and much better luck than with EMGO pods so hopefully I have similar luck.

I've started a leisurely search for a stock air box (didn't get one with my bike) in case these can't be made to work however. Hopefully it doesn't come to that.

ArBrnSnpr said:

I looked into a matching rear but apparently they only make 17's so I'm looking into something similar from another brand.

Click to expand...

What size are your wheels? The Shinko 705 is a good (affordable) dual sport tire with an 80% street 20% dirt tread. Pattern looks similar to what you have there.

ArBrnSnpr said:

I've read of guys having better luck getting these 2 to 1 K&N filters to work on DOHC bikes than they do with single pod K&N's and much better luck than with EMGO pods so hopefully I have similar luck.

I've started a leisurely search for a stock air box (didn't get one with my bike) in case these can't be made to work however. Hopefully it doesn't come to that.

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A commonly overlooked option would be to make a custom plenum.

DohcBikes said:

A commonly overlooked option would be to make a custom plenum.

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I had some ideas about making what I would call a "shroud" around the filter to partially encase them like the old school bread box intakes did, but I'm up for other suggestions - what do you mean by "plenum"?

Also, you'll be happy to know I might have a buyer for the front tire so it might never see the streets on the 750!

ArBrnSnpr said:

I had some ideas about making what I would call a "shroud" around the filter to partially encase them like the old school bread box intakes did, but I'm up for other suggestions - what do you mean by "plenum"?

Also, you'll be happy to know I might have a buyer for the front tire so it might never see the streets on the 750!

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If you continue with the shroud idea I recommend having a divider between the two filters.

A plenum is an airbox. CV carbs almost require a contained volume (varied) of air to ensure the correct balance of intake velocity across the 4 cylinders. However, the big ugly restrictive boxes that most stock bikes have are not always necessary to maintain an acceptable range of tuneablity for cv's. Experiment with using the stock carb to airbox boots attached to different designs of mocked up airboxes in which you have incorporated a single filter, to force the carbs to draw air evenly. Start with a filter that has a large surface area so that you can do r&d simply by restricting with tape to find the optimal results, then make a box that accepts a filter that size. Flat, square lawn tractor filters are a great place to start playing. Sometimes a mix of straight and angled boots provide the most even flow. I've had great success in finding a balance between looks and function.