Diamo 250 V-Twin Street Tracker

[JimL]

New to the forum, I will try to post some pics of this project. I will make a separate post to show more about the manifold and exhaust, and carb setup info.

Right and left side views, plus a closer shot of the carb setup:

This was built by cutting off the original frame behind the steering head and just above the swing arm pivot. A 1971 Suzuki TS90 frame backbone and gas tank were fitted, while the rest of the frame I constructed from .090 wall 1" steel tubing.

The front wheel is a 1971 Honda CB350 drum (to get the old TT/Flat Track look and feel) laced to the original front rim with heavy spokes from Buchanons. The rear wheel is original Diamo hub laced to an Excel WM3 18" rim with spokes from Buchanons. Tires are K70 front and rear, with a 4.00x18 rear and 3.50x18 front.

The swing arm is notched and reinforced to clear the larger diameter rear tire.

The side plates and rear fender are made from fiberglass, from molds I made for this job. The seat is Harley Davidson XR Flat Track seat from AirTech Streamlining. Front fender is original.

Headlight is a universal on mounts from Dennis Kirk. Tail light is from a 1967 Honda 305 Super Hawk. Footpegs are adapted from a 1983 Honda CX650C, using brake pedal and shift pedal from the Suzuki TS90 that I cut up. Kickstand is stock.

Speedo is from an old Honda CL450. Electrics were relocated to get better cooling for the rectifier and provide a nice "see through" look appropriate for a Street Tracker.

More info in my next post.
JimL

[Weldangrind]

Welcome!

That's quite a recipe. I'll bet making the motor mounts was tough, since you had to line up the sprockets, get the motor level and position it properly fore and aft. Nice work.

[JimL]

I cut just above the rear upper mounts. You can see them in some pics in the "TM28 carb..." post. Look at the rear exhaust pipe pic and you will see where I cut off the frame tubes. The joiner bar anchors them to my new outside tubes. Those new outer tubes carry accurate swing arm holes (the originals are sloppy and the rear wheel rocks back and forth). The swing arm pivot bolt is a cut-down Honda part; stronger and more accurate. I had to turn the swing arm bushings on my metal lathe...the originals are not very round.

The lower tubes are stock from the steering head through the swing arm pivot. Everything stayed in stock alignment during the build. The key is welding the support framework before cutting on the frame. When the build was nearly finished I simply cut the support frame out from underneath with an air hacksaw.

JimL

[JimL]

First, I apologize about upside down pics. That is some kind of weird iPad problem. Even after I flipped them on the PC, I see they get inverted.

Some things I learned about these Virago clones:

- the tube between the carb mouth and frame is through a short stub pipe welded into the frame backbone. I found the backbone has a large amount of loose weld slag and pieces of weld wire that had gone through gaps during frame manufacture. This was discovered when I cut the original frame open. If you experience an unusual engine failure (damage in the bores or combustion chambers), your engine may have swallowed metal debris. This stuff is all after the air filter. If in doubt, pull the carb, duct tape a piece of plastic tube onto your vacuum cleaner nozzle and clean the loose stuff out. Be careful feeling around in there with your finger tip. Or...do the side draft carb conversion and dont worry about whats inside the frame.

- wheel bearings....replace them with decent parts. You can get a package of 10 for little money from Amazon. They will be better than what is in there.

- Steering head bearings...they build them too tight and the balls are miss-sized. Mine was a near new bike that had never been disassembled. It was built with 1 ball missing in the top race! Too tight and missing ball bearings makes the handling feel lazy and the steering notchy.

- A new Yamaha clutch cable fits perfectly and doesnt "grind feel" when you pull the lever. $25 from the Yamaha dealer may keep you from breaking down, and it helps the lazy clutch engagement when shifting. The Virago has stronger clutch springs than the stock Chinese parts, maybe because the better quality cable allows for them? I will change clutch springs soon; the stock ones feel weak.

- Front fork preload can be increased by removing the stock upper spring spacers and cutting a piece of Schedule 40 PVC pipe about 3/4" longer than the stock spacer. You need to block up the bike under the front of the frame area when removing the fork caps (one at a time, gentlemen). Get someone to help hold the caps/spring down when you start threading the caps back in with the increased preload....careful with the threads, please. This mod gets rid of the hard front end dive under braking. These front forks are pretty rough inside and are pretty sticky feeling.

- Head nuts....the chrome covers over the heads are mounted on some stamped steel plates, held down by the head nuts. I decided to make the engine more "mechanical" looking by ditching the covers. When I tried to loosen the head nuts, I could feel the long head studs twisting like a torsion bar between the top of the head and the crankcases. I had to heat each nut with a butane pencil torch before I could get enough nerve to pull the nuts loose. Do not simply jerk on them with a long wrench; you may be sorry. After you get a nut off, use antisieze on the threads before you reinstall.

- Nuts and bolts. Worst parts on the bike, other than rubber stuff. Replace with decent hardware and you will solve a lot of problems.

- Rubber stuff......crumbles away in a few years. Replace with Yamaha stuff or bits cut/gathered from used Japanese bikes. For example: The original Diamo/Lifan gas tank mount rubbers were cracking and crumbling on this 2006 model bike. The 1971 Suzuki gas tank mounts I used (from the original TS90 bike) are in excellent shape after 44 years (the last 10 years lying on the ground under a tree). Even the original Suzuki fuel shut off rubber is still good and works well.

This has been a long post, but I hope it helps someone with their project. The very low cost of these bikes make them good candidates for radical rebuilding as I have done. Homemade mods are cheap and fun, and the financial risks are much lower than messing with an expensive late model Japan bike.

[Weldangrind]

Homemade mods are cheap and fun, and the financial risks are much lower than messing with an expensive late model Japan bike.

Indeed. That's one of the concepts that draws me to China bikes.

Thanks for the excellent and well-thought out tips. I would have never considered the frame slag to be an issue.

I've considered building a Greg Hageman style bike with one of these, but they're hen's teeth where I live.