1971 Kawasaki A7 Avenger

[Mike.Gayner]

Did a quick blog entry on tearing it down, no real detail but some pictures for this interested.

http://a7avenger.wordpress.com/2014/...-rebuild-time/

Crank is being rebuilt at present - currently optimistic we'll find enough parts to make a good crank (both rods need replacing).

WIP.

[husaberg]

post the sizes length of the crankpin and the rod sizes and lengths, I am sure we can find something that will work and be new.........

[Mike.Gayner]

People smarter than me have already done their homework on this, and I'm leaving it in the hands of an experienced local to do the rebuild. Some people have used H1 rods, or as a substitute these rods: http://www.powersportsuperstore.com/...tm?Click=35177

They're about 3.5mm longer though, so you have to use a little spacer under the barrels. I'd rather try to rebuild with good A7 parts if possible. It'll be new main bearings, small end bearings and new machined pins if necessary.

[Ocean1]

People smarter than me have already done their homework on this, and I'm leaving it in the hands of an experienced local to do the rebuild. Some people have used H1 rods, or as a substitute these rods: http://www.powersportsuperstore.com/...tm?Click=35177

They're about 3.5mm longer though, so you have to use a little spacer under the barrels. I'd rather try to rebuild with good A7 parts if possible. It'll be new main bearings, small end bearings and new machined pins if necessary.

Most tooling workshops will make you new pins. If there's any left.

And just occasionally you find there's a bearing available that's half a tad larger OD than the OE spec bearing. Means you can bore and hone the rods. For the sake of 5 min in a bearing book or on the phone it may be worth a look.

[husaberg]

Here you go
bugger has stepped pins so they have to go....
http://a1a7.com/forum/index.php?topic=341.0

http://a1a7.com/forum/index.php?acti...ge;topic=160.0

[Mike.Gayner]

Thanks, I've already read all the threads in that forum.

[Flettner]

My Kawasaki F9 350 has almost no Kawasaki bits left inside it. A longer rod is a good thing, no one will notice small spacers. The original rods are rubbish, I would not bother fitting them. Mine has a Hot Rod ( brand ) out of a Polarus of some sort, a much more modern design and very robust. The bike will handle 9000 rpm, four race seasons now without going near the crank. If I used original I wouldn't see one season out. I repeat the original rods are rubbish.

[Mike.Gayner]

Cheers Flettner, point taken. I caught up with the guy who is doing the crank work for me today. He has pulled apart 4 cranks to find a good set of rods and couldn't get a single usable rod, which I guess is a testament to how bad they are.

We will be going with YZ125 rods, which will require:

• 1mm machined off the cylinder (as the rods are 1mm shorter)
• About 20 thou machined off each side of the webbings as the YZ125 rods are slightly thicker
• YZ125 big end pins will need to be turned down slightly to fit the original webbing

Going down 1mm is probably better in terms of keeping exhaust fitment etc right, as opposed to going up 4 or 5mm. I'm not building this for performance so the slight decrease in crankcase volume isn't a bit deal for me. I'm pretty much building a brand new crank on the old webbings, so it should be good for a long time once completed.

[Flettner]

Good on you, use modern stuff!

[Mike.Gayner]

After pricing up the YZ125 rods and related machining work it was going to be WAY too expensive. In the end my guy wound up tracking down enough great parts to make one frankencrank. It has one new rod, one great used rod and assorted parts from mine and other cranks. Going to be starting the process of putting everything back together soon.

http://i.imgur.com/6HuvMHTl.jpg

[JDS]

I recently purchased a Kawasaki A7 350 Avenger, have been plotting/planning to modify her, but reading all the posts in this thread, it has me feeling bad about it and that maybe i should just tidy her up a little and keep her as is.

In an effort to keep me off a sports bike, my old man has very generously given me his 1971 Kawasaki A7B Avenger. The engine runs and it's a pretty good starting point for a restoration. I'm not going to go nuts with this, but I'll strip it down and clean everything up, and hopefully get it back on the road in relatively short order.

Are there many of these around? Any members on here own this or a Samurai? The two-stroke twins sure seem to be an uncommon bike these days. I'm worried about finding parts, but there seem to be a lot of bits available on ebay (for a price).

This is the bike, currently sitting in my dad's garage. Definitely looking forward to shifting it into my own garage as soon as I've done a bit of a clean-up at home.

http://i.imgur.com/PA9vA6n.jpg

Attachment 289213

[Mike.Gayner]

JDS, got any pictures? I wouldn't be too swayed by what people tell you to do - it's your bike and you should do what you want. These bikes are definitely uncommon and hard-ish to come by, but they're far from "rare", and I wouldn't be nervous about modifying one. I've decided to leave mine more or less exactly as it is rather than restore it, mainly for financial reasons. Personally I don't care about the future value of the bike (some people say it's worth more unrestored) because I own bikes to ride them, not to record them on my balance sheet.

[ellipsis]

...Welcome JDS...is this a first bike or just a project...are you fairly familiar with, or, ready to learn about two stroke's...just inquisitive, that's all...

[JDS]

...Welcome JDS...is this a first bike or just a project...are you fairly familiar with, or, ready to learn about two stroke's...just inquisitive, that's all...

It's my first road bike but I rode mx bikes plenty.

Will post a pic of the bike soon.

I bought it as a family bonding project with my brother and old man. If all goes well, might do another one or if lucky two.

I had planned to build an old brat style bike. Not sure if this lends itself to that, may keep her closer to what she is and build a brat for my next one. Will see.

[ellipsis]

...cool...good luck with the overall project...