1976 360CR GP project

Ok after getting a bunch of my 360 questions answered last week , I fell into a 79 390WR which was pretty hammer, but the price was right, FREE. The plan was to see how similar a 360 & 390 motor where, as already had a75 360GP frame & now a 79 390 motor. Could I make a early GP replica, out the parts I have?

The 390’s motor was already out , as it had a made a crunching noise?, so I messed around with mounting it in the 75 frame on Friday. Here’s what I found, the 390 fits ,but has slightly different cases in the front motor mount area vs the 360. The 390 uses 4 motor mount bolts in front , the 360 uses 3 bolts or a single engine bolt lug vs 2. The rear mounts line up, as long as you use the earlier rear swingarm motor plates, & the banana swingarm I had, bolted right on. As I wasn’t too keen on using the 360 front engine plates & leaving 1 motor mount without a bolt, so I stopped.

Rather then butcher up a set of 390 front mounting plates, I made a last minute decision & bought a 76 360CR I had earlier in the week, made an offer on , over the phone.

Actually it worked out much better then I 1st thought, as on Sunday I noticed the 75 frame was repaired once & the job didn’t look to swift. Also I pull the top end of the 390 & low and behold the piston broke on the intake side, and as bad luck would have it, the pieces jammed in the front side of the rod & broke the cases. And I mean really broke them, there was gear oil in the crank journal area.. So much for using parts i already had

As with most projects, very little goes by cheaply, now’s when I’m glad I bought the bullet & sprung for a 76 360 which had low compression , but was surprisingly all original. So starts another Vintage restoration project, to build a mid 70’s works style GP bike.

The plan is to take a stock 360, install a banana style Swingarm, install long rear shocks, take the triples off a 77 or 78 125CR & install either 79 CR or WR front end, to balance out the added shock length. Of course while I’m at it, it will get a new top, & most of the bike will get prettied up.

Sound simple right??
Husky John

This bike had been kicking around PA, for a couple years now, I’ve seen it on Ebay & of course craigslist. I remember think I should have bid on it when it was on Ebay, but never did. Anyway the Guy I got it from was the winning bidder, but it sat for probably a year before it started to pop up off & on craigslist for probably 6 months. Time was on my side & I got it for ½ of his original asking price & he said he sold at a slight loss.

The bike ,though a number matching CR was ridden as a woods bike, bar busters, bash plate & the like. What I find cool is the old school garage mechanic up grades. The bash plate looks home made, but someone thought enough to cut a slot in it , to drain the oil with it on. Also check out the cut off screws welded on the foot pegs & the brake pedal bolts that keep your foot from coming off. Not the prettiest modification but they sure do work. Bike has Preston Petty side number plates & a “Flying Finn” embossed red mud flap, along with a top of a spackle buckle front plate (I kid you not).

Here's what it looked like off the truck... homemade bash plate, foot peg & brake lever , too wide original bars ..

more to come... Husky John

Yeap that's the plan use as many 79 parts as i can. Here's a few pics of the banana swingarm on the 75 360 frame, one without any shocks & one with a 15"c-c Ohlins from
the 79.

Started cleaning her up, took off those rototiller style handle bars, & bash plate, it will take some time.
Stay tuned to this Bat Channel

Well, fiddled with the old girl today, got her running, had to jump start it, but hey she got low compression, so i was surprised she fired up.

Time to play around with the swingarms & different shock lengths.

1) Pull off the stock length? 13" shocks, & put on 15", but i think there too long as it really jacked up the rear end.

2) Then i tried a banana style swingarm, with those 15" shocks, but this change required using a later model wheel as the swingarm is wider. A 79 wheel
fit fine, but i'm still not sure the 15" length is right still. Also it looks like i have to get another brake hub, as the 76 wouldn't work properly.

Still not sure which direction, yet til i put some different longer fork on..

I'm really surprised they said the 77's handle so well, jacked up so high like it is ....

JIm,
14" length is what i was thinking as well, my 15" Ohlins, i was told can be shorten easily. The adjustable turnbuckle is a great idea, the biggest thing is to
NOT have a crazy angle on the swingarm, so the chain just digs into it.
Husky John

I'll be at Snoops