GR 650 Tempter Motor In A GS 400???

[t500racer]

Hi guys. I posted here a month or so ago about finding a larger motor for my GS 400 cafe project. The original plan was to find an early GS 500E motor, which from initial measurements appeared to be almost a direct bolt in. The only problem with that is the 500 uses a perimeter frame and the 400 has twin downtubes that are located exactly where the 500 exhaust pipes bolt to the cylinders. The 400 has splayed exhausts to clear the downtubes, the 500 does not. This was a bit more fabrication than I wanted to get into, and a decent GS500 motor has not been forthcoming.

I recently had a look at pictures of a Suzuki GR 650 Tempter twin. The engine cases look so much like the GS twins I did a doubletake. The exhausts are also splayed out as the 400s are. I have not been able to find a Tempter locally to measure. I am curious if anyone knows anything about the Tempter or if you've got one you could possibly get some measurements from. I just found one cheap 200 miles away, but at the asking price I don't think the owner would be willing to take any measurements. I appreciate any information on the 650 Tempter you guys can give me. Thanks in advance.

Kris Larrivee

[beby99]

Yep...as I'm at work right now, I'll post the measurements tomorrow.
You just need the exhaust measurement correct? Engine mount locations?

[t500racer]

Yes, I can use any measurements you can give me relating to the overall height and width of the engine, the distance between the exhaust ports, width of the motor mounts on the engine, distance between the motor mounts front to rear and engine mount locations. Basically anything you can give me. I'm just trying to get an idea if it's worth it or too much work for not enough gain.

I'm also curious what you think about the power of the 650? I know it's not a fire breather, but conventional wisdom would say that a 650 twin would be better than a 400? Can anyone compare the two? Thanks.

Kris

[Desolation Angel]

Yep...as I'm at work right now, I'll post the measurements tomorrow.
You just need the exhaust measurement correct? Engine mount locations?

Ready to sell that to me, yet?

[jpaul]

Would it be possible to put the head from a 400, 425, or 450 on the 500 engine. They are basically the same, and I can't see them changing the bolt pattern for the heads. Just a thought.

[Dave8338]

Yep...as I'm at work right now, I'll post the measurements tomorrow.
You just need the exhaust measurement correct? Engine mount locations?

No info to add here but, WOW!!! that is one sweeeeeettt looking motor, would love to see the rest of the bike. Damn, that's nice! :shock: :-D

[t500racer]

I was told that the 400 and 425 are different than the 450 and the 500 is altogether different than any of the others. It seems almost impossible to get a clear idea of what will work on what.

I read a post on the GR 650 message board about a guy that put a Tempter motor in a GS 500 frame. He said it was not a direct bolt in, but that the 500 motor was actually wider than the 650! I tried to ask the same question regarding measurements of the 650 motor mounts on that forum, but even after joining I can't seem to post anything.

Kris

[beby99]

I'm also curious what you think about the power of the 650? I know it's not a fire breather, but conventional wisdom would say that a 650 twin would be better than a 400? Can anyone compare the two? Thanks.
Kris

Hey Kris...not sure what year 400 you have but here's some figures:

GS 400 E 1978
Overall Length: 2 080 mm (81.9 in)
Overall Width: 835 mm (32.9 in)
Overall Height: 1 125 mm (44.3 in)
Seat Height: 780 mm (30.7 in)
Wheelbase: 1 385 mm (54.5 in)
Dry Weight: 172 kg (378 lbs)
Engine type: Air-cooled 398 cc inline-2, DOHC, 4 valves. 37 hp/ 9,000 rpm, 34 Nm (3,3 kg-m)/ 7,500 rpm.


GR 650 Tempter 1983
Overall Length: 2 125 mm (83,7 in)
Overall Width: 735 mm (29,0 in)
Overall Height: 1 110 mm (43,7 in)
Seat Height: 775 mm (30,5 in)
Wheelbase: 1 430 mm (56,3 in)
Dry Weight: 184 kg (405 lbs)
Engine type: Air-cooled 652 cc inline-2, DOHC, 4 valves, two-stage flywheel. 62 hp/ 9,500 rpm, 4,8 kg-m/ 8,000 rpm.

[beby99]

Yes, I can use any measurements you can give me relating to the overall height and width of the engine, the distance between the exhaust ports, width of the motor mounts on the engine, distance between the motor mounts front to rear and engine mount locations. Basically anything you can give me. I'm just trying to get an idea if it's worth it or too much work for not enough gain.

Ok....looks like I have more measureing to do. The pipes are 1 1/2" and are 6" between (inside) exhaust ports. There are 3 mounting locations that I show here (red arrows) and down pipes are 14". Front mounting tabs are 3" apart (wide). I will get you the rest of measurements tomorrow.

[beby99]

No info to add here but, WOW!!! that is one sweeeeeettt looking motor, would love to see the rest of the bike. Damn, that's nice! :shock: :-D

Gee..thanks Dave, always nice to show her off.

Ready to sell that to me, yet?

Herb...you will be the first to know....hey, how about a swap ;-)

[t500racer]

Thanks for the info so far, and your Tempter really does look sweet! From the initial info you gave me, it sounds like this motor just might drop in there.

As far as those horsepower figures, I have seen those posted on another site, and I believe they are extremely optomistic. I read the Cycle World test of the Tempter and according to their dyno it was good for about 38 hp! Now there's a big difference between 38 and 62. I'd be happy with somewhere right in the middle, about 50 or so would be just fine. The bike currently weighs around 350 pounds. Obviously the 650 motor will add some weight, and I see that there is no kickstart on the Tempter, so I guess I will have to live with a heavy electric starter! Or maybe I could just bumpstart it. (I could live with that, until I stalled it at a stoplight!, ask me how I know!)

This bike is about as bare bones as you can get and still be almost legal. No gauges, no ignition switch or key, fiberglass fenders, mini-turn signals and an IT 400 yamaha tail light (it says "Not For Highway Use" on it, but the cops don't ever look that close!). Thanks again for the info, looking forward to the other measurements.

Kris

[Desolation Angel]

Gee..thanks Dave, always nice to show her off.






Herb...you will be the first to know....hey, how about a swap ;-)

Stop teasing me! You know you wouldn't! :-D

Your bike and 8Track's are my favorite smaller ones!

[Dave8338]

Gee..thanks Dave, always nice to show her off.

This gives the rest of us something to shoot for...That bike didn't look that good the day it rolled off the line. CLASSY RIDE BEBY!! =D>

[beby99]

Ok Kris...got a few more figures for you:

Engine size:
19" High
15" Long
17" Wide

Mount size:
3" Front (wide)
4" Rear (wide)
13" from Front to Rear



As far as the horsepower goes, those above figures are at different RPMs so yes I think somewhere in between would be close.

If you need anymore measurements....I'll be away from the computer till Tuesday so I'll catch ya then.

Thanks all for the compliments.

[jinxz]

didnt mean to barge in but when i seen this i couldnt resist http://seattle.craigslist.org/oly/mcy/242943642.html i think i like your tempter better beby99