Kawi2strokes.com Forum

Enthusiasts from around the world dedicated to the preservation and ritual flogging of the infamous Kawasaki 2-stroke Triples
It is currently Fri Mar 29, 2024 3:05 am

All times are UTC - 5 hours




Post new topic Reply to topic  [ 20 posts ]  Go to page Previous  1, 2
Author Message
PostPosted: Mon Mar 12, 2018 10:19 pm 

Joined: Tue Jul 24, 2012 6:06 pm
Posts: 1135
Location: Honolulu
Yeah for that hinge in the middle.


Top
 Profile  
 
PostPosted: Tue Mar 13, 2018 3:21 am 

Joined: Thu Jun 09, 2011 11:25 am
Posts: 3137
Truths, these frames flex, to the point the most stress is between the swing arm pivot and steering head, upper rear engine mount point gets most of that flex stress. Also proven the cases break at that mounting point. Also proven, the whole mess works better when the bolts, nuts and link bars are left on the workbench.

And, yes, every rider we ever had at Team Kawasaki Road Race told us the frames, both stock street bike, and R, felt like they had a hinge in it's middle. Now, we tried to do work around measured to the issues, best one was to remove the upper rear link plate and leave the mount lugs on the chassis as rear fairing mounting lugs only

The C&J, Nico Bakker and Harris frames of the time didn't even have the mount lugs fitted to their chassis. Those chassis had less stress movement in the engine bay than the factory frames, and less "hinge in them, all with no case damage.

Nobody is saying you have to leave the upper rear mounting bars off the bike, all said is that removing them helps in more than leaving them in place. You have suffered two case failures, some of us have as well. The sensible fix is to leave them off, but, do as you wish, and learn to weld aluminum.

Just info we old guys are posting as real world info.


Top
 Profile  
 
PostPosted: Tue Mar 13, 2018 7:52 am 
User avatar

Joined: Wed Jun 08, 2011 10:23 pm
Posts: 3821
Location: Colorado Springs, CO. USA
H2RTuner wrote:
Then, make the two link plates out of rubber, and leave the steel ones off the bike. Tell people it helps cornering.


:lol: :lol: :lol: :lol: :lol: :lol: :lol:

_________________
This is true. Where I grew up the hills were so steep and long, when your ball rolled down the hill you just said "screw it"...


Top
 Profile  
 
PostPosted: Tue Mar 13, 2018 9:29 am 
User avatar

Joined: Fri Jun 29, 2012 7:22 pm
Posts: 564
Location: Syracuse , New York USA
Im having trouble understanding how removing the rear mount and letting the frame flex more will help in cornering, it would seem if there was that much flex that it would be needed more than ever..
It also seems without the rear bracket it would let the engine twist more under load and cause more frame flex..
Interesting ..

_________________
1977 KH 400
1976 KH 250/350 rat bike
1971 KV 75
1976 KV 75


Top
 Profile  
 
PostPosted: Tue Mar 13, 2018 7:57 pm 

Joined: Thu Jun 09, 2011 11:25 am
Posts: 3137
The combination of engine vibration and frame flex is causing the added mounting stressing of the upper rear mount to fail the upper engine case to boss failure. Also, when the conflicting vibration stress on the upper frame rails occur, the handling is adversely effected.

Think about the stresses created against themselves with all 4 mounts in place, vs the 3 lower/front only mounts. It is a lot more friendly for the frame and steering head with only the 3 lower/front mounts. The upper rear mount is a conflict to the other 3.

As I said, I don't use the upper rear mount, don't crack/break frames, and have no vibration issues in the steering heads.

Please, do as you a wish, the way I have outlined, has worked on every triple j have done since 1971.


Top
 Profile  
 
PostPosted: Wed Mar 14, 2018 7:52 am 
User avatar

Joined: Fri Jun 29, 2012 7:22 pm
Posts: 564
Location: Syracuse , New York USA
Years ago I had an old Ironhead chopper and the top motor mount broke the bike was virtually un rideable and Im lucky that after it broke I didn’t crash,, It behaved similar to a bike with the head stock bearings to tight almost unbalanceable..
That has always stuck in my mind and hard to get out,,,thinking that more is better..
Im curious how this would affect the S series being smaller and lighter and with less Hp,,
I understand your explanation and it may be completely plausible but still have my doubts,, so you are saying this is better for all triples or is your experience with this limted to the H series bikes?
Again,,, just curious because I may remove mine on my S and see if I can detect any noticeable improvement this summer, Its my feeling that I wouldn’t even notice a change because I really don’t ride that aggressive anymore..
If I was the OP I would remove my front motor mounts and inspect for worn bolts and enlarged holes as well as other possible frame issues..

_________________
1977 KH 400
1976 KH 250/350 rat bike
1971 KV 75
1976 KV 75


Top
 Profile  
 
PostPosted: Wed Mar 14, 2018 8:14 am 

Joined: Thu Jun 09, 2011 11:25 am
Posts: 3137
Please, enjoy your doubts, but, you weren't at all the track tests, nor the vibration, nor frame tests we did at Cal Tech, nor other testing with on. Ike movement devices to find that opposing mounting. Caused frame tube and steering head vibration, oscillation, and just plain problemsand leaving the upper feR mounting bars off the frame, lessened them significantly.

And, a POS 17th century ox cart of a Harley ain't even close to a Kawasaki triple, the HD is a mess, even with the upper mount in place, extreme apples to oranges.


Top
 Profile  
 
PostPosted: Wed Mar 14, 2018 8:18 am 
User avatar

Joined: Thu Jun 09, 2011 3:06 am
Posts: 4364
Location: PARIS FRANCE
You're not the firsts Ja-moo and H2Rtuner to say H1 H2 frame works better w/o the top rear motor mount fitted.
But until H2Rtuner explains why I didn't understand.
Great explanation I will try next time I put off the engine of one of my triples.


Top
 Profile  
 
PostPosted: Wed Mar 14, 2018 9:28 am 
User avatar

Joined: Fri Jun 29, 2012 7:22 pm
Posts: 564
Location: Syracuse , New York USA
H2RTuner wrote:
Please, enjoy your doubts, but, you weren't at all the track tests, nor the vibration, nor frame tests we did at Cal Tech, nor other testing with on. Ike movement devices to find that opposing mounting. Caused frame tube and steering head vibration, oscillation, and just plain problemsand leaving the upper feR mounting bars off the frame, lessened them significantly.

And, a POS 17th century ox cart of a Harley ain't even close to a Kawasaki triple, the HD is a mess, even with the upper mount in place, extreme apples to oranges.



I wasn’t doubting,, in fact just the opposite,,, hearing what you where saying...
I also wasn’t comparing ox carts either,, just explaining why I had my doubts because of an experience I once had,, you also never answered the question on the s series frame,,, if or any testing was done on that frame ?
This will be my last post in this thread,, I should of known better ..

_________________
1977 KH 400
1976 KH 250/350 rat bike
1971 KV 75
1976 KV 75


Top
 Profile  
 
PostPosted: Wed Mar 14, 2018 10:46 am 

Joined: Thu Jun 09, 2011 11:25 am
Posts: 3137
Yes, on both S and KH series street frames, and 2 very special S1R frames. I think Dave Crussell still has the only S1R still in existence.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 20 posts ]  Go to page Previous  1, 2

All times are UTC - 5 hours


Who is online

Users browsing this forum: No registered users


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group