Hard shifting in/out of first when engine is hot

Joined
Oct 31, 2015
Messages
20
Location
Coronado, Ca
2004 ST1300 with 45,000 miles, sidecar fitted a long time ago. The bike will periodically refuse to shift in/out of first when the engine gets fully warmed up, followed by driving in stop and go traffic. This has been going on for several years, mostly a nuisance. More recently, I've noticed the bike may creep slightly when stuck in first, clutch fully pulled in and motor running? Switching the engine off then provides normal gear selection between first/neutral/second, etc. Otherwise, shifting thru the gear box underway is reasonably smooth and uneventful. I have recently fitted new gear shift linkage, clutch slave cylinder, SS clutch pipe, and full clutch flushing etc, in an attempt to resolve this. I use Valvoline 30/40 synthetic brake fluid, and Rotella T6. Looking for advise for next steps to eliminate this nuisance. Thanks
 
How far does your lever travel before it meets the resistance of the fluid.
My first thought is that you still have air in the line, preventing the clutch from disengaging properly.
I know that you have just bled it. But bubbles can hide anywhere. Tap / flex the lines when bleeding - get the bubble dislodged.
Did you make sure that the clutch slave seal went in with the flared end first ?

I know this article is aimed at brakes - but watch the bubbles videos in the first post.
Article [13] - ST1300 - Brake Maintenance - Getting all the air out of the brake system | ST1300 Articles | ST-Owners.com

There is a weep hole in the casing of the clutch housing - I doubt it is this since you have just had it apart but if it is blocked it can make the slave cylinder movement awkward. (Air pressure, build up of fluid). The hole is at the 6 o'clock position in the joint between the clutch slave housing and the crankcase.

Did you make sure your new gear linkage lined up in the same position - the punch holes on the old have to line up, but I doubt the new linkage has the punch holes. (I don't know what I am talking about here as I have never done it, but I know that the position of the linkage in relation to the shaft is important. You will know if that is likely to be an issue)

I hate to suggest it might be drag caused by indentations in the clutch basket caused by the tabs on the friction plates. I'e only ever had this issue once on the very first bike that I owned. Easy to fix then - I did it at the side of the road. I've never had to do anything with the clutch itself on the 1300. I'm dreading the day I might need to. Very little space, very big hands.

I wonder if this is possible with the extra load of the sidecar. I know my XS650 struggled to take off with a sidecar and family fitted - and the gear changes became progressively worse.
 
Have you noticed if the clutch starts to engage closer to the hand grip when this happens? In other words, the hotter it gets, the more free-play there is in the lever? If so, you're in need of a clutch-fluid flush and bleeding, despite your already having done it.

My '01 got so bad that, when it was real hot, the clutch would not disengage at all, and would stall the engine when i tried to stop. Two vacuum-pump flushes later and the clutch now has perfect operation no matter how hot it gets, even in stop'n'go traffic.
 
Thanks for your reply and suggestions - Clutch handle pulls in about 15mm before resistance - I will tap and bleed the line again, and like I have done previously with the brake handle after bleeding, I will strap the clutch handle tight to the handlebar overnight to see if that helps as well. AS to the clutch slave cylinder, I installed a new unit. I believe I clean the weep hole you mentioned. Yes, the gear linkage is lined up correctly to the output shaft, with the marking on the splines, etc. The securing bolt is tight also. That has loosened before, and the shifting then was generally sloppy, thru the gears. Tightening that bolt has become regular maintenance. Agree, I dread the day I have to pull the clutch cover from the front of the engine, for lots of reasons, but I want to exhaust all my alternatives before I take that step. Sidecar is a concern, but relieved by reading the many other threads on this superb forum about shifting issues.
 
Have you noticed if the clutch starts to engage closer to the hand grip when this happens? In other words, the hotter it gets, the more free-play there is in the lever? If so, you're in need of a clutch-fluid flush and bleeding, despite your already having done it.

My '01 got so bad that, when it was real hot, the clutch would not disengage at all, and would stall the engine when i tried to stop. Two vacuum-pump flushes later and the clutch now has perfect operation no matter how hot it gets, even in stop'n'go traffic.
Thanks Larry - I haven't noticed that, but that's a good reason for a ride - I will check that out!
Have you greased the linkage?
Fortunately, the new OEM linkage that I fitted came with grease in the joints!
 
I should add that, after a cool-down rest period, or after cool-down riding, the clutch operation would return to normal. That has to be fluid-temperature-related, and not due to mechanical issues.
 
I should add that, after a cool-down rest period, or after cool-down riding, the clutch operation would return to normal. That has to be fluid-temperature-related, and not due to mechanical issues.
I tend to concur with your assessment, as this issue does generally resolve itself when I am able to find open road again. The issue appears only in stop and go traffic after several minutes, or when I am waiting for my garage door to open. My ST1300 runs on the hotter side compared to other bikes that I have owned. The routing of the OEM and my aftermarket SS clutch line alongside the left frame adds some heat to the fluid, as does the location of the clutch slave cylinder at the back of the engine, which sees very little airflow in stop and go traffic. I have thought about changing out the fluid from the Valvoline that I have used for many years in other bikes and cars, without issue, to a different DOT 4 moto fluid, maybe with a higher boiling point, if such exists?
 
Thanks for your reply and suggestions - Clutch handle pulls in about 15mm before resistance - I will tap and bleed the line again, and like I have done previously with the brake handle after bleeding, I will strap the clutch handle tight to the handlebar overnight to see if that helps as well. AS to the clutch slave cylinder, I installed a new unit. I believe I clean the weep hole you mentioned. Yes, the gear linkage is lined up correctly to the output shaft, with the marking on the splines, etc. The securing bolt is tight also. That has loosened before, and the shifting then was generally sloppy, thru the gears. Tightening that bolt has become regular maintenance. Agree, I dread the day I have to pull the clutch cover from the front of the engine, for lots of reasons, but I want to exhaust all my alternatives before I take that step. Sidecar is a concern, but relieved by reading the many other threads on this superb forum about shifting issues.
15mm is a lot, 5 to 10mm is what it takes on my ST.
That first made me uncomfortable with the gear shifting, it feel like there is no middle range but that's the way it is designed to work.
Flush, flush it again and check for air leak on the line.
This not the DOT loosing properties when hot, that's the volume of air when hot that is expanding in the line.
 
I would suggest another clutch fluid bleed (squeeze the lever, crack the bleed bolt,then re tighten and repeat) and possibly use motorcycle oil, like Honda recommends. :)
T6 diesel oil has changed their formulation I believe (read on here) and may be causing issues.
The other variable is the slave cylinder, which you already replaced.
 
Thanks Larry - I haven't noticed that, but that's a good reason for a ride - I will check that out!

Fortunately, the new OEM linkage that I fitted came with grease in the joints!
Went for a ride around town, slow speeds and low rpms, etc. Getting home, Bike repeated the hard shifting out of first gear. Position of the clutch lever for engaging/disengaging seems to remain unchanged whether cold or hot. I switched off the ignition, and easily moved the shift lever to the neutral position. Rolled the bike out of the garage, started her up, shoved the shift lever into first, could not shift back to neutral. Rode down the alley 50 yards, and the bike then shifted to second, albeit reluctantly. No change in the clutch lever engagement position or firmness, (which firmness hasn't changed for my 9 years of ownership.) On to some bleeding.
 
The firmness of the clutch lever is not meaningful, the action of the spring inside is hard to differentiate from the effective pressure buildup.
Your transmission is obviously not the concern, same for the clutch basket. You have some air trapped in the line or maybe behind the clutch slave cylinder by itself.
One way to get it out is to loosen the slave cylinder a bit and to pump from the handle until you get some of the fluid dripping from the slave gasket assembly (do not release the handle). When done, tight everything back. You will still have some air in the line but not behind the slave piston which is very hard to get out by any other way.
Last, flush again, this time using the drain.
It worked for me, good luck.
 
Changed oil from Rotella T6 to Mobil 1 Racing 4T 10/40 motorcycle oil, and bleed the clutch line again - Hasn't solve the issue. Fortunately, the issue is manageable, by avoiding extended slow speeds, and by switching off the engine when needed to return to neutral, and then restarting the engine.
The firmness of the clutch lever is not meaningful, the action of the spring inside is hard to differentiate from the effective pressure buildup.
Your transmission is obviously not the concern, same for the clutch basket. You have some air trapped in the line or maybe behind the clutch slave cylinder by itself.
One way to get it out is to loosen the slave cylinder a bit and to pump from the handle until you get some of the fluid dripping from the slave gasket assembly (do not release the handle). When done, tight everything back. You will still have some air in the line but not behind the slave piston which is very hard to get out by any other way.
Last, flush again, this time using the drain.
It worked for me, good luck.
Thanks for the advice - A couple of questions - at the slave cylinder, what should I loosen up? The double banjo bolt securing the feed and bleed lines to the top of the slave cylinder? When you say, flush again, this time using the drain, which drain are you referring to? Thanks again!
 
Changed oil from Rotella T6 to Mobil 1 Racing 4T 10/40 motorcycle oil, and bleed the clutch line again - Hasn't solve the issue. Fortunately, the issue is manageable, by avoiding extended slow speeds, and by switching off the engine when needed to return to neutral, and then restarting the engine.

Thanks for the advice - A couple of questions - at the slave cylinder, what should I loosen up? The double banjo bolt securing the feed and bleed lines to the top of the slave cylinder? When you say, flush again, this time using the drain, which drain are you referring to? Thanks again!
I mean these bolts, just until you see a little drip of fluid, keep the handle pressed. They are hard to get, sorry. And last flush using the regular bleed valve.
I hope it will help.
Edit, you can try to just loosen the banjo bolts instead, may work too...


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Last edited:
I mean these bolts, just until you see a little drip of fluid, they are hard to get, sorry. And last flush using the regular bleed valve.
I hope it will help.


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Thanks for this. If I loosen the circled bolts to the rear cover, I would not expect to see a drip of any kind from the slave cylinder? Am I missing something? As to the drain, got it, thanks for the clarification. Agree as to the bolts, yes, they are very difficult to get to!
 
Thanks for this. If I loosen the circled bolts to the rear cover, I would not expect to see a drip of any kind from the slave cylinder? Am I missing something? As to the drain, got it, thanks for the clarification. Agree as to the bolts, yes, they are very difficult to get to!
Sorry for the confusion, you are absolutely right about the 3 bolts, no oil. It would just help the piston to fully retract and release the air trapped behind.
 
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