Poor throttle response /5

schrader7032 · Post by **schrader7032** » Sat Jul 11, 2009 1:27 pm

Sounds like the clutch kit (EZ clutch?) needs adjusting. The kit is nice in that it reduces the pull at the hand lever, but because of the design, there's little room for error in where the clutch engages and disengages. Sounds like your clutch is slightly disengaged even though the hand lever is all the way out. A slipping clutch is exacerbated in higher gears.

If you did get the EZ clutch, go to http://www.benchmarkworks.com and click on FAQ - Tech Advice. There's an article there on the kit and installation.

Kurt in S.A.

armymutt · Post by **armymutt** » Wed Jul 22, 2009 1:47 pm

Well, figured it out. I hadn't tightened the lock nut on the clutch release at the back of the engine. I must have had something come up while I was working on it and got distracted. Easy fix.

VBMWMO · Post by **VBMWMO** » Mon Feb 15, 2010 2:52 pm

I had the carbs rebuilt on my '72 R75/5 and installed a clutch lightening kit from Vech. The bike has sat for a couple months while I've waited for time and good weather to ride it. I took it out today and noticed that when it's in 4th gear, once I get above 4.5K RPMs, it's almost like the bike is in neutral. The tach needle keeps climbing but the speed stays the same - around 45MPH. Any ideas?

armymutt · Post by **armymutt** » Sat Apr 28, 2018 3:53 pm

Bringing this back from the dead because I'm getting a forum is locked message and can't post a new message. Took the bike out today after a few years of sitting around. I cleaned both carbs this past winter and got the bike running in the garage. Out on the road, it's like I have no power. The engine doesn't race, the bike doesn't pull like it should. It almost died going up a hill. Only thing I can think of is mixture screws. Both are set a 1 turn out from full in. Plugs are good.

schrader7032 · Post by **schrader7032** » Sat Apr 28, 2018 4:01 pm

I don't recall the carb numbers, but typically the idle mixture screw is at 1-1/2 out. Note, though, that these values are just starting points...it's necessary to do a full carb synch to find the optimum settings as well as the cable tension.

No oomph on acceleration could also be a plugged air filter. Could also be holes in the carb diaphragms.

armymutt · Post by **armymutt** » Sat Apr 28, 2018 4:25 pm

I tried to synch the carbs with my carb tune that I use on my modern triumphs, but the /5 isn't pulling enough vacuum to lift the indicators inside it.
My diaphragms appear intact. I suppose there could be pinholes. Are there supposed to be springs in the carb tops? Mine doesn't have any, but I've seen rebuild descriptions with and without them. I'll check the air filter.

Got another issue. There's a severe oil leak coming from the bolt on the tranny that the battery ground to. Oil is squirting out. Any thoughts on this?
https://ibb.co/hMZCJc

Twocams · Post by **Twocams** » Sat Apr 28, 2018 4:39 pm

armymutt that is the breather hole for the transmission. Maybe to full of oil or water in the oil. You cant let a bike, car, truck just sit around for a few years then start it up and just be where you left off. Ride that baby once in a while.

twocams

schrader7032 · Post by **schrader7032** » Sat Apr 28, 2018 4:48 pm

That bolt should have a hole through it to let the transmission breathe. It's hard to tell from the image, but the oil is either very clean or is coffee colored which indicates water intrusion. It's a little hard to over fill the transmission since you put fluid in at the fill hole on the left side of the transmission...once the fluid gets to the level of those threads, it's starts pouring out onto the ground...that's full.

Spring or no springs...I don't think that's the issue. It would appear that the slides are not lifting when you open the throttle...all the springs would do is push the slides back down, seemingly making your problem worse. You could remove the air horns, start the bike, and look at the action of the slides. They should be responding to throttle input...raising up and then falling. You could also spray carb cleaner around all the carb connections, like the tops of the carbs and the connections to the rubber hoses leading to the heads. If those connections are tight, then the engine RPM should not fluctuate from idle when you spray them.

Can you provide the steps you went through to synch the carbs? There are three basic steps in that process.

MikeL46 · Post by **MikeL46** » Sat Apr 28, 2018 7:06 pm

Was the bike sitting outside (in the rain) at all? If the speedo cable rubber gasket is loose on the cable, the cable will direct water into the transmission.

Mike

armymutt · Post by **armymutt** » Sat Apr 28, 2018 10:02 pm

The bike has never been in the rain since I've owned it, except for the day I brought it home. It's had the transmission replaced since then. It lived in an elevated shed for most of the last 10 years. As far as synching the carbs, I disconnected the crossover tube and connected the carb synch to each vacuum port. The idle was running about 1500. I hadn't ridden the bike yet. I was mostly trying to get an idea of where they were. The right carb has been having issues with fuel delivery, so I've taken it apart a few times in the past 3 months. It's working now. I'll pull the airhorns and do a visual check. They are such a pain to put back on.