Stuck in high rpm

Your math has to be off somewhere in regard to the intake valves. They're NOT loose by double the spec.

Valves don't get loose; they tighten. I'm highly suspicious of a ".229MM" measurement on valves that normally run .11~.15MM. You initially said a couple of the intake valves were so tight you couldn't get a gauge under them, now all of a sudden they all have twice the spec'd clearance?

You've got a decimal point out of place somewhere. I was serious about a metric feeler gauge.

 

I'll echo Fitz, Autos, made the job so much easier. Wish I had purchased one years ago. And it's cheap.

 

Also, using either the metric or english feeler gauges make sure you don't get two blades stuck together. It happens.

 

Fitz I was backwards on the intake being tight. It was the exhaust. I figured the exhaust was intake cause I thought NO WAY could the intake be loose like that and the exhaust so tight. Ok let me clarify what I used. Originally I had a sparkplug feeler. The bike was warm when I first read them and once it cooled down my .11 feeler wouldn't work.I went and purchased a feeler designed for this. I never knew they went so small. When I went through with the right feelers and read them right things looked all different. I know it looks wierd that the intake is soooo off. Thats why I kept thinking maybe I'm backwards on which is intake and which is exhaust. But if the intake is near the carb then these readings are exact. I'd swear to them. I honestly suspect a PO did this and messed them up. But even if my gap readings is off +/- 0.01mm they still fall right in on the chart for those shim swaps. I have rechecked the gap multible times now and they are always the same.

 

oh yeah it was 0.11 inch sprak plug feeler.

 

The motor would have been making a terrible racket with intake valves at TWICE their specified clearance.

If you're absolutely 100% sure you're using the feeler gauges correctly and you really DO have .22mm (almost .23mm) intake clearances, then proceed.

I'm still not convinced. Highly doubtful a PO ever touched the motor, hence them being so tight. Plus you were reading WAAYYY tight on the intakes, now you're saying they're TWICE as LOOSE as they should be. Something doesn't add up.

I would honestly get a metric feeler gauge and re-check. ESPECIALLY after adjusting but before you fire up the motor again.

 

Way too tight when you look at the motor backwards LOL Yeah I was foolish when I first looked at it. And it did seem to be a noisy engine but I thought it was me cause this is my first ever motorcycle. There was evidence on the bolts on the valve cover of being pulled off many times before I got the bike. I could see someone who never knew what they were doing messing up the shims. I'll buy a new feeler after I get the shims done to double check my readings. Yeah this looks crazy insane on these readings. I was shocked too. My first readings were all wrong just ignore them.

 

Oh yeah Fitz you may not remember but when I did my clutch I found all my clutch plates aligned to the hub DOT by the PO. Makes me think he didn't know how to do things right so he could have done the shims wrong too. I think I am the luckiest man ever here on this bike. Lucky to have found the shim issue and lucky I may have the shims already.

 

Yay I got a new probablem!!! Just tested my ignition coils and the secondary coils are dead to the world!!! Yay more stuff to buy, but now I know what caused some of my other issues.

 

Ok so I have shims on the way. Found local shop with plug boots for $2.60 a piece. Hope to be riding by the end of the week. Fingers crossed.

 

Ok shims done and in spec. What a bit of a pain. Ignition coils tested spec. Caps tested spec. Carb bench sync with buissiness card. Spark is present. Fuel is present. BUT SHE WON'T START!!!! Where did I go wrong? It started before I messed with ignition coils. Maybe I missed something on reassmble.

 

I just tried again, Checked spark on all 4. It's there. I can smell fuel from exhaust. It grumbled for one hot sec this time around. According to the manual if spark is present across the board ignition system can be considered good. So I have spark. fuel. air. but no running motorcycle.

 

IF, ...

You got Spark ...
You got Fuel ... and,
You got Air ...

You need Compression.
What you got for Compression Numbers?

 

plugs changed or cleaned very recently? It is very easy to foul them during diagnosis...
All your safety switches checked, in neutral, clutch in, etc

Cheers
Dave

 

I see this topic went in a totally different direction, but thought I should post my recent experience. Especially since the first post of this thread sounded very similar to my problem.
After having my Maxim 750 sitting in storage for the last three years, I decided to get it out, rebuild the carbs and see if I could get it running. It runs beautiful, but would occasionally start to run at a higher RPM and get stuck for a short time in the 3-4K area and sometimes slightly increase RPM. It also did this years ago and was pretty frustrating since it wouldn't always do it. Well recently we had a really hot day and it got a lot worse and I finally found the problem. It was the throttle cable! The throttle cable was getting slightly pinched between the gas tank and frame and not releasing the carbs to their idle position. I rerouted the cable and the problem is totally gone now.

 

Have you checked the battery recently? Just because you have spark doesn't mean it's enough....

 

Haven't checked compression. Plugs I will swap out and try again. safety switches so far all seem fine. Throttle cable fully functional no hang ups. Battery full of juice with great charge. I have the pilot screws out 2 1/2 turns. Thought maybe fuel too rich to start. Also am thinking fouled plugs. Possible wrong gap as well. Going to try plugs first.

 

Ok today changed plugs and she fired up. Got a good idle and shut it down. Hooked up manometer to start working on vacuum and started it up. Kicked into high rpm around 3.5k. Turned off and restarted. Same result. Did it again started stalled. Open choke started. rpm started rising fast and lowered choke then stalled. What am I doing wrong?

 

Did you leave any of the vacuum caps open when you hooked up your manometer? Could be an air leak there.

How far off was the synch? if it was way off then that can cause your issues.

 

The carb was just rebuilt. So I'm sure it's off. The manometer is a homemade one. If I missed a spot it would just pull the fluid into the engine quickly.