Getting pretty irritated.....

[JustynCRX]

Recently decided to get the Malossi MHR for my SE50. I ride this thing ALL THE TIME. Sometimes for upwards of over 4 hours a trip. So this last weekend I bought the BBK and installed it. I took my time, making sure everything was seated right and lubed up nicely. I even heat cycled it 5 times before going to be late saturday night. Sunday morning I decided I would take it out on the road. I took it very easy, never going over half throttle. All of a sudden I heard a buzzing sound, which quickly got louder so I slammed on the brakes and pulled over in time to hear the whole engine suddenly stop. I hit the starter button once to see if it would even turn. Nothing. So I start walking it home. I got about halfway back and decided to try to start it up again. It turned over and reluctantly started. I was able to idle it all the way home. When I got there I decided I would let it cool for a while. Later I went out and checked out a few things and was able to get it to start again. Lemme say before this whole thing. during the heat cycling it would fire up almost instantly. Now its just like before, I have to crank it over and over giving it gas and it coughs to life then I have to use the throttle to keep it running until it warms up. So back to the story, I tried taking it out again, and almost in the exact same spot it happens again. I get it running again and limp it home. This time I take the head off and notice that it was 90 degrees from where it was supposed to be. so I'm thinking its a cooling issue. I decide to add more 2 stroke to my gas and zip tie the pump open. Also I taped up my pod filter to restrict air flow, and changed my 9 and 10g weights out for 6 and 7g's. One thing I noticed is the lighter weights rev the nuts off this thing which I really dont like. I took it out for another ride and the same thing started happening. I was able to catch it in time so the engine didnt stop. Can anyone tell me what the * is going on?

I have a stock de-restricted exhaust, new carb, brp6hs plug, pod filter (previous owner didnt have stock), 91 octane gas, koso variator, aftermarket coil and wire I also dont have the heat shield on the engine. it didnt seem to want to fit over the BBK. Someone please help.

[Mystic]

you gotta have the heat shrouds on the cylinder, sounds like it is siezing on you. It can only withstand so many before it is junk. I would put the heavier weights back in till you get the issue sorted so you dont wind it out too much from 1/4th to midrange. What jets are you using and what is the position of the needle clip?

[JustynCRX]

Sorry I meant to put that on there. I am running an 88 jet and the clip is on the bottom notch.

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[JustynCRX]

I think 88 is the largest they make for this. I could be wrong

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[paulpauly7]

Yes you are wrong.You need a much larger jet a stock carb aint the best for a bbk since you cant change the pilot jet. your rings could now be toast you should have done more reading befor you fired it up

[Wheelman-111]

Greetings:

Sorry for your irritation, but you really can't just transform an engine by screwing down parts. One change mandates another. You could read for a week here to gather what you need. Ask questions and someone will try to help.

The absence of fan shrouds almost certainly is the most proximate cause of your seizing. C'mon, dawg, ya think Honda-san put them on for looks? You have to put the head on correctly for any chance of fitment, but even then, you may have to re-locate the plug hole. Go the extra mile and seal up the resultant gap.
You may even need to grind down some of the corner fins a bit. Do that or risk grenading all those shiny Italian parts for good. (If it's not fried already...I hope not.)

Although I ran the Noble Experiment for over a year, I have concluded that an SR pump has no business on a big-bore engine. The S pump is even worse, as it delivers a maximum of 70:1. Drop it, plug the hole, and run 32:1 as suggested. Use good oil.

Daytona sells stock-carb jet kits to 105. No matter which Main you install, there's still the problem with the too-small Pilot circuit in your PA carb. Off-throttle, the heat spikes up as the engine continues to compress gas mixture that is woefully too lean to cool the 72cc beast. You can try to enlarge the Pilot as I did, but nobody's reported on results from this that I know of.

Check your compression before anything else for now. Good luck on the rebuild.

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[JustynCRX]

I will do just that. I have to get this on the road reliably. I am looking to get a CT intake and Carb. I got the heat sheild back on now. I'm gonna look for a decently priced exhaust.

[JustynCRX]

Oh yeah, and I'm ordering new rings and circlips too

[Red Eft Performance]

Sorry your having trouble. 6-7g rollers are too light. That main 88 main is too small especially without a airbox.. If your going to run stock carb I would suggest you find a stock air box to help keep the pilot circuit a little richer as well.
You have to run the fan shroud. Did the fan shroud not fit cause the head was on backwards?

[JustynCRX]

I think the BBK was just a little too big for the shield. I was able to get it on with a little persuasion. I just ordered a CT intake, 24mm oko carb, filter, rings, circlips, and spark plugs (bpr9hs). I dont know what jets come in the carb. what should I use for this setup?

[bakaracer]

before you ordered all the stuff, you should have pulled the cylinder off and see whats going on inside first. if it got seize marks on the wall of the cylinder then a next over bore will be needed. putting new rings on a seized cylinder will run the same as it does now. the mistakes you made were you rushed to get it together and to ride it. you didnt tie open the oil pump from the get go. you ran to small a jet for not having a airbox.you ran a stock heat range plug on a bbk and you added oil to the gas tank without measuring the amount and not jetting accordingly to the premix. slow down and take your time.there is alot of info on here because alot of guys run into the same issue so the same questions are always asked and the same setup is being built or wants to be built. pull the cylinder then go from there first.

[JustynCRX]

I did wire the pump open, I forgot to mention that. What plugs do you recommend I use?