Temperature dilemma hobbit PA50II

Recently installed DR kit w better head. Circuit and 15.15 sha. reading about these kits running hot, WOT temps of 380-440 sound common... but...

I was riding other day and trail tech read 380 and bike just shut off. Gave it 5min ~300 deg and it fired right back and no change to performance noted, happened on ride back home once more.

I closed points gap to retard timing and am noticing I’m approaching 380 again. I feel like it’s where i should be running this kit in this heat range for performance/tuning, but am concerned - was my bike soft seizing? Should I be avoiding temps around 400 given my history with shutting off around 380?

Re: Temperature dilemma hobbit PA50II

Did u check the ring gap? When piston is at dead bottom are the transfers open or is the piston a little too high.

If this cut off is a possible soft seize , if it were me I would pull off the cylinder and head and carefully inspect the piston and rings looking for any signs of the ring/rings acting as a welding rod. Also do you know how to perform a leak down. If not learn how.

Re: Temperature dilemma hobbit PA50II

Dirty30 Dillon /

I have smashed my old DR kit into the hi 400's and it didn't cut out. I would say that you need to look elsewhere.

Re: Temperature dilemma hobbit PA50II

DrGeorgeTompson (Alan) /

if it actually just stopped and didnt make any death rattle sounds, try another condenser

Re: Temperature dilemma hobbit PA50II

William Johnson /

My bikes don't run less than 380 WOT. I've hit 475 with an airleak and didn't seize. Only bike that seized on me at 380 was lean AF.

Re: Temperature dilemma hobbit PA50II

No to the condenser. Honda condensers are the best out there. Sick condensers always have symtoms of irregular firing. Unless it is totally astounded internally look elsewhere.

Try this, With the bike just idling apply the choke and see how it reacts. If It does not die then yes you could be too lean on your main.

Search for leaks with carb clean or brake cleen

Re: Temperature dilemma hobbit PA50II

Jason White /

Thank you all for replies. Definitely not condenser, have brand new superbeetle condenser on it. No air leaks detected w/ thorough spraying of carb cleaner to all joints. Plug is nice chocolate brown, but perhaps I'll try going a little more rich and see how things do in the high 300s and beyond.

Will look into ring gap and leak down Marc, not something I've done to my point in maintenance and building - but would certainly like to learn how to do and when they're indicated.

Re: Temperature dilemma hobbit PA50II

So u built up the case with a Dr kit right ? So before the cylinder was slipped over the piston to build it all up , it's been said by many that one should carefully slip the rings off the piston or better yet if packaged separately, slip the ring into the bore of the cylinder. Now for a 45mm bore ( Dr I think ) the space between the two little ends of the ring ( there are several variations on the end and how they relate to their respective centering pin that has been carefully we hope placed along the groove that the ring lives at ( don't put wrong ring in wrong ringway ) the gap between the two ends should be 0.18mm NOT INCHES. IF U NEED THAT conversion let me know and I will look it up. Gentle filing if less is necessary for the simple reason that metal expands when hot. If the ends expand and kiss each other the ring will now gap out of it's little home. And the ring will accumulate even more heat until it decides to be come a welding stick and attach itself to the cylinder ....soft seize?? Hard seize....??? That's all I know. Sort of.

Re: Temperature dilemma hobbit PA50II

15615024722766197037580338815679.jpg
15615020886579216544442823320736.jpg

So this is measuring ring gap an the upper ring ( pretty sure dykes type ) on this mallosi watercooler I'm building. Unfortunately it measures 0.15 mm. 0.18 doesn't fit so if I am to believe crazy Wayne's ring gap deal that he previously posted it's a little bit of file time. Then remeasure and move to ring number two. Don't make it more because compustibles will sneak through there. ( More heat mama )

Re: Temperature dilemma hobbit PA50II

15615030387451705682926778770474.jpg

Voila !!!

Re: Temperature dilemma hobbit PA50II

Jason White /

Thank you Marc, wonderful thorough explanation with pictures. Makes lots of sense. Perhaps that 380deg point (which is much lower than everyone claims to run these kits to) was enough for that metal to heat, expand, and lose it’s grove. Will get to work on this!

Re: Temperature dilemma hobbit PA50II

Removing rings is a total bitch. I actually zipped up to my mechanic and friend Bobby to show me how he would get the lower one out. I've broken them before. Plus the rings on this mallosi kit look pretty high tech. So don't want to go searching for another set before I even run the monster.

Re: Temperature dilemma hobbit PA50II

Dirty30 Dillon /

Removing rings is not that hard at all. If you are having a mechanic remove the rings from your pistons, maybe I can interest you in some Snake Oil?

Re: Temperature dilemma hobbit PA50II

> Dirty30 Dillon Wrote:

> -------------------------------------------------------

> Removing rings is not that hard at all. If you are having a mechanic

> remove the rings from your pistons, maybe I can interest you in some

> Snake Oil?

Better yet , I have a variety of flavored breathable air for sale . ;)

Re: Temperature dilemma hobbit PA50II

Motor all built. Ring gap set. Needed a bit of filing. And yes I don't have the feel for the rings.

Re: Temperature dilemma hobbit PA50II

Jason White /

Sorry to wake an old thread.

I finally got around to taking top end apart for inspection. Piston and cylinder show smearing consistent w/ soft seize. Why would it soft seize at such a low temp (~380 max)? If I rebuild this I want to be sure to avoid whatever caused this.

My timing was retarded and jetting was a bit rich - dark plug and a bit of carbon build up to top end of piston

Re: Temperature dilemma hobbit PA50II

Have you verified that whatever you were using to monitor temps is indeed accurate?

Re: Temperature dilemma hobbit PA50II

seized my metra kit at 430*

went malossi water cooled, havent broken 310* since,, i've been out riding in 95* days where the feel here in MD is 105-110 with humidity.

DR's are great kits,, but water cooled is wasssup

GL to ya! hobbits are titz either way,, amazing bikes !!!

Re: Temperature dilemma hobbit PA50II

Jason White /

themotorhead

Good question, using the same type of trailtech temp gauge I run on my tomos and puch. I am pretty confident this is not the issue.

chris

Loving my hobbit, was running so nice and I love the variable transmission. Proma and kit really gave this a nice kick - til it crapped out. Would like to keep the build simple, but may considered water cooled if i'm not able to figure out why this seize occurred

Re: Temperature dilemma hobbit PA50II

I've said this repeatedly on Hobbit builds after my stockoshocko initial install. At bottom dead center the transfers were still 50% blocked so it was always lean regardless of the jetting. I raised the kit up with a mlm spacer and voila no more issues.

Re: Temperature dilemma hobbit PA50II

Jason White /

Very interesting Marc, would you recommend 1mm vs 0.8mm?

Also, if I use this... Do you put base gaskets on each side of it as well or go without them?

Re: Temperature dilemma hobbit PA50II

Put the piston at bottom dead center with the kit on and figure out what up with it. Measure the distance that the piston is above the bottom of the transfers, if it is. Then u need two paper base gaskets sandwhiched between the plate so figure out what thickness the paper is then double it and subtract from the piston to bottom of transfer. That's the thickness of the mlm plate u pick. Remember paper will get a bit compressed. Now u will have raised the top so if u r really serious u need to deck the top but really see how it works before decking. Pm me if u want me to call and talk to you about all this.

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