Hobbit DR Temperatures?

Hi everyone,

I have a Hobbit with a DR kit cylinder, Wizard kit piston, Proma, .4mm carbon reeds, stock 12mm carb w/ 92 jet, PA1 weights, and stock belt.

Riding at just ~35mph, I have hit 408˚ on my trailtech, which seems way too high. I have not pushed it past that. Letting it cool off riding at ~10mph, it seems to settle right around 360˚. Again, that seems too high.

The crank seals have been replaced, carb cleaned, points gapped to .14". When I rev the engine from down low, there is a weird high pitched sound that seems to come from the intake. It does not like to idle. It also will not start when hot. The engine turns over but doesn't seem like it wants to go.

What temperature does your Hobbit run at?

Thanks!

Re: Hobbit DR Temperatures?

That seems high, and the lack of idle is a good indication that there is a leak. Even with poor jetting, with a good seal a bike should still idle.

Re: Hobbit DR Temperatures?

Intake leak from your carburetor to the intake or intake to the motor. Maybe head leak. I haven't had too much trouble with base gaskets leaking, specially on a hobbit you will see it.

Re: Hobbit DR Temperatures?

News flash!

DR hobbit kits run hot, dare i saw the hottest running moped kit?

even without air leaks. No fins on the exhaust side? Huh? That's just stupid.

Then once heat soaked, they have a hard time dropping temps, especially on hills.

If you make sure you have no leaks, the easiest way to drop temps is the hpi cdi so I'm told. But it's $300.

Lower compression, get a bigger more finned head would be cheapest.

Re: Hobbit DR Temperatures?

Overpriced Parts /

Yep curve ignition is needed for all kitted mopeds really

Re: Hobbit DR Temperatures?

But I want a worry free WOT all day ped, oah well.

Re: Hobbit DR Temperatures?

Overpriced Parts /

Dude your telling me I got several bikes that will benefit from the 350+ bucks Hpi. I can't afford 4 or 5 of them. I can run WOT with point ignition but my bikes are running highly retarded timing so I'm losing some power and a few mph

Re: Hobbit DR Temperatures?

There are still idling issues unfortunately :-/

I have made sure the intake/carb/reedblock is sealed (used permatex motoseal just to be sure), the basegasket, headgasket, and exhaust are sealed (motoseal on base gasket and heated/cooled the head gasket several times/new crush gasket on exhaust), cleaned the decomp, and I have replaced the crank seals. I just don't know where else to look for a leak.

Temperatures still climb to high 300's pretty easily, would definitely go into 400's if I did not keep an eye on the gauge. What kind of temperatures are normal on a set up like this??? Am I worrying over nothing because Hobbit DR kits just run hot (JBOT help?!)

The HPI CDI looks sweet, and I'm sure it would help a ton, unfortunately it's not quite in the budget right now :(

This bike used to idle so I don't know what is going on. I can set the idle speed super high and it will stay running, but that doesn't reallllly solve whatever the problem may be.

Could I have an idle circuit issue perhaps? Maybe that's why it only runs when I increase the idle speed, because it opens the throttle some and the main jet can supply fuel?

Re: Hobbit DR Temperatures?

Christian Giron /

well the idling issue could jus be your carb. Hobbits are notorious for not idling well. theres somethign in the wiki as to how to clean the carb correctly.

As for the temps... wish I could help you.

Re: Hobbit DR Temperatures?

DRs run hot

DRs run hot

DRs run hot

DRs run hot

DRs run hot

DRs run hot

400s are normal on them. Search and you'll see.

Before my fan mod, I would routinely cruise at 375-430

I'm proud to say with the fan mod I rarely break 400 anymore. Or it takes a lot longer to get there when really beating on the motor.

You can cut temps by reducing compression, retarding timing, running a thinner mix (Amsoil @80:1) bigger head, making sure your weights are correct to hit the poweband. If you're lugging the motor due to too heavy rollers that will build up heat too. Did you add a squish to the stock head?

As for idle, it's probably your idle circuit. Clean it better.

I personally dont like the stocker carb.

Re: Hobbit DR Temperatures?

Dominic Valentino /

Also check your crank seals, if they are original/you have a rusty crank could def be your issue.

Then retard the timing, do this no matter what, can't remember how much I did exactly but maybe 18-16 deg btdc? made a huge! difference in temps on my hobbit

Also, as JBOT said, weights can really affect the temps, like a huge amount, I am surprised we don't hear about that more often. In my case I saw better temps with slightly heavier weights (lower RPMS), but JBOT seems to have had a different experiense (i.e. heavier = hotter), so . . . you need to also experiment with you weights!

summary:

1. crank seals (starter fluid test)

2. timing (16-18 deg btdc or something)

3. weights

Re: Hobbit DR Temperatures?

My power comes on currently at 9k.

With heavy weights that's just lugging n chugging (equals heat) until I hit the power.

I'm modifying my pipe today though. Hopefully I'll get a bit more lows out of it.

If you never modified that sharp edge on the stock 50cc head, you need to.

Add a squish either by using Graham's or crazy Wayne's services, or do it yourself with a rubber ball/sandpaper style.

Re: Hobbit DR Temperatures?

clean clean clean your carb! that will help with the idle. use a bit of mig wire in those passages. when i first was running my DR and had a temp gauge it was getting up ~450 and never siezed. if you do though, the iron cylinder takes it better than almost anything on the market. now my trail tech is long broken so who knows after braking in if the temps went down. either way i ride that WOT all day with no problems.

the acting funny when heat soaked is odd though, can't help you there.

Re: Hobbit DR Temperatures?

Ive seen big increases in temp when rpms went down . Rpms = velosity @ intake and threw the stock carb . That same velosity brings/sucks more fuel threw the main jet decreasing temps .

Heavy weights or notching your variator can lower rpm and increase temps . Depends on your setup . DR is mehhh at best , buy a parmakit or a wizzard kit and replace the piston with a good one that wont fall apart . Aluminum kits FTW . Aluminum will send heat packing , iron kits will see less damage when they seize . imo

Re: Hobbit DR Temperatures?

i'm pretty sure my DR was dieseling yesterday after a few 5 minute long WOT blasts in ~100 degree heat. the cylinder must have been hot as fuckkk because i run 91 octane and a super low compression. DR held together like a boss. didn't start leaking, didnt seize up, just kept on rockin like a champ.

Re: Hobbit DR Temperatures?

William Johnson /

I always wondered how people are running such large jets on those stock carbs. I am running a 85 on mine, anymore would make it 4 stroke. Ive never seized, and I run WOT all day if I want, and havent done any mods to reduce heat. As others have said, you may want to recheck your carb thoroughly, hobbits are finicky, but Ive never had an idle problem that wasnt related to a dirty/clogged carb or fuelway.

Re: Hobbit DR Temperatures?

what pipe ray william johnson?

Re: Hobbit DR Temperatures?

yea i was running about 380 constant, 420 peaks

seen one hit 480 and survive

check out the wiki for cleaning the stock hobbit carb and pay attention to the part about idle and tip-in circuits

Re: Hobbit DR Temperatures?

[Radium City] kyle k $ /

just got my temp gauge on yesterday so I'd figure I'd chime in after checking it out today. max temp was 424 on about half mile wot sprints. I'm running dr, stock head, pai weights notched, vm18 90 main, mlm people's. seems to me like it is ok with it but yea temp goes from about 380-390 when the pipe hits to 410s-20s very quickly

Re: Hobbit DR Temperatures?

stock head guys, that's part of the problem...

Re: Hobbit DR Temperatures?

Ryan N. Wrote:

-------------------------------------------------------

> stock head guys, that's part of the problem...

if i go from stock head to stock milled with a squish band, it's gunna up the compression.

are you saying that having a squish band has so much of an effect that it will make up for the increased heat from the increased compression?

my thinking was run the stock head seeing as the interior volume is so huge and the compression will stay low, therefore the heat will stay low.

Re: Hobbit DR Temperatures?

Just do a squish band without raising compression. That squish will help cool.

Add a gasket.

Compression is best buddies with heat.

Re: Hobbit DR Temperatures?

Emil Kniemel /

the high pitch sound could be coming from your reeds.

Re: Hobbit DR Temperatures?

Beard Road Bruiser (SoB) /

I am running vm18, 95 jet, polini, and motzing milled head. Temps climb to 390 on test run before I killed the engine to let it cool.

Re: Hobbit DR Temperatures?

nick i have the same set up as you but i have cdi and heavier weights. i can run 38mph and stay under 380. i can run wot for a half of a mile or so and it will climb to 430 and hit 49 mph. i have touched 460 a hand full of times and never seized. i would look at jbot's fan mod and a better head, thats the next thing i am looking at doing to mine.

Re: Hobbit DR Temperatures?

Gromosaurus Rex - Brad Pitt /

¥mike honcho.I call bullshit.

Listen guys. hobbits are like satan. They dont sweat the heat. Hit 470+ on dead ped hills on the Natchez trace. 1800 miles later still cockstrong and faster than mike honcho. Head to head. Btw ....wastedx.

Re: Hobbit DR Temperatures?

Current temps for elWillow's redped.

high 30's 400 1/4 throttle

45 440 1/2 throttle .. I run a bit lean in the middle.

50+ WOT after about 3 mins… 460

idle drops to about 360

I rigged up my decomp lever to my choke to dump gas into the engine after reading someone talk about using the choke to cool it off.

so like a jerk .. when I want to blast long and hard I just put my thumb on the lever and keep that bad boy at about 460. Nice thing is, since the lever is bent it acts as a throttle lock…

Annnnnnd easy to hit the choke when its cold.

I could probably upjet, change my needle fix the minor intake air leak, tune harder, but I am just soooo sick of pulling out my phbg from its little nest in my bike.

I can assure you.. the hobbit I am building now will have the carb sticking out the side like a glorious shiny tumor.

Re: Hobbit DR Temperatures?

90 degree elbow radiator hose is your friend, my friend

Re: Hobbit DR Temperatures?

Timothy Hilla /

sounds alot like a gasket leak

Re: Hobbit DR Temperatures?

460 is wrong. but around 400 is fair. 460? really?

i believe it tho that they can take it. solid as hell

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